Mg@ft G11{1g - World Radio History

MAKING A TORSION BALANCE

NEWNES

Mg@ft G11{1gEDITOR: F. J. CAMM

DECEMBER 1946

A WALRUS SPOTTING PLANE BEING CATAPULTED FROM THE WHALING SHIP BALAENA (See page 96)

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December, 1946 NEWNES PRACTICAL, MECHANICS 73

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PRACTICALMECHANICS

Owing to the paper shortage "The Cyclist," "Practical Motorist," and "Home Movies" aretemporarily incorporated.

Editor: F. J. CAMM

VOL. XIV DECEMBER, 1946 No. 159

BY THE EDITOR

The Technical and Scientific RegisterTHE Technical and Scientific Register,

which is a centralised branch of theMinistry of Labour Appointments

Department, offers a valuable service toemployers seeking professionally qualifiedtechnicians and scientists, and to technicallyand scientifically qualified people who areseeking employment or a change of employ-ment.

The minimum qualification for enrolmenton the register is, in general, a Universitydegree or its equivalent in subjects appropriateto the profession concerned.

In the case of engineers the Higher NationalCertificate or the professional examinationof recognised engineering institutions, or aregular training as a pupil orfollowed by an executive position (normallyfor at least five years) above the rank offoreman, are alternative qualifications forenrolment.

The register is divided into sections asbelow, each in charge of technical officerswith high professional qualifications andstanding in the professions and subjectswith which they deal.

Section A.-Mathematicians, physicists,engineering scientists, teachers of mathematics,physics, general sciences.

Section B.-Engineering graduates.Section C.-Engineers, other than civil

and electrical engineers.Section D.-Electrical engineers (including

radio engineers).Section E.-Civil engineers (including

structural and water engineers).Section F.-Chemists, chemical engineers,

metallurgists (including graduates andteachers), patent agents.

Section G. - Agriculturists, foresters,botanists, zoologists, patholog'sts, veterinarysurgeons, geologists, geographers, archmolo-gists (including graduates and teachers inthese subjects).

Section K.-Architects, town planners,quantity surveyors, valuers, building -landsurveyors, mining surveyors, fire -loss assessors,hydrographical and topographical surveyors,land and estate agents, etc.

Advisory CommitteesSIX advisory committees widely repre-

sentative of the professions assist theregister in its efforts to provide the bestpossible service and also to maintain closerelationships with the profession. Thesecommittees are

Mechanical Engineering committee-(Chairman, Sir William Stanier, F.R.S.,M.I.Mech.E., M.I.Loco.E).

Electrical EngineeringCommittee-(Chair-man, Sir Arthur Fleming, C.B.E., M.Sc.,D.Eng., F. Ins t.Pet., M.I.E.E., M. I . M ech.E).

Architecture and Public Utilities Com-mittee-(Chairman, T. E. Scott, F.R.I.B.A.).

Scientific Research Committee-(Chairman,Sir Lawrence Bragg, 0.B.E., M.C., F.R.S.,M.A.).

Chemistry Committee-(Chairman, SirRobert Pickard, D.Sc., F.R.S.).

Civil Engineering Committee-(Chairman,Sir Pcirson Frank, M.Inst.C.E., F.S.I.).

Close co-operation already exists and isbeing still developed between the register,Professional Engineers' Appointments Bureau,University Appointments Boards, and similarbodies, and by this means the register isable to keep closely in touch with the supplyand demand position generally, and with thebest methods of matching supply and demand.

The number of home and overseasvacancies notified average about 80o permonth, and during the past five weeksvacancies filled total 589.

It is interesting to note that increasinguse is being made of the Register's AdvisoryService, particularly by ex -servicemen seekingadvice on careers.

Employers are invited to visit the register,and special facilities are provided for thosewho wish to interview selected candidatesfor vacancies.

The address of the Technical and ScientificRegister is : York House, Kingsway, London,W.C.2. Telephone : Temple Bar 8ozo.

Our Query ServiceOUR query service is confidential. We ask

readers to submit their names andaddresses in good faith and to append a nomde plume if they do not wish this to appear inprint. Readers should remember that all repliesare sent through the post, and a selectionof the more interesting queries is publishedeach month. Such replies do not necessarilyrepresent current queries. They arepublished for the information of otherreaders. Where samples are submitted,enclose sufficient postage for return, butremember that we do not undertake anyresponsibility in connection with the safereturn of them, nor for any damage whichmay happen in transit.

World Engineering ConferenceARISING out of the International Technical

Congress held in Paris, 16th to 21stSeptember, 1946, the delegates and observersfrom 3o nations, appointed by the various

Governments, and National EngineeringInstitutions and Associations unanimouslyadopted the following Resolution :

" To establish an international organisationunder the name of ' World EngineeringConference ' constituted under the FrenchLaw of July 1st, 1901, continuing from thedate of its legal establishment the existingorganisation now known as ' InternationalTechnical Congress.' "

The principal objects of the Conferenceare :

To prepare for the establishment of thefuture World Engineering Federation.

To assure, if need be, the holding offuture International Engineering Con-gresses.

To establish contact especially with theEconomic Social Council of the UnitedNations Organisation and with U.N.E.S.C.OThe Council, composed of two delegates

appointed by the National Committees orby agreement between the Engineerir gInstitutions or Associations who are membersof the Conference, will elect an ExecutiveBoard, with a maximum of 12 membersand a President, who will administer theConference.

A provisional Board, comprising oneperson from the following countries, wasappointed, whose duty will be to preparethe constitution and to form the Conference :

China, Egypt, United States of America,France, Great Britain, India, Poland,Switzerland, Czechoslovakia.Mr. A. Antoine, Inspecteur General a

l'Electricite de France, President of theCongress, was unanimously elected the firstPresident of the Conference, with Mr. W. R.Howard, Great Britain, and Mr. P. Soutter,Switzerland, as Vice-presidents.

The Resolutions were signed by the officialdelegates from the following countries andalso by a number of individuals acting asobservers, but having no mandate from theirparticular Institutions or Associations :

United States of America, Poland, Iran,Switzerland, Czechoslovakia, China, France,Great Britain, Egypt, Belgium, Luxem-bourg, India, Eire, Indo-China, Rumania.Dr. Joseph Needham, Senior Councillor,

Dr. Yeh Chu Pei and Dr. Sires ChandraGuha of U.N.E.S.C.O:, the latter gentlemenhaving attended the Congress as observers,welcomed the formation of the Conferenceas a means of future co-operation withengineers of all nations in accordance withthe policy of U.N.E.S.C.O. in furthering thefree exchange of information on the appliedsciences throughout the world.



A Simple TorsionConstructional Details of an Instrument for Accurately

Weighing Small Quantities of Chemicals, etc.By T. J. MULLIGAN

AMATEUR photographers and all whodabble in chemicals in the pursuit oftheir hobbies will find the delicate

torsion balance to be described a usefulaccessory to the workbench.

Operations such as the preparing of solu-tions for developers, bleachers, toners,intensifiers, etc. ; the weighing of chemicalsrequired for silvering, lacquering, polishingand colouring of metals ; all require carefulmeasuring of ingredients for satisfactoryresults. The familiar practice of using " alittle of this, and a pinch of that," may pro-duce tasty results in the kitchen, but whenapplied to chemicals such methods can bedisastrous.

year of Pointer painted White

Alarm Clock Minute Hand

Soldered Joints

4. Brass Pod orBicycle Spoke

21'9,

balanced against ameasurable known one.

A weight placed in thepan applies a tangentialtorque to the spring, andthe balance indicator isdisplaced to the left, or" high " side ; the dial isthen rotated in a clockwisedirection until the twist ortorque thus imparted tothe spring is sufficient toreturn the indicator tozero. The balance beingonce more in a state ofequilibrium, it follows that

34'

Alarm Clock Balance Wheel

Fig. 3.-Balance arm and

The delicate and precise scales used bychemists are very costly and usually out ofthe question for occasional home use, andthis torsion balance has been designed toMeet the need for a simple and inexpensivemethod of weighing small quantities.

The torsion balance in its original formhas a long and honourable history ; it hashad an important role in many far-reachingscientific discoveries. One was used byCoulomb in his researches into the funda-mental laws of electrical and magneticattraction ; Cavendish used a torsion balanceto measure the density of the earth. Thetype of balance used in these experimentswas exceedingly delicate, and the forcesmeasured correspondingly small.

The balance which is the subject of thisarticle is of a more robust nature ; insteadof a single straight fibre a steel spring isused, giving a range of about 18 grammesto 36o degrees of torque.

As can be seen from the photographs, theinstrument consists in effect of a spiral wirespring with a wire beam attached at rightangles to the axis of the spring. One endof the spring is anchored, this anchoragebeing adjustable, and the other end is fixedto the dial spindle.

A balance indicator is placed above theinstrument for ease of observation insteadof at the side, the more conventional method.

Principle of OperationIn principle the torsion balance is a

mechanical equivalent of the WheatstoneBridge, in which an unknown quantity is

indicator pointer.

the torque due to the rotation of the dialmust be exactly equal to that originallyproduced in the opposite direction by theweight ; therefore the amount of rotationof the dial is a direct measure of theweight. This can be read off in degreesand converted to grammes or grains, or thedial can be calibrated to read grammes orgrains directly.

It will be noticed that the balance -armOpen Coils

'411 I

HP

Frif 3f

This straight pieceto be soldered to

Balance Wheel

Fig. 2.-Details of the spring unit.

L

I

Balance

Front view of the completed balance.

and indicator assembly is " top-heavy." Atfirst sight this would appear to represent asource of error due to the unequal disposi-tion of weight which would be caused byslight inaccuracies of construction ; such,however, is not the case, as a little reflectionwill reveal.

Before the balance can be used, the dialis set at o degrees and the indicator pointerbrought exactly to zero by means of therear zero setting screw. Fig. i is a diagram-matic representation of the balance arm andindicator after this adjustment has beenmade.

Let us consider the forces acting onpoint P.

It is clear that there is an excess of weighton the left-hand arm due to the weight ofthe empty pan (W). There is therefore aturning moment exerted on P equal to WL,where L represents the distance of the panfrom the point P.

Since, however, the balance is in a stateof equilibrium, it follows that the adjusting

screw has applied an opposingtorque to the spring which isexactly equal to WL. Any extrainequalities of weight, such asblobs of solder, etc., which wouldtend to bias the balance to one sideor the other, are taken up by thisinitial adjusting torque and becomeconstants.

The placing of the centre ofgravity so far above the pivot is an

asset, since the sensitivityof the instrument isthereby increased.

OpposingTorque

Opposing Torque = WL

Fig. i.-Diagram indicating the principle of operatic.' of the balance.


December, 1946

A test made with a lighted cigarette givessome idea of this sensitivity: the cigarettewas placed across the pan and its weightnoted ; the dial was left in this position forone minute. The indicator during thisperiod was observed to drift to the low

NEWNES PRACTICAL MECHANICS

the torsion balance are such as might befound in any junk box.

A discarded alarm clock was robbed ofits balance wheel and minute hand foruse as the spring pivot and indicator pointer.The dial and spindle fitting were taken

from an old variable con -

The balance with casing removed.

side ; the dial was adjusted at the end ofthis period and the new reading noted. Thedifference of the two readings representedthe loss of weight due to the combustionof the cigarette and was a measure of theweight of the smoke leaving the cigarettein one minute.

The indicator pointer must always bebrought exactly to zero for accurate measure-ments. For this reason a mirror is fittedbehind the pointer so as to avoid parallaxerror ; the rear of the pointer is painted whitefor ease of observation. Accurate dial read-ings are facilitated by the inclusion of avernier scale ; this is purely optional, andcan be replaced by an arrow. A slow-motiondrive for the dial has been provided ; thishas another important function-that of abrake to prevent the dial from slipping backwhen it is desired to hold a reading. Thisis a useful factor when weights are to becompared or when several identical weigh-it.gs are required.Materials

The materials used in the construction of

37;

Vernier orArrow Zero 0

Ivo'rine

Dimensionto suit sizesof Dial and -Rubber Washer

Hole forfitting

Slow MotionDrive

Size of Holeto fit DialSpindle Bush

44

Fig. 5.-Front panel with dial removed.

denser ; the spindleused in this case wasof the old - fashionedscrewed variety,' but themore usual type ofspindle would serve justas well ; in this case acollar and grub screwwould be used in placeof the two locking nutsand the dimensions modi-fied accordingly.

One - sixteenth - inchbrass rod was used forthe balance arm, but 'abicycle spoke would suitthis purpose admirably.

The pan was madefrom a scoop suppliedwith a patent food.

A suitable spring can

Uprights for locatingBox Cover

probably be found, or, if not, one could bepurchased ; if steel wire of a suitable gaugeis available, the spring can be wound, usinga 5/16in. mandrel. The sensitivity andrange of the balance depend upon the gaugeof wire used ; a heavy gauge spring will givegreater range, but reduced sensitivity and a" crowded " dial ; a light spring will providehigh sensitivity over a small range. Itshould be noted that provision is made forweights to be added to the right-hand armto increase the range of the balance.

Three-ply wood is used for the box coverand panel, and the whole assembly is screweddown to a stout base.

The SpringA light spring, about 24 S.W.G. and about

;in. diameter, is chosen, and a piece cut fromit about 4in. long. The spring must be" pulled " so that the turns are clear ofeach other ; this is very important, as thebalance will not function correctly if thereis any friction between adjacent turns. A

Conical holes tor Balance Pivotsmade with Centre Punch

79

really good elastic spring should be usedfor this purpose, a soft spring being quiteunsuitable. A steel spring which is inclinedto be soft can often be brought to a satis-factory temper by plunging into molten leador solder and withdrawing it when it hasreached a deep straw colour, then coolingin air.

The middle coils are opened up with apair of pliers to form a straight portion 3lin.long. This is bent to the " S " shape shownin Fig. 2. The extreme ends of the springare then opened to a point in. from theends of the " S " and bent to form the " U "shapes. The form of these ends is to providea longitudinal tension along the spring. Thetwo in. spirals remaining should have theiraxes in alignment.

The spring is now.ready for soldering tothe balance wheel and balance arm.

Balance Arm and IndicatorTwo pieces of i / i6in. brass rod, or bicycle

spoke, are cut and bent to the dimensionsshown in Fig. 3. The alarm clock minutehand is soldered to the short bent piece ;this joint must be sound, as must all otherjoints. A constant zero setting and accurate

Fig. 4.-Details of baseand uprights.

measurements are impossible if there is anylooseness anywhere.

The hooks for suspending the pan andadditional weights are not to be formed atthe ends of the balance arm until the balanceis calibrated.

The balance wheel is carefully placed intoposition in the bend provided for it in thecentre of the long arm and soldered intoplace.

The centre bend of the spring-the crossbar of the " S "-is now laid alongside thebalance wheel and bound to it with a fewturns of fine copper wire ; this is to simplifythe soldering of the spring to the balancewheel, which would otherwise be a difficultand exasperating operation. The spring issoldered into place with its axis in line withthe balance wheel spindle.

A touch of white paint to the rear of theminute hand and the balance arm assemblyis complete.Balance Assembly

The block used for this purpose was a. Hole drilled through 4 BA tapped holescrew to take end

of Spring

Countersunkfor wood screws

This distance to suitBalance Wheel Spindle

Fig. 6. --Balance wheel brackets

1r; Ebonite

-

and rear adjustment plate.

4BA screwand knurled

nut

Countersunkfor

wood screws



Fig. 7.-Side view of the complete assembly.

piece of thick wood ;in. thick ; this is cutto the dimensions shown in Fig. 4, 41in.x zgin. If a thinner block is used, the brassbrackets which support the balance armassembly should be raised on packing piecesto bring the axis of the spring to the levelof the dial spindle and rear adjusting screw.

The front panel is cut from 3/16in.3 -ply wood to the dimensions shown inFig. 5 ; ebonite or metal can be used ifpreferred. The hole for the dial spindle isdrilled to fit the bush used, care being takento keep the centre height igin. The holefor the slow-motion drive will have itsposition determined by the diameter of thedial and the type of rubber washer used. Apiece of ivorine or white card is cut as shownand screwed to the panel ; this can be usedfor indicating the dial calibration, as shownin the photograph. The vernier was madefrom a piece of thick card, which is gluedto the ivorine. The vernier scale can bereplaced if desired with an arrow, drawnwith a fine pen in indian ink.

The panel is screwed to the block, usingcountersunk wood screws so as to clear thedial.

The rear adjustment plate is cut from3/56M. ebonite and drilled and tapped asshown in Fig. 6. Ebonite has been chosenbecause a good thread can be tapped in it.A tin. 4 B.A. screw is screwed in the tappedhole with a nut, knurled preferably, foruse as a locking nut. The screw shouldhave a small hole drilled diametrically toreceive the end of the spring.

The adjustment plate is screwed to therear end of the block.

The two brass brackets, also shown inFig. 6, are cut to shape, drilled and bent.The conical holes which serve as bearingsfor the balance wheel pivots are made witha slightly blunt centre punch.

The brackets are screwed down to thebase block ; no dimensions can be given inthis case, since balance wheel spindles mayvary in length.

To determine the position of the bracketsthe dial and spindle are assembled andpushed home into the bush ; a hole is drilledin the end of the spindle to take the frontend of the spring. The spindle is securedin its bush by means of lock nuts andwashers as shown in Fig. 7.

The balance arm and spring assembly islaid along the block, and the ends of thespring are inserted in the holes providedin the dial spindle and adjusting screw.

It should be necessary to pull the springslightly to insert the spring ends ;, if thespring is at all slack, the " U " ends mustbe bent inwards until this condition oflongitudinal tension is achieved.

Slot for Indicator

Cut -away to fitRear Adjustment

Plate

3f3"'

Fig. 8.-Plywood casing, or

The position of the ends of the balancewheel spindle is marked on the block witha pencil.

The spring assembly is then removed,and the two brackets mounted in the positionindicated. A little latitude is allowable here,since the brackets can be bent as requiredto support the balance wheel spindle.

When replaced into position the balancearm assembly should swing freely, but noslackness in the bearings can be allowed.The ends of the spring are soldered intothe holes provided.

The two uprights shown in Fig. 4 serveto locate the box cover. They are cut from3/ i6in. plywood and are rounded, as shown,and screwed to the block.

The baseboard is a piece of gin. thickwood, 7in. x 4zin., and can be drilled forscrewing down to the bench.

Box Cover and Indicator MirrorPlywood 3/16in. thick is used for the box

cover, the dimensions of which are shownin Fig. 8. The position of the slots is givenas a guide, but these may require to bemodified to suit the position of the balancewheel. The parts are panel pinned andglued and finished off nicely with sandpaper.The triangular cut-out serves the purposeof locating the rear end of the box cover.

The dimension given for the pointer slotcan, if required, be increased to avoiddamage to the pointer when placing thecover into position ; the ivorine indicatorstop will cover a large hole and prevent itfrom having an unsightly appearanceEdges Rounded byRubbing on Emery

/

MirrorBrass Bracket

Mirror CementedTo Bracket

Ivorine Indicator stopFig. 9.-Mirror and indicator stop ' plate.

Slotsto clearBalanceArms

ifs.

6"3 -Ply WoodBox Cover

box cover.

The brass bracket on which the mirroris mounted is made as shown in Fig. 9. Thedimensions of the mirror are also' shown ;this is cut from a discarded pocket mirrorwith a glass cutter The edges are rubbed smooth by rubbing on successive coarse,medium and fine emery paper so as to givea nice finish.

The central zero line is cut on the backof the mirror with the glass cutter in onefirm stroke, using a straight edge. The cutis blacked with indian ink or black paintand allowed to stand a little time to dry.When dry the mirror is cemented to thebracket, care being taken to set the zeroline square with the base of the bracket.

The mirror bracket and ivorine plate arescrewed down over the indicator slot so thatthe pointer is clear of the mirror.The Pan

The pan used on the balance illustratedwas improvised from a scoop supplied witha patent food, the handle being removed.Something of the sort should be availableabout the house ; shape and dimensions arenot particularly important so long as thearticle selected is reasonably light.

The suspension is made as shown inFig. to, using iron wire. Small holes toreceive the wire are pierced in the edgeof the scoop t20 degrees apart.

One piece of wire is used for two arms ;a loop is twisted in the centre of this pieceand the two ends neatly bent to form thetwo arms. A shorter piece is bent to formthe third arm and joined to the other twoarms with a touch of the soldering iron.Slow-motion Drive

The sketch (Fig. to) shows the type ofdrive used. The rubber washer was oneof the small type lubber " feet " which areoften used for the bases of clocks, etc. Theslow-motion drive can be dispensed with ifdesired, but should be replaced with someform of brake.Calibration

It will be assumed that the instrumentto be calibrated in grammes. A standard

gramme weight should be obtained for thisRubberWasher

Pan

$:

Fig. m.-Pan, and enlarged deta 1 of slow-motion drive.


December, 1946

purpose ; if such a weight is not available,one cubic centimetre of water, dropped intothe pan from a graduated tube, makes asufficiently accurate improvised standardgramme.

By means of the rear adjusting screw thebalance is adjusted so that the two zeros,indicator and dial, coincide, the empty panhaving been placed in its approximate posi-tion on the right-hand arm. A nick in thearm at this point made with a three -corneredfile will serve temporarily to prevent thepan from slipping from this position.

The standard weight is placed in the pan,causing the indicator pointer to move to theleft. The dial is then rotated in a clock-wise direction until the indicator pointer isonce more opposite the zero line on themirror. The number of degrees the dial hasbeen rotated is noted.

NEWNES PRACTICAL MECHANICS 81

Let us suppose that to balance onegramme a rotation of i8 degrees is required.Fractions of grammes would be very awk-ward to compute when one gramme equals18 degrees, so that the position of the panon the arm will require to be altered soas to bring the reading to 2o degrees. Theamount of torque required to balance theweight in the pan is in direct. proportionto the distance of the pan from the pivot;in this case it is desired to increase thetorque from 18 to 20 degrees, or one -ninth,so the pan must be moved away from thepivot by a corresponding amount.

The weight is removed from the pan,which is then moved to its approximate posi-tion. This movement will have altered theoriginal zero setting, so the two zeros willrequire to be adjusted by the rear adjust-ment before proceeding further.

The standard gramme is replaced in thepan and balanced as before ; this time thereading should be nearer 20 degrees.

This procedure is repeated as often asnecessary until the gramme weight isbalanced by a torque of exactly 20 degrees.When this has been accomplished the rearadjustment is locked by means of the locknut.

The distance from the pan suspensionpoint to the balance wheel pivot iscarefully measured.

The arm is now bent around this pointto form a hook ; this is to be done in sucha manner as to ensure that the lowest pointof the hook is the measured distance fromthe pivot. The right-hand arm is nowmeasured and bent in the same manner, thedistance from hook to pivot being the sameas the left-hand arm.

Notes and NewsNew Halton Aircraft for B.O.A.C.

LADY WINSTER, wife of the Ministerof Civil Aviation, recently christened

with the name " Falkirk " the first of thefleet of Handley Page Halton aircraft whichhave now gone into service with the BritishOverseas Airways Corporation. The Haltonis the civil transport version of the HalifaxCVIII bomber with its interior completelytransformed in order to provide comfortableaccommodation for the carriage of passengers.Alterations include a new, large entrance dooron the starboard side of the aircraft, a galleyand toilet accommodation, and a large windowadjacent to each of the passenger seats.Seats are upholstered in blue all -wool rep,there is a blue carpet and curtains of acontrasting rust colour. Adjustable tablesare provided, and there is a wardrobe forthe stowage of top coats and similar articles.Ten passengers will be carried in the Halton,and the bomb -bay has been converted into acompartment which will accommodate8,000lb. of baggage, freight and mail. Theseaircraft, 12 of which have been ordered forB.O.A.C., will be operated on the UnitedKingdom -Cairo and Karachi (India) routeand the United Kingdom -West Africa Trans -Sahara route. Their still air range will besome 2,7oo miles. Payload is i r,000lb. ;cruising speed is 26o m.p.h. at approximatelyro,000ft. ; maximum speed is 320 m.p.h.

New Electrical Resistance AlloyANEW electrical resistance alloy with a

wide variety of uses is now beingmanufactured by a famous United Kingdomfirm. It is claimed to be specially suitable

for such apparatus as voltage regulators,switch -gear controllers and instrument shunts.In addition it can be used for all kinds ofresistances, the properties of which must beconstant during service.

Another advantage of the new alloy, whichis known as kumanol, is that it can be easilyspot-welded and needs only slight abrasivetreatment before being readily brazed orsoldered.

Kumanol has a copper base, and thetensile strength of annealed wire is twenty-eight to thirty tons per square inch (44 tonsin hard drawn wire).

The manufacturers are Metals Division

of Imperial Chemical Industries, Witton,Birmingham.

Decca Navigator for Merchant NavyTHE Decca navigator, claimed to be the

most accurate and reliable navigationalsystem in the world, may be installed in allships of the British Merchant Navy.

This systeni, which is a British develop-ment, enables any traveller by land, sea orair, to tell his true dead course and exactposition by the simple reading of two dials ;no other instrument is necessary. At presentaccuracy to within 200 yards at a range of30o miles is claimed, and an extreme range

Two views of the " Falkirk," the first of thefleet of Handley Page Halton aircraft to go

into service with B.O.A.C.

of 5,50o miles gives an accuracy of half amile in daylight and two miles after dark.D -Day and After

The Decca navigator was used to goodeffect on D -Day by the leading ships of theminesweeping flotilla as they approached theFrench coast. Since the end of the warits field of operation has been widenedconsiderably. It is now being used inScandinavia (with the exception of Norway),France and the French colonies, and Holland,in this case for the clearance of minefieldsalong the coast.


82 NEWNES PRACTICAL MECHANICS 4 December, 1946

Por/METE'

REMOV-BLE BACK

SHOWN .-

cur AWAY

Fig. 5.-The complete " electric -eye

MANY interesting experiments may beconducted with the easy -to -makechemical " photo -cell " to be described.

Although inexpensive to make, the cell isquite efficient and passes a current of several

Copper Plates

32 Thickapprox

Rubber Bands

EboniteSpacers

Fig. 1.-Dimensions of theplates and method of

assembling the principal parts of the cell.

microamps. when light from an 8o -wattlamp is directed on one of the plates or" electrodes."

Two thin copper plates, each measuring

Power orS Power Va/ve

Pot/Meter.1 Meg .C1

*-41114AMI.-2 Meg fl

PhotoCell

-H7

rapping at25-30V +

T4 /00 V

0

Fig. 4.-A circuit arrangement to increase thepower of the cell and enable -various apparatus

to be operated.

A Simple Photo-electric CellTRY' FOCUSSING

MAGNIFYINGCLASS HERE

W/NO W

A Cheap Home-made Apparatus

for the Experimenter

" is fitted together as here shown.

about 41in. by t 1 in., form the electrodes ;to these are soldered short flexible leads.Ebonite strips, about 1- in. by t in., spacethe plates at top and bottom ; rubber bandssupport the assembly. This is placed in a

- WiresThrough

C)

- - - - -I /

_ L

Slot

L

Light TightBox (Optional)

Plate

light -tight save for a front slot measuringin. by 3 in. to expose one plate.

Constructional details are given in Figs.and 2.

Practical ApplicationsIf the photo -cell is connected in series

with a neon lamp and battery, light from a4o- or 6o -watt lamp falling on the exposedplate causes electrons to flow to the oppositeplate, the cell becomes conductive and theneon lamp lights. Placing the hand or acardboard screen between the lamp and thecell instantly extinguishes the light in theneon lamp (Fig. 3). To increase the minutephoto -electric currents for the operation of a

Thin Glass Jaror Tumbler

Facing Window Copper SulphateSolution

Fig. 2 .-The completed cell is mounted in a light -tight box in the manner shown in these diagrams.

clear glass jar or tumbler, and a solutionmade with copper sulphate 33 grains, dis-tilled water, 3 oz., added to the level ofthe top ebonite spacer. The cell is nowcomplete, but before use should be placed ina dark cupboard for at least two days.

