Page 1July 2003

July, 2003Vol. 20, No. 7

U.S.A. $3.50

R/C Soaring DigestPage 2

ABOUT RCSD

R/C Soaring Digest (RCSD) is a reader-written monthly publication for the R/C

sailplane enthusiast and has been publishedsince January, 1984. It is dedicated to sharingtechnical and educational information. Allmaterial contributed must be exclusive andoriginal and not infringe upon the copyrightsof others. It is the policy of RCSD to provideaccurate information. Please let us know ofany error that significantly affects themeaning of a story. Because we encouragenew ideas, the content of all articles, modeldesigns, press & news releases, etc., are theopinion of the author and may notnecessarily reflect those of RCSD. Weencourage anyone who wishes to obtainadditional information to contact the author.RCSD was founded by Jim Gray, lecturerand technical consultant.

RCSD should not be considered to endorseany advertised products or messagespertaining hereto. An advertising rate card isavailable for businesses, and clubs.

Feature ColumnistsBill & Bunny Kuhlman (B2),

Lee Murray, Tom Nagel, Mark Nankivil,Dave Register, Steve Savoie, Jerry Slates,

Greg Smith, Gordy Stahl

ArtworkGene Zika is the graphic artist

who designs the unique ZIKA clip art.

RCSD StaffJerry Slates - Editor/Technical EditorJudy Slates - Managing Editor, SubscriptionsLee Murray - RCSD Index/Database

(available on-line)Bill & Bunny Kuhlman - RCSD Web Masters

PayPal Coordinators

Copyright © 2003 R/C Soaring Digest.All rights reserved.

R/C Soaring Digest556 Funston Drive

Santa Rosa, CA 95407phone: (707) 578-7871

e-mail: rcsdigest@aol.comhttp://www.b2streamlines.com/RCSD.html

OTHER GOOD STUFF

19 Classified Ads - New Products 4 Schedule of Special Events

Monthly Feature Photography & Web Version of the Printed Article (where appropriate)Highlights & Mailing Status of the Current IssueAbout RCSD..................................................................................... Subscription Information...................................................Advertising Rate Card (Adobe Acrobat PDF format).............................................RCSD Feature Columnists, Reporters, and Editors....................... (E-mail/web addresses, plus general information about their areas of interest)"Getting Started in RC Soaring" ........ Getting started guide - Adobe Acrobat PDF formatLinks to Organizations, Special Interest Groups & ClubsOn-Line Articles - Great articles originally written for the printed version of RCSD......................................... "Trimming Your Sailplane for Optimum Performance" by Brian Agnew.................................................................................................. "Flys Faster" by Dr. Michael Selig.............................. "The Square-Cube Law and Scaling for RC Sailplanes" by Dr. Michael Selig.................................. "Modifying & Building the MB Raven (Parts 1-4)" by Bill & Bunny Kuhlman............................................................. "Butterfly and Moth Airbrushing Tutorial" by Joedy DruliaBookshelf Listings - A listing of recently published books of interest to aeromodelers.Complete RCSD Index, 1984-2002

RCSD ON THE WEBhttp://www.b2streamlines.com/RCSD.html

TABLE OF CONTENTS

3 "Soaring Site" ....................................................................................... Judy SlatesEditorial ....................................................................................................................... In the News.................................................................................................. World Chanpionship F3B Results...........New Model Aircraft World Record Claims, New Aeromodeling F3B World record Attempt

6 "On The Wing..." ......................................................................Bill & Bunny KuhlmanFlying Wing Design & Analysis ..................... Blackbird XC.3 Update and BW 05 02 09 Revisited

10 Event Coverage ................................................................................... Jack Mullen......................................................................... Photography by Dave Garwood, and Jack Mullen......................................................................................................................... PSS Festival 2003............................................................................ (PDF file available from the RCSD web pages.)