It is suggested that a wooden box be madeto house the completed cell ; this should be

60-80 w Lamp

Screen Here to//rStop Current Flow

Fig. 3.-The complete arrangement

relay or similar device, valve amplificationis essential. A suitable " electric -eye " circuitis given in Fig. 4. As there are but threecomponents in the amplifier it could be accom-modated in the same box as the photo -cell(as in Fig. 5). A small power valve, a 2 -voltcell and too -volt H.T. battery complete theinstallation.

of the photo -electric cell for light experiments.



The Aircraft Gas TurbineGIVING the first of the annual memorial

lectures, inaugurated by the Stoke-on-Trent Association of Engineers, in

honour of Reginald Mitchell, Potteries -borndesigner of the famous Spitfire aircraft, AirCommodore Frank Whittle, C.B.E., M.A.,Hon. M.I.Mech.E., inventor of jet aircraftpropulsion, read a paper in Hanley TownHall, on October 14th, on " The Advent ofthe Aircraft Gas Turbine."

Air Commodore Whittle said there wasnothing new in the basic idea of the gasturbine as a prime mover, but it was onlywithin the last ten years or so that it hadbecome a practical proposition. A gas tur-bine, working on the constant pressure cycle,consisted basically of a compressor, a com-bustion chamber, and a turbine. The usefulwork produced was the difference betweenthe power generated by the turbine and thepower required to drive the compressor. Itwas obvious, therefore, that the ratio of posi-tive to negative work was of great importance.That ratio was limited by the temperature theturbine materials would stand. It may,therefore, easily be seen that the materialsavailable, and the compressor and turbineefficiencies, were very important factors inthe consideration of the gas turbine. Up toa few years ago compressor efficiencies wereof the order of 70 per cent.; turbine efficien-cies were not much higher, and the materialsavailable limited the positive to negative workratio of the ideal cycle to about 2: t. Withthose figures, an efficient gas turbine was notpossible. To -day, material developments hadmade possible a considerable increase in thepositive to negative work ratio, and the effi-ciencies of compressors and turbines hadbeen raised very substantially.

Important FactorsIn the jet propulsion application of the gas

turbine only a sufficient part of the expan-sion took place in the turbine as was neces-sary to drive the compressor, and so only aDart of the expansion was subject to turbinelosses. Two other factors operating in favourof the aircraft gas turbine, as compared withother applications, were:

(1) A certain degree of compression couldbe obtained by the ram effect of forward

The Mitchel! Memorial Lecture

By Air Commodore FRANK WHITTLE

speed at high efficiency, thereby raising theaverage efficiency of the whole compressorprocess ;

(2) the low temperature of high altitudesmade possible a greater positive to negativework ratio for a given maximum cycle tem-perature.

The lecturer continued:"There are two basic types of compressor

commonly in use in aircraft turbines-thecentrifugal type and the axial flow type. Thecombustion problem was the biggest obstaclein the development of the aircraft gas turbine,and it remains to -day the most uncertainfeature in any new design. Some designershave favoured an annular type of combustionchamber on the ground that a very muchsmaller diameter can be achieved, and that itfits in very much better with an axial flowcompressor and axial flow turbine. I, per-sonally, have always avoided it, because thedevelopment problems it presents are verymuch more severe than with the multiplecombustion chamber system. Moreover, Iam a great believer in complete symmetryabout the axis of the fuel nozzle.

" Aircraft gas turbines usually have cnlyone or two stages. They develop enormouspower in proportion to their size. We can,for example, expect to get about to,000 shafthorse -power out of a single stage wheel ofabout 22in. diameter.

Axial Velocity of Gases" In the turbine of a jet engine we can

afford to have the gases leaving the wheelwith a very high axial velocity, and that isthe chief factor which enables us to get suchenormous powers in proportion to size. Thataxial velocity ultimately contributes to thekinetic energy of the propelling jet, and so isregarded as part of the useful output. Whenwe talk about turbine efficiency we includethe kinetic energy of the leaving velocity onthe credit side. In modern turbines, we canexpect to get about 90 per cent. That is tosay, the shaft power plus the kinetic energyof the gases leaving the wheel is about 90 percent. of the adiabatic heat drop.

" We owe a tremendous amount to the woikof the metallurgists in developing materialswhich will withstand a combination of highstress and high temperature. Any furtheradvances in this direction will show bigdividends in engine performance."

Air Commodore Whittle showed illustra-tions of various turbo jet engines, and saidthat the low weight was by no means theonly advantage of the jet engine. There wasvirtually a complete absence of vibration, somuch so that he had heard of one case wherevibrators were fitted to the instrumentpanel in order that the instrument could beshaken into giving proper readings. Therewas also much reduced noise within the aero-plane, though from the outside it sometimesseemed that they were noisier than the moreconventional power plant.

I am told (said the lecturer) that peoplewho have flown in the Lancastrian, which hasbeen experimentally fitted with Nene enginesin place of the outboard Merlins, had somedifficulty in believing that the jet engineswere running after the inboard Merlins hadbeen stopped and the propellers feathered.

Jet engines, as well as other aircraft gasturbines, use low-grade fuels, with conse-quent big reduction of fire risk. We startedusing kerosene in the very early days whenwe were trying to make a vaporiser systemof injection work, and we stuck to it whenwe changed over to atomised liquid injection.chiefly because, as compared with other low-grade fuels, it has a very low freezing point.

In quantity production, the first cost ofa jet engine should be very much less thanthat of the piston engine and propeller,especially in the case of the very simpleengine with a centrifugal compressor. Jetengines are intrinsically more reliable andeasier to maintain and service., For example.the establishment for engine maintenancepersonnel in the jet fighter squadrons of theR.A.F. has been reduced to half that of thepiston engine fighter squadrons

Easy to StartThe jet engine is very easy to start and

does not require warming up. Neitheris it necessary to run up to full poweras a check, though I am afraid it will bea long time before the habit dies out. The

A Lancastrian fitted with two Rolls-Royce Merlin engines and two Rolls-Royce gas -turbine units. In a recent test this 'plane flew too m.p.h.faster on the two jet units alone than when operating on the four Merlin engines.


84

installation is very simple and uncompli-Cated by elaborate cooling systems, etc. Itis possible to change an engine in twohours or less, and most of that is due tothe time taken in undoing and refasteningthe cowlings.

The development time is also very muchshorter than for piston engines ; at leastthat is true once more for the engines withcentrifugal compressors. Another impor-tant factor is that jet engines are veryamenable to scaling. That is to say, thatif an engine is required similar to one alreadyin existence, but of different power, then itcan be quickly obtained by scaling up ordown from the existing engine.

Air Commodore Whittle continued : " Theuse of turbo jet engines makes possible bigimprovements in aeroplane design. Under-


passing through it can be of the order of34 per cent. when flying in the stratospherewhere the maximum benefit is obtained fromthe low temperature ; but, because the speedof the jet is very much higher than thespeed of the aeroplane, the propulsiveefficiency is low. It is basically more efficientto induce a small increase of velocity in alarge mass of fluid than to induce a largeincrease of velocity in a small mass offluid.

The jet speed is usually of the order ofthree times the forward speed, and at thiscondition the propulsive efficiency (the" Froude efficiency ") is about So per cent.,giving an absolute overall efficiency of about17 per cent. This is better than one couldobtain with a piston engine and propellerat speeds of the order of 60o miles an hour,

The D.H. io8 jet-propelled 'plane with de Havilland Goblin gas -turbine engine. An ex-perimental aircraft designed for research into high-speed flight.

carriages can be much smaller than withconventional types ; moreover, a much betterstreamline can be obtained. That is onereason why jet aircraft have intrinsically amuch lower drag than the conventionaltype. The drag coefficient of one well-known type is said to he not more thantwo-thirds that of the best of the piston -engine types. The absence of propellerslipstream is a factor contributing to this."

Properties of Jet EnginesOn the properties of the jet. engine Air

Commodore Whittle made the followingpoints :

The thrust of the turbo jet does not varymuch with speed. It drops off a little fromits value when stationary, then remainsmore or less constant over a wide speedrange, and at very high speeds begins torise again. This means that the effectivethrust horse -power is almost proportionalto speed. With the conventional powerplant, on the other hand, thrust power doesnot vary much with speed, and tends todecrease at the top end of the speed rangewhen the propeller begins to lose efficiencydue to compressibility effects.

The thrust of the jet engine is very sensi-tive to rotational speed of the engine ; infact, near the maximum speed it is almostproportional to the fourth power of ther.p.m.

The efficiency of the jet engine as adevice for producing a high velocity jet isquite high. The overall thermal efficiencymeasured in terms of the increase of kineticenergy produced by the engine in the air

because at those speeds the propellerefficiency would be unlikely to be more than6o per cent. At lower speeds, however, theoverall efficiency of the jet is definitely lowerthan that of the piston engine and propeller.Both the thermal efficiency and the propul-sive efficiency improve with speed, so thatthere is a double reason why high speedis necessary for efficiency. Height improvesefficiency up to the stratosphere at least,because of the low atmospheric tempera-ture, but, generally speaking, speed is muchmore important than height in its effect onefficiency.

Speed and RangeAt 600 miles an hour the turbo jet engine

is the most efficient propulsive device foraircraft that we have available, even if wethink purely in terms of fuel consumptionper unit effective horse -power. Height isof tremendous importance in its effect onthe range of a jet-engined aeroplane. At4o,000ft. the range is nearly three times asgreat as it is at sea level. The effect ofspeed on range is relatively small, so thatone might as well fly fast, because thereis nothing to be gained by flying slow.The aeroplane with conventional power -plant, on the other hand, is very sensitiveto speed, but not very sensitive to height,though the speed corresponding to maximumrange increases very considerably withheight.

The lecturer continued : " A great deal ofwork is going on in this country and inAmerica on gas turbines for propeller drive,and several engines are now in an advancedstate of development. In the turbo jet

December, 1946

'engine only sufficient power is developed bythe turbine wheel to drive the compressor,but in the propeller gas turbine a muchgreater proportion of the expansion takesplace in the turbine system. I use theexpression ' turbine system,' because insome cases the propeller is driven throughreduction gearing from the turbine -com-pressor shaft, whereas in the Bristol Theseus,for example, a turbine mechanically indepen-dent of the compressor drives the propeller,also through reduction gearing.

The Ducted Fan" There is yet a third way to use the gas

turbine in aircraft propulsion. It can beused to drive what we call a ducted fan.This is really a compromise between thepure turbo jet and the turbo prop. In thisarrangement the gas turbine drives a lowlift compressor inside a Lollow fuselage ornacelle. Whereas a propeller produces aslipstream of very large mass with only asmall increase of velocity, and the jet engineproduces a low mass high velocity jet, theducted fan produces something in betweenthe two, so that its propulsive efficiency liesbetween that of the pure jet and thepropeller.

" One big advantage of the ducted fan isthat it is possible to obtain a very largetemporary increase in power by burningadditional fuel in the low pressure air fromthe ducted fan. The fuel consumption isenormous when this is done, but that is notimportant where the boost required is purelytemporary, as, for example, for take -off orfor short periods of combat. It is arguedby some that the range of speed over whichthe propulsive efficiency of the ducted fanis superior to that of both the propeller andthe turbo jet is so small that it is not worthwhile. My own view is that the absenceof slipstream, reduced noise, and vibration,and the peissibilities of power boost by afterburning, are very powerful arguments in itsfavour."

Future PossibilitiesIn conclusion, Air Commodore Whittle

said : " I hope I have said enough to convinceyou that the piston engine is dead for air-craft propulsion, except possibly in the fieldof light aeroplanes. I make this reservationbecause we do not yet know enough aboutthe problems involved in designing gasturbines of very low power. At present itseems easier to design for much higherpowers than we are using to -day than todesign for power of the order of zoo h.p.We are as yet only at the beginning ofthis field of engineering. The possibilitiesare immense. In the piston engine the com-pression, combustion and expansion all takeplace in the one organ, the cylinder, andthat seriously limits the possibilities ofvariation. In the gas turbines these pro-cesses take place in specialised organs, eachof which may take many forms. As youhave seen, you can have centrifugal com-pressors, axial flow compressors, or combina-tions of the two types. There are widepossibilities of variation in combustionchambers and turbines, and there are allsorts of ways in which these major com-ponents can be combined together. Addedto all that are the possibilities involved inheat exchangers, intercoolers, and so on.

" The next few years will see a very rapiddevelopment in the aircraft field as a resultof the advent of the aircraft gas turbine.

" I believe that speeds ,of the order of 500to 600 miles an hour will soon be quitecommon in commercial aviation. Mostpeople find thii a rather horrifying thought,but then there was a time when peoplewere horrified at the thought of travellingat 3o miles an hour in a railway train."



H.T. Battery EliminatorsA Few Alternative Circuits forUnits Suitable for Use with

D.C. and A.C. Mains Supplies(Reprinted at the request of many readers,

fro n an issue now out of print)

ALTHOUGH it has become customaryfor those who have a mains electricitysupply to use a normal type of mains -

fed receiver, it is clear from the correspond-ence we receive that, there are still manybattery -set users who wish to obtain theirH.T. current from the mains supply. Someof them explain that they consider that abattery set gives better reproduction; othersapparently feel more confident to build abattery set than one of the all -mains type.It is not for us to dictate, for everyone isentitled to his own opinions, but we are infavour of the mains set every time. In spiteof that, however, it is often cheaper to builda battery set, whilst the constant experi-menter who frequently rebuilds his set cancertainly effect a saving by making batterysets and keeping a power -supply unit thatcan be used with practically any type of setthat he might construct.

120-150v0

30mA 3wHI +

i0020

HT,

HT+

Hr

Fig. i.-Auzioon

simple form of D.C. eliminator in theoreticalpractical form.

5 AMP

220v.D.C.MAIN

A good example of a home-made eliminator,showing the use of perforated zinc for

ventilation.

screening grid of the H.F. or I.F. valves, andthe third for the L.F. and output valves. Weare not strongly in favour of providing tap-pings on the eliminator for it is in manyways better to include the necessary voltage -

dropping resistors in theset, placing them andtheir corresponding by-pass condensers as nearto the points they feedas possible. The fixedresistors shown can eachbe rated at one watt, thepotentiometer should,for preference, be of thewire -wound type and thevariable resistor shouldbe rated at not less thanthree watts.

FUSE PLUG

The D.C. UnitThe simplest type of eliminator is, of

course, that intended for use with D.C.rains. All that is normally required is asmoothing choke, a couple a smoothing con-densers, a fixed and variable resistor, and afew connectors and small items. A circuitand pictorial illustration of a unit of thistype are given in Fig. I. It will be seenthat there is only one H.T. positive lead, andthat the voltage supplied can be varied tosuit any type of battery set. Extra tappingscould easily be arranged if desired, but theyare seldom necessary with a fairly moderntype of receiver. This is because voltage -dropping resistors and potentiometers forscreening -grid supply, and the like, areusually included in the circuit of the set itself.

In case any reader wishes to provide addi-tional tappings, however, we show how thiscan be done in Fig. 2. The three positiveoutput terminals are marked with the voltageand current which they will provide whenthe mains voltage is about 220. Of the threeoutputs shown the first would be suitable fora leaky grid detector, the second for the

and

400 ohms. Actu-ally, these valuesare not critical, butit would be unwiseto employ a chokewith a lower in-ductance than zohenries, or with alower maximumcurrent - carryingcapacity than 5omA: _,,Nearly a 1 lchokes Of this typeand of mediumprice have a D.C.resistance of be-tween 30o and Sooohms ; any valuebetween these twolimits will providet h e approximateoutputs indicated.

The smoothingcondensers can beeither electrolyticsor of the paper

ComponentsNote the inclusion of

a fused connector forthe mains supply, andalso observe that thesmoothing choke is ratedat 20 henries, 5o mA,and has a resistance of

type, rated at not less than 25o volts working.A very convenient system is to employ atwin tubular electrolytic condenser mountedon a small metal bracket, as shown, fromwhich the negative lead can, be taken.Alternatively, a twin block condenser bracketis not required.

The components are shown mounted on awooden baseboard, but it is a good plan tomake a cover from perforated metal or tin-plate with ventilation holes drilled in it.This must be clear of all connections, butshould be earthed to the- common H.T.negative -earth terminal.Negative or Positive Earth

When the eliminator is used on a D.C.supply with negative earth it is necessaryonly to connect it in place of the H.T.battery, although it is generally desirableto take a second earth lead to the appro-priate terminal on the unit. This canconsist of a short wire from the earthterminal on the set. If the positive sideof the mains is earthed, greater care mustbe taken, and the earth lead to the set musbe taken through a fixed condenser witha capacity between .1 and r mfd. Thatis, the earth lead is joined to one terminal

Fig. 2.-How addi-tional resistors canbe added whenvoltage - droppingarrangements arenot included in the

set.

tzo- &D... ,.AH1.3

0-150rHT+ 2

470,.

H.T.. I

HI-E .5TArt).



of this condenser and the other condenserterminal is joined to the earth terminalsof the set and of the eliminator. It is alsoimportant that a condenser be includedbetween the set and the aerial lead-in. Evenif there is a small condenser in this positioninside the set it is wise to fit an externalone of not less than 25o volts working. Theomission of the condenser might result itshocks being received should the aerial betouched.

Simple A.C. UnitAn A.C. eliminator is slightly more

complicated, due to the fact that a rectifier

and transformer are needed in addition tothe parts used in the circuit alreadyexplained. When an H.T. current of notmore than 3o mA is required-and, this issufficient for most types of battery set-avery satisfactory arrangement is to use aWestinghouse style H.T. 15 metal rectifierin a half -wave circuit as shown in Fig. 3.When this is fed from a mains transformergiving a secondary output of 25o volts,3o mA the maximum, unsmoothed outputfrom the rectifier is 230 at 3o mA. Thisis, of course, approximately the same voltageas that of the D.C. mains used for the circuitfirst described. Consequently, any additionalvoltage tappings can be provided in thesame manner as shown in Fig. 2.

The general form of construction can bethe same as that mentioned in connectionwith the D.C. unit, and the eliminator canbe used in the same manner, except thaten earth connection is not required unlessthere is a long lead between the unit andthe set.

In those rare cases where a current inexcess of 3o mA is required, a larger metalrectifier could be used, preferably in avoltage -doubler circuit as shown in Fig. 4.For a maximum output of 33o volts 6o mA

SO -150v.6O mA

300on 15w. -

a suitable rectifier is the H.T. 16, and itshould be fed from a transformer providinga secondary output of 240 volts, 200 mA.For either of these A.C. units it is bestto use smoothing condensers with a maxi-mum working voltage of 500, to ensure areasonable factor of safety.

Valve RectificationA very satisfactory method of obtaining

a D.C. output, before smoothing, of 230volts, 6o mA, is by employing a full -wavevalve rectifier such as the Cossor 506 BU.Connections for this are given in Fig. 5,where both theoretical and pictorialarrangements are illustrated. Here againthe few simple parts may be mounted ona baseboard, with or without a metal shield.The shield, made of iron or tinplate, isalways desirable since it helps to preventmains interference, and also prevents the

MAINSTRANS FUSE PLUG

Fig. 3.-AA.C. eliminator using ametal rectifier in a half -wave

circuit.

constructor from accidentally touching any"live " parts when the mains are connected.For the screen to be fully effective it shouldalways be earthed.

Grid BiasWhen using any type of eliminator it

is a convenience to employ automatic gridbiasing, although a G.B. battery is perfectlysatisfactory, and will last for at least sixmonths. An alternative system when usingan A.C. eliminator is to use a transformer

2000 A/10Wf 20H 100 rnA

000n.5W

HT+

4MfaHT -

Fig. 5.- Th isA.C. eliminatoruses a full -wave rectifier.

(Left) Fig. 4.-Circuit of anA.C. unit withvoltage - doubler

rectification.

HT+

H T -

AC

.250V

\4VIA

with an additional secondary winding inconjunction with a low -voltage rectifier, butthat is rather an expensive method and notone that most readers would favour.

Trickle ChargersAs we are dealing only with the simpler

types of mains unit we are not going todescribe an eliminator with trickle chargerbuilt integral with it. As small tricklechargers suitable for two -volt accumulatorsof average capacity are not expensive, weare inclined to favour the use of two separateunits. If two small accumulators areobtained, one of them can be charged whilethe other is in use, or a single accumulatorcan be used, a change -over switch beingfitted to bring the charger into circuit whenthe set is switched off.

SwitchingThere are two simple rules which should

be borne in mind when using eliminators :the filaments should be switched on beforethe eliminator, and the eliminator shouldbe switched off before the filaments.

If these rules are reversed additional strainis thrown on the valve filaments and alsoon the various fixed condensers in the set.It is just permissible to switch on botheliminator and L.T. at the same time, butthis is not very good practice wheit usinga metal rectifier, because a fraction of asecond elapses between the time that thethe rectifier supplies the H.T. and the timethat the filaments reach their workingtemperature.

TWO VEST-POCKET BOOKS!

WIRE AND WIREGAUGES

By F. J. CAMM3/6 or by post 3/9

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Obtainab!e from booksellers, or bypost from George Newnes, Ltd.,(Book Dept.), Tower House,Southampton Street, Strand, W.C.2.

1,00011SW.

CHOKE

;2%

250 V

230 V

200V



Rocket Propulsion

14,121..1-+

Fig. 82.-An Arado development in early stages of production at thetime of the surrender. This tiny rocket fighter was to be carried into

action beneath a jet -powered bomber.

ANOTHER special purpose fighter makinguse of the Walter 109-509A1 rocketengine was found under construction

in the Arado works. This was an exceptionallytiny monoplane (Fig. 82), and its smallproportions can be gauged from the factthat it could not accommodate the rocketunit in the extreme tail, a " step " havingbeen embodied in the lower fuselage throughwhich the exhaust emerged at ' a slightdownward angle.

The mainplane had a high root fixing,and twin fins were fitted at the tips of anoblong tailplane. A prone piloting positionhelped to reduce the cross-sectional areaof the fuselage and to delay critical " g "pressures, but most interesting of all wasthat it was intended to operate the machinefrom a jet -powered bomber.

Test flights had, in fact, already beenmade, using the then newly produced Arado234C -I as the parent. This four-engined" jet " was a particularly enterprising aero-plane, for despite a fully fuelled weight of24,2oolb., its maximum speed (between 530and 55o m.p.h. at 2o,000ft.) was greater thanmost of the fighters which accompaniedAllied bombers. The tiny Arado fighter wasfixed beneath its broad fuselage and, undercombat conditions, would have been releasedjust out of range of enemy fire.

In comparison with the designs whichother manufacturers had in stages of project,the Arado development seemed no greatdeparture from the orthodox. It was justanother bold attempt to " out -fly " Alliedaircraft, but like the majority of its con-temporaries, came a trifle too late.

A further interesting project was the D.M.2(Fig. 83), a rocket -powered flying -wing.Again, intended as a high-speed interceptor,this particular design was originally the workof Professor Lippisch, and was based on astandard pattern which had been evolved asthe result of extensive tests with rocket -driven research models.

It was not simply a " tail-lesS " machine.There was no fuselage at all, the all -wingstructure, thick in section at the root andtapering sharply towards the tips, sweepingback within a contained angle of 6o deg. A

Projected Rocket and Composite Rocket-athodydFighters

By K. W. GATLAND

(Continued from page 53, November issue.)

large vertical finemerged on thecentre -line at the rear.

The pilot was ac-commodated in asemi -prone positionentirely within thecontour of the wingsection, and there wasno cabin " blister "or other excrescenciesto spoil the shape.His cabin affordedexcellent vision in alldirections except rear-wards, the nose beingcompletely coveredwith " clear -view "Plexiglas. Flight athigh altitudes wasmade possible by pres-surisation, suppliedby three large oxygencylinders.

The propulsion unit was of a type similarto that employed in the early versions ofthe Messerschmitt 163, known as the WalterR2 -21I. Its main difference was a moreslender combustion unit to suit the thin wingsection, having a smaller chamber and a longtapering nozzle. The tanks, designed to havea total capacity of 8,000 litres of T and Cstoff, were naturally disposed over thec.g., so that balance would not be upset as thepropellant was consumed.

A retractable tricycle undercarriage wasembodied, the nose -wheel folding directlybackwards between the pilot's heels, whilethe two main wheels came upwards, rotatingthrough 90 degrees to lie flat in wells situatedat the sides of the grouped engine accessoriesand behind the main propellant tanks.

It is obvious that the landing speed wouldhave been high, and for this reason thedesigner had em-bodied a large flaparea. The flaps, infact, extended almostthe entire length ofthe trailing edge,and it would appearthat the outer pairalso operated aselevons (single aero-foils serving the dualpurpose of elevatorsand ailerons). A 2in.gap separated allcontrol surfaces fromthe main structure,wing and fin, andthis refinement in thecase of the flaps wasprobably to increasethe lift when theywere lowered forlanding as it per-mitted air from theupper wing surfaceto be deflected down-ward to supplementthe under flow. Theincreased mass ofair deflected whenthe elevons and

rudder were operated made for increasedsensitivity, which was particularly desirablefor a machine of this type at low speeds. .

The control column, which, owing to theprone piloting position was only about

ft. 6in. high, was coupled to a servo gearto compensate for the decreased leverage.

Although no performance figures areavailable, it is obvious that the machine wasintended to operate at high speeds, possiblybordering on supersonic speeds. It was,however, only one of several all -wing projectsdesigned to Lippisch formula.

Another was an athodyd powered fighterwith rocket booster (Fig. 84), said to becapable of travelling at 1,500 m.p.h. Theremarkable feature of this machine was thefact that it used no fuel other than blocks ofcarbon, these being set inside a simple" straight -through " duct and preheated toincandescence just prior to flight. The pilotwas to be installed near the nose, lying prone,the air entering from a central intake beingducted around his slim cockpit and flowingto the single heating chamber.

Launching was to have been by powerfulassisted -take -off rockets, the machineaccelerating along an inclined ramp, and oncethe air began to ram. into the intake thehigh -velocity draught would serve to inflamethe carbon, raising its own temperature in theprocess. At high speeds, large masses of airwould he continually ramming through theduct and at a pressure so great to make anymechanical means of compression entirelysuperfluous. Expansion in the heatingchamber would be rapid as the result of theintense heat thrown off by the carbon,the resulting jet finally emerging througha narrow slit in the trailing edge.

As far as is known, only model researchhad been conducted, but the numerousfree -flight tests the Germans had been ableto make in the few months available to them

Fig. 83.-From research with flying models came this design for arocket -driven "flying-unng," the D.M.2.



prior to the surrender would seem to havebeen particularly encouraging. The originalexperiments using carbon alone permitted aflight of 45 minutes' duration, but employinga paraffin spray to prolong the life of theheating blocks, the period of power was saidto be virtually doubled. With this system,however, there would have been littleopportunity for varying the thrust, althoughtwo possibilities that come to mind are theobvious ones : (a) of varying the area of the*exhaust duct, and (b) the provision of bypassducts so that a proportion of the air could

. be deflected. away from the heating chambershould it be desired to " throttle -down."

A further machine making use of athodydpropulsion was one projected by the Focke-Wulf company (Fig. 85). This was a typenot far removed from the normal high-performance fighter, though with twooutstanding differences, namely, a 45 -degreewing sweep -back and the unique mountingof its two propulsive ducts.

The fuselage was exceptionally slim,tapering smoothly to almost a point at thenose. The shape of the rear was almostidentical but the provision of a rocket unithad necessitated a slightly larger sectiontowards the tail. A neat " Plekiglas " hoodemerged slightly more than half -way backfrom the nose, the single fin joining the lineof the cabin and projecting beyond thefuselage end.

The tail -plane itself -raked back at an evengreater angle than the wings, and at its tipswere fitted the two 4.4ft. diameter athodyds,an arrangement made possible by their lightweight. This must have involved somethingof a nightmare for the company's stressdepartment, and it is clear that the necessityfor a strong angular transport member wasthe main reason for the acute tail sweep -back.It did not, however, interfere with the controlsystem, which remained orthodox with normalrudder and elevators.

The Walter bifuel rocket engine developeda thrust of 6,600lb. and was to be used intake -off to accelerate the machine to the speedat which the ram pressure was sufficient tooperate the ducts. A kerosene fuel wasspecified as the _heating agent, the resultingjet to provide a 68o m.p.h. top speed atsea -level and a climbing rate of 31,000ft. perminute at 3,000ft. If, however, the 'planewas climbed to 36,000ft., the maximumspeed in level flight would fall to 590 m.p.h.,and naturally the climbing rate also suffered

a loss, reducing to 5,tooft. per minute.In consequence, it is suspected that the

rocket system would have its main purposein boosting the climb, and it is obvious thatit would have been employed also in landingas athodyd units cut out at about 200 m.p.h.

At sea -level, themachine was said tobe able to fly underfull power for 13minutes, but thiscould he much im-proved by a directclimb to 36,000ft.,when 43 minutes'endurance could beexpected.

The main weightsand dimensions givenin the design tenderare as follows : anempty weight of5,9oolb., and a fullyloaded weight (in-cluding fuel andpilot) of 12,000lb.The wings had anarea of 205 sq. ft.

A High-speed Heli-copterAs the war in

Europe drew to aclose, yet anotherdesign for an athodydfighter was takingshape in the Focke-Wulf project office, this time a high-speedhelicopter (Fig. 86).

Of all the schemes, this was by far the mostunorthodox, for it was an entirely newapproach- in aircraft design. The machineembodied a nicely streamlined fuselage withthe pilot contained in the extreme nose, butthere all semblance of conventionality ended.It was intended to stand vertically on wheelsmounted on its tail fuselage andto- take off from that position with the aid ofa three -blade rotor which revolved around thefuselage. This rotor was unique in itself, forit had no means of internal drive. Itspropulsion arose from athodyds mounted ateach blade tip, and once started by rocketsthese would cause the rotor to spin round athigh speed.

The launching procedure would consistfirst in driving the rotor up to a speed at

which the athodydscould operate. The

Fig. 84.-1,50o miles per hour-and on no other fuel than solid carbon.That was the estimate made by Professor Lippish for this athodyd-

powered flying -wing."

blades would be set togive zero thrust during

'this operation and thusthe ducts could befunctioned withoutcausing the machineto lift.

Within a few secondsthe ducts would heworking smoothly andthe pilot had then onlyto operate a controlto cause the bladesto assume a slightangular pitch sufficientfor the machine to risegently upward. Thevertical speed could beincreased to a maxi-mum of about 75m.p.h., and havinggained sufficientheight, the machinewould be turned intoa horizontal path bydeflecting its ruddersand elevators, appear-ing as in Fig. 86.

An increase in theblade pitch would

progressivelx improve the forward componentof the duct thrust, the rotational speed of therotor naturally falling as the result of thegreater load.

At sea -level, the maximum speed expectedwas 62o m.p.h., the rotor operating at 52o

Fig. 85.-A " tail -drive" athodyd project from the Focke4Vulf stable.

r.p.m., which in terms of the speed would be690 m.p.h. The initial rate of climb quotedis 25,cooft. per minute, with an endurance of0.7 hours and a 400 -mile range. At analtitude of 36,000ft., however, the forwardspeed would be 52o m.p.h., the duration 2.3hours, the range ',too miles, and the climbingrate only 4,000ft. per minute.

The descent was just the take -off procedurein reverse, the machine coming to rest gentlyon its tail-or so it was said. How it wasproposed to remove the pilot from hisprecarious position remains a mystery.

The profile drag of this design was said tobe about one -fifth that of a normal machineof the same dimensions, but the induced dragwould have been twice as great as a wingequal in span to the diameter of the rotor-37.4ft. The ducts themselves were little morethan 2ft. in diameter and involved practicallyno resistance.

The structural weight was 7,000lb.,Somewhat greater than that specified for theprevious Focke-Wulf project, while theall -up weight at take -off was 11,4001b.

Other Athodyd ProposalsThe projects illustrated in these pages were

by no means the only ones to be based onathodyd propulsion. There was, for instance,the Heinkel P.1080, a tail -less machine withswept -back wings and two duct units, 16ft.long and extending quite two-thirds itsoverall length, fitted at each. wing joint.

At the Skoda works was being planned anathodyd fighter in which a 31 ft. Saenger ductformed the basis of its bulky fuselage. Thegeneral layout, however, was orthodox, witha mid -wing fixing and a single vertical finon which the tail -plane was mounted justabove its root fixing at the rear.

A nose cockpit enclosure was incorporatedabove the intake duct in which the pilot wasto lie prone. There was provision for aheavy calibre cannon to be mounted justabove his head, and a large capacity fuel tank,also installed on top of the duct, took up aposition over the aircraft's c.g.

The machine was estimated to have asea -level speed of 63o m.p.h., with a maximumthrust of 9,7oolb.

Yet another proposal was for an adaption



Fig. 86.-Another Focke-wulf project, this time a high-speed helicopter.Three athodyds were to drive its rotor, but most unorthodox of all, themachine was to stand vertical on wheels fitted in the tail -end. It wouldrise directly upward and then operate in horizontal flight, travelling

at a maximum speed of 620 miles per hour:

of the Messerschmitt 262 with two Saengerathodyds in addition to its standard Jumo004 turbo -jet units. The performance figuresderived for this combination, however, werenot particularly encouraging. The maximumspeed at sea -level was estimated to be620 m.p.h., but the climb to 36,000ft. wouldhave taken over six minutes with fuel

consumed within 40minutes.

SummaryThe foregoing is

some slight indicationof what promises forthe future, thoughundoubtedly a greatdeal of further researchwill be required beforethe athodyd becomes apractical means ofaircraft propulsion.

In very high-speedaircraft, the prospectsare particularly great,for it has been cal-culated that at speedsupwards of Mach - 1.4and at a height of4o,000ft., the athodydwill develop a greaterthrust per square footof frontal area thanthe most efficientturbo -jet.

There are, however,serious obstacles.Even at quite highforward velocities, theathodyd's fuel con-sumption is between5o to too per cent.greater than that of

the mechanical -compression type.It loses power with height because, unlike

the rocket and turbo -jet, it is not super-charged." The- performance figures quotedfor the Focke-Wulf " tail -drive fighter telltheir own story ; a reduction of 90 m.p.h.from top speed at sea -level was registered at36,000ft., while the climbing rate for the

same conditions involved a loss. of 25,9ooft.per minute. For efficient operation, it isclear that a rocket booster is essential, andalthough extra tankage would be requiredto contain the rocket propellant, the fuelneeded for the athodyd could be muchless.

The higher the speed of the athodyd, thegreater is the thermal efficiency. A speedof 5,30o m.p.h. at sea -level would producean intake pressure of about 6o1b., sq. in.(a figure which compares favourably with the4 -to -I compression ratio of our best turbo -jets)with the fuel consumption then also a morereasonable proposition.

The U.S. Navy Department was one of thefirst to produce working examples of theathodyd. A number of various applicationshave been tried, and among the most successfulwere athodyd projectiles weighing 7o1b. andcapable of speeds up to 1,500 m.p.h.

An interesting point about them is thatthey required no auxiliary fuel feed. Thefuel was contained simply within a double -walled liner positioned over the heatingchamber, and it was only necessary to pre -heatthis tank to cause the fuel to start issuingthrough the burner jets as the result of itsown expansion.

IgnitionThe jets were ignited immediately and the

missile fired into the air with the aid of itsauxiliary rocket. Its speed would quicklybecome sufficient for the ram pressure totake over, the high temperature created bythe burners in the pressurised regionproducing expansion and jet reaction. Theself -feeding process naturally continuedthroughout.

(To be continued.)

Modern AbrasivesTheir Composition, Manufacture and Uses

THERE is no doubt of the fact thatman has always been an abrasive -using animal. For, from far back in

the mists of remote antiquity there havecome to us man-made tools and implementswhich, crude although they may be, showunmistakably the marks of a rubbing -downprocess which has been applied to them.

The stone arrow, the ancient axe, thefirst attempts at the fashioning of knivesand other metallic cutting instruments mustall have been submitted to some processof grinding and shaping, and, indeed, onmany of these prehistoric articles the actualmarks of the grinding implement can beplainly seen.

The earliest form of grinding, which,incidentally, has persisted right up to thepresent day, consisted in the rubbing of onething over another, as, for instance, thefrictional contact of one stone across anotherone of similar or, perhaps, harder texture.

Common GrindstoneThe common grindstone forms an example

of this, the earliest of abrasive operations.Actually, however, the grindstone as anabrasive agent is not a very efficient article,for it neither grinds nor cuts. The traditionalgrindstone merely rubs the article against itanti exerts rather a haphazard tearing -awayaction on the object than a true grindingeffect.

The first real scientific advance in theapplication of abrasives came with the moregeneral utilisation of emery and its making

up into compact stones and grinding wheels.Emery is, of Course, a naturally occurring

mineral which has been known (yetsurprisingly little used) for thousands ofyears. It occurs plentifully in Greece and,indeed, it derives its name from Cape Emeri,in the Greek island of Naxos, near which itwas once mined.

0 00 00 00oo x00000 a a 00 00 00 00 0°0 a00 c:,004`52);i0 oto 000

CorbideGroins

Emery grains wear round with frictionalrubbing, but grains of silicon carbide (carbor-undum) split under friction and continually

present fresh cutting edges.

Oo 0 0 0 0°0 0 00 Oa0 ° 00 00°00 0000 noC700 od-'oEmery Groin;

In composition, emery is an impure formof aluminium oxide mixed with iron oxide.It is reasonably tough without being undulybrittle and, although at the present time ithas to meet much competitioi from the

' synthetic abrasive agents, it still retains itsmany large-scale and commercial uses.

Powdered flint used at one time to be afavourite abrasive, but such material is now

less used, in view of the varying nature of itscomposition and physical characteristics.

GarnetGarnet, however, is a natural abrasive

material which still has its uses. In com-position it is a silicate of aluminium mixedwith iron oxide, resembling in this directionthe precious stone, which is a crystallisedform of it. Abrasive garnet, however, usuallyoccurs in the form of a gravel, which iswashed, ground, and carefully graded as toparticle size and employed either as asubstitute for emery or in admixture with it.

Sand, of course, has long been employedas an abrasive, as witness, for example, thenow almost traditional sandpaper. So, also,have powdered glass, brick dust, and similarmaterials, although, strictly speaking, theparticles of these substances exert a tearingrather than a true abrasive action.

The era of modern abrasive materialswas initiated, perhaps, by- the coming ofcarborundum, or silicon carbide, a materialwhich was invented by the American chemist,Edward Goodrich Acheson, in 1891. Thisnowadays well-known and, indeed, indis-pensable material is made by fusing in anelectric resistance -furnace a mixture of cokeand sand, together with a little salt to makethe mass more readily fusible and a smallquantity of sawdust to render it porous.

During the 36 hours of continuous fusing-which -the manufacture of carborundumrequires, a temperature of no less than3,500 degrees C. is reached, a terrific heat


9Q

in which all metals would not only be boiled,but actually gasified.

Yet it is at this enormous temperaturethat the two elements silicon and carbonenter into combination to produce siliconcarbide or carborundum, which, whenunloaded from the furnace, takes the formof massive and many -hued resplendentcrystals.

Carborundum CrystalsThe carborundum crystals are crushed

and then acid treated in order to remove allimpurities. Finally they are washed, dried,and then passed on to further crushingmachines, which reduce the material todefinite grain sizes.

A companion product to carborundum isfused aluminium oxide, which under thename of "aloxite," now forms a syntheticsubstitute for emery.

In aloxite manufacture, bauxite ore, whichis a naturally occurring form of aluminiumoxide, is electrically fused with coke, where-upon the bauxite melts and subsequentlytakes upon itself a crystalline structure.

From the aloxite furnaces, the abrasivematerial is extracted in the form of immenseblocks, which are broken up, crushed, andthen carefully graded for grain size.

Silicon carbide (carborundum) and alu-minium oxide (aloxite) are the only syntheticabrasive materials known, yet, in manyrespects, they have ousted all the naturalabrasives for many types of grinding work.

Both these synthetic materials may beused in the form of powders of varyingdegrees of fineness, or, alternatively, theymay be employed in the form of compactedmasses of various shapes, as, for instance,blocks, wheels, sharpening stones, and soforth.

BondingThis bonding of carborundum and aloxite,

and also, of course, of emery and othernaturally occurring abrasive materials, isusually effected by mixing a small proportionof china clay with the material and bycompressing the mixture hydraulically. Thecompressed material is then fired in speciallyconstructed furnaces, in which operation thebonding clay is melted and converted into aporcelain -like substance in which the grains-if abrasive are firmly embedded.

Of all known abrasive materials, with theexception of diamond powder, which isused by manufacturing jewellers for diamondpolishing and drilling, carborundum isthe hardest. Carborundum, however, is nottough, but brittle. Consequently, undergreat rubbing pressure, the carborundumgrains do not wear down to smooth surfaces,but they actually split, thereby presentingnew cutting edges.

Aloxite (aluminium oxide) and emery, onthe other hand, possess grains which aretougher but not so hard as those of car-borundum. Hence these grains wear downsmooth and do not tend to produce theconstant cutting action which is so character-istic of carborundum.

Carborundum cuts, but emery, aloxiteand other materials grind. The differencebetween these two effects will be evidentfrom the fact that the tiny portions of metalremoved by the agency of a carborundumabrasive, when microscopically examined,appear as " curls " or shavings of metal,whereas metal removed by means of aloxiteor emery, when similarly viewed, presentsthe form of tiny globules which have beenrubbed away and melted by the heat offriction.

Cutting ActionThe characteristic cutting action of silicon

carbide or carborundum abrasive has resultedin the rendering of this material supreme for


many purposes. Relatively speaking, car-borundum is as non -tiring an abrasive as isdiamond dust. Since the material cutsinstead of rubbing or grinding, a better -finishedresult is usually apparent, and much lessfriction is produced during the process.

Dentists, for instance, employ carborundum-tipped drills when they proceed upon theirunpleasant but highly necessary excavationaloperations in our mouths, the carborundumdoing its work quicker, more cleanly andwith less friction than any other material.

For the same reason motor engine cylindersare frequently re -bored with carborundumboring bars, since the carborundum grainscan be relied upon to produce a clean resultwith the minimum of effort.

In the general run of engineering grindingwork it is more or less a rule to employ ahard, brittle abrasive, such as carborundum,for the grinding of materials of low strength,as for example, aluminium, brass, copper,cast iron, hard rubber, stone, marble, andnumerous other non-metallic materials. Fordealing with materials of high tensile strength,such as steel and its various alloys, the tougheryet softer emery or aloxite is employed inabrasive operations, since, being tougher thancarborundum, they are better able to with-

Electro-MagnelPole

Charged Sand orEmery Grains FlyingUpwards to GluedSurface of PaperOr Cloth -

Cloth or PaperWith FreshlyGlued Surface

1( -;.-.---Conveyor Belt ':--",-,-_,'-:.

Containing Loose _I-- -.,'--_--';',.-, :-

Sand or Emery Electro-MagnerGrains Pole

4

L

Illustrating the modern method of sandpaper making.

stand the frictional strain against asurface without breaking down.

hard

Chromium OxideIn addition to the abrasive materials

enumerated above, there are, of course, anumber which have lesser uses. Amongthese may be mentioned chromium oxide,the green polishing powder used in finemetal working and, of course, that gentlestof all abrasives, jeweller's rouge, which is,of course, merely a form of iron oxide, whichhas been heat -treated and carefully gradedfor particle size.

Added to these are the whiting and theTripoli powder or kieselguhr (a diatomaceousearth) beloved of metal -polish manufacturers,and one or two other naturally occurring fineabrasive materials, such as cuttle-bonepowder which is the ground internal shell orbone of the cuttle fish, and rottenstone, afinely ground mineral, occurring in Derby-shire, which is often employed for polishingoperations.

NEW NES

ENGINEER'SPOCKET BOOK

712 PAGES

10/6 by post II/ -From George Newnes, Ltd., Tower House,

Southampton Street, Strand, W.C.2.

December, 1946

Such materials, whilst being strictlyabrasives, are only extremely mild ones, forthey remove merely the thinnest of depositsfrom smooth metallic surfaces, and henceare employed merely as polishing agents.

Bound up with the developments whichhave taken place in the sphere of modernabrasives is the manufacture of abrasivecloths and papers.

At one time sandpaper was a very unreliablematerial, consisting of sand grains of veryunequal size glued down to a thick brownpaper. In recent years, however, a demandfor improved abrasive papers and cloths ofmany varying grades has arisen in consequenceof the increased activities of the light en-gineering industries, the result being thatthese modern papers and cloths have nowbecome highly efficient and specialisedarticles.

Synthetic ResinsIn addition to special glues, various synthetic

resins now form the bonding agents forcementing down the abrasive grains of theserubbing cloths and papers. Paper millsprovide special grades of tough paperfor this branch of the modern abrasiveindustry, whilst the cloths employed are

specially woven, sizedand pre -coated withmaterials to render theirshrinkage impossible.

Perhaps, however, themost interesting develop-ment' of abrasive clothand paper manufactureis the modern mode ofCoating these materials.In order to secure absoluteuniformity of distributionof the abrasive particlesupon the surface of thepaper or cloth, the glue -coated material is passedthrough an electric fieldproduced by a ofbetween 40,000 and so,000volts. Through the samefield, also, and aboutbelow the glue -coatedpaper or cloth, is passeda conveyor belt carryingon its surface the grains.

of abrasive which are to be coated onthe paper or cloth. Under the influence ofthe powerful electric field, the abrasiveparticles acquire an electric charge and flyupwards to the glued surface, to which theyattach themselves in an absolute uniformityof distribution.

The " Whipping Machine "Any excess of the abrasive grains which

may be present upon the paper or cloth issubsequently removed by passing the coatedmaterial through a " whipping machine,"which knocks off the surplus abrasive particleswhich have not become firmly embeddedin the glue and returns them to the mainfeed of the coating machine.

Finally, the coated abrasive paper or clothis passed on to a room in which it is hungup in festoons for the adhesive materialto dry and harden, and afterwards, in specialcases, an additional adhesive coating may beflowed over the abrasive surface in order toanchor the grains still more securely inposition. _

Such is one of the most recent of develop-ments of the now world-wide abrasivesindustry, a development which, comparedwith the erstwhile simple peppering of- drysand on to a glued brown -paper surface, isalmost as great a measure of progress as isrepresented by the superiority of the present-day synthetic abrasive over the age-old andtradition -haunted grinding wheel:

41



A Spot Welderfor Use on A.C.

How to Adapt the Battery -operated Spot Welder, Described

in the November Issue, for use on A.C.Mains Supply

BRIEFLY, the differences between thebattery -operated welder and the' mainsoperated appliance are that the latter

machine is operated from a transformer andthe finger push switch dispensed with. A footswitch is used leaving both hands free to holdthe work, etc.

Start the work by removing the contactswitch and then drill another hole throughthe bottom arm so that the whole may bebolted down to the bench or a large woodenbase.

The TransformerThe transformer is the heart of the machine

and must be made with care. A 500 -watttransformer can be operated from a lightsocket and is heavy enough for most work,but a t,000 watt transformer requires a 5 amp.plug and this wattage is too great for the lighting,wiring. If possible try to obtain a second-hand transformer with an open casing ratedfor your supply, and with an output of over50o watts. On conversion it will be as efficientas a commercial 50o -watt transformer, andthe work of the conversion will be easy.The output required is a maximum of too to200 amps. at t, 1.5, 2, 3 and 5 volts. Inwatts this is 500 or r,000 depending on theCurrent required in the home shop. To carryover too amps. large cables are necessary,and as the resistance has to be kept very low weare using sections on the heavy side to allowfor drops in voltage across joints, etc. On acore of this size, which must not be less than3.5 sq. in., we can allow 5 turns per volt ; thus,one needs a total of 25 complete turns withtaps at the 5th. 7th, loth, and t5th turnrespectively.

The length of strip of suitable section isobtained, and, if hard drawn, is annealed.The section must not be less than o .7in. \:o. tin. It must be cleaned and then insulatedfrom end to end with good quality tape.Do not try to economise by scraping off thetape from the section required for taps, butleave this until finished, and scrape offafterwards.

CONNECTINGPOD

5w/rcH

SeiRAL. 50R/NO

The TappingsThe taps are brought out as double lengths

of wire to avoid soldering, etc., and theyshould be hammered flat so as to lie neatlytogether. The starting end is connecteddirectly to the bottom bar as before, whilethe top bar has the flexible connector foruse with the taps. In making a tap, bringout the wire for 6in., bend it over on itself,and take it back and continue winding to thenext tap. Remove the insulation from thebent end, clean the copper and press together,and then run solder between the two to makea solid bar. Drill the bar and tap with a jin.fine thread, and fit with a cheese -headedscrew.

When the transformer is mounted on thebase, the taps also are screwed down to thewood by two small wood screws, countersunkand passing through the copper, one in frontand one behind the tapped hole. The top

JECavD.40y

T of

Fig. 2.-The circuit diagram.

Fig. 1.-The finished transformer:

through the spaces : this may sound tediousbut remember you are dealing with only25 turns. It is a matter of minutes with thecore clamped in a vice. The reason for thisis that we cannot reassemble the core andclamp it tightly as the maker does. Severalthat we have made are only about 25 percent. efficient when tried out again. Wehave assumed that the primary was suitablefor your supply. If not rewind to suit. Thismeans 1,15o turns to take 5 amps.

As the transformer is short rated we cancut the wire size down a little to economise.Winding 1,15o turns on a fixed core when thewire is passed through and through is

tedious work, but in this caseyou would have to dismantle thecore and wind in the ordinarymanner.

A Soo -watt transformer of thistype will cost from £7 los. od. tomake, and so we do not think itnecessary to deal with the con-struction of a new instrument.The Foot Switch

The foot switch will now beconsidered. Here we have the

same idea as that used for closing the points.Mount both the Bowden Control to thepoints and the switch on the same base.The switch pedal is a piece of woodSin. wide and gin. long, and is hinged, atthe end nearest the operator, to the base.The switch proper is a tumbler switch with abrass knob. It should be capable of carrying5 amps. with a quick make and break. Acheap one will do quite well. This is mountedunder the pedal and is connected to it througha short brass connecting rod. Make a saw cutat right angles to the pivot in the knob, openit out with a file until it will take a -kin. pinthrough the knob. The connecting rod, whichis a strip drilled with -111 in. holes at each end,

FoorA9/41,4,9Y

surface of the copper is dead flat. A suitablewasher must be used under the screw in orderto make good contact. When differenttappings are often required, the screws arcfitted with an easily turning head. Do thisby drilling a 313,in. hole diagonally throughthe head and then hammer a zin. length ofa silver steel rod through it. Thespade end of the connector is made to suitthe taps. Arrange the five taps in a neatrow behind the welder. Keep the leads asshort as possible.

The Primary and SecondaryIf a second-hand transformer is used, do

not dismantle it but thread the secondary

'632441e(rrFoifg. t3h.e-f( oLoeft)tsiDvitectha.ils

",4,07" FORCONNECTING

.PODFig. 4.-(Right) Themethod of making the

taps.

WASHER

rixilv6 54-Rews


92

is cut from sheet brass -11,fin. thick. Put theswitch in the off position, place the connectingrod in the knob and push the pin in, nowwork the switch by ITaanipulating the knob.

Pedal GearThe pedal must work the switch, and for this

mount two small brackets on the under sideof the wood, drill and put in the rod. Thebest position for the brackets and switch willbe found by experiment, but it can be usedwith the bracket on the end of the wood andthe switch about zin. from the end, the rodbeing Sin. from centres. A strong spring ishooked round the knob and round a screwin the base so that the switch is always Off. Itshould take quite a good pressure to closethe switch, and on removing the foot it shouldfly open. Fig. 3 shows the finished switch.With this means, it is possible to get very


Fig. 5-The connections for earthing thewelder and the foot pedal.

accurate time control and good work can bedone. Twin flex from the switch is taken upwith the Bowden wire to the welder base

and there connectedbox. This gives afinish. Fig. 2 shows

December, 1946

to a porcelain junctignneat and workmanlikethe circuit.

A Press SwitchA simple press switch can be made frog

pieces of brass similar to a bell push, but v.tr,do not recommend this because of the,difficulty of protection, etc. The wholewelder must be earthed, and so must thefoot pedal, etc. (see Fig. 5).

(Since the transformer is worked off themains, and the little extra electricity used isnot noticed-, it is a good plan to arrange asmall light just by the points. This shouldbe a 6 -volt car side lamp with switch on thebase, and is run from the 5 -volt tapping.Mount it on a small flexible arm, and cut atin shade so that the light is exactly as required)It will dim a little when the 5 -volt tap isused.

Wot! No En ineerinThe Marquis of Donegal! Makes a Tour of the "Britain Can Make It" Exhibition With Mr. "Chad"

IHAD almost forgotten how to drawMr. Chad when I ran into him at the" Britain Can Make It " Exhibition.

And he said : " Wot ! No Engineering ? "I replied : " My dear misguided Chad,

all these things that transport toys round incircles, not to mention the chap whose littlespeech repeats itself through a loudspeakerevery 45 seconds ; or even the switchingout of the lights just as you are gettinginterested, arc far more important. Fancyall these engineering wonders in an old -established firm like the Victoria and Albert.They should both fair turn in their graves,they should ! "

Pshaw ! " says Chad, rather rudely, Ithought, " there is nothing here that Butlindoesn't make go round faster and better-and with more fun ! Starts from scratch onthe ground, he does. Engineering, my foot ! "

However, I won't let Chad get away withthis, so I grab the little wretch and take himon a compulsory tour. First we see thecrashed Hurricane on the background ofblitzed London. Strings leading from everypart of it go to show what, from toys toplastic trays, can be made from its components.

" Isn't that Engineering for you ? "" Was," says Chad, " but it's had it ! "What can you do with a guy like that ?

However, I continued.

Plastic DrapingsWe go through all the lovely plastic

drapingS festooning in wish -I -could -get -itpale dove grey. I try again and point outthe engineering feat that made these plasticspossible.

" Chemists," says Chad. " Atomic. Don'tlike 'em ! "

The Hall of Fashion, with its giant revolvingroundabout, embodies no new principles ofEngineering. But it is nevertheless a majorjob very well executed and gives us a lazyview of these modernistic fashion dummies intheir " creations "-and note particularly thenylon wigs.

Chad, however, is still looking over thewall (probably with one of the promisedGovernment Inspectors) into Butlin's and isunimpressed.

By this time Chad is too much and I pushhim into the " Space Ship " with the remarkthat anyway that is Engineering. (Wot !Aren't we off to the moon ? ")

As a matter of fact, Chad is nearly right.You will not find an Engineering exhibit,as such, in the whole of the " Britain CanMake It " Exhibition. By that I mean that

you will not find a Rolls-Royce Derwent 5jet engine or even a Hillman Minx. I onlymention that particular car because I happenedto drive and service one 70,000 miles for the

wOT! NO EAVN£ER/NC?

Home Guard, and I consider it one of thefinest things that Britain does make.