16 "Sloper's Resource" .............................................................................. Greg SmithSlope Flying Tips ................................................................................... Written by Russ Whitford..................................................................................................................Bernoulli and the Slope

4 Cavazos Sailplane Design9 R/C Soaring Digest

Special Interest Groups19 Eastern Soaring League (ESL)19 International Scale Soaring Assoc.19 League of Silent Flight19 Sailplane Homebuilders Association19 T.W.I.T.T.19 Vintage Sailplane Association

Advertiser Index

Events5 Last Fling of Summer - OK17 Tangerine Soaring Championships - FL18 Texas National Tournament - TX

Don't forget to check out the RCSD web pages each month.Cover photographs are always available for viewing, and

usually available for downloading, as well. Special article .pdf filesare frequently available for a limited time, and of course our webmasters update the highlights and status information of each issueas it becomes available.

Page 3July 2003

TheSoaring

Site

Back CoverPSS Festival 2003

Brian Laird’s latest design, anEPP-foam “Air Rage”

Mustang Reno racer. Afterdesigning in fiberglass for 15years, Brian applied his talentsto EPP foam, and this develop-ment led to two new kits fromLeading Edge Gliders, a P-51and a Me-109.

Photography by Dave Garwood.

PSS Festival 2003

Boeing B-29 Superfortress,designed and scratch built by

Carl Maas Jr. It has a carved bluefoam fuselage, molded enginenacelles, balsa-sheeted foamwings, and caries a model Bell X-1 rocket plane.

Photography by Dave Garwood.

In the News:

Several items of interest wereforwarded via e-mail this past

month, from Bill & Bunny Kuhlman.Making news around the world, thefirst tidbit is regarding the WorldChampionship F3B.

World Championship F3B

From D’Anne Thompson:

F3B Individual Results

1. Andreas Böhlen (SUI)2. Pasi Väisänen (SWE)3. Reinard Liese (GER)4. Martin Weberschock (GER)

17 Daryl Perkins (USA)19 Darrell Zaballos (USA)20 Michael Lachowski (USA)30 Gavin Botha (USA)

F3B Team Results

1. Switzerland2. Germany3. Sweden4. Austria5. Belgium6. USA

Check out the following sites:

USA F3B website: http://www.speakeasy.org/~gavinb/index.html

WC website: http://www.f3b-wm-2003.de/

Photo of the USA team during theopening ceremonies:http://www.f3b-wm-2003.de/pic-tures/03.08.03/Seiten/03_08_03%20-%20077_jpg.htm

New Model Aircraft WorldRecord Claims (2) - 13.08.2003

“This is a message from the FAI‘Aeromodelling Information mailinglist.

CIAM Home Page: http://www.fai.org/aeromodelling/

“FAI has received the following ClassF (Model Aircraft) record claims:

Claim number 7882 :Sub-class F3A (Aeroplane, pistonmotor)

F3: Radio controlled flight CategoryType of record : N°142: Distance in astraight line

Course/location : Cape Spear, NF(Canada) - Mannin Beach (Ireland)

Performance : 3039 kmPilot : Maynard L. HILL (USA) & TeamDate : 11.08.2003

Current record : 832.43 km (14.06.1998- Ronald C. CLEM, USA)

==

Claim number 7883 :Sub-class F3A (Aeroplane, piston

motor)F3: Radio controlled flight CategoryType of record : N°141: DurationCourse/location : Cape Spear, NF

(Canada) - Mannin Beach (Ireland)Performance : 38h 23minPilot : Maynard L. HILL (USA)Date : 11.08.2003

Current record : 33h 39mn 15s(01.10.1992 - Maynard L. HILL, USA)

“The details shown above are provi-sional. When all the evidence requiredhas been received and checked, theexact figures will be established andthe records ratified (if appropriate).”

New Aeromodelling F3B WorldRecord Attempt - 22.07.2003

“This is a message from the FAI‘Aeromodelling Information’ mailinglist.