It so happens that we make very good lifts.In fact, we made the one with which a Shahwas so impressed that he had one put up inhis back garden. It didn't go anywhereexcept up its scaffolding ; but it kept theharem quiet for years.

Machine ToolsAlthough few people seem to realise it,

we are now making machine -tools on anincreasing scale to compete with anybody.It is only due to British engineering that weare the only country that can stamp outa pair of spectacles in plastic to any pre-scription.

King George the Fifth wore a pair ofBritish plastic spectacles for the last threeyears of his life. They were made byCombined Optical Industries (Slough), asfar as I can remember.

I am not suggesting that the exhibitioncould house a full-scale N.F.S. pump andescape, recognised even by the New YorkFire Service to be the finest in the world.Obviously, you could not have one of thenew " Merchant Navy " locomotives, aDe Havilland Dove or a Miles interchangeablePassenger and Freighter. This, incidentally,is so revolutionary in design that the meresight of the thing gives the " willies " toantediluvian pilots like myself. (Wot ! Noproper tail !)

I do not know whether our Tube escalatorsarc the best in the world. I could go onfor ever with things that Britain can make,ending up with the Queen Elizabeth. Peopledon't order a Queen Elizabeth every day, butthe fact remains that the cruiser Argentina

that I had the honour of inspecting offGreenwich recently was built at Barrow-in=rFurness in 1939. I dare say half those t5dArgentine cadets who came here on theirgraduation cruise thought she was built inBuenos Aires, or, more likely, in Texas.

RemindersYou have to remind people of these things,

just as you have to remind Americans thatit was a Briton who invented the phonograph,the wireless, the marine chronometer, thebicycle, the pneumatic tyre, penicillin, anda few other useful little devices ; not to men-tion that we have to take the blame for theirmisunderstanding of our Constitution whichhas resulted in their being stuck with thatmisunderstanding commonly known as theConstitution of the United States.

However, all that is by the way, and whatI am really trying to say is that there couldhave been an Engineering Section in " BritainCan Make It " by the simple expedient ofborrowing a few models that were shown atthe Model Engineering Exhibition not solong ago. Possibly the Authorities were wisein that had they done so they would neverhave got the dense queue to circulate past it.

As Joad says, ad nauseam, it depends whatyou mean by Engineering. I can describe toyou toasting -machines that tlfrow the pieceof toast at you (I had one in 1935), as also thestandard lamp that wakes you up and startsthe kettle (1938, and I still have the remains,portable gas heaters, standard -lamps cumbed -warmers, washing machines (Wot ! NoBendix !), grand toys that are near -engin-eering jobs, radios (most disappointing indesign), thermostatic beds, prams that convertinto a cocktail cabinet or grand piano (Iforget which !), lovely packaging, a futuristicbicycle that doesn't work and never could,watches that would make a Swiss wince andclocks to which he would give his approval.'

There are alleged to be cameras andbinoculars (I have a grand pair of Wraylite(: 8) replacing my Zeiss stolen in Singapore, soI know we can make them), but as yet, on fivetours of the Exhibition I have not been ableto find them.

In fact, I am forced to agree with theFrenchman who, on first being confrontedwith a " Mild -and -Bitter," said : " C'estmagnifique, mais ce n'est pas Lager."

Britain Can Make It is " magnifique "in lots of ways. But there is about as muchEngineering as there was Lager in theFrenchman's Mild -and -Bitter.


December, 1946 NEWNES PRACTICAL MECHANICS 93'

Science NotesTrouble With the LawT HAVE often photographed noise with

a view to proving to a hard-hearted judgethat Mr. Jones was suffering from noisenuisance. It is usually accepted that if thenoise of which complaint is made is greaterthan that which might commonly be expectedfrom such things as traffic, then the noise isa nuisance.

-Now I had a case where a man complainedof a perpetual singing due to a motor, so Iwent into court with a buzzer making thesame sound, and asked the Judge how hewould like to sit there all day with thishalf -heard sound in the air. In my view,things of that kind are very irritating.

You will remember the tale of the man atthe hotel who was woken up by the residentabove him throwing his boots into thecorridor. He complained. The next nightthe offender threw out one boot, rememberedhis promise and carefully put the other downvery gently. Three hours afterwards the mandownstairs tapped on his door and said,wearily : " For heaven's sake throw out .theother boot ! "

The " ping " of a gnat is another trouble-some sound and no one knew how it is caused.So we took a glass chamber, greased theinside so that gnats could not buzz after onelanding, and then took high-speed cinemaphotographs. The gnat produces much of itssound as it flies by rubbing together the innerportion of its wings. A pity we do not silenceaircraft, for some are so noisy as to be amenace to health and comfort.

Pussy is not Crazyj WONDER if you have read about cats

and bats. Some people like cats best solet us put them first. Why do cats fall on theirfeet ? It is true that they do, and a seriesof high-speed cinema pictures have shown thereason very clearly. Cats have been droppedfrom a suitable apparatus to make sure thatthey do not as it were kick themselves straightas they leave your hands should you trythe experiment in that simple way. As arule they put their front paws near their body,

-leaving their back feet extended. Thisincreases the inertia of the rear part of thecat. Using this fact pussy twiddles thefront half of his body right side up, then sticksout his front paws, draws his back feet closeto his tummy and twiddles the back quicklyagainst the increased inertia of his frontextended paws.

It sounds very complicated but all thesethings are relative, and if in fact provisionwas not made to carry the twist of an air

'screw in a 'plane it would be quite as logicalfor the 'plane to revolve round the airscrew

= instead of vice versa. If you touch theaccelerator of a car momentarily the car leansover sideways, and if it could do so it wouldgradually, having more inertia than theflywheel, begin to revolve round the engine.Cats seem to have learned all about thiscenturies ago, so I thought perhaps we oughtto understand it as well.

Bats are not BattyNOW about bats. I mean the winged

mammal which startles everyone byflying round the belfry. For many years ithas been known that the squeak of a bat wasvery quick. In short, it is pitched so highthat only youthful ears can respond. Butmore wonderful is it that if bats are allowedto fly free in a pitch dark room across whichinnumerable wires have been stretched theywill fly in and out of the wires without

By Prof. A. M. LOWtouching them at all. Is it that they see byinfra -red light reflected from the bats ? Itis not. Careful tests with instruments farmore delicate to higher pitches than our earshave found that the bat emits short bursts ofsqueaks with a frequency of about so,000 persecond. These supersonic sounds bounce offthe wires, are picked up by the bats hearingapparatus, and the creature flies in safetyexactly as if it was using radar with soundsubstituted for ether waves. The wholesubject of these ultra -high-pitched sounds orsupersonics is interesting, for they have beenknown to kill fish and to metamorphosisecertain types of bacteria. It is not likely thatthey will be used one day as a death ray foralthough sound has great power, and can dogreat harm by battering our bodies, I thinkit more probable that the Walls of Jerichowere pure allegory.

The Radarange, so called because it operates on the magnetron tube,the heart of radar, produces. heat rays that penetrate the interior offood as fast as they do the exterior, and so cut cooking time to seconds.It will cook a six -pound beef rib roast in 2 minutes. The temperatureis only about 220 degrees Fahrenheit. This model, suitable forrestaurant or very large family, costs about 600 dollars. It is

manufactured by the Raytheon Manufacturing Co., America.

Are You aight ?co many things seem to me obvious and" yet so much is a matter of opinion thatI ought to be used by now to being wrong.Upon the few occasions in my life when Ihave been absolutely accurate knowing wellthat black was black and so on, it has givenme enormous satisfaction. Once upon a timeI went to see a stereoscopic cinematograph,and I was shown a report by a scientist ofsuch international fame that I almost tookoff my hat before reading his words of wisdom.

When I read the first six lines I went backto the beginning and read them again. Theystated that by taking a right and left pictureof an object it was only necessary to showthese alternately upon the screen when,true stereoscopy would be obtained.

Being a cautious Scotsman I reservedjudgment, but the conviction soon grew.upon me that I was actually right. It isobviously true that real stereoscopy can onlybe obtained if the audience wears glasses and,the method of showing alternative picturesonly functions if the right picture is notallowed to be seen by the left as well as bythe right eye.

Hence the coloured glasses which whenused to look at pictures alternately dyed redand green on the film gave a stereoscopiceffect which was positively astounding.Hardened old men ducked their heads as

someone on the screensquirted a siphon ofsoda -water at the audi-ence. There are nowmany methods forobtaining " shadow "stereoscopy by screenswith curved surfaces orby the use of prismaticviewers, but none ofthem really achieves itsobject and glasses arestill despised by everymember of a well-conducted audience. Itis, in short, like theprinting of colour pic-tures at high speed, avery tricky problem.

To make it moreimpressive let me re-count the other occasionwhen I was right. Atleast I think so ! Anannoyingly cocksurefriend once explained ata lecture that the long -handled screwdriverwas a farce. He pointedout that it was width ofhandle that mattered ingaining the necessaryleverage. Try it foryourself. My theory isthat with a very longscrewdriver the bladecan be tilted withoutfumping out of the slot,thus allowing the de-"parture from vertical atthe top of the handle tobe appreciable. Thescrew is then pulledround, just as if onestuck the blade of a pen-knife into the screw slotto pull it round.

One can hardly dealwith screws in summer-time without thinkingof wasps. These

creatures, appear to have stings like theblade of a stiletto. When you have beenstung, you knock the wasp away with ahowl of rage and the beast flies offseemingly none the worse for wear.

In the interests of science you should beprepared to suffer, so make the same experi-ment with a bee. The bee, like the dog in thepoem, is the one that dies. The bee walksround and round your hand screwing out itssting which appears to be in the form of acorkscrew.



A LarAe UkuleleConstructional Details of an Inexpensive but Efficient Instrument

By R. J. CHAMBERLAIN

THE reader wishing to construct a real" vamping" musical instrument,easily and cheaply, will find such a

type illustrated herewith. It has beenspecially designed so that any amateur wood-worker can make a success of its construc-tion.

34-

-Head

Pegs

Nut

FretS

FingerBoard

Fig. t (Above).1-Front andside elevationshowing themain parts.(Left) Thefinished instru-ment, after

polishing.

It is the new shape which facilitates con-struction. There is no difficult bending ofthin wood to form the sides. Only straightstrips of wood are used, which require only,to be mitred at the corners. Although theside strips are cut from in. thick wood (theside strips on conventional -shaped ukulelesare often cut from veneer x/t6in. thick), thishas very little effect on the resonance of theinstrument.

The model constructed by the writer hasexcellent tone-in fact, its tonal qualitiescompete with those of a guitar. It is apleasure to use the large ukulele. The manydelightful, harmonious chords produced byordinary -sized ukuleles are much amplifiedby the larger instrument.

One can, too, owing to the length of thesteel strings, get a more sustained chord.For choir practice purposes, the big " uke "provides an accompaniment which is betterthan an organ. Vocalists are aided by theukulele. It gives rhythm and harmony.

Being a ukulele, the chords are easier toplay and memorise. A person does not needto know a note of music, because ukulele

Handle'

Body

SoundHo/es

Bridge

chords (vamps), as you may know, areindicated by small charts (above the treblestave on sheet music) which show the fingerpositions between the frets on the finger-board. No " reading " of music is necessary,except in the case of new, unheard melodies.

The large ukulele should, therefore, be aboon " to budding vocalists. If, on the

other hand, a would-be performer cannotsing, he can at least learn to play the ukulele

and provide a mas-terful accompani-ment to a group ofsingers or a vocalist.And as most of uscan hum and whistletunes a good ukuleleaccompaniment i sonly necessary tohelp the " perform-formance " along ina professional man-

- T ner.1

Incidentally, it is1 possible to p 1 a y

melodies on a uku-lele, but as the

1 tuning is unsuitable/8' for melody playing,

the task is rather adifficult one. Still,it can be done, with

Anchor practice. One of5 the easiest melodies

that can be played is_ _ "In the Mood."

By " holding " avamp and plucking alternate strings, thefirst phrase (eight bars) can be played withtouches of harmony, a second vamp pro-viding the second phrase of the music, andso on.

Front and Back ShapesThe elevation in Fig. t gives a good idea

of the size and shape of the instrument. Italso gives the names of the various parts.The writer made his model from scrap

-

Ij

, i

6 Rad

16'

Fig. 2.-How to mark out the front and backpiece.

ShoulderSection

-r

/94-r

Fig. 3.-Constritc Tonal details of the handleand head.

plywood and deal. The pegs, however,require to be made from hardwood ; soft dealis useless. Alternatively, it should be pos-sible to purchase a set of four pegs, suchas, for example, violin pegs.

The front and back of the instrumentbody should be cut from kin. plywood. Inthe writer's case, a cheap " backing " ply-wood (alder) removed from an old cabinetwas employed. It was somewhat rough andknotty in places, but after glasspaperingsmooth, with all crevices filled with plasticwood, it took an excellent polish, includingthe deal handle, head and body sides.

The shape of the body front and back isall compass work, as shown in Fig. 2. It islargely a matter of ruling a line, ticking offthe length (18in.) and then setting the com-passes to scribe a 6in. radius. Withoutadjusting the compases, two further radiilines are scribed (see dotted lines), theselines giving the " corners " of the shapewhere they pass through the tzin. circle.

The top half of the shape is found bysetting the compasses to scribe an 8in. circle.Having obtained the shape of the front piece,scribe the sound holes, then cut the wood toshape with a fretsaw. The shape can be cutwith a fine panel saw, if the fretsaw is notavailable, the sound holes being made withsuitable centre -bits which, by the way,should be used at both sides of the wood tomake clean-cut holes. The back shape isidentical to the front piece, excepting that itis pointed at the top and not made flat likethe front. The back, of course, is minussound holes. The front piece, when cut, canbe used as a template for marking out theback shape.

Handle and Head ConstructionThe most difficult part about the construc-

tion of the ukulele, perhaps, is the handle andhead. The latter has to be dowelled at anangle to the handle, following which thehandle has to be built up to thickness.

The best way to go about the job is toprepare the handle and head shape from;in. deal. The head (see Fig. 5) is notshaped up until it has been dowelled to theneck end of the handle. Have three 8in.dowel stumps in the joint, as shown in thesection. Use a hot liquid glue, such as boiledScotch glue. A reliable cold liquid glue,such as " Certofix " or other brand, may beused. It is imperative that the joint is neat,


December, 1946

true and strong. This will be ensured byhaving the dowel hole positions truly scribedand marked.

While the joint is setting, build the handleto thickness at the shoulder end. This isdone by rub -jointing on a gin. and 51in.

110ireth,_ ShouldersWi Blocks -

SideStrips

%1410.

Anchorage _,,Strip Block

44%%%4N44

Corner Blocks

Fig. 4.-How the side strips are nutred aroundthe front piece prior to adding the back part.

length of 2in. wood (see dotted lines inFig. 3). When the glue has set, the handleand its thickening pieces are roughly cut witha knife, and planed to an angle, this beingseen in the shoulder section.

When bevelled, mark out the side shape inpencil, cut away the waste by paring, thenbevel the underside of the work in themanner indicated, using a penknife, rasp andspokeshave. Note that the underside of thehead is cut to taper to about din. thick atthe tip.

The Peg HolesThe four peg holes are bored with a +in.

bit, then " reamed " via the underside witha tapering round file of suitable diameter.This is to make a " tapered " hole so that thepegs will obtain the maximum grip. Aftertapering, it is advisable to countersink the" rims ' of the holes a trifle at each side,using a rosehead countersink bit or a " poke "of glasspaper.

Fixing the FrontBefore the body front can be attached

to the surface of the handle at the shoulderend, a din. deep recess must be cut here sethat the front will lie flush. The recess isSins. in length.

Both the front and back body shapesshould be cut from the plywood so that thegrain runs across and not along the length.In other words, the grain runs crosswise withthe length. This is advised in case the ply-wood is bendy in the centre.

A straight central pencil line should beruled along the surface of the handle, andthe body front piece. The latter is attachedto its recess with, glue and panel pins. Lookalong the length of both parts with theeye to ensure that the straight lines are inalignment, or else test with a straight -edgedpiece of wood, or by applying a stretchedstring. This test is very essential ; if theparts are not in true alignment, the stringsWill not be properly stretched over the fingerboard.

Adding the Side PiecesA piece of deal 4ft. by 21in. by lin. will

now be required. This provides sufficientmaterial for making the body sides. In case


of difficulty, a length of 31 -kin. wide by in.thick tongue -and -grooved board (sheeting)could be bought, free from cracks and knotsas much as possible. The wood is cut towidth, gauged to ,in. thick, then reduced byplaning ; it can be done easily enough witha smoothing plane, this allowing for anyslight curvature in the wood.

Beginning at the bottom end, cut, mitreand attach two 6in.-long strips. A mitreblock, cutting a 6o -degree mitre, would behandy. However, by having the strips cutsquarely to size, the ends can be pared tothe approximate degree of angle with a sharpwood chisel, then " trued " by trimming witha metal block plane.

The strips are glued and pinned to theinterior side of the front. The work shouldlie on a flat surface. Continue to add thepieces until the shoulder end is reached.Here, owing to the bevel in the handle shape,care will be needed.

NeckSection

DiaDowels

Fig. 5.-The finger board, with details of head.

To ensure true fitting, place the back shapetemporarily on the work. Rule a guide linefrom its top end to the end of front. Attachcorner blocks, keeping them 5/16in. inwardsto allow for the thickness of the side pieces(see constructional side view at Fig. 4).When all the sides have been attached, gluein corner blocks, as shown. When the gluesets, trim the wood and attach the back, butnot before an anchorage strip is adhered to

wePoundRod :)

I -

I In n

Metal Rod fixedin Positron

Fig. 6.-The bridge, anchor, and details ofnut and pegs.

the inside of the front at the bottom, thisstrip being about +-in. thick.

The Finger BoardThe finger board is cut from 3/16in. birch

plywood or plain wood, same measuring r5in.by 2in. Mark off the top " nut " piece, thenthe fret positions, using a small set squarefor the latter. It is then cut to the shapeshown.

Glue the finger board on the handle so thenut end is level with the neck joint. If thewood has a tendency to rise, bind it on withtape. Nails should not be used.

While the glue is drying, the body couldbe cleaned up. All nail heads are sunk witha punch and filled with plastic wood. Edgesare trimmed, then the whole thing rubbed

The instrument before polishing.

smooth with M2 and No. rl grades of glass-paper.

Nut and FretsThe nut is a piece of bone or celluloid

buckle measuring 'din. by din. by +in. Itis rounded at the top edge, then filed to makefour string nicks (see Fig. 6). The preparednut is attached behind the finger board withglue and its backing piece (see Fig. 7).

The frets are strips of black celluloid abouti/r6in. thick by 3/16in. wide. These stripsare embedded in saw -cuts din. deep. Thesaw -cuts are best made with a small" Eclipse " hacksaw. However, to ensureneatness, the guide lines should be scoredwith a penknife, then " pared " slightly atan angle to make a groove for the hacksawblade.

When fret positions are cut, tap in the fretmaterial. Thin sheet brass could be used forfrets, of course. The frets are-or shouldbe-a force fit. When fitted, level them offwith fine glasspaper held in a flat piece ofwood. The frets should sit up r/r6in. Thestrings should " cleat " them by r /16in.



Anchor, Bridge and PegsInstead of having the strings anchored to

the bridge which, as a result, is a permanentfixture and cannot be adjusted along the" belly " of the instrument, the strings areattached to an anchor glued and screweddown.

The anchor is made from a strip of hard-weed 3;in. by sin. by lin., as 'shown atFig. 6. It is bored for three fixing screwsand four / 16in. holes made through theedges for the strings.

While three roundhead screws may beused, it is better to use countersunk round -headed screws. The position for -the anchoris shown at Fig. 1. It must be central withthe body.

The pegs are cut from gin. hardwood;then shaped, is shoWn. The string holesshould be iin. froth the top.

The bridge is cut to shape from .1in.-,thick hardwood, as shown. A 21in. piece of

diam-brass rod fits into the top reeerstightly.* The rod is filed to -make string nicks

apart.

Finishing OffTo finish off the woodwork, apply (with a

soft brush) a thincoat of light walnut frenchpolish to all parts of the work and allow todry, following which the wood is rubbeddown with a fine grade of glasspaper. Brushon a second coat,. allow to dry, and add athird application.

This applies to all the work with the exccp-

StringsMust ClearFrets ByAbout

Fig. 7.-How the strings are fittedrespective pegs.

to their

-tion of the finger board. The surface of thismust be several shades lighter. Followingthe third application, rub it down with a" four " grade of glasspaper, then finish off byrubbing a very thin.polish on,

The rubber is a piece of soft linen wrappedaround a. pad of cotton wool. Make the pada conical shape so that it can reach all corners.You will find that polishing is much easierwhen the polish is thin.

The body should be a nice warm walnutcolour. The grain in the wood will showthrough attractively. The bridge, pegs andanchor should be given a single applicationof the polish, or two coats, if necessary.

TuningYou will require a half -set of guitar (steel)

strings, i.e., the rst, 2nd, 3rd and 4th string,the last two being covered. Have the stringsattached to their respective pegs in themanner indicated at Fig. 7.

The strings are tuned similar to the tuningof. an ordinary ukulele, i.e., A, D, F -sharp,and B on a piano. But, the tuning is anoctave lower. Further, the 4th string mustbe tuned an octave lower than written. Abook highly recommended is The First Corn-inunity Uke Book, this containing 120 songs,with complete melody line, words and uku-lele accompaniment. It is published byKeith Prowse and Co., Ltd. It must bestated, however, that the above tuning appliesto every number throughout the book. Thismeans an extraordinary variety of differentchords, some of which, due to the increaseddistance between frets in your home-madeukulele, may be hard to finger properly. Themajority of chords can be played easilyenough.

ModernTHE United Whaler's 15,000 ton factory

ship Balaena, the first ship of its kind tobe fitted with aircraft for whale -spottingand weather reconnaissance, underwent her

One of the Walrus spotting 'planes on boardthe Balaena," showing the catapult

apparatus.

trials in Belfast Lough recently. The shipcarries three amphibian Walrus aircraftwhich will be piloted by former. members ofthe Fleet Air Arm. The machines,Irg housedin a hangar constructed at the -afte,/, end ofthe boat deck. They are launched by adouble-acting catapult, working on'a corditecharge ; this catapult was previously installedin H.M.S. Pegasus, the Fleet Air Armtraining ship. The Balaena will act as mothership for a fleet of about to whale catchers,

Whale -factory Shipand she is well equipped to carry outmaintenance and damage repairs duringthe whaling season, which starts on December4th.

The " Balaena" undergoing her trials in'planes can

Factory EquipmentHer factory, for dealing with the whale

meat, contains one of the largest oil -producingplants ever installed in a ship, and alsoelaborate plant for dealing with by-products.Refrigerating machinery will freeze thechoicest parts of whale meat 'for humanconsumption. The majority of the crew areNorwegian, and the womenfolk of a numberof them are coining to Belfast from GreatBritain to make the return journey in theship. She will call first at a Norwegian portand then at Buenos Aires on her way to theAntarctic.

(A close-up view of the centre deck of the" Balaena" is given on the front cover.)

Belfast Lough recently. One of the Walrusbe seen on board.


December 1946 NEWNES PRACTICAL MECHANICS 97

Napier's NumberznSome Modern improvementsBy CHARLES H. KAY, A.M.I.Mech.E.

THE numbering rods, since known as" Napier's bones," were invented byJohn Napier of Merchiston in 1617.

They have been fully described in the recentarticles on " The Calculating Machine,"by F. W. Cousins.

These rods were much used -for facilitatingthe multiplication of numbers, and naturallyinspired many slight improvements in con-struction to render easier reading and setting.There is, however, a slight mental effortrequired in adding the numbers along thediagonals from rod to rod.

Genaille's RodsThis repeated effort was eliminated by

M. Genaille, who in 1885 invented a systemof rods which added the adjacent figurestogether and gave a direct result. Thisoperation of carrying the tens to the nextrod was performed by triangular pointers.By commencing at the top right hand cornerof the section required for multiplication,and noting the figures at each apex or pointer,the result can be read without any furthermental effort. The triangular pointers not onlyadded the adjacent figures together, but byallocating numbers up to nine to one triangle,and those above to another, the tens obtainedby the addition of the diagonals are carriedforward also. Genaille's rods are shownin Fig. r.

The rods described are entirely for use inmultiplication, and although there is a methodof using " Napier's bones " for division, it isvery indirect, and involves much troublesearching for the nearest dividend, andsubtracting, when the rods are set to therequired divisor.

There appears to be a scarcityof attempts to modify this type ofcalculator to give direct resultsfor division.

New System of RodsThe writer has developed a

system of rods which will notonly give a direct reading, butwill automatically carry on thedivision to as many places ofdecimals as required.

The rods are shown in Fig.2, and are prepared for use withdivisors up to nine.

They can be made, however,for numbers above this, but getunduly long when used in thisway for higher numbers, as thesectors have to be capable ofdealing with any number up toone less than the divisor asremainder. The use of the rodscan be extended for divisors abovenine, by resolving them intofactors, and dividing one afterthe other.

Example : To divideby 504

Using factors 9 x 8 x 7=-504421,344. - 46,81646,8

916 -

85,852

5'852 = 8367

I 2 3 4 5 6 7 8 9 0laml

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Fig 2.-A system of rods for giving a directreading.

To get the full benefit ofdivision to many decimal placesa number of rods under theheading o should be prepared.These should be placed tothe right, after the number tobe divided. By using morethan sufficient o rods, it canbe seen when the last of thedecimal figures has been com-pleted, as the lines finally leadto o and continue to do soif carried through to the nextrods. Division can thus becarried on to as many astwenty places of decimals with-out mental effort, or furtheradjustment.

For Money CalculationsThe writer has also prepared

rods on this system for moneycalculations. They have to bespecially made for shillings andpence, in order to carry forward

Fig. I (Left).-Dia-gram illustrating

Genaille's rods.

Fig. 3 (Right).-Asection of special rods /2for money calcula-

tions.

the pounds remainder in shillings, and theshillings remainder in pence.

A section of these special rods is shown inFig. 3, which is set for, the example below.

Example : If the cost is £76 8s. 9d. for adozen,what is the price each ?

Commencing at the top, left-hand cornerwith o, and passing through and followingthe line, leads to 6. Again passing through,and following the line to the shillings rod,leads to 7. Following the same processon to the pence rod is 4, and, thence to theapex of the triangular pointer is K.

The answer is, therefore, £6 7s. 41d.The rods thus described give a completion

to the system started by John Napier, andenable tedious calculations to be performedmerely by placing one rod alongside anotherand reading the result direct.

The writer wishes to acknowledge hisindebtedness to the Science Museum, SouthKensington, where he was shown many,examples of this type of calculator, and whichenabled him to apply, on these lines, theapplication direct for division.

POUNDS SHILLIAGS PENCE7 6 8 9 PARTHING4

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Inventions of InterestLight Under WaterTHE worker under water needs some

method of illuminating the submergedregion. This is particularly the case inunder -water electric arc -welding and cuttingoperations.

An inventor who has devoted his attentionto this subject remarks that it has beenfound that an ordinary electric inspectionlamp in a water tight case has only a feeblepenetrating power. And, in turbid watersuch as is produced by welding or cuttingoperations, this affords little assistance to theperson using it, partly owing to the glare.

The inventor has conceived an improvedilluminating device. This is a mercuryvapour lamp mounted in an opaque water-tight case provided with a window throughwhich a beam of light from the lamp can bedirected on to the object to be illuminated.

Preferably, the beam of light is also passedthrough an optical condenser in line with thelamp and the window. As a consequence, thebeam is concentrated and less liable to createglare by diffusion.

The condenser may be placed between thelamp and the window. Or it may besecured externally adjacent to the window.

An adjustable bracket arm may be pro-vided. This can be affixed to the case atone end and furnished at the other endwith means for attaching the arm to anobject. Such means may consist of a mag-netisable base, or a permanent magnet, so asto enable the device to be easily fixed toany position desired on ironwork below thesurface of the water, for example, on the hullof a ship.

,When a magnetisable base is employed, itmay be energised from the same source asthat supplies current to the mercuryvapour lamp.

To Prevent Car DippingANinventor has devised a method for re-

sisting dipping movements of roadvehicles, particularly those having indepen-dently sprung wheel suspensions. He pointsout that it is well known that, when thefront wheel brakes are applied on a vehicleand especially if violently applied, thereresult an overturning force acting forwardat the centre of gravity of the vehicle. Suchforce is equal to the sum of braking forcesat road level.

This force tends to lower the front of thevehicle and raise the rearward portion, pro-ducing the objectionable action known asdipping.

The new device uses the reacting forcesof the front brakes to resist the dipping ofthe forward part of the vehicle.

The brake back -plate of each front wheelis mounted in such a manner that it will turnabout the axis of the wheel axle. And alongitudinal and rearward extending arm isanchored at one end to the sprung part ofthe vehicle, and at the other end is con-nected to the brake back -plate in such a waythat this plate is prevented from turning ina vertical plane in relation to the arm.

When the brakes are applied, the reactingforce on the front brake back -plates tendsto rotate them forwardly, that is to say, inthe same direction as the wheels. Conse-quently, the forward arms tend to be raisedto press up the front of the vehicle. Andthis tendency can be arranged to balance outthe inclination to dip.

The lift, from the forward arms may bemade so as to overbalance the dipping effect.As a result, when the front brakes areapplied, the front of the vehicle will rise.

Supplies by ParachuteIN modern warfare supplies occasionally

have to be delivered from aircraft bymeans of parachutes. And difficulty is ex-perienced in locating the position of the

The information on this page is speciallysupplied to " Practical Mechanics " byMessrs. Hughes & Young, Patent Agents, of7, Stone Buildings, Lincoln's Inn, London,W.C.2, who will be pleased to send free toreaders mentioning this paper a copy of theirhandbook, " How to Patent an Invention."

packages. This is particularly the case atnight.

To assist the finding of these packages itappears to be a general practice to applylights to them. But if they fall in longgrass or growing corn, for example, theselights are not easily visible.

The object of a new invention is the pro-vision of an attachment to the packageswhich will ensure that, upon reaching theearth, a light or pennant or both are dis-posed in an elevated position, so as to bevisible above ordinary vegetation.

The inventor provides a position -markingdevice for application to parachutes or thelike comprising a tripod or a similar arrange-ment, having its legs hinged and foldableside by side to a closed position. When inthe closed position the tripod is detachablycarried by a carrier attached to the package,and also attached to the same by means of aflexible lead. There are spring means forbiasing the legs of the tripod to the openposition and a retarding device on the tripod.The latter is adapted to separate from thecarrier when the package is dropped. There-upon the tripod opens and the retardingdevice becomes effective to keep it clear ofthe parachute. On reaching the earth,

If British scientists' ideas for an atomic -powered " space ship" are fulfilled, trips to the moonin from two to five days come easily within the range of possibility. Glasgow -born industrialist,Mr. Warnett Kennedy, has designed a five-foot model of a possible space ship, as shown in theillustration, and this model is now on view at the " Britain Can Make It " exhibition at the

Victoria and Albert Museum, London.

attached to the package by the lead, one ofthe legs of the tripod will adopt an uprightposition visible from a distance.

Supple SolesAN inventor has been devoting his atten-

tion to footwear, and he' is theoriginator of an improvement in the solesof shoes. He points out that, owing toreasons of economy and the dictates offashion or other causes, there has sating upa demand for the use in the manufacture ofsoles of materials which do not possess theflexibility of leather and rubber.

V

The demand exists especially in connec-tion with footwear designed for sport andleisure. As a consequence, the soles ofsandals, beach shoes and slippers are beingmade of wood, wood composition or. corkboard.

The principal object of the new inventionis to provide soles made of stiff or hardmaterial which are so constructed as to beflexible and supple, and, consequently, tocontribute to ease in walking.

Further objects are soles which are com-fortably light and also furnished with meansintegral therewith for the securing of straps,ribbons, laces, or other means for fasteningthem to the foot of the wearer or for thepurpose of ornamentation.

Inflexibility is imparted to the new soleby a series of slots passing entirely throughthe thickness of the sole and extendingtransversely from opposite edges across amajor part of its width.

In the manufacture of soles by thismethod there may be employed rigidmaterials such as moulded plastics, hardrubber, some kinds of glass, pasteboard,vulcanized fibre, ply wood, plain wood andcork.



Transformer Bulk:MO2The Design and Construction of Small Static

MENTION should be made in passingof special cores, again more usefulin radio work, which are composed

not of sheets or stampings, but of nickel -ironalloy in powder form. This metallic powderis mixed with a suitable binding materialafter being carefully graded for size andgranular formation, and then is pressed intothe desired shape and heat treated. Theavoidance of the magnetic joints, and theadaptability of this construction to difficultshapes of core, is, of course, a valuablefeature, but it is not a process that lendsitself to amateur facilities.

Overlapping StampingsMagnetic joints in a transformer core must

be arranged so as to reduce air -gaps to anegligible amount. This is met by assemblingthe stampings in such a way that the jointsof one layer arc overlapped by the unbrokensurface of the next layer. Fig. 14 illustratesthis method. Here the succeeding odd andeven layers are seen assembled with theirjoints alternately right and left, so as to avoidany serious interference with the passageof the magnetic lines. Another point to benoted in core building is that all bolting -upstuds passing through the stampings forclamping purposes must be lightly insulatedto prevent contacting with the edges of thestampings, otherwise they will short-circuitthem and defeat the object of lamination.

Obviously, the least expensive type of coreis the one that can be built up from plainstrips without the need for special tools.These can be built up after the manner ofFig. 6, and a range of standard cores ofstandard dimensions arrived at that will coverthe requirements of most experimenters.Each core will consist of two long and two

By A. H. AVERY, A.M.I.E.E.

(Concluded front page 63, November issue.)

by the frequency of the circuit to which it -isconnected, that is the speed of the magneticflux reversals. In this, a resemblance to thebehaviour and output capacity obtainablefrom generators and motors will be traced ;their outputs also largely depend upon speed,

although in their case itis in the form of rotationof the armature instead ofoscillation of the flux.Another thing to note is

Layers that although the weightsand sizes of core specifiedare found to give satisfac-tory performances fromextended use and trial overa number of years, itdoes not follow that theyare the only possibledimensions from whichthese performances areobtainable. Larger andheavier iron cores withsmaller copper coils couldquite well be used toattain the same outputsand vice versa. But ingeneral, there is a relation -

> ship to be found betweenthe proportions of ironand copper which givebest all-round results, andwhich entail the least ex -

construction.working at a definite flux density incore of a transformer, the number

I- _Bridge-,

0

(yenLayers

Fig. 84. Showingmethod of over-lapping stampings.

pense inWhen

the iron

CoreNo.

Sectionsci. inb.Weight Watts OutputContinuous 13.ating

z5 50 too

CoreDepth in

in.

A I 13 C D cycles cycles.

I 4 21 I 7'32 I 31 35 7023

4144

28

3Ir1

932 i 1 ..

9 32 z}69

6ogo

120180

240360

II11

4 Si 34 li 1, 32 3 t5; 150 300 600 Its 6 31 2 13 32 4 22 220 440 880 2

.4

F.- a

short sides, all stampings being of the samewidth, sufficient being used to pile up to adepth equal to their width. The result is acore the limbs of which have a square cross-section when clamped up, which has theadvantage that coils of circular section, woundin the lathe, can be employed, leaving smallair spaces at the sides for ventilation (Fig. r6).The table of sizes (Table 1) will be foundvery useful for those who have limitedexperience in working out their own designs,the output capacity of each sized core beingalso stated for all ordinary commercialfrequencies, between 25 and ioo cycles.

Output ObtainableIt will be noticed that the output obtainable

from any core size in Table 8 is determined -

Table Jr. Particulars of transformer cores.

(Left) Diagram showing forms of stampings.

of turns required in either the primary orsecondary coil will depend on the cross-sectional area of the iron, and on the frequencyof the circuit. If a stalloy core has asectional area of one sq. in., for instance,and is working at a frequency of fifty cycleswith an economical flux density, eight turnsper volt would be required in either primaryor secondary coils. If the core had asectional area of two sq. in., there would betwice as many flux lines as before threadingthe coils and, therefore, only four turns pervolt would be necessary. If the frequencywere doubled to one hundred cycles, onlyone half the turns required for fifty cycles

Transformers

arc wanted ; if reduced to twenty-five cycles,twice as many turns would be needed.These facts are included in Table II, thefactor " Turns per Volt " will be foundgiven for each of the core sizes appearingin Table I for all commercial frequenciesbetween 25 and too cycles per second, andcan be applied direct to all calculations ofvoltage for either primary or secondarywindings.

Transformer Coil CalculationsFifty cycles per second is almost universal

for public services of A.C. supply nowadays,but the other frequencies mentioned werein constant use formerly, and are stillsometimes met with. These two tables -I and II -enable the core dimensions andthe turns per coil to be quickly arrived at inorder to suit any specified output. Forexample, if it is desired to select a suitablesize of core for a transformer to develop5o volts 6 amperes on the secondary output,when supplied with an input of 23o volts5o cycles, and to ascertain how many turnsof wire there must be in each of the coils,

SteelPins

Fig.

Stampings

Wood Base15. Simple jig for assembling stampings.

turn first to Table I. Find the loading inwatts by multiplying together the secondaryvolts and amperes ; this is 5o x 6-30o watts.At fifty cycles frequency, Table I showsthat core No. 4 is suitable for this rating.Next refer to Table II, and this at oncegives the turns per volt as 2.6. The primarycoil turns must, therefore, contain 23o 2.6 =598 turns, while the secondary will require50 x 2.6 -13o turns.

Gauges of Coil WindingsThe next step is to decide upon suitable

gauges of wire for the two coils, and Table IImust be consulted after first ascertaining theapproximate value of current in each coil.The secondary current is, of course, alreadyknown by the specification as 6 amperes,and to find the primary current the loading inwatts is divided by the primary volts, namely30o watts±23o =1.3 amperes approximately.As a matter of fact, the input current will beslightly greater than this, to allow for theinevitable copper and iron losses, and ato per cent. increase will safely cover therequirements in this range of small sizes,so that the figure of 1.3 becomes 1.34 0.13 -that is, 8.43 amperes for the primary current.Reference to Table III now indicates suitable

CoreNo. Turns per Volt for Various Frequencie-

'

25 cycles 33 cycles 40 cycles 50 cycles 6o cycles 83 cycles roo cycles

1 16 12 10 8 6.7 4.8 42 10.2 7.7 6.4 5.r 4.2 3.1 2.63 7 5.3 4.4 3.5 2.9 2.1 t.84 5.2 3.9 3.3 2.6 2.2 1.6 t.35 A 5 2.S z 7./ 1.2 1

Table it. Transformer coil specifications.


190

gauges of wire for each of these currentvalues, namely No. 20 for the primary andNo. 15 for the secondary.

The complete specification can now bestated as follows :

Rating. -Input : 230 volts, 5o cyclessingle phase. Output : so volts, 6 amperes,continuous rating.

Iron Core. -No. 4, Table 1. Stalloy strips.Secondary Coil. -13o turns of No. 15

S.W.G. d.c.c. copper.Primary Coil. -598 turns of No. 20 S.W.G.

d.c.c. copper.If great accuracy is required in the voltage

ratios a few additional turns should beallowed for on the secondary coil to com-pensate for drop of volts due to internalresistance when full load current is passing.Workshop Hints

In conclusion, a few workshop hints maybe useful as regards handling the variousstages in general assembly. The first stepconsists in building up three sides of theiron core, leaving the fourth side open for thetime being, so that the coils can be mountedin position before putting in the bridgepiece.The long studs used for bolting up theCorners are fixed in an upright position atappropriate centre distances in a wood base,and the stampings threaded on them inlayers, the joints coming alternately right andleft, as in Fig. 15. When the stampings havebeen piled up to the required depth, allowingfor compression, the nuts on the studs aretightened up and the partly -built U-shapedcore set aside while the coils are prepared.

Except for the very smallest coils, it isbest to use cotton covered wire, as enamelcoverings are so easily damaged by inexperthandling, and the slightest defect in thecovering may lead to internal short circuitsand a general burn -out. One circular" former " does for winding both thesecondary and the primary coils. This is afairly easy job in the lathe, the former beingshaped as in Fig. 17, the body and one flangebeing in one piece, the opposite flange beingloose, and the whole held together by a longbolt through the centre. Note the shallowgrooves running along the body, correspond-ing with saw -cuts made readily in eachflange. This enables fine string to be threadedthrough the coil and tied securely in fourplaces before removing the coil from itsformer, thus, preventing it from collapsingand losing its shape. Remember to wind thesecondary on first, following this by theprimary, placing at least two layers of to -millet theroid sheet between them as insulation.Keep the turns even and closely wound ;any turns that slip down at the ends in contact

Fig. 17. Details of the coil former.

with the lower layers will have a tendency tobreak down owing to the increasing differenceof potential which exists between layersas the coils build up.Counting Turns of Wire

The most important detail is to keep anaccurate count of the turns and the best wayto avoid mistakes is to use a " Veedercounter attached to the lathe head, whichwill indicate the exact number of revolutionsmade. When both coils have been wound,tie them securely with fine twine, removethe loose flange and slide them carefully


Fig. 16. Stampings and coil assembled, show-ing air spaces at the sides.

off the former body. A little french chalkapplied to the latter before starting facilitatesthis. The coils must be thoroughly driedin an oven to expel any moisture, and whilestill hot immersed bodily in a tin of suitableinsulating varnish. Shellac is not advised,being often acid, and special insulatingvarnishes, such as " Ohmaline," are pre -

December, 1946

highly inflammable vapour and guard againstnaked lights near it.

The final treatment consists of wrapping thecoil radially with cotton tape, half -lapped,and brushing the surface over with one or twocoats of air -drying, oil -proof varnish, such asPakyderm. "Dry " coils (that is, unvarnished)will never stand up long without trouble,but the above doping process is well repaidin making a permanent job.

Finishing and MountingThe finished coil after taping is then

ready to assemble over one of the long limbsof the iron core, which should be first wrappedwith two complete turns of to -mil leatheroid.Finally, the bridge piece can be put in andthe stampings clamped up by the studsand nuts, tapping them into line, if necessary,with a light wood mallet until flush on allsides and well squared up. Do not forgetto insulate the corner studs by wrapping oneturn of leatheroid round them as they arepushed through the holes.

S. '.G..

Diameter inInches

Safe currentin amperes

Ohmsper lb.

Yardsperlb.

Turusperlinearinch

Enamelcovering

Singlecotton

Doublecotton

14 .o8o 7.54 .082 16.7 -- II .3 10.615 .072 6./0 .140 21.2 -- 12.6 11.916 .064 4.82 .202 24.8 -- 14.0 13.//7 .056 3.69 .420 35.1 17.1 15.8 14.718 .048 2.71 .639 45-0 19.8 18.5 17.219 .040 ,.88 1.32 68.8 23.7 21.7 20.020 .036 1.52 2.01 80.o 26.1 23.8 21.721 .032 1.20 3.23 107.4 29.4 26.3 23.822 .028 0.92 5.52 129.4 33.3 29.4 26.323 .024 o.67 10.22 191.0 38.8 33.3 29.424 .022 0.57 14.48 215.3 42.1 35.4 31.225 .020 0.47 21.19 275.2 46.0 38.5 33.326 .018 0.381 32.21 340.0 50.6 41.7 35.727 .0164 0.316 46.55 410.0 55.9 44.6 37.928 .0148 0.28 0.12 0 .0 61.4 48.1 40.2

Table III. Winding tables for small transformers.

ferable. After all air bubbles have ceased torise, lift the coil out and let it drain well,then return it to the oven and bake out for

It is important that this is done before thecoil is put to work, as " wet " varnish is afrequent cause of breakdown. Rememberwhen drying out that the varnish gives off a

For mounting the finished transformer,angle iron strips can be attached to the bottomof the core to form a foot, as in the accom-

drawing of the finished job (Fig. 16).The two-way standard moulded terminalblocks make a satisfactory means of attachingthe coil ends, and at the same time providingmeans for connection to the outer circuit.

Switchboard at Wembley Stadium

This huge switch-board, like the controlpanel of a large powerstation, is the link be-tween the sellingmachines and the delicatemachines which countthe bets on every dogand combination. Thesefinely - adjusted instru-ments, which act as thenerve centre of thetotalisator, record everybet, whatever theamount, and trans-late .then into termsof two -shilling

An operator at the switchboard.

41



THE WORLD OF MODELS

A scale model of a Scotch malt whisky distillery.

SCOTCH whisky is a " commodity "which requires scarcely any introduc-tion to the peoples of the civilised

world to -day. So with Christmas loomingso near (a Christmas, let us hope, not toodevoid of good spirits in every sense ofthe word!) we start off with a picture of'a typical Scotch malt whisky distillerymodelled to the scale of loft. to tin.

The principal Scotch whisky, Highlandmalt whisky, is produced in a wide area ofScotland lying north of an imaginary linedrawn through Dundee on the east andGreenock on the west, and this model showsthe typical Highland setting of a moderndistillery. Distilling in the Highlands wasoriginally carried on as a subsidiary tofarming, but demand has increased until theproduction of whisky has superseded agricul-tural pursuits, and the barley grown ispractically all used to make Scotland's world-famous spirit.

The process of whikky distilling, whichgoes back many centuries, and usuallyoriginated from a small still at the backof a farm, is plainly depicted in the model.The farm buildings still remain at the rearof the picture, while the modern distil-lery has grown up in front and is operatedby a self-contained community. The modelshows workers' cottages, exciseman's house,and the community possesses its own .socialhall. In the background can be seen a

- .

A 241n. gauge scale model " Flying SCotsman," made by Mr. A. Hale, of West Kensington,

small lake, which which the water is drawnfor cooling purposes.

This model has been built by Bassett-Lowke, Ltd., for the Scotch Whisky

Distillers' Association, and at the presenttime they are also engaged on a much largerdetailed model showing the whole process

Seasonal Notes from "Motilus,"including Details of a ModelMarine Engine Thought to be

the Sma[lest in the World

of distilling. A model. like this to a very.large scale was shown at the 'Wembleyexhibition of 1926, and this new modelin progress should be of interest to.connoisseurs 'of both " Scotch " and the.gentle art of modelling.

A Tiny Model Marine EngineA reader from East Africa has sent me

photographs of a vertical marine engine,Which he believes to be the smallest work-ing model in the world. Built by a Scots:Tan. in Kenya, Mr. W. J. Ewing, it wasseven - months in construction, working onan average of three hours per day.

The description and overall dimensionsare as follows-: three cylinder double-acting,fitted with piston valves and Stephenson'slink motion and screw reversing gear. Thecrank shaft is built up of 13 pieces withbalance weights. There are eight bronze

Two views o' a tinymodel marine engine,built by Mr. W. 1.Ewing, in Kenya. Theillustration on the leftshows the model full

size.

main bearings with mild steel bearing caps,and the connecting rods have marine typeknuckle joints at the crosshead ends. Thebedplate is machined from solid mild steel.

The cylinder bore is 3/64in. and pistonstroke r/i6in. Steam passages are o.008in.diameter. All bolts are o.008in. diameter-not screwed, but a friction fit. The onlypart with a screwed thread is the reversinggear spindle, which is o.ot5in. diameter.

The trunk guides are silver steel and con-tinued up into the cylinder block, and actas liners. The cylinder block is made frombronze, also pistons and crossheads. Theoverall size of the engine is: length tin.,height 7/16in. and width in., and itcontains nearly zoo parts.

The engine works from compressed airobtained from a rubber bulb similar to thoseused on a scent spray. It will run fromdead slow to high speed, and is -reversible.

Mr. Ewing has now started to build a



railway locomotive to the same scale, andwill use the boiler part as a compressedair cylinder. Some of the parts alreadyfinished are a pleasure to see, especially thebogie wheels, which are made from mildsteel and only a little larger than a pin head,having spokes which can only be seenthrough a watchmaker's glass. Although.Mr. Ewing has never been a watchmaker,he uses a watchmaker's lathe for making allthe parts. These facts and photographs weresent -to me by Mr. A. J. Haris, of Nairobi,and J. shall look .forward to hearing fromthis gentleman again.

Full-sized Sectional Locomotive-Several readers have from time to time

asked if it would be possible to publish 'apicture showing the interior of a modernFrench lacornotive: Fortunately I have beenable to obtain a phbtograph of the Baltictype 4-6-4 locomotive of the Nord Railwayof France. This locomotive was speciallyproduced in section for the -Paris Exhibitionof 1937, and was very much admired byall who visited the exhibition.

The making of a model locomotive insection in this country is not very often -done, but this full-sized sectional modelmight be an incentive to those who like

Full-size sectional Baltic type 4-6-4 locomotive of the Nord railway of France.

only available recently. He had no troublein making the locomotive, working in theevenings and at week -ends. Mr. Hale wroteto me because he had previously heardthat so-called " standard " castings did notwork very well. " I have not found this

Mr. A. Daffern, Long Lane, Dalton, Huddersfield, a heavy engineering draughtsman employedby David Brown Fs' Sons (Huddersfield); Ltd., with his home-made half -inch to one foot scale modelof an R.A.F. air-sea rescue launch. C. Fitzpatrick & Co., Ltd., one of the companieswithin the David Brown group, made vee drive propulsion units for this type of craft and forM.T.B.s during the war (one of which is shown on the right of the launch), and Mr. Daffern'smodel is complete in every engine -room detail. It is 4oin. long and has a beam of 81n. and

does 3i knots.

to try fresh ventures in model construction.Models of this description are especiallyuseful for museums and technical institu-tions.

I am indebted to the Societe National desChemins de Fer Francais of Paris for per-mission to reproduce this interestingillustration.

zlin. Gauge Model LocomotiveThis zlin. gauge kin. scale "Flying

Scotsman" was made up from the Bassett-Lowke set of parts issued before the war,which soon we hope will be back " in totoon the market again. Mr. A. Hale, of WestKensington, the maker, says it took himabout eight months to build. He startedabout two years ago, and made the mainframes, tender frames and sides, but at thetime he had no lathe, so could not do muchmore. Again, when he did obtain one, hewas held up for finished parts, which were

so," he writes ; " the model runs very well,especially considering that the cylinder portsare only drilled the size stated on the draw-ing, not milled slots, owing to the lack ofa milling machine. This is only the secondloco I have made.''

Bassett-Lowke's London ShopThere has been a considerable change in

the familiar appearance of that centre ofmodels and model engineering-the Bassett-Lowke shop in High Holborn. The tre-mendous increase in the field of model work,which now embraces model aircraft andmotor -cars, petrol and compressed ignitionengines-in addition to model railways andships-has created the reed for an increasein demonstration and display room. To theoriginal shop has been added a second show-room, in which are now displayed all kindsof equipment and sets of parts for the aero-modeller and accessories for the follower ofthe newest and most exciting hobby-petrol-driven model cars. Full use is to be made ofthe increased space to show demonstrationlayouts in gauge " o " and gauge " oo" modelrailways, and the long - awaited develop-ment in scale " oo " gauge model railwayequipment will be shown to full advantage.

The double -fronted window displayenables the visitor to see an attractive displayof finished models of railways, ships, engines,aircraft, and a wide range of parts for thebuilder-these last are now reappearing inever-increasing quantities. The showroomstaff has been increased with specialists inthe new developments of the hobby, andit now only remains for the supply of goodsto gradually increase until models, like mostother things, are no longer " in shortsupply."

.......BOOKS FOR ENGINEERSBy F. J.

Screw Thread Tables, 5/-, by post 5/3.Refresher Course in Mathematics, 8/6,

by post, 9/-.Gears and Gear Cutting, 6/-, by post, 6/6.Workshop Calculations, Tables and

Formula, 6/-, by post, 6/6.

Engineer's Manual, 10/6, by post, 11/-.

Practical Mechanics' Handbook. 12/6, bypost, 13/,

Engineer's Pocket Book, 10/6, by post

CAM MWire and Wire Gauges (Vest Pocket

Book), 3/6, by post 3/9.

Screw Thread Manual, 6/-, by post 6/6.

Newnes Engineer's Reference Book,42/-, by post 43/-.

Published by

GEORGE NEWNES, LTD., TOWER HOUSE,SOUTHAMPTON STREET, STRAND, W.C..1



The "Mariner" Inboard MotorDetails of a Compact Engine for Small Cruising Yachts

THE answer to the yachtsman's plea fora small, compact power unit whichcan be tucked away in the stern of a

small yacht, or underneath the cockpit, hasbeen developed by the British Motor BoatManufacturing Co., Ltd., of Ampton Street,London, from their 4 h.p. "Mariner"inboard motor.

This motor, which gave sterling wartimeservice, is now being marketed in two designs ;a standard model for normal fixing which isstarted from behind, and a special modelwith the power head reversed so that theengine can be started and all maintenancework carried out with the engine located rightin the stern of the craft.

Since the complete engine, including fueltank, measures only Lttins. high, 14ins. wideand Itins. long, and weighs only 521b.,the value of this special model will be readilyappreciated by owners of small cruisingyachts on which space is severely limited.In its standard form, the " Mariner " isparticularly suitable for installation in launchesand dinghies.

Horizontally Opposed CylindersCompactness has been achieved by design-

ing the engine on the lines of an outboardmotor, with horizontally opposed cylinders,a vertical crankshaft, and a flywheel magnetoto which is attached a rope sheave startingpulley. The cylinders are cast in close grainednickel iron, and the pistons are of aluminiumalloy and the connecting rods of phosphorbronze. All the shafts are made of stainlesssteel with ball bearings and phosphor bronzebushes. The entire unit is, in fact, aremarkable combination of lightness anddurability.

The "Mariner" develops 4 h.p. at 3,000r.p.m., and there is a reduction of 2 to

in the bevel drive to rthe intermediate shaft.Cooling is by means 1

of a gear -type waterpump, and the silenceris efficiently water-cooled. The engine islubricated on the petrolsystem, and it has atank capacity of 51pints. It is suppliedready mounted on abedplate with waterinlet and outlet skinfittings and pipes, sothat installation issimply a question ofbolting to the enginebearers and connectingup. The shaft is atright angles to thecrankshaft and theengine can be installedto give a through driveup to an angle of todegrees, a flexible coup-ling being used ifgreater angles arenecessary.Equipment

The equipmentwhich can be suppliedwith the " Mariner "includes a loin. revers-ing propeller whichprovides neutral andreverse controls, a 5ft.length of lin. bronzeshaft with trunnionoperating gear, Ift. ofbronze stern tube, abronze stuffing box, an outboard bearing,an auxiliary silencer, and 5ft. of copper

The " Mariner " inboard motor for small launches and yachts.

exhaust pipefittings.

Letters from ReadersFilm Strip Projection

SIR, -I was very much interested in thearticle on film strip projection

published in the September issue of yourjournal, but I find that it is impossible toshow a picture for even five minutes withoutdamaging the film. The heat absorbingglass, as mentioned, is unobtainable, and soI have devised this gadget (see sketch),which I think may eliminate the trouble andso prolong the exposure without bucklingthe film.