“FAI has received the following ClassF (Aeromodels) record claim:

Claim number 7851 :Sub-class F3B (Glider)

R/C Soaring DigestPage 4

F3: Radio controlled flight CategoryType of record : N°157: Gain in alti-

tudeCourse/location : St Vincent les Forts

(France)Performance : 2068 mAeromodeller : Frédéric JACQUES

(Monaco)Date : 19.07.2003

Current record : 1950 m (11.06.82 - JackR. HINER, USA)

“The details shown above are provi-sional. When all the evidence requiredhas been received and checked, theexact figures will be established andthe record ratified (if appropriate).”

TransAtlantic Model

Note the record claim above for MaynardHill is dated the 11th. And, we received thefollowing message dated the day beforefrom Bill Kuhlman...

Per Bill Kuhlman, “TAM is aTransAtlantic Model airplane. Lastyear four attempts all ended in failure.This is #5 and the first of another fourattempts for this year, and it lookspretty good so far.”

“For more information and an up todate map of aircraft location, go to<http://tam.plannet21.com> andfollow the link for TAM 5.”

And, the message from Maynard reads:

2016 UTC - 1081 MILES!From Maynard Hill

“This is just over half the total distanceto Ireland.

“As of 1708 UTC (18.9 hours afterlaunch), TAM-5 had traveled 903 mileson course towards Ireland. The air-plane appears to be flying slower thanprojected for two reasons. 1) It seemsto be flying in a “draggy” mode withnearly full up elevator trim, and theengine is running a little slow (3800 onthe average vs. 3900 desired). 2) Ourtailwinds have been substantially lessthan were predicted when we commit-ted for the flight. The latest speednumbers say we’re traveling at about55 miles per hour. If we continue atthat rate we have yet 17.9 hours to gofor a total projected flight of 36.8 hoursfor the whole crossing.

“If the engine is running slow becauseit is lean, we probably have 38 hours offuel. But if it is running slow because itis rich, we’ll be in the drink well beforewe reach Ireland. Yet another factor isthat our weather maps here show thatwe will have still less tailwind andmore crosswind as we approachIreland. That could put the totalrequired flight time up to 40 or sohours. With a little luck, it might gothat long!

“What this message says is that ourarrival in Ireland will be somewherearound 1030 UTC (11:30 am Irelanddaylight time). We are presently at 32degrees longitude, about ten hoursaway from the 20 degree longitudeline. The estimated time after we crossthe 20 degree longitude line would beanother 10 hours.

“If you want me to give you my bet,I’d say the odds are 50 percent thatwe’ll make it. But if you want me tosay absolutely we’ll make it, I willquote the famous lines of AbrahamLincoln to General Joe Hooker whenHooker bragged about how he wasgoing to annihilate General Lee andthe Confederate Army atFredericksburg during the winter of1863. Lincoln wrote him to say I ampleased with your confidence and wishyou well. But back in Illinois, we had asaying the hen doesn’t cluck until shelays the egg. I hope we all get to cluckon Monday morning.”

Successful Landing

And, the next message spelled out theirsuccess!

“TAM 5 successfully landed within 35ft. of designated spot in Clifden Co.Galway Ireland after 1888 mile flightfrom Cape Spear, Newfoundland,duplicating Alcock and Brown 1919Vickers Vimy Flight. Another Brown -Dave Broun landed it.

“See http://tam.plannet21.com/

From John O’Sullivan, Nova ScotiaWind and Wave Modelshttp://www.windandwavemodels.com

So, in the news this month, some excitingnews, indeed! Our best to all!

Happy Flying!Judy Slates

SPRIN G TIM

E!

ZIKA

SCHEDULE OF SPECIALEVENTS

September 20-21, 2003Last Fling of Summer Broken Arrow, OKDave Register, (918) 335-2918regdave@aol.com

October 10-12, 2003Texas National Tournament (TNT) Dallas, TXwww.SLNT.org

October 17-19, 20032003 Electric Soaring Moriarty, NMWorld Challengewww.soarabq.org

November 29-30, 2003Tangerine Soaring Orlando, FL Championshipswww.orlandobuzzards.org

Please send in yourscheduled 2003 events

as they become available!