The glass discs which prevent the filmbuckling are about 5in. diameter with a 4in.hole drilled through the centre of both, andto lessen the risk of the glass breaking itshould be annealed. The film strip is cut upinto separate pictures, and so placed betweenthe two glasses that when the disc is turnedeach picture comes into alignment with theaperture, which is the same size as the picture.The metal spindle helps to conduct some ofthe heat away from the glass. The rotatingdisc can be turned quickly backward orforward to the desired picture, and theywould hold as many as 10-20 pictureseach. The spindle should be so made that thedisc can be quickly taken off and anotherone replaced. Canada balsam can be usedfor mounting the films between the glassplates.-WM. DE'ATH (Bristol).

Neglected InventorsSIR,-I was extremely interested in your

editorial in the October issue of

2 Glass DiscsJoined TogetherWith Films Between

Aperture

Between. CondenserAnd Lens

A rotatable holder for film strips.

with all necessary

PRACTICAL MECHANICS, especially in yourcomment that " Only a few firms take thetrouble to watch Patent Office specificationsfor inventions in their own fields."

I would like to put before you a very recentexperience of mine, in this connection.There may, of course, be a good reason, butI am puzzled to know what, as I understandthat once a patent is filed it is quite secure;added to which my request was without anyreason other than learning of a new inventionof great business interest to me.

I wrote the British Patent Office abouttwo months ago requesting a copy of a certainspecification, in the belief that on paymentof a fee this would be provided.

The reply I received from the PatentOffice was as follows :

The Patent Office,25, Southampton Buildings,

London, W.C.2.September 19th, 1946.

Sir," With reference to your letter of the 14th

inst. I am directed by the Comptroller to in-form you that British patent applicationNo is not open to Public inspection underSection 91 (4) of the Patents and DesignsActs, 1907-1939, and the desired photographiccopy cannot therefore be supplied."

Perhaps this is explained in your previousparagraph that the machinery of the PatentOffice is too slow and too costly, andfurther explains the lack of interest of com-mercial firms towards new inventions.-" ENQUIRER " (Belfast).


104 NEWNES PRACTICAL MECHANICS *December, 1946

QUERIrSENQUIRIESA stamped addressed envelope, three pennystamps, and the query coupon from the currentissue, which appears on back of cover, must beenclosed with every letter containing a query.Every query and drawing which is sent mustbear the name and address of the reader.Send your queries to the Editor, PRACTICALMECHANICS, Geo. Newnes, Ltd., Tower House,

Southampton Street, Strand, London, VV..C.2.

French PolishingWOULD you please tell me how to make

" French polish," and method of usingsame ? Also, can you suggest one -or two books onthe subject ?-G. F. Aldworth (Poole).FRENCH polish is merely a solution of shellac in

methylated spirit. Success in its use depends onthe skill with which it is applied rather than on theexact composition of the polish. A full description ofthe method of french polishing would be very lengthy,but essentially the polish is applied sparingly and insuccessive stages by means of a " rubber " or a flatpad of fine cloth which is damped with the polish, andby means of which the polish is gradually worked intothe surface of the wood. In this way, a film of thepolish is gradually built up on the surface of the wood-work so that when the final coat is applied it is ableto take upon itself the perfectly smooth, homogeneousand glossy appearance which is characteristic of it.French polishing is a specific trade in itself, and skillin this art can only come after long practice.

A modern book on the finishing of woodwork of allkinds is :-H. T. Davy : Wood Finishing.

This was published in 1940 at 12s. 6d. nett. Otherpractical descriptions of french polishing are containedin practical books on cabinet-making.

We would advise you to write to Messrs. W. & G.Foyle, Ltd., Charing Cross Road, London, W.C.2,asking them to quote any books which they may haveavailable on this subject.

French polish and other shellac polishes can beobtained from Messrs. J. Beard & Co., Ltd., Manu-facturing Chemists, Great Ancoats Street, Manchester,

Manganese ResinateCOULD you answer the following two queries :

(a) What is " resinate of manganese " ?(b) In past issues I have noted that a no per cent.

solution of formalin insolubilises glue. Can youtell me if the formalin causes a chemical changein the composition of the glue ? Is there anyother agent which has the same effect on glue ?-Edward Poison (Edinburgh).

n's, Certain resin acids derived as by-products(a) from the paper -pulp and other industries canbe combined with metallic salts and oxides to formcorresponding metallic complexes or " resinates."" Manganese resinate " which you mention is one suchproduct. There are also copper, zinc, tin and 5,thermetallic resinates. Most of these, we believe, can beobtained, price about 3s. per lb., from Messrs. A.Boake, Roberts & Co., Ltd., Carpenters Road, Stratford,London, E.15, this firm being actual manufacturers.

(b) Formalin has the most powerful insolubilisingaction on glue and gelatine. Partial insolubilisation takesplace after treatment of the glue with common alum,chrome alum or sodium tungstate. The mechanismof the gelatine or glue insolubilisation is not as yetcompletely understood. Certainly a chemical changetakes place whereby the constituent " units " or atom -groups of the gelatine molecule are entirely re -arrangedin a manner which renders the product immisciblewith water, but exactly how this change is effected isnot yet clear.

" Crackle Enamel "COULD you please tell me where I can obtain

an enamel or varnish which will give onmetal a black or brown dull crystalline surface ?I believe that this type of surface coating is knownas " crackle enamel " finish, and is used forcovers on photographic apparatus, tricklechargers, H.T. eliminators, etc.-L. Booth(London, S.E.)." CRACKLE enamel " is not sold commercially.

Indeed, there is, as yet, no enamel which canbe painted on to a surface and then merely left to drywith the required wrinkled finish. The crackle effectis obtained by making -up a special varnish or enamelcontaining a substance destructive of the paint film;such as aluminium stearate. Immediately afterpainting (spraying) the articles are heated at to -D5deg. F. until the wrinkles are formed. Baking is thencontinued at 30o deg. F. for three hours to harden thefilm.

Most firms maintain the exact technique more orless secret, but there is no doubt that, by experiment,you could get the results which you seek. Make trialswith an ordinary black enamel, preferably of thecellulose type. Incorporate with it about .7i per cent.

of aluminium stearate. This material is as yet hardto 'obtain, but we believe that it is now beingmanufactured by Messrs. A. Boake, Roberts *& Co.,Ltd., Carpenters Road, Stratford, London, E.15.

Linseed Oil Emulsion ; Electrically drivenStirrer

WOULD you please supply me with informationon the following points :

(a) How can I obtain an homogeneous mixtureof linseed oil and water in proportions 4 : 96respectively ? A suitable emulsifying agentseems to be indicated.

(2) I require to make an efficient mechanicalstirrer (electric motor). Assuming the containerto be about the size of a bucket and the liquid tobe slightly more viscous than water, what horse-power would I require ? Would a sewing -machinemotor suit ?-D. Hall (Stoke-on-Trent).

Water and linseed oil are immiscible. Hence,(.1) in order to obtain a mixture of the two you willhave to resort to emulsification. It is just possiblethat you might get a suitable emulsion by shaking up4 parts of raw linseed oil with 96 parts of soapy waterin which r per cent. of glue or gelatine has beendissolved. But if this scheme does not work, youwill have to resort to one of the well-known emulsifyingagents, one of the best of which is triethanolamine.In this case, the following formula should be Mowed :

Raw Linseed oil .. .. 56 C.C.S.Oleic acid ..TriethanolamineWaterMix the triethanolamine, the oleic acid and one-half

of the oil. Then add water slowly with rapid stirringuntil a thick cream results. Finally, add the remainderof the oil and then the remainder of the water. Theresult will be a creamy emulsion which will be quitestable. It can then be diluted with water to anyrequired proportions.

We must point out that linseed oil slowly absorbsoxygen from the air, thereby becoming thicker andmore viscous. This oxygen -absorption will proceedstill more rapidly in the oil's emulsified condition.Hence linseed oil emulsions cannot be expected toremain effective for very long.

(2) Using a fairly light agitator, a sewing -machinemotor would be quite suitable for the mechanicalstirrer which you mention. For constant use, however,it would be better to use a more powerful motor, sayone of t, h.p. Such motors can be obtained from SmallElectric Motors, Ltd., Beckenham, Kent.

" Anti -freeze" SolutionT HAVE been informed that calcium chloride-1 has anti -freezing properties of high potentvalue. Can you please tell me the correct quantityto be mixed with water, per gallon, to preventfreezing in radiator of motor -car ?

Can you also tell me how long the mixtureremains potent, and if it has any deleteriouseffect on metals ?-J. Knott (Monaghan).'THE usual " anti -freeze " strength of a calcium4. chloride solution is about 5lb. of calcium chloride

dissolved in r gallon of water. Its potency remainsalmost indefinitely, but the solution is open to theobjection that it tends to attack metal.

A better anti -freeze solution can be made by dissolving15 parts of glycerine in 85 parts of water. To thisabout 5 parts of calcium chloride can be added anddissolved without appreciably affecting the metal.

Staining and Polishing a FloorTAM shOrtly taking over a new house with a large

living -room, the floor of which is boardedwith red deal, very close jointed.

AI floor covering cannot be obtained for thesurrounds I would be glad of your advice regardingan easily applied polish or stain.

The surrounds would not get much wear.-E. W. Fryer (Ormskirk).YOU do not mention the colour you wish your floor

to be. This is a very important factor. However,we presume that you wish the floorboards to have adark and enduring colour, in which case the best andsimplest method is to apply liberally to them a mixtureof equal volumes of white spirit and boiled linseed oil.If you wish to have the boards dark, mix a proportionof Drop Black pigment with the liquid. Let the boards

dry out well after treatment with this mixture. Thenpolish with beeswax.

This treatment will give a perfect floor like polishedoak and it will wear for 20 years without requiring anyfurther staining, provided that it is polished regularly.

An alternative method is to treat the floorboardswith a liberal application of hot creosote. This will beabsorbed readily and will act as a most efficient preserva-tive against dry rot and wood -boring beetles. Thesurface of the floor can then be " built up " by theformer linseed oil treatment, previous to fitsfinalpolishing.

There is no possible doubt that a first treatment withhot creosote is most effective and preservative, andthis is the treatment which we ourselves would give.Yet it is objected to by many on account of the strong,penetrating smell which lingers often for months,

Another alternative is to purchase a ready-madefloor stain -varnish and to apply this in one or two coats.This sort of treatment is not particularly preservative,and the varnish -stain wears quickly.

Rectifying Alternating CurrentTS there any way of rectifying or otherwise making-L an alternating current available for chargingbatteries when the A.C. dynamo generating theA.C. current varies in speed ? I have in mindrunning an A.C. dynamo by wind motor.-FrancisMartyn (Ballyvaughan).WHEN an ordinary alternator is driven at a variable

speed both the voltage and frequency will vary.A metal rectifier could be connected between thealternator and a battery, with a resistance in circuit tolimit the current at high speeds, or a choke coil could beused for the same purpose. The voltage absorbed bythe choke coil would be increased with increased charg-ing current, and also with increased frequency.

There may be a possibility of designing a smallalternator with a fairly high leakage magnetic flux andhigh reactance, so that the volt drop in the machineincreases considerably with the frequency. This wouldreduce the voltage variation and tend towards a stablevoltage at high speeds, although the arrangement wouldnot be highly efficient. If a separate exciter is proposedto supply the field windings this should be designed tohave as little voltage variation as possible on varyingspeed.

Filtering Dirty OilT HAVE a quantity of motor -car oil that I wish-1 to purify owing to it accidentally being mixedwith some oil that has already been used. Wouldyou plea se inform me if it is possible to clean theoil by filtration, and the best method to use?-A. Smith (Penzance).YOU do not give us an idea of the actual quantity of

oil which you require to treat. We take it, how-ever, that the quantity is not very, large, in which caseyour best plan is to heat the oil (in order to reduce itsviscosity) and then to pour it on to a bed of clean sand(or a mixture of sand and coarse charcoal) containedin a cylindrical metal vessel. The filtering bed neednot be more than 4in. thick and it will work morerapidly if it is heated so as not to cool the heated oil.This process should render the oil quite usable.

If the oil is only slightly contaminated with solidparticles, a simple filtration of the heated oil through acoarse mesh cloth will give the required result.

On the other hand, if the accidental mixture of theoil with used oil has only resulted in a darkening ofthe oil and not in the introduction of solid particlesinto the oil, no filtering will be required, and theadmixed oils can be used in the normal manner withoutany detriment to the engine.

Colouring Electric Light BulbsCOULD you please give me some information

about the colouring of electric light bulbs ?I desire to colour them red, yellow and blue forstage lighting.-C. J. Emberton (Walsall).'THE following is a suitable formula for the making-1 of a coloured lacquer for tinting electric light

bulbs :Bleached shellac .. 25 partsPowdered resin .. 8Methylated spirit .. .. 75 -too

To the above a little spirit -soluble dye is added insufficient quantity to colour it strongly. When lacquer-ing the bulbs, use the smallest possible amount ofmaterial in order to afford the maximum degree oftransparency.

MASTER

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December, 1946 NEWNES PRACTICAL MECHANICS . 105

Artificial Marble PanelsT AM interested in the manufacture of artificial

marble panels of the type mainly used forwall tiles for bathrooms and kitchens, and forbath panels.

I understand that the ingredients are : gypsumcement, lime, granite dust, and metal oxides(for colouring). Can you give me any advice onthe mix and ratio ?-G. Rogers (Southgate).'THERE are several British Patents extant on the

subject of artificial marbles, and a search throughthe Patent Office files would, no doubt, disclose toyeu information which would be of interest to you. Amore or less standard formula for this type of com-position is the following :

White Portland Cement.. .. s partQuartzite or other powdered spar .. 2Calcium stearate (or equal parts of stearic

acid melted up with slaked lime) .. 0.3The above is 'mixed intimately, and then slakedwith water to mortar consistency. The mass istrowelled into moulds, and a little earth colour (redoxide, blue, etc.) is scattered here and there on thesurface of the mass and then trowelled lightly in.

Another composition utilises as a base calcinedmagnesite, which is mixed with a suitable white fillerin about equal parts and then slaked with a solutionmade by dissolving go parts of magnesium chloride in6o parts of water, the earth colours being surfacescattered as before. Unfortunately, however, magnesiteand all magnesium compounds are at present veryscarce, so that it seems you will perforce have to relyon white cement for your base.

" Crystalline " PaintPOULD you please let me know if there is any%-4 method of making black " crystalline "paint similar to that used on photographicapparatus, or whether it is obtainable readymade 3-P. E. Smith (Bath).THE "crystalline " paint or enamel to which you

refer is produced by heat treatment. If you paintan article with ordinary hard enamel and then, when theenamel film has reached the tacky stage, you place theobject in an oven and heat it for about an hour at atemperature of to -r is deg. F., the enamel film willbe broken up so as to give the " crystal " or " crackle "effect. The object is then baked in the oven for threehours at a temperature of 30o deg. F.

By adding certain metallic soaps, such as aluminiumstearate, to the varnish (to -the extent of about 5 per cent.)the destructive action on the varnish film is greater.Even ordinary soap (sodium stearate) has an effect inthis direction. " Crackle " or " crystal " varnishes andenamels are not commercial products.

Watch Cleaning SolutionsTN cleaning a watch I understand that fourA different solutions are used, the formulaeof which I have mislaid. Two of the solutions werepetrol and carbon tetrachloride respectively, and,if I remember rightly, green soap was one of theingredients of the first bath.

Could you please enlighten me on the correctformulae for these four solutions, or any othersolutions which will clean minute watch partswith the same result ?-Glyn Huckridge (Neath).AN efficient four-fluid watch cleaner is the fol-

lowing :Fluid r.

Carbon tetrachloride or pure benzene.Fluid 2.

This is made in two sections, viz :(a) Boil 'oz. oleic acid with t quart of water.(b) Add 402. ammonia to r quart of water. Then

add 20Z. of acetone. Warm the liquid and then addit to liquid (a), which should be nearly boiling.

Stir the mixed liquids until uniform. The liquidwill have a soapy feel and appearance.

Fluid 3.Pure benzene.

Fluid 4.Pure alcohol or rectified spirit.

Iso-propyl alcohol will suffice instead of ordinaryethyl alcohol. It is very much cheaper and is obtain-able from Messrs. A. Boake, Roberts & Co., LtdCarpenters Road, Stratford, London, E.15, price about3s. 6d. per pound.

Petrol should NOT be used for watch cleaning, sinceit is liable to contain greases, oils and various otherimpurities.

The above solutions are used consecutively : I, 2, 3, 4*

Gelatine Moulds : Wood FlourT WISH to produce a replica of an ornament

made of plaster and copper -plated. Owingto the complicated design it will be necessary touse a gelatine mould. Can you give me a formulafor such a mould ? Further, can you give me thename and address of a firm who can supply woodmeal or wood flour ?-W. H. Crockett (Bungay).'TO make a gelatine mould dissolve 20 parts of cookingA gelatine in 8o parts of hot water. This will set

solid on cooling, and it can be used to take the shapeof the original design. In the gelatine mould plaster-of-paris casts can be made. Remember, that beforecasting, the inside of the mould should be treated withfrench chalk, which is brushed on and then dusted off,this treatment being followed immediately by rubbingover the inside of the chalked gelatine mould with acloth charged with paraffin -oil, in which a little paraffin -wax or candle grease has been dissolved. This treat-ment will make the interior of the mould nice and

smooth, and will greatly facilitate the separation of theset plaster from the softer gelatine.

The gelatine can be made much stiffer and harderby brushing it over with commercial formalin solutionand allowing the latter to evaporate. The formalinhas a hardening and insolubilising effect on the gelatine.

In a similar manner, a mould may be made fromordinary glue, but gelatine usually gives better moulds.

Wood flour and meal are obtainable from thefollowing firms :

Atomill, Ltd., Amber Wharf, Watt's Grove, London,E.3. Rothervale Manufacturing Co., Ltd., WoodhouseMill, nr. Sheffield. Kinghorn Mills, Ltd., Kinghorn,Fife.

If you only want a small quantity of wood flour youwill probably be able to obtain sufficient by passingfine sawdust through a fine wire mesh.

Induction Motor : Short-circuiting DeviceT HAVE purchased an American -made electric1. motor, details of which are as follows : h.p.,Ito or 220 volts ; 5 or 25 amps. ; too cycles, single-phase ; 2,000 r.p.m.

I am having trouble in running this motor asthe field gets very hot and tends to smoke after afew seconds' running on 240 volts.

There are four brushes with no actual wiredelectrical connection. The wiring to the motorfield consists of two pairs of wires, one pair ofwhich has to be closed before motor will run.Also, there is a centrifugal device in front ofthe commutator consisting of a spring -loadedslotted plate and ball -bearings, as in accompany-ing sketch.

Brass Balls (4) Spindle Cups (4) CircularSlotted_Plate

Sectional view of a short-circuiting device fitted to an inductionmotor. (K. Fountain-Letchworth.)

Could you tell me how I can run this motorwith the minimum of modification, also the useof centrifugal device and two pairs of connectingwires 3-K. Fountain (Letchworth).

YOUR machine is evidently a repulsion -starting'induction motor. It is intended to start up with

a high torque as a repulsion motor, i.e., with the statorwindings fed from the supply and the rotor windingsshort-circuited only by the electrical connectionsbetween the brushes. When the motor has acceleratedto a certain critical speed at starting, the centrifugaldevice should operate to short-circuit the whole of thecommutator segments by pressing the slotted circularplate on to the commutator, the motor then continuingto run as an induction motor with short-circuitedrotor winding.

The stator windings are evidently arranged in twosections, hence the four leads. These sections shouldbe connected in parallel if the motor is to be used on

to volts, and in series for use on 220 volts, on a too -cycle supply. On the higher voltage overheating wouldoccur if the windings were connected in parallel, or ifonly one section was connected. It should be notedthat the two sections should be connected to create thecorrect magnetic polarity; if the connections to onesection are reversed the coils will be in opposition.

In your case, the position is apparently complicatedby the fact that your voltage is actually 240 volts, not220, although this should not make a great deal ofdifference ; and by the fact that your supply ispresumably at so cycles and not too. The change offrequency will make a considerable difference : besidesreducing the speed of the motor to half its originalvalue, the motor will require a very high magnetic fluxand high magnetising current. Even with the windingscorrectly connected in series, the effect of the lowerfrequency is almost certain to render the motor un-usable. The windings really require completelyre -designing for your supply. As an alternative youcould probably use the motor with the sectionsconnected in series and fed with Ito volts through atransformer ; the speed would then be about halfnormal, as would also be the permissible loading.

Eliminating WoodwormT AM pestered with woodworms in my furniture

and have been trying to get rid of them forthe past two years with little success. I sent toMessrs. A. Boake & Co. for the copper naphthenateyou previously mentioned for adding to creosote,but they do not supply it in small quantities.Could you tell me of any other firm where I mayget a few pounds of copper naphthenate ? Willit kill woodworm and eggs if injected into holes

with a small oil -can Also, what is the best timeof year to start work on this pest 3-R. Atkinson(Bangor, Co. Down).

TF Messrs. A. Boake, Roberts & Co., Ltd., cannotA supply copper naphthenate to you at the presenttime, we do not know from where you could obtainthis material. However, you need not be at all dis-couraged. If you will exercise patience and persistenceyou will assuredly be able to eliminate the woodwormpest by the use of paraffin and creosote alone. Theonly advantage of the copper naphthenate is that itimpregnates the wood and remains there, therebyrendering the wood permanently toxic to woodworms.

Mix together so parts (by volume) of paraffin oil orwhite spirit (or even solvent naphtha) and 2 parts ofa good quality creosote oil. Stir well together and,using a brush, apply this mixture liberally to theaffected and unaffected woodwork. If possible, usethe liquid hot (by standing the jar containing it in apan of boiling water), but be careful to rememberthat the liquid is inflammable.

The adult wood beetles begin to emerge from thewoodwork during April, and they continue to do sountil August. Hence, the treatment should becommenced during April and the same treatmentshould be applied every month during this period.Repeat the same treatment next year also, and, perhaps,once or twice during the following year. You willthen have successfully eliminated the woodworm pest.

It is quite useless merely to apply the liquid to thewoodworm holes in the wood. That would be merelylocking the stable door after the horse has gone, foreach hole in the wood represents a place from whichthe adult beetle has emerged and proceeded elsewhere.

These beetles are able to flyduring the summer months.Hence, they readily infect otherfurniture.

Your best plan, by far, in abadly infected room, is to applythe paraffin -creosote mixture to

- all the woodwork in the room,that is to say, to all the furniturein the room and to all thestructural woodwork in the room,such as the floorboards, etc. Onlythen can you make absolutely surethat the room is made uninhabit-able to the pests. Turn all thefurniture upside down, and bemost liberal with the applicationof the liquid to these hiddenparts of the furniture, for it is inthese areas that the beetles mostlylay their eggs. Polished surfacesof the furniture will not beharmed by the liquid, although,of course, they will require asubsequent rubbing -up with anyordinary waxpolish.

De gummingPipesTN servicing refrigerators I sometimes come

across gas supply pipes which have a" gummy " substance coating on the inside, due,no doubt, to poor quality gas. Could you adviseme as to the best method to get rid of this guminside the pipe, say, by immersion in a solution,which would not be detrimental to brass or copperpipe ? The pipes have often many bends, and tostraighten them out and clean with a brush isquite a Job. The pipes are often short pieceswhich could be easily immersed.-J. B. Fleming(Edinburgh).

FOR small pipes which can readily be immersed ina solution, you will find nothing better for their

de -gumming than gently boiling in a solution made bydissolving to or 15 parts of caustic -soda in go or 85parts of water. A 15 minutes' gentle boiling shoulddo the job, after which the pipes should be well washedout with water.

For the larger lengths of piping, stop them up atone end and then fill them with the above warm solution,allowing the solution to remain therein for several hours.Two or three such treatments will be necessary.

Alternatively, you can use white spirit or solventnaphtha for the same purpose.

Neither of the above liquids will attack the brass orcopper pipes, but they will, of course, remove anypaint which may be present on their external parts.

MASTERING MORSEBy the Editor of PRACTICAL WIRELESS

3rd EDITION

This handbook, written with special regard for servicerequirements, will enable even the beginner rapidlyto become proficient in sending and receiving.

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BELL TRANSFORMERSThese guaranteed trans-formers work from anyA.C. Mains, giving 3, 5or 8 volts output at 1amp., operate bulb,buzzer or bell. Willsupply light in bedroomor larder, etc. PRICE71.. Post 64.

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December, 1946

Xmas Greetings fromELECTRADIX RADIOSTELEPHONES For House and Office.Constructors Parts for Your OwnSet-up.WALL TELEPHONE SETS. BracketMike, vertical or horizontal, 101-. Trans-former and Condenser for same, 51-.Magneto Bell fitted, 51-. Switch Hook andContacts, 216. Walnut Cabinet, Bin. x 6in.x 3in., fitted terminals and connections, 516.Two L.R. Watch -pattern Earphone, 81-.Hand Magneto Ringer, 101-.SET AS ABOVE 301- or 501- PER PAIR.BELLS. Large Tangent IIC bells, 6in.gong, 230 volts A.C. New condition, 42/,Circular A.C. bells, 518 volts, 616. HouseBells, battery type, 21.in. gong, 519.Magneto bells, SI-. Twin Bell Wire, 151 -per 100 yards. Bell Transformer, 230v./ 3.5.8. A.C., 716.SWITCHES. Dewar key panel type 8 -poleC.O. flush fitting, 51-. Yaxley 3 -pole 3 -way,316 ; 8 -pole 1 -way, 316. D.P.C.O. toggles,vitch 250 v. I amp., flush panel, 313.8 -way Lucas switch box, 316 ; 6 -way, 31,DIMMER RHEOSTAT SWITCHES.

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new Aetna Co., U.S.A. Price 216 each.Postage 6d.RELAYS. We have a large stock for allpurposes. Send for Relay Leaflet " P.M."and state your requirements.BUTTON MICRO-PHONES provideinteresting experi-ments for makingoutside listeners,sound transmission,etc. These ex-G.P.O.Voice Units are underI in. diam., filled carbongranules and fittedmica diaphragm, 316 each. Special Trans-former and Condenser, 51-. InstructionLeaflet with each Button. G.P.O. Mikeinsets, 316. Special armoured inset, latestpattern, 51-, useful for making a HomeBroadcaster.G.P.O. Candlestick Microphone, carboninset with switchhook for receiver, 5ft.cord, 716. Postage II-.MAGNETS. Permanent powerful flatbar, 2iin. x lin. x ;On. drilled 2 holeseach end for any pole pieces, 316 pair.The wonder midget Magnet, Alni perm.steel disc, weight only:'oz., dia.,fin. thick with 31I6in. centre hole, 316each. Large selection of horseshoe magnetsin stock. Send for Leaflet " P.M."D.C. ELECTRO MAGNETS, 2lin. x2fin. x I lin. Lift 111b. on 2 volts, 31b.on 4 volts, 416. on 6 volts, 716.VIBRATORS. Mallory 12 -volt BatteryVibrator, new, type 629c in metal can, I51-.Special Transformer, 351-.VIBRATOR CONTACTS. Thin H.F.reed, bakelite mounted, fine threadadjustment, miller locking nut, 41-.TRANSFORMERS. Double wound,230112 v., 3 amps., 32/6; 20 volts, 2 amps.,301-. Totally enclosed type for smallwelding jobs, 230 volts112 volts, 250 watts,751-. 230 v.112 volts, 100 watts, enclosed,35/-. Small bell transformers, 3-5-8 volts, 716.AUTO TRANSFORMERS. 2301110 v.,85 watts, 251- ; 150 watts, 351- ; 300 watts,601- ; 350 watts, 651- ; I k.w., £711010 ;

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December, 1946 THE CYCLIST 17

4't

Editor : F. J. CAMM

VOL. XV DECEMBER, 1946 No. 298

Comments of the Month.