Page 5July 2003

R/C Soaring DigestPage 6

bsquared@appleisp.nethttp://www.b2streamlines.com

Blackbird XC.3 Updateand BW 05 02 09 Revisited

A couple of related topics this month. First,an update on our Blackbird XC, then somenotable improvements to the BW 05 02 09

airfoil, including added coordinate points,which was used on this latest Blackbirdrendition.

Blackbird XC.3 update

Afew days after the second installment of the Blackbird XC.3 series

was submitted for publication in RCSoaring Digest, we had the opportunityto fly the aircraft again and we wereable to make the minor changes weoutlined at the end of the originalarticle series.

Since then, a large number of flightshave been put on the airframe, andmore than a dozen Seattle Area

Soaring Societymembers have hadturns at the controls.The aircraft is incred-ibly stable in the air,and a number of pilotshave stated it respondsvery much like atrainer.

The 2.5% static marginhas not been changed.The aircraft reactsactively to controlinput, but elevatorcontrol is not in anyway overly sensitive.Additionally, there isno “nodding” duringsustained straight andlevel flight. Thisindicates the aircraftpitching moment andcenter of gravity arewell coordinated.

The tow hook has beenmoved back to a pointa quarter inch in frontof the CG. This gives agood steep climbwithout any tendencyto pop off or wanderon tow.

The zoom off launch isstrong enough thatwe’ve had to replacethe main wing rod - 3/8” drill rod - with thesame diameter hard-

ened steel. The replacement rod hassurvived powerful launches with noresidual bending in evidence.

We finally settled on a flap-to-elevatormix of 75%. This setting thoroughlyinhibits any pitch change as the flapsare deflected or retracted. Putting theflaps down 45 degrees noticeablyslows the aircraft, steepens the glideangle, and dramatically improvessteadiness in both pitch and yaw whenflying through turbulent air. Theavailable down elevator deflectionwhich remains, although small, issufficient to maintain full controlduring landing approaches.

Page 7July 2003

As is common with this design, youcan take advantage of small bubbles oflift by flying straight through them.The nose rises as the aircraft climbs.Once you see the climb slowing, atouch of down elevator brings it backto level flight at the higher altitude. Ifsubstantial lift is found, the BlackbirdXC can be banked steeply and broughtaround quickly to center the thermal.

The Blackbird XC is truly a joy to fly, asentiment shared by an increasingnumber of SASS members.

BW 05 02 09 revisited

We first learned of the BW 05 02 09section when we found it as an alterna-tive airfoil on the plans for Dave JonesRaven S. We scanned the best of theoutlines, then used the coordinatecreation function of Gregory Payne’sFoil 1.2 to obtain the basic coordinatetable. We’ve now used the airfoil on anumber of aircraft with chord lengthsranging from five to 27 inches andhave found its performance to bedownright exceptional. The pitchingmoment is less than that of the CJ-25209, and it is definitely more “slip-pery,” both of which are gross im-provements. As we’re going to use theBW 05 02 09 on another project, wedecided to take a look at how smooththe contour of our plotted sections hadturned out to be.

We now use Dave Johnson’s MacFoil1.5 for all of our airfoil plotting.MacFoil does not use a spline tosmooth the contour but rather drawsstraight lines between coordinatepoints. This is OK for most model usewhere the chord is usually less thanten inches, but blow up the chord to 27inches, as we did for the Blackbird XCwe just finished, and you begin to seesome minor but obvious variations.This is particularly true given thelimited number of coordinates we’vebeen using. In addition to smoothingthe contour, another goal was toincrease the number of coordinates forMacFoil to use during the plottingprocess.

We took our original BW 05 02 09coordinates and plotted a 100 inch

chord on our Sony 21 inch flat screendisplay using MacFoil 1.5. We lookedat the “jaggies” on the screen andmade adjustments to a couple of thepoints so the step increments appearedbetter proportioned.

Once everything looked good on thescreen, we printed the 100 inch sectionon paper — eighteen sheets of legalsize bond. Using ships curves and anoblique viewing angle down the lengthof the chord, we refined the existingpoints and took measurements using adecimal ruler. We also decided whereadditional points were needed andwrote down rough ordinates for each.

From there we began adding pointsbetween the previously establishedpoints within the coordinate table,adjusting the Y ordinates until theairfoil segment looked good on thelarge monitor.

We then used MacFoil to increase thecamber by a factor of ten and the airfoilthickness by a factor of five. Thisaccentuated very small differences sothat any irregularities could be easilyseen. Smoothing this contour consistedof fine tuning the ordinates of just afew of the added points.

The next step was to remove thecamber entirely and make sure thethickness distribution looked smooth.A bit more tweaking was found to benecessary. By alternately increasingand decreasing the camber and thick-ness, we eventually had a shape whichlooked smooth across both the upperand lower surfaces. Camber percent-ages ranged from zero to 50, thicknesspercentages from zero to 100, andlengths up to 200 inches.

Overlaying the new profile over theold showed a few very small differ-ences, but nothing of great signifi-cance. In fact the variations betweenthe original and modified sections atten inch chord length are probablysmaller than variations in contourwhen using an X-Acto blade and ametal template. The added pointsprovide a more defined surface.

Once completely satisfied with the

modifications, we took the EH 1/9airfoil which we know to be smoothand changed its thickness and camberto match that of the BW 05 02 09,plotted it at 200 inch chord on themonitor, and then overlaid theBW 05 02 09. With the smooth contourof the modified EH 1/9 as the back-ground, the red BW 05 02 09 profilelooked very good indeed.

The differences between the twosections, EH 1/9 and BW 05 02 09,when adjusted for the same percentthickness and camber, are noteworthy:The BW 05 02 09 has a sharper leadingedge back to the area of the high pointat 30% chord. This applies to both theupper and lower surfaces. The maxi-mum thickness point of theBW 05 02 09 is about two percentfurther aft than that of the EH 1/9. Theupper surfaces aft of 60% chord matchfairly well. The trailing edge of theBW 05 02 09 is thicker. This is espe-cially desirous if you’re constructingthe trailing edge with wood sheeting.Because of the greater camber linereflex, the lower surface is muchdeeper.

The coordinate table for the enhancedBW 05 02 09 is included here. As statedpreviously, this section is extremelyclose to that used on several of ourown aircraft with excellent results.This coordinate table is also availableas a downloadable file at our web site:<http://www.b2streamlines.com/BW050209.txt>.

To assure a smooth surface contour, afellow member of the nurflugel e-maillist, Andre L. Martins, ran our ex-panded coordinate table throughXFoil. The XFoil smoothing processuses inverse design; that is, it smoothsthe pressure distribution and thenderives a “new,” practically identicalairfoil, using the smoothed pressuredistribution. As a bonus, the numberof coordinates was increased to 200.

Full geometry similarity was nottransferred to the smoothed airfoil. Thesmoothed section ended up with aslightly greater thickness (from 9.15%to 9.34%) and slightly less camber(from 2.14% to 1.93%). The main

R/C Soaring DigestPage 8

BW

05 0

2 0

9 - B

W 0

5 0

2 0

9 sm

oothed

BW

05 0

2 0

9 - E

H 2

.0/9

.0

Page 9July 2003

contour differences between the twosections are a larger leading edgeradius and a significantly deeper lowersurface beginning at the leading edgebut tapering in magnitude to thetrailing edge. The effective aerody-namic differences appear to be negli-gible. The zero lift angle and pitchingmoment depend on the Reynoldsnumber, but for a tentative value of Re= 0.3 million (300K), the smoothedsection zero-lift angle is -0.33 degreesand the pitching moment is 0.014. Thiscompares favorably with our numbersfor the original Foil 1.2 derived sectionzero lift angle of -0.15 degrees and apitching moment of 0.018.