All letters should be addressed tothe Editor, "THE CYCLIST,"George Newnes, Ltd., Tower House,Southampton Street, Strand, London,

W.C.2.Phone : Temple Bar 4363

Telegrams : Newnes, Rand, London

New Plans for Herne HillTHE disastrous blow to the prestige of

British cycle sport struck by our poorshowing in our first post-war events

abroad indicates that some radical change isnecessary in the control of internationalcycling sport. The joke to -day is " Join theN.C.U. and watch the foreigner's back wheel."This is not a criticism of British cyclingsportsmen. They are superior to those ofany other nation, but they must be givenopportunities to train at present denied tothem due to the attitude of the NationalCyclists Union, which endeavours to exercisea stranglehold of control, and to frown uponany attempts to modernise the sport and totake it out of the atmosphere of the eighties.

Perhaps the N.C.U. thinks it is in keepingwith the times in exercising control. It mayeven feel that it is the Government of sport.Certainly it has exercised the principle of theClosed Shop, and also certainly it is to someextent a dictatorship.

All of these things are realised by thosewho have the best interests of the sport atheart. These sincere people haveendeavoured by normal democratic meansto get these things changed. All of theirefforts have failed, and so the N.C.U. hascontributed to its own downfall by itsendeavour to regard as antagonistic criticismall suggestions which have been made forits improvement and progress. It has takenthese criticisms as a personal affront, andseems to have regarded itself as thepersonification of perfection when there isroom for improvement.

When the matter of massed -start racing,for example, was raised, the N.C.U. chairmanruled the matter out of order on a technicalpretext. All efforts on the part of somethousands of cyclists interested in cyclingsport whom the N.C.U. preferred to regardas a " dissident " body have been abortive.Finding themselves frustrated in this way,they formed the British League of RacingCyclists. The N.C.U. seems to forget thatit has bred serpents in its own bosom by itsattitude towards the end of the last century,when it threw all forms of cycle sport exceptracing on closed circuits overboard.

There is no need for us to reiterate theN.C.U. v. massed -start controversy. It issufficient to say that the N.C.U. still continuesto nail its flag to the tottering mast of tracksport. This mast badly snapped in the latterhalf of the last century, is now rotting at itsroot, and the mast tends to fall upon theheads of those who have now endeavouredto prop it up.

Herne Hill TrackHOWEVER, having eected as a bulwark

against future attacks to intensify itstrack programme, the N.C.U. has obtaineda lease of Herne Hill Track from theproprietors, Dulwich College, and last year,with a great fanfare of trumpets, it launcheda programme which failed to attract a crowdand was severely criticised by its own

adherents, not only on the score of the poorquality of the, events and the lack of manage-ment and promoting skill but also on thescore of the lack of amenities provided forthe crowds the N.C.U. hoped to attract.

Their programme for 1947 is nebulous,and those interested in this form of sportare highly dissatisfied with the way things aregoing. The possession of a lease is onething, but the successful promotion of eventson the track so leased is another, and it isthought by those best able to judge that theN.C.U. is not by its past experience the bestbody to ensure that the track is used to thebest advantage for cycling sport.

Accordingly a number of those best able todeal with the matter have prepared someproposals for future cycling promotions atHerne Hill, and these proposals take the formof a report prepared by the Committee for1947 Track Sport which will be submittedto the National Cyclists Union with a view toadoption for the 1947 season.

The N.C.U. relies upon the defeat of theseproposals upon a clause in its agreement withthe owners of Herne Hill Track which forbidssub -letting. It will depend upon the legalinterpretation of these terms as to whetherriders who are members of the NationalCyclists Union and wish to rent the track froma body which is really their officialrepresentative are inviting the N.C.U. tocommit a breach of its sub -letting clause.

We have not inspected the agreement,but we are quite prepared to advise the newcommittee that it would not be a breach ofsuch a clause if the N.C.U. allowed them topromote their own events on Herne HillTrack. Presumably the clause really meansthat the N.C.U. may not sub -let the trackto any other body.

The new Committee and its adherentswould be held in law to be corporate entitiesand really signatory to the real agreement,since as members and affiliated members ofthe N.C.U. the agreement was reached ontheir behalf, and they are therefore entitledto have the use of what is already theirs.

The N.C.U. holds a 21 years' lease on thetrack, and those behind the new proposalsfeel that the track will be a white elephantunder the present management. It is obviousthat there is no effective liaison between thevarious promoters with the following effect :

There is no centralised publicity to buildup the sport as a whole ; no organised attemptto build up a pool of young riders of thefuture; no planned economies by sharing thecost of visiting Continental riders over morethan one meeting ; no common standard ofentertainment for the public; no continuityof promotion, resulting in occasional blanks,and no carry-over of costs in the event of awet day.

CompetitionAS the promoters of the new scheme say,

if cycle racing at Herne Hill is to be puton a proper footing as a public sport with

By F.J.C.

regular gates it is obvious that it mustcompete with other attractions.

In 1946 these other attractions were butweak rivals, but as the effect of the war andits restrictions are thrown off, the competitionwill mount up.

It is understood, of course, that promotingclubs will wish to maintain their individuality,for they have kept the sport going through thelean years, and they must be allowed tocontinue not only to be prominently associatedwith races which they have built up and madefamous but also to share financially in anyprofits which might result.

Provided that every cycling organisationcurrently promoting meetings at HerneHill joins in the proposed schemes a limitedcompany will be formed to undertake thepromotion of all cycle events at Herne HillTrack. A graduated scheme of improvementwill be put into effect as fast as materials,labour and the necessary permits becomeavailable, and first priority will be given toimproving accommodation.

There would be a properly plannedseason -long programme of first-class meetings,together with a subsidiary mid -week pro-gramme of club meetings at which all LondonClubs could, free of charge, run off their clubevents.

A Veteran's BirthdayEVERYONE associated with the sport and

pastime of cycling knows the name ofE. Coles -Webb, affectionately known as" Coley " throughout the trade and pastime.Those who know his spritely step, his quickmentality, his repartee and his ability as araconteur may be surprised to know thatrecently he celebrated his 8oth birthday,and a dinner to celebrate the event wasgiven in his honour at the Waldorf Hotel,when a small cross-section of his thousandsof friends in various business and sportingspheres met to wish him many happyreturns.

Among those present were the Marquis ofDonegan, W. G. Bailey, W. G. James,R. A. West, J. Dudley Daymond, W. J. Mills,H. H. England, Rex Coley, Vic Jenner,W. Hind, A. H. Bentley, H. B. Clarke,J. A. Masters and Peter Hunter.

This veteran, in years only, managed toextinguish the 8o candles on the cake withthe proverbial one puff, and in a speechacknowledging the many gracious tributespaid to him he paid tribute to the effect onhis longevity achieved by his cycling exploits.One of the earliest record breakers, he hadraced on the old Ordinary, and prior to thathad achieved great success as a runner. Hewon an enormous number of prizes andtrophies and at the age of 73 won a BathRoad handicap. It is good that we have suchveterans as Coles -Webb who remains a linkwith the past, an adviser for the present, anda guide for the future.

Mr. F. J. Camm was in the chair.


s..

18 THE CYCLIST 'December, 1946

Is the N.C.U. Redundant?THE world's championships have come

and gone with results that I, for one,expected.

There have been the usual excuses andhard luck stories, but the fact remains thatwe have come back from Zurich empty-handed and with our prestige lower than itever was.

It would seem that the N.C.U. has decidedto make Herne Hill its home for the next fewyears ; if so, we can expect the " mixtureas before," that is, dull and uninterestingmeetings, the complete ignoring of thepublic, and the same clubby, cliquey atmo-sphere of old men infesting*the centre, and thesame sham amateurism that has prevailedfor a couple of decades or so.

In view of the fact that the Olympic gameswill be held here in 1948, what does theN.C.U. propose doing about that. It isan insult to expect crack continentals to ridein a place like Herne Hill; it's just not goodenough for them or the spectators.

What we need is a new track, and theonly way we will get it is to get rid of thepeople who are stopping us from gettingit ; that is the N.C.U. Have any of theseofficials tried to whip up any interest with thetrade ; there is more money in the cycle tradethan some people would think. Recentlyone manufacturer gave away enoughmoney (to another cause) to have builta real track with real amenities, buthe was not approached.

What we want is a track capable ofaccommodating a dozen cracks behind motorpacers at anything up to 6o m.p.h., room for40,000 spectators, all elevated over the

Bad Start

By R. L. JEFFERSON

track, and under cover, an announgerwhoknows the game inside out, plenty of publicityin the national papers, and, of course, theriders.

We have these latter according to ourcontemporaries, and all they need is a chance,so we are told. Very well, give it to them,either by waking up or getting out.

One writer in a contemporary deploresthe publicity that has been given to ourfailure in the cycling press ; he advocatescarrying on in the same old way and notbothering whether we beat the foreignerat all. His theory is that every now and thenwe will produce a Harris 'or someone who willbeat the foreigner at sprinting, and he airilydismisses the road game as not worth bother-ing about. I respect this gentleman's opinionson a lot of cycling points, but I just can'tstomach that.

By the sponsoring of specialist events runon selected courses we have developed a typeof " racing " man without parallel in theworld to -day. These men are selected torepresent us abroad on the strength of a fewso-called mass starts on enclosed circuits.To prove my point, at the so-called N.C.U.championship held recently in FinsburyPark out of nearly too starters only eightfinished ; the winner, of course, was anex-B.L.R.C. man. If, the riders are as goodas the N.C.U. say they are, what happenedto them ? Quite a lot of them crashed, sodid some of the foreigners who came overand rode at the Crystal Palace before thewar, but the foreigners got up and chased thefield, wounds or no wounds-put plainly,they had guts.

The faces of Maes, Leducq or a host ofother continentals are not pleasant to lookat finishing an event. These men are trying;is it beneath our dignity to do the same ?Men like Meredith would have riddenthrough plate glass if necessary to keep theirwheel in front ; it's that spirit we needto -day, not the wishy-washy, clubbydefeatist attitude of Doughty Street andCraven Hill.

The issue now is Whether we want to bea first-class cycling nation or a back number.Ask yourself these questions : do you thinkthe N.C.U. have the ability, brains and driveto put track cycling on the map in thiscountry ? Do you think the R.T.T.C. arelikely to produce by their methods riders whowill beat the foreigner at massed start racing ?I say no, and if you are honest you willsay the same. We must all get together andeither overhaul the N.C.U. for track events,or give our support to the B.L.R.C., a modernbody, who are in touch with modern con-ditions, and whose minds are not cloggedwith the cobwebs of 1898 and all that.

The road game is a must for the B.L.R.C. ;in no other way can we hope to competeabroad. Give them your support, join them,and if you are young enough race with them,ask for and get tougher and tougher courses ;get tougher and tougher yourself, ignore thebigots and old-fashioned " cyclists " who arecompletely out of touch with internationalcycling. Let us get our wheels-Britishwheels-in front and keep them there. Turnyour back on defeatism, and look up andover the heads of the so-called cyclingexperts who have helddecades. It's up to you, and you can do itif you want to-do you ?

TWO fatal accidents marred the first day of Nuneaton'sSafety First Week. In the first accident, a cyclist

was riding behind a lorry when a large packing casefell from the lorry and crushed him. The case caughton the bridge just as the lorry had passed the cyclist.The second accident resulted in the death of a lorrydriver upon whom the body of his lorry fell while hewas looking underneath it.

Suggests Cycle RegistrationIN the course of a talk to Wellingborough Rotary

Club, Captain R. H. D. Bolton, Chief Constableof Northamptonshire, mentioned that when the Forcewas up to strength he hoped to introduce a voluntaryregister for cycles which, he hoped, would lead to thespeedy recovery of any cycles stolen in his area. Healso pointed out that if every cyclist locked his machinewhen leaving it, the police would be saved a great dealof work.

All from JunkMR. ARTHUR BAKER, of Hough -on -the -Hill,

near Grantham, a sufferer from rheumatoidarthritis, has built himself a hand -propelled invalidchair from the remains of half -a -dozen old bicycleswhich he obtained from a nearby dump. Mr. Bakerdesigned the chair himself and built it in his back yard,using a good deal of improvisation to get the workcompleted to his liking. The chair is propelled bytwo handles in the orthodox manner and each wheelis fitted with an independent brake, and there is also abrake to hold the machine stationary while Mr. Bakergets in or out. The only part that Mr. Baker boughtwas a small front wheel, as the one he salvaged wasnot satisfactory.

Worse than War YearsMAJOR C. E. LYNCH-BLOSSE, Chief Constable

of Leicestershire, speaking at a meeting of theLeicester and County Accident Prevention Committee,referred to the " striking," figure of 213 adult cyclistsinjured in Leicester during the nine months from January1st to September 3oth this year as compared with174 during the 1945 period. A safety week for bothcity and county was organised for November, andone interesting feature was an errand boys' reliabilitytest.

ParagramsKeep It Dark !D UTLAND, England's smallest county, is still" apparently living in the 1940 invasion -scare days,or else it is desired to discourage " foreigners." Sign-posts are almost non-existent, and in a few cases wherethe posts remain they have no arms or there is just anindecipherable blur where a name was painted sometime in the dim past. The Rutland attitude may, ofcourse, be that local inhabitants know their way roundtheir tiny county, and if any outsider comes to Rutlandhe does so at his own risk.

Full HouseTHERE was a record entry of 162 riders in the

Leicestershire Road Club's open 25 -mile cyclerace on October 13th. The winner was E. James,of Birchfield C.C., in !hr. 3 min. 41 sec. with W.Whiley, Halesowen C.C., second, and W. Cassey,Leicester, coming third. The winner of the team prizewas Birchfield C.C.

Too ManyCONCERN was expressed at a meeting of Scunthorpe

Accident Prevention Committee when it wasstated that so cyclists were involved in road accidentsin the town during July, as compared with one motor-cyclist, five pedestrians, one passenger, four driversand one pillion rider. It was suggested that intensivepropaganda was needed to make the cyclists take morecare on the roads.

Mechanised Paper BoyAA DEVICE has been brought out in America for

attachment to any standard bicycle to enable apaper boy to roll the papers for each householder intoa neat bundle as he rides along. The device works offthe front wheel. The papers to be bundled are putinto a wire basket above the front wheel, and when alever is pulled the papers fall into position and arerolled and wound round five times with thin cord. Thecord is then automatically cut, and as the bundle islifted from the basket a knot is formed. The wholeoperation is completed in ten feet at whatever speedthe cycle is being ridden.

Job for the ParentsTHE Police Traffic Department at March, Cambs,

which is carrying out an inspection of the cyclesridden by local schoolchildren, states that in the majorityof schools 75 per cent. of the cycles used by the childrenhave been found defective. Bad brakes, one of themost serious defects, and one of the most easily reme-died, are found in most cases. Until children are oldenough to look after their own cycles it would seemthat the parents might use a little common sense andsee that they are kept in order.

I Worth of EnergyCHARGED at Loughborough (Leics) Police Court

with failing to obey a Halt Sign, a cyclist wroteto the Bench : " It is common knowledge that one doesnot come to a stop if there is absolutely no need, becauseextra energy is needed to start off again." The Benchmay have agreed that present-day rations do not allowmuch margm for extra energy, but all the same theyfined the ingenious cyclist Li.

Unusual OffenceVOR an unusual offence, described in the summonsIt. as "having a four -foot wooden measure in hispossession not bearing a stamp of verification," aLeicester cycle -dealer was fined Ins. by the citymagistrates. Defendant pleaded guilty, but said hewas ignorant of the law on this question.

Decorated LandmarkTHE day following the Nuremburg executions,

Caxton gibbet, a well-known and conspicuouslandmark on the old North Road, near Cambridge, wasfound to have swinging on it a life-size effigy of the lateunlamented Goering, complete with jackboots, medals,and all the trimmings. When times were less civilisedthan they are to -day, the gibbet was used to hanghighwaymen who infested the North Road.Too Much DazzleDURING the hearing of a charge of dangerous

driving at Daventry Borough Magistrates' Court,the chairman appealed to the police to take actionagainst all motorists who use headlights which dazzleother road -users. The police -superintendent agreedto do all he could, saying that private motorists werethe worst offenders, but lie pointed out that so longas the cars were fitted with devices to dim the lightsthey complied with the law, but he knew of no law toforce the drivers to use such devices.



Around the Wheelworld

Another Wisecrack"JOIN the N.C.U., and follow the foreigner'sJ back wheel.

The Official's School

THE N.C.U. is running an officials' school !Apparently you appoint the officials

first, and then train them ! The Londoncentre of the N.C.U. wishes it to be knownthat " permits " (how in keeping with thetimes !) are necessary for roller contests.Those sufficiently interested should write toS. Jones, 149, Dominic Drive, S.E.9.

The B.L.R.C. Irish Visit

ON the occasion of the visit of theAustralian, Scottish, and English

cycling teams to Ireland recently, upon theinvitation of the National Cycling Associationof Ireland, all the riders attended a receptionat the Mansion House, Dublin, on the daypreceding the race, given by the Lord 'Mayorof Dublin, Alderman John McCann, T.D.

At this reception Alderman J. McCannhanded messages of greeting to Alf Strom,Australia George Edwards, Scotland ; andJames Kin, Hon. Sec., B.L.R.C. ; eachmessage being addressed- to the respectiveLord Mayor (Edinburgh, Lord frovost) ofthe capital city of the bearer's country.

Sir Charles was keenly interested in thestory of the race, and in the photographs(autographed by the Irish Prime Minister,Eamon de Valera) taken at the MansionHouse, Dublin. Sir Charles will reply toAlderman McCann personally.

Transport of Cycles by RailTHE sign " Cycle Store Full " became a

familiar sight at stations during thewar, and the practice of using the bicyclefor transport between railway and home stillpresents problems of storage on stationpremises. We publish elsewhere a letterfrom the Chairman of the National Committeeon Cycling welcoming agreement by therailway companies to consider both thefurther provision of cycle racks and the bestmeans of transporting cycles by train.Accommodation problems are not the onlyones presented by the bicycle. In Denmark,during the war, for example, passenger trainshad to be given considerably extended stopsat stations to permit traffic to be loaded andunloaded. The number of cycles carried bythe Danish State Railways rose from 252,000in 1938-9, to 2,181,000 in 1944-5, and onJuly 3 and 4 in the latter year 3,981 cycleswere brought to Copenhagen Central Stationfor transport. On some days about fiftyspecial wagons had to be loaded with cyclesat this station alone. With cars in shortsupply and expensive, and public roadtransport vehicles liable to be increasinglysubject to restrictions on standing passengers,the present is an opportune time for railwaysin this country to tackle a problem that haspossibilities of increasing to formidabledimensions.

The Highway CodeMR. G. R. STRAUSS, Parliamentary

Secretary to the Ministry of Transport,recently broadcast a message on the NewHighway Code, which has been passed byboth Houses of Parliament and is now beingdistributed to every household in the country.

By ICARUS

The latest returns show that the number ofaccidents is decreasing, and, according toMr. Strauss, recent figures are remarkable.In September, 1939, 559 people were killed onthe roads. In September, 1945, 452 werekilled, and in September, 1946, the numberfell to 353.

Why, therefore, all this talk of carelessnesson the road ? Surely we are not attributingthe drop last year to the War Widow poster ?You know the one, which a Member ofParliament suggested should have the caption" She voted for a particular political party."

The important thing is that there has beenno drop in the number of people injured inroad accidents. Twelve people, includingthree children, are still being killed on ourroads every day, and over too seriously injured.Those statistics were given by Mr. Strauss,and I blame his Ministry and the Ministriesbefore his for this state of affairs. TheMinistry of Transport listens far too much topolice reports. It has so congested our roadsby traffic control and by lack of traffic control,paradoxical though that may sound, that itcontinues to make our roads daily moredangerous. The fact that the number of fatalaccidents has dropped is no doubt due to thecircumstances that traffic has been broughtpractically to a standstill. It does not seemto have occurred to the Ministry of Transport,nor to the traffic branch of Scotland Yardthat as more and more vehicles come on tothe roads it needs to be speeded up, notslowed down. All they do is to increase trafficdensity by means of more and more controls.

Now the Highway Code has not the forceof an Act of Parliament, but if an accidentdoes take place, and it is proved that it wasin any way due to the failure of one of theparties to obey the code, that fact will countagainst the party in any court proceedings.

Mr. Strauss went on to draw attention tothe importance of the pedestrian crossings,which, in my views, are illegal crossings, inthat no Government has the power to setaside the common right of every individualto use any part of the road on all lawfuloccasions. No Government has ever had thepower to set aside a part of the road for theexclusive use of one very privileged section ofthe public, namely, the pedestrians, who,incidentally, cannot commit any offence onthe highway except the mild offence ofobstruction concerning which less than adozen cases are brought every year.

Cyclists object to being " segregated " tocycle tracks. It seems also that pedestriansobject to using pedestrian crossings for thesame reason.

Mr. Strauss thinks that people have notyet regained the habit of using pedestriancrossings, partly because the police have notenough men to enforce the regulations. Thepolice, with all respect to Mr. Strauss,have never been able to " enforce " regula-tions ; they may bring prosecutions forbreach of them, but it is only one person inten thousand who is so prosecuted. A lawwhich needs enforcing, or which cannot beenforced, is bad law.

B.L.R.C. 1947 Programme

AT the two-day meeting of the NationalExecutive of the B.L.R.C., dates of

events to be promoted by this national bodyduring 1947 were fixed. I list them here :

Dates of Road Race Classics, 1947Brighton to Glasgow. Six Day Cycle Mara-thon. Start, Brighton, August 4th.

British Road Race Championship : June22nd. Approx. 129 miles, over a 24 -milecircuit, starting and finishing at Weston -super -Mare.

" Circuit of the Cinque Ports "-Sand-wich - .Dover - Hythe - Romney - Hastings :Possibly a Two Day Race. Whitsun BankHoliday.

Fifth Annual General Meeting : To beheld in Birmingham, January 12th, 1947.

Professional Event Organisers : Owing tcthe increasing scope and importance ofLeague road events, the time has comewhen the work entailed far exceeds thecapacity of honorary officials, and Sectionsare now empowered to grant Event OrganisersLicences to professional organisers, subjectto the approval of the Section concerned.

Official League Journal: Advance plansfor the production of a league journal weresubmitted by the hon. secretary, andauthority given to start publication at earliestpossible opportunity.

Union Cycliste Internationale : The hon.secretary was instructed to make furtherapplication to the U.C.I. for recognition asthe competent controlling body of RoadRacing in England, the application to besubmitted in time for consideration by thenext Congress of the U.C.I., to be held inLuxemburg, February, 1947.

Election of New Clubs : Shrewsbury RacingClub. Hon Sec., G. M. Hughes, " Wynn -cote," Longden Road, Shrewsbury. EastDorset Coiffeurs. Hon. Sec., D. Cutts, 14a,Station Road, Parkstone, Dorset. North LondonRacing Club. Hon. Sec., G. Stone, 63,Barclat Street, London, N.W. SedgeleyRacing Club. Hon. Sec., R. W. Woodall,87, Rosemary Crescent, Woodsotton, nr.Dudley. Petersfield Bicycle Club. Bourne-mouth Olympic Racing Club. Leyton CampWheelers.

Applications from the Strathmore C.C.(Dundee) and Scottish Road Club (BothwellHaugh) were referred to the newly formedScottish Cyclists' Union.

Statement of Policy : A new statement ofpolicy, based upon proposals circulated bythe hon. secretary, were approved. It willcontain bold and far-reaching proposalsaffecting English road sport, and will becirculated generally as soon as ready.


20 THE CYCLIST

I I

-t

WaysideThouhil;:ights

1,11111figi,,By

F. J. URRY

Fall<la,ici Palace ,

Tifeshire.The home Samossad wilted mane times byMary , queen of Seats

The Lighting ProbleinWE are in the days of the equinox and some of our

miles have to be lamp -lit. And we are stillawaiting many improvements in cycle illumination,

I saw in token form more than a yearago, and those samples have probably been furtherimproved by now. But up to the moment of writingI have not seen any great changes in the battery lamps ;and that is a pity, for with all the popularity of the,many types of dynamo, the battery lamp, front and rear,is still the most widely used and in my opinion willcontinue to be if its reliability can be improved. It isso convenient that on such ground alone it will commanda big sale always. We want from it improvement inits contacts, a little sturdier case of the non -rattle type,and, if possible, a little longer life from the batteries.If these things can be done-and on that question Iadmit my ignorance-then the battery lamp will bemy wear for the daily journey to and from work. WhenI go night riding for pleasure, it is usually the oldHolophote inch wick oil lamp that shciws me a mellowbeam ahead, a job it has been doing most winters forover 35 years, which says something for its designand construction, when a famous firm used to advertise" we make light of our labour." You can't buy itskind now, and even the good acetylene headlamp ishard to come by ; so the modern rider is rather thrownback on the dynamo if his pathway on winter nights isover unlighted roads ; and that is another reason whythe dynamo will become increasingly popular. Per-sonally, I do not like it because I always feel I'm revers-ing the slogan of the famous lamp maker quoted above ;but it seems I am a voice in the wilderness and amamong those old cyclists-a decreasing band-whoare out-modeil. I should want my dynamo very lightand very easily detachable, with the wires collectedinto a neat tube lying close along the top rail. ThenI may fall for the work of manufacturing my ownillumination.

This Needs Stern AttentionISUPPOSE we cannot expect any considerable

improvement in our catering establishments untilfood rationing is eased or cancelled. No doubt manyof our roadside hostels are taking some advantage ofthe present situation, and the promiscuous travellergets the cold shoulder far more frequently than theregular customer. Indeed, this question, will need alot of attention in the near future, for a publican holdshis licence by grace of the public exercised by thelicensing magistrates, and this hold on the individualwho is supposed to offer, us reasonable refreshmentwill require putting into force in some cases before wereturn to the status of a hospitable country. I had an'aperience of this utter indifference to the needs of alegitimate traveller at the end of July last, when ridingfrom Newport (Mon.) to Birmingham. An excellentlunch at Raglan made me feel as idle as the day waswarm, so I lounged along the beautiful road throughMonmouth and Symonds Yat to Ross, expecting topick up the refreshment of tea at the latter town. Itvas Sunday and every cafe was closed, and all the hotelspolitely informed me they had barely sufficient foodfor their guests ; so I bethought me of several wayside

pubs on the road toNewent and went overthoie switchbacks in searchof 'sustenance. But thepubs. were shut tightlyagainst wayfarers, and theproprietor of the only hotelin Newant, kept on repeat-ing the formula that " weopen at seven ; nothinguntil then " ; and I beganto feel an outcast. I hadintended to pack iron rationsin Newport but forgot allabout them, so perforce Itook the hard 'Tewkesburyroad by Corse Lawn withjust seven sweets to see meover the fourteen miles.They did the job and keptme comfortable enoughwith a strioke or two, -80no harm was done ; but theannoyance did not easilydepart from my mind and Iwondered what a' strangerin the land would havethought of our boastedBritish hospitality. Weshall have to do a lot betterthan this if we are going tosell touring.