Coordinates for the smoothed versionare available for download at <http://www.b2streamlines.com/BW050209sm.txt>. Additionally, a fivepage PDF document showing thebefore and after pressure distributionscan be downloaded from <http://www.b2streamlines.com/BW050209.pdf>.

R/C Soaring Digest556 Funston Drive

Santa Rosa, CA 95407

e-mail: RCSDigest@aol.comhttp://www.b2streamlines.com/RCSD.html

A MONTHLY LOOK INTO THE WORLD OF SAILPLANE ENTHUSIASTS EVERYWHERE

R/C Soaring Digest Subscription Form

R/C Soaring Digest (RCSD) is a reader-written monthly publication for theR/C sailplane enthusiast. Published since 1984, RCSD is dedicated to thesharing of technical and educational information related to R/C soaring.

RCSD encourages new ideas, thereby creating a forum where modelers canexchange concepts and share findings, from theory to practical application.Article topics include design and construction of RC sailplanes, kit reviews,airfoil data, sources of hard to find items, and discussions of various flyingtechniques, to name just a few. Photos and illustrations are always inabundance.

There are RCSD subscribers worldwide.

USA: $30 First Class (CA res., please add $2.25 tax.)Canada & Mexico: $30 AirEurope/U.K.: $45 AirAsia/Africa/Pacific/Middle East: $52 Air

Check or Money Order, only, please. U.S. funds.

Name_________________________________________Address___________________________________________________________________________________________________________________________________

Our thanks to Andre for the XFoilsmoothing. Anyone using either ourenhanced version or the XFoilsmoothed version of the BW 05 02 09 isencouraged to share their experienceswith other RCSD readers.

Suggestions for future columns mayalways be sent to us at either P.O. Box975, Olalla WA 98359-0975 or<bsquared@b2streamlines.com>.__________

References:

Drela, Mark. XFoil. <http://raphael.mit.edu/xfoil/> (There areseveral versions of XFoil available forvarious Windows systems. Accordingto some members of the XFoil e-maillist, it’s possible to run XFoil on an OSX Macintosh. We’re trying to trackdown a version which will work withOS 9.2 and earlier.)

Johnson, Dave. MacFoil 1.5. <http://dogrocket.home.mindspring.com/

GONE SOARIN’Zika

macfoil.html> (MacFoil 1.5 will run onany Mac using OS 8.6 and greater.MacFoil v1.0b3 works onolder Macs using System 7 and OS 8.1.)

Payne, Gregory. Foil 1.2. (GregoryPayne’s personal web page with a linkto Foil 1.2 has been down for sometime. We do, however, maintain Foil1.2 as a downloadable file on our website. <http://www.b2streamlines.com/Foil12.sit.hqx>)

n

R/C Soaring DigestPage 10

Bell X-1 rocket plane, built by Carl Maas Sr.a model of “Glamorous Glennis” the plane

in which Chuck Yeager broke the soundbarrier. Built from carved EPP-foam and

released from Carl Maas Jr.’s B-29.

Patton Aircraft EPP-foam P-51 Mustang. Steve Patton is known forthinning the wings for reduced drag and increased speed. His

slope planes are kitted by Patton Aircraft.

The Bell X-1 rocket plane enjoys its free rideto altitude nestled in the belly of the B-29

mothership. Photo by Jack Mullen

By Jack MullenRialto, California

Photography byDave Garwood

& Jack Mullen (as noted)

The Inland Slope Rebels (ISR) heldtheir 6th annual Spring PSS Festival

May 23-25, 2003 at SouthernCalifornia