PerforationPerformancesON that two hundred

mile journey to SouthWales I had the extra-ordinary experience ofsuffering five punctures.The tyres were nearly new(Dunlop Sprites saved upfor such a journey) and thefive perforations were asurprise, for on the averageof the years they were morethan double the number Igather in my 8,000 milesannually. All but one werein the front tyre, and two ofthem were very fine slivers ofglass which had probably

been embedded in the treadfor weeks, and happened towork through the casing withthe aid of a few miles of wet road. The others werejust slow mysteries, except one I know was a slightpinch as a result of the rough surface of the old coachroad from Elan Valley to Cwmystwyth. And, by theway, that fine old way through the hills is, or was, asrough as I ever remember it, and I've known it fairlyintimately for over forty years. Some day, and perhapsnot in the distant future, it will be redesigned and serveas a relief road to mid -Wales ; but at present thetrouble in that connection seems to be that it passesthrough three counties, and the councils thereof cannotagree as to the division of cost and subsequent upkeep.Fortunately, all these punctures were considerateones inasmuch as they allowed me to make a feedingplace and do the repairs at leisure and with the con-.venience of a water test. What I should like to .seeundertaken is a regular clearance of the broken glasson the roads. It certainly has improved, but it is stillbad, and to the workaday rider these fragments ofmilk _Potties are a constant menace to his property,and often a deterrent to good timekeeping. And nowlet me give you a tip on easy tyre removal. Years agoI ,had shaped in the works a three-inch section of oldhacksaw blade fin. wide, the ends reduced to form ascrewdriver, and the burrs taken off. It is the perfecttyre lever, for it is stiff, takes up less room than a pocket-knife, and is a handy little tool for innumerable pur-poses. I wonder such a small and useful tool has notbeen marketed.

They Are ComingAWAY back in the merry month of May, I was

informed by someone who ought to know thatgood tyres of real rubber and lively casing would beavailable in the course of the year. Up to the momentof writing I have seen no sign of them and I am anxiouslywaiting, for my little stock of pre -wars, which I boughtand had stored for me in the middle of 1941, have allbeen used except one, and a couple of repaired coverswhich may see me over a few thousand miles on a frontwheel. I have been lucky in the matter of tyres, orwise, for I've been travelling on the best of tyres allthrough the war period right up to the present moment,and folk who know the value and ease of good tyres willrealise my good fortune. How great is the differencebetween war -grade and Sprite, measured in speed orease ? I do not know and can only guess, and myguess is a couple ofmiles an hour, used in my case tomake travelling a lighter and happier progress. Iknow many riders do not believe the difference is sogreat, and also imagine the frailer cover means the riskof more punctures and far less wear. In practice Ihave not found this so'; usually, my yearly average ofpunctures is three (it has been a trifle higher these lateyears because the tyres have been run to the very endof their usefulness), while pre-war six and seventhousand miles sound wear from rear and front was 'anormal performance. And, remember, I ride somethree to four thousand miles a year over city roads,including six miles of granite setts daily. This record,for the pre-war price of 7s. 6d. a cover, was the cheapestthing connected with the running of a good -classbicycle. My tyres outwore my chains, and sometimes

December, 1946

my pedal bearings. No wonder then that I am lookingfor an early return to the open market of the open -sidedcover, to -the days when the Sprite set the fashion sosoundly in making cycling a more comfortable pastime.

A Wonderful RecordOF course, it is not surprising that we have been

waiting for the return of the first-class tyre forwell over a year, for consider this, that counting thewar years as from 1940 until the end, the manufacturingmembers of the Tyre Manufacturing ConferenCemade a total of well over 47,000,000 cycle tyres, and ,nearly the same number of all other vehicle tyres. Areport on this remarkable effort has recently beenissued under the wgis of the Conference of whomMr. H. L. Kenward is the president, and it makesmost interesting reading to anyone who has a regard forthe value and comfort of the pneumatic tyre. - It is abig switch -over to peacetime production that the tyrepeople are undertaking, and if the process is slowerthan we who are growing older quite like, I think it isunderstandable 'in the light of this recently -releasedinformation. The co-operation and co-ordination theTyre Conference practised during the war years 'should'mean, and will, I think, produce, better tyres than everfor you and me to ride.- _

Such IgnoranceON various occasions during the summer, and

autumn I staved at hotels as far apart as Pembroke-shire and Cumberland, places full of holiday folk, mostof whom had travelled by car. In some of these places.I was the only individual with a bicycle, and the mentalreaction of my fellow -hostellers to a man who preferredcycling to motoring was most curious. Firstly, theydid not believe it possible for an elderly indiyidual to'ride a couple of hundred miles in three days and enjoyevery furlong. of the journey, when he could make' thedistance in a car in one day. He must be doing it fora wager or some form of Profit ; and when I agreed tothe 'latter suggestion designating the profit as health,"observation and intimacy with the countryside and nota mere glimmer of it in passing by, they could notunderstand' the activity and pleasure implied. Cycling'was " hard, work," yet because I did not look worn-out,thinned down or stale, they wanted to know what thesecret of my apparent fitness was due to. The simplereply, cycling, could not convince them, so I trottedout all the old arguments-which, I'm' afraid' havebecome assertions on my tongue-that the cycling wayof life is the most satisfying expression of fitness andwell-being that anyone of average physical abilities,irrespective of age, can undertake. Some of themexamined my bicycle, .,remarked on its lightness, andequipment ; and it was then that the Profoundignorance of the general public-of whom they werea kind of Gallup sample-was made manifest.- It isdifficult to define this ignorance : a Cyclo gear was amystery, slightly -dropped bars awfill, light tyres a risk,and felt bars to pedals a profundity. I wish some ofthe charming people of the trade, and especially theiradvertising experts, could have listened to theseconversations, because I'm so frequently and sometimesforcibly told by them that the great G.P. know all thereis needful for them to know about" the modern bicycleand cycling.

Is It Lack of Faith?AND the reason for that is the innumerable diverse

interests that have entered the lives of men sincethe advent of cycling. There is no need to name them ;they are self-evident to anyone over 3o years of age.Cycling has not kept its " light shining before men "with a brightness comparable to all these new diversions.By making that statement I do not mean it shouldendeavour to directly compete with the new distractionsand interests of life, but that it should make known thequiet joy of its peaceful ease, its perfect freedom fromdistraction, its outlook on the country scene and,above and beyond all, its benison of health and activityright down the ringing years of life. I have proven thetruth of these values over and over again, and personallyI am as certain of them as I am sure the sun will riseto -morrow. Yet I have heard people apologise forbeing a cyclist, as if it were something to be ashamedof, as if the very -possession of a bicycle rated you as akind of social outcast, an " untouchable " ! Actually,the man who rides a bicycle is a man using himself asa man should ; he is an athlete in the subdued senseof the term if he rides for joy, and an athlete of highstanding if he races. But these national virtues of cyclingare not widely recognised ; they should be, for there isno finer tonic to life in all the gamut of games ; and Iblame, most of all, the industry of the bicycle for wantof liveliness and that alert sense of possible expansionresiding in their business. Plainly, I can see and sensethis failure, but how can a few enthusiasts hope toremedy it without the backing of the dependent trade' ?

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THE CYCLIST December, 1946

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CYCLORAMA H:ELE,

A Tiplor Dealers.

NOWthat we have the first signs of winter,

and our thoughts turn to indoor pur-suits, firesides, and we feel that the summeris past, I think it is wise to suggest to thosewho are engaged in the retail side of cycleselling that there is a very strong " salesstory " ir winter itself! Gone are the days,surely, when we regarded cycling as a sum-mer pastime only ? It is my belief thatthere is as much enjoyment to be got outof a winter ride as out of one undertakenwhen the sun shines strong in the sky, andall the land is gay and flower -strewn. Whynot capitalise this fact? Why not enlist theservices of the manufacturers from whomyou buy machines, and see if they cannothelp with the installation of a special " win-ter riding " display? Lots of points to bemade: the all-weather character of themachines you sell ; the need for tyre renewalsfor winter roads ; the healthy side of winterriding . . . that glorious tang in the air ona crisp December morning ; the beauty ofthe wintry landscape. To the live salesman,every season brings its own sales aids, andI commend this idea of capitalising winterriding to all who seek aids to the develop-ment of their businesses.

Sunday Morning Pilgrimage.IT was in Hertfordshire, but only just overI- the Middlesex border-to be exact, atElstree, that pleasant little place whichachieved immortality when the film magnatesselected it, and nearby Boreham Wood, as ascene for their picture -making. A pleasantplace still, with those old timbered housesgiving, it an air of the medieval. And thereare one or two fine old inns, notably the OldHolly Bush, which dates back over five hun-dred years ; the little " Farmer's Boy " downthe road whch leads to Aldenham lakes isgood too . . . but I did not intend to writeof inns, but of a Sunday morning pilgrimageby a band of young cyclists. I met themat the corner of the St. Albans Road, andwe fell to chatting. They had cycled fromsomewhere in the Islington -Holloway laby-rinth, and the object of their journey wasto visit a country church ; and here theywere at Elstree, and I commended them to

Ina Suimj 6mwatirclitnrme of Merrovi

chunk thio.sq. ;he 'trees .

the church there, dedicated to St. Nicholas,and a quiet and pleasant place in which toperform one's devotions on a Sunday morn-ing. Fields nearby . . . with fine blackand white Friesians grazing therein ; a well -treed countryside, with the leaves of theoaks and beeches turning to amber and gold.And, after service, if the fates be kind, thechance of a pint of ale from a pewter tankard,in an inn which maybe was dispensing hos-pitality to travellers prior even to Tudortimes.. .

The Cyclist's Ideal Road Surface.\A THIGH is it ? The smooth metalled

v road, the evenly -laid wooden block,the somewhat dazzling whitish concrete ? Iheard a heated discussion on the subjectquite recently, and after hearing it I wasreally no wiser as to the solution. I am nota road -surface expert, but I must say thatI do not greatly enjoy riding on concrete ; on

a very sunny day I have often thought thatthe glare was bad and uncomfortable. But Ishould like to hear the views of experts, forthis question of selecting the best road sur-face is highly important-and not only forthe motorist !

For Naturalists in London.TO the man really interested in wild birds,

and the wild life of the countryside, Isuppose it is always rather an exile for himto have to live in London ; in spite of theparks and lakes, he craves for the more openspaces, for the moors and thickets where hemay study his hobby. But there are com-pensations, and it behoves the naturalist tokeep his eyes open even in London itself.Surprising birds visit the city ; even the fast -disappearing native red squirrel may be seenoccasionally but a mile or two from theMetropolis, and one day in September, in apark -cum -wood quite near to Town, Iwatched a pair of goldfinches disportingthemselves on a clump of Michaelmas daisies.They are dainty, colourful little birds, andare particularly fond of the Michaelmas daisywhen it is seeding. Yes! London is morecountrified than we sometimes imagine, andall summer wood -pigeons have been cooingin a tree which is within sight and soundof a Tube station.. . .

When You Send Your Bike by Train.DID you notice that story in the news-

papers this week about the resolve ofthe railway companies to take more care ofbikes consigned by rail? We all know how,all too often, the machines are " pitched "into the guard's van, and how they getdamaged by tumbling about, and jostlingwith other goods. Now, it appears, the rail-ways have awakened to this fact, and proposeto sling bikes to the roof of the van byspecial hooks-keeping them out of harm'sway. It is a good idea . . . of course, longoverdue. But I welcome it as further evi-dence that our railways (which bore such aheavy burden during the war years) arealive to the urgent need for many improve-ments. Maybe, one day, we shall saygood-bye for ever to the traditional buffetbun!


24 THE CYCLIST December, 1946

5

"::-.....".-`1"", "4.

''. J,

My Point ':

.

of ViewBy "WAYFARER "

Grey AboundingTHE middle Sunday in October, in my part of the

world, was a perfect study in grey. The sunsteadfastly refused to shine ; the morning air waspermeated with moisture ; and the wind sat persistentlyin the north-east, which is not (to put it mildly) themost popular of the points of the compass ! Visibilitywas very restricted. But what a cycling day it was-this day of grey abounding ! I did 32 miles in themorning and brought an outsize in appetites to thedinner -table, which was actually only half that distancefrom home, by the direct route. Another 23 milesmade me more than ready for tea, and a final 21 milesin the dark carried me home in a fit mood to tacklemy supper.

It was all very pleasant. The austerity of the daykept the traffic well within bounds, and I experiencedno discomfort in this respect. As regards my fellow -cyclists, I saw a party of about zo in the morning, andencountered them again in the afternoon. At thedinner -place there were about half a dozen. At thecottage where I usually have my Sunday tea, there wasnot a single bicycle-which was most unusual. Iwondered whether I had gone to the right house !On voicing my doubts to the caterer she smiled andsaid nothing. " Stale bread all this week for you ! "I murmured. " Never mind ! " she replied. Comein ! " I opened the door of " the room," thinking tofind it empty-and there found a party of 22 ramblerstalking quietly amongst themselves. The place was notso deserted as it appeared to be I

Yes ; this day of grey abounding was a truly excellentone. How good to conquer any little reluctance toturn out in the slightly repellent conditions of themorning ; how grand to ride so many miles with suchjoy and benefit!

611111l9f010\IIYCk.Susses .

One of Ersqlondr smallest-churcler. Alm* littleIwrldirrq surrounded by treesof( the MIN road from WeltDent to Al6iston...Only the chancel rPraili ofke anginal building ik.th rqtdestroyed =hares 630,61lire,.

Heretic Viewsir.THILST I very readily acknowledge that our

railway companies have lagged behind those ofother countries in their, treatment of cycle traffic-their progress, indeed, has been backwards ; for instance,where are the buffer -mats which used to be providedfor the protection of our machines when stacked inguards' vans ?-I cannot help feeling that too muchattention may easily be given to this whole question.If my views are those of a heretic, that cannot be helped.I have always held that bicycles were made to be riddenand were not simply a form of luggage to be carriedabout the colliery in trains-at ridiculously heavy cost-receiving :there the treatment usually accorded tomilk -churns. (A case came to my notice a short timeago where a congenital idiot, dressed in a porter'suniform, had actually lifted the rear portion of a heavily -laden bicycle by means of the celluloid mudguard-to the marked disadvantage of the said mudguard !) In my view, we are thinking too much about givingour bicycles train -rides. If I lived in London-which,thanks be, I do not !-I have no doubt that my attitudewould be different, and that I would be glad to buy" home rails " to get me quickly into the country,and to enable me to miss miles and miles of suburbia.I am fortunate in living in a provincial city which it isfairly easy to quit on a bicycle, and I would thereforethink twice-perhaps three times-of using trains, saveon very special occasions. The cost is a factor forconsideration, as also is the bother of arranging one'sprogramme to catch trains, whilst I, personally, wouldbe very peeved at the waste of time if the train I wanted

were running late. As aroutine matter, I cannotsee that the game is worththe candle, as the sayinggoes.

If, however, I wereintent on touring inScotland, I would certainlygo thither (or, at least, tothe border) by train, thefolly of burdening aScottish tour with a week'sEnglish travel beingself-evident. If I weretouring in the south-westof Ireland, I might taketrain:to and from Fishguard,as I did on one occasion.On the whole, then, it isbetter to use the bicyclefor the purpose for whichit is intended-which isnot giving it rides intrains ! - falling back onpublic transport only onspecial occasions. Thatbeing so, can we expectthe railway companies togo to much expense inthe way of providingadditional facilities for us ?I hardly think so, butperhaps I am a heretic inthese matters.

Touring ExperiencesA- FRIEND who carried

out a late summertour in the West Countryreports very satisfactoryexperiences, except asregards that easiest ofall meals, tea: Nightaccommodation wasreadily obtained withoutany booking, andbreakfasts, lunches and

suppers left little to be desired, making allowances fordifficulties over supplies. But teas, on the whole, arewritten down as travesties, and this remark appliedespecially in Bath-not exactly a resort for cyclists !-where the food portion of the meal was just about onemouthful. There is no need for this ultra -skinniness,and caterers ought to have enough sense to realise thattouring cyclists, using their own power, need a lotmore sustenance than motorists. When 1, personally,have tea at a place which looks as though it wereaccustomed to providing for people who sit in cars,I make it very clear at the outset that it's a meal I want-not two or three wafers of bread and butter thatwould go into a hollow tooth (if I had one). Anotherfriend, who carried out an even later tour, also in theWest Country, tells me that the search for nightlyaccommodation proved more troublesome than heexpected. In fact, on one or two occasions he had" the wind up."

.37f,

Good HearingIT is indeed good hearing that the' standing joint

committee of the Royal] Automobile Club, theAutomobile Association and the Royal ScottishAutomobile Club has appointed a committee to securethe introduction of measures for the prevention of" dazzle " from vehicle lights. The reform is longoverdue. I presume that we are all agreed that motor-cars should be adequately lighted, but there is noreason in the world why every other road -user (includingother motorists) should be inconvenienced throughthe medium of " dazzle " and excessive lighting.Cyclists are the worst sufferers from this form ofselfishness, and we shall welcome any measures whichmay be taken to abolish a real danger in connectionwith night riding. Moreover, we cannot help remem-bering that, at one stage of the late war, when our ownlighting- arrangements were eased, something was saidas to the undesirability of our " dazzling " motorists !I hope that the committee above referred to will getdown to their task with good heart and make suchsuggestions as will speedily pqt an end to a dangerousand unpleasant state of affairs, involving the temporaryblinding of cyclists through the medium of excessivelighting.

It Broadens the MindT T has been my fortune (?) of late to ride much in

motor -cars, buses and trams, out of alliof which I havehitherto kept as much as possible. This newish phaseof life broadens the mind : it helps one to understand(though not to approve or endorse) the impatiencedisplayed by so many drivers. Some people get hotunder the collar at the thought of their to, zo or 3ohorses being restrained and obstructed by the funerealadvance of a single horse drawing a quite unimportantcart. But, so long as the position endures where theroads, paid for by all, are for the use of all, it is to bepresumed that the hurriers (with, very often, littlecause for haste) will have to put up with the annoyancesarising from the speed of non -mechanical dust -cartsand delivery vans. Modem traffic conditions some-times provide us, one and all, with an, exercise inpatience. If we can accept the position in the rightspirit, so much the better for everybody-and particu-larly for those most intimately concerned with thedelays which, for the moment. may be mostexasperating.

Their Point of ViewTHE portions which I have read of the Scottish

Council's Tourist Committee Report for 1946are quite interesting. However " fed " we may feelat hitting a patch of what we call bad weather, we must.surely agree that Scotland's " high rainfall contributesto natural beauty by preserving verdure and feedingbeautiful lochs and rivers." That remark is true ofother parts of the country, and we must all be aware-even if we admit it grudgingly-that a vet summerhas its advantages, if only in the matter of water -falls." Recently collected' facts," says the Report, " provethat our climate is not so adverse as we have been ledto believe," support for this dictum being found inthe fact that the rainfall in the 'Western Isles is as lowas it is in the Isle of Man, while the winter meantemperature is even higher than it is in the Isle ofWight. Be that as it may-and I see no reason fordoubting what are admittedly surprising statements-Ithink we may accept the Committee's submission" that historical evidence supports the conclusion thatthe weather is an integral part of the varied experienceto be offered to visitors." Varied ? Yes-variety ofthe " infinite " type, with good days jostling bad days !And I think it may be added-the remark not beingrestricted to Scotland-that the most reliable: featureof our climate is its unreliability !

Rewarding PolicyTT certainly is a remunerative policy to look over one'sA bicycle from time to' time in order to ensure thateverything is in apple-pie order. The machine as awhole should be scrutinised, with a special eye on thetyres, on which so much responsibility rests. Also, thenuts should he gone over with a spanner,- to make certainthat they are all fast, while the position of the brake -blocks in relation 'to the rims on which they operateshould be noted, and corrected, if required, I suggestthat this policy of carrying Out a periodical examinationis a rewarding one. It takes up little time-but what alet -of time it may save ! One day recently, in lookingover my No. i bicycle, I observed a tiny slit in the backrim, and that discovery sent me post-haste to my repairer,With instructions to provide a new rim forthwith. Imay be ultra -careful in such a matter as this. I am notprepared, however, to run the risk of a breakdown" miles from anywhere," with the possibility of a longwalk home and of the general inconvenience which sucha catastrophe would entail. So I " played safe,"and had the wheel rebuilt. I don't mind " livingdangerously," but not-thank you l-in this respect.

What is Truth?IT was Pilate of old who raised the question, and I do

not believe a satisfactory answer has yet beendiscovered. At the end of August a man in Surreywrote to The Times to say that ".at the present momenttyres, inner tubes, rims, etc., are unobtainable." Curious !A few days earlier, in a Shropshire village, I bought aninner tube of best quality, and could have had severalmore had I desired, while on the day the letter inquestion appeared I bought a second tube, of the samemake and quality, in Birmingham. So, where are we ?Inner tubes may be scarce : they are not "unobtainable."

Opinions DifferJUST as there is no prettiest village, and no finestJ view, and no best bicycle (though here I make acertain mental reservation !), so divergencies of opinionmust exist with regard to caterers and catering. I recallonce taking a family holiday at a Yorkshire inn where aman assured me that he and his friends had " lived likefighting -cocks." He was right-if birds of that typewere sustained on poultry which had been far too longin the septitagenarian class, on coarse butcher's meatwhose spiritual home was really a cobbler's shop, onbacon which was a fair imitation of canvas, and on cakescompacted of sawdust and lubricating oil.

I have been waiting for some time to sample a cateringestablishment of which a cycling acquaintance told me,speaking words of praise in a confidential whisper whichwas obviously intended to impress. Unfortunately, orotherwise, the place stands in an awkward position, andwhen, at long last, I was able to put my fortune to thetouch, I was turned down on the score of sheer busy-ness. " Better luck next time," and " A treat in store,"'were my thoughts as I went on my way. Before a secondopportunity occurred, however, a letter came to handfrom one of my regular correspondents, and it said,bluntly : " Whoever put this place on the list ought to beseverely reprimanded." So there you are, and we seeonce more that " one man's meat is another man'spoison." In view of this second, and up-to-date,opinion, some of my enthusiasm for sampling that.establishment has evaporated.

Priority No. IDEFORE taking a softening tyre to pieces in order2-P to find the leak, it is well to pay a little attentionto the valve. One evening recently, when I wascompleting a longish ride, I became aware that myfront tyre was dragging slightly. Thumb pressureconfirmed my suspicion that something was amiss, butI pumped up and hoped for the best. The " best "happened. A further supply of fresh air saw me rightand on the following morning I decided that I hadbetter tackle the problem-rather reluctantly, becauseit is an awful waste of time (from my point of view)messing with tyres. First I pumped the tyre very hard,feeling that, if the valve were at fault, that actionwould " put paid " to it. Then I held an egg -cup ofwater round the valve, and the series of bubbles toldme all that I wanted to know, and the " trouble " wassoon remedied. But how easy it would have been todismantle the tyre without testing the valve ! So letthe valve he Priority No. r !


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SHORTHANDDUTTON'S ONE -WEEK SHOE I'.RAND is used by over 6111.000 menand women. Accepted by Service,and examining bodies. Test Lesson3d. Write neut. P.11.. 93 GreatRussell St.. London, W.C.1.

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MR. R. BECKER,

(Dept. 7581,C9, Fleet St.,

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ELECIR IC ENGRAVERS. -Powerfulinstruments In cylindrical case, onstand with spring attachment andswitch. Suitable for dog collars, toolmarking, etc.. 4-6 volt model, price55i- ; A.C. Mains model. 200-240 volts,

postage I',TELEPHONE SETS, comprising 2

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FOIL TRICKLE CHARGING CARCELLS, parts with diagram. Output11 amps, for 6v. cells, 30.- set. For12v. sells, 32/6 set. tiv. 643 amp, set.5510.SWITCHBOARD METERS, A.C.-D.C. N.P. cases. li' dial. Any read-ings up to 0-25 volts, 0-25 amps. Price15/8 each.100.&T MOTORS, low centre, woundfield, high-speed. weight 18oz. Size5in. x Ilin. x 21n. Well made --NoRubbish. Price 241-, post paid,

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ADANA PRINTING MACHINESPrint in the odd hours with anAdana -still the most absorbing

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WANTED. " PRACTICAL MECHAN-ICS." January 1941, August 1941,December 1941, January 1942, February1942, May 1942, November 1942, March1943, November 1943, March 1944,April 1944. Write Box No. 219, c.oDawsons, 129, Cannon Street, E.C.4.

" PYE " cycle chain rivet extractor tools.2s. 6d. each retail.-Pye Stores. HookGate, Market Drayton. Post Paid.

NEW VALVES 3s. 6d. ; M C. Speaker8s. 6d. 3d. for Lists. -Lee, 49, BoothFarm Road, Birmingham, 22.

FILMS. -9.5 mim. and 16 mum. in Silentand Sound. Enormous selections. Sale,Hire or Exchange. Projectors. Cameras,Sound Conversion Parts and Cine Acces-sories. Lists 3d.-Watsonian Film Supply,78, Cox Street, Coventry'. 'Phone 4551.

WORKING Toy plans. Bucking Bronco,Paddle Steamer, Tumbling Clown. CyclingClown. Doll's Folding Pushchair andmany others at Is. 6d. each, two 2s. 9d.,three 4s.. four 5s. AL. etc.-Mech. andModel Draughting Agency, 51, WellingtonHill West, W.O.T., Bristol.

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SPARKS' DATA SHEETSProvide full constructional details.theoretical diagram, component list.and full-size black and white printsof Tested and Guaranteed Designs.

LATEST RELEASETILE TINY TWO PORTABLE. Size51 x 51 x 51 ins. Self-contained All -drybatteries. Aerial and Speaker.Med-wave. Local stations on Speakerfor " Individual Listening." Greaterrange with 'Phones. 18v. H.T.ALL -DRY 3 -VALVE PORTABLE.M.,L. Waves. Self-contained Speaker,Aerial and Batt. Size 9 x 6 x 4 ins.MIDGET 1 -VALVE PORTABLE.

-All-dry batt. M./L. waves. 9v. H.T.MIDGET 2-VALVER. All -dry batt..9v. H.T. Med. waves. Good range.A.C./D.C. MIDGET PORTABLE.ML waves. 3 -valves, plus Rect.COMPACT TWO. MIL ,Waves. (Batt.)COMPACT .`STRAIGHT"3 -SALVER. (Batt.) Med.-waves.THREE -VALVE T.R.F. SET. (Batt.)MIL waves. Good range and strength.FOUR -VALVE T.R.F. SET. (Batt.)As above but with Push-pull Output.A.C. QUALITY 2-VALVER. MILwaves. 31 watt output. A popular set.A.C. THREE-VALVER. (Pius Rect.)T.R.F. Circuit. Range and Quality.A.C. SUPERRET. 3 Valves, plusRect., S., M., and Long waves.A.C. 31 WATT AMPLIFIER.Ideal for P.C. 2 Valves, plus Rect.A.C. 8 -WATT AMPLIFIER. Neg.Feed -back, P.P. Output. 5 Valves.TWO -VALVE AMPLIFIER. (Batt.)THREE -VALVE Dlt to. P.P. Output.SUPER S.W. TWO. (Batt.)S.W. THREE -VALVE RECEIVER.T.R.F. Tuned or Untuned H.F.RADIO UNIT. Two valves for usewith A.C. or A.C.ID.C. Amplifier.A.C. L.T. CHARGER. 2 and fiv.SHOCKING COIL, Very effective.All the above 2/8 each plus stamp.

ELECTRIC GUITAR UNITS... 5,-A.C. QUALITY RADIOGRAM. De-signed for Quality rather than range.8 Watts. P.P. Output. Neg. F.B. 3/8A.C./D.C. PORTAIRLE AMPLIFIER.6-8 Watts, P.P. Output, Neg. F.T. 3/6CRYSTAL SET. MIL waves. ... 21 -NEW "UNIT" SERIES. Progressivebuilding for the. beginner. Make aOne to Four -Valve Set in easy Add-on progressive Units. Ready Shortly.Other Data Sheets available. Stampwith order or for list.

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MAKE MONEY INYOUR WORKSHOPMake and sell your own TableModel (Torch Battery operated)Cigarette, Fire and Gas Lighter.Very easily obtainable materials onlyneeded. Cost about 4/- ; sell 151.upwards. No wheels. flints or springs.nor special tools. Last 8-9 months.SET of Clear DIAGRAMS and Instruc-tions and 6 lengths of Element.

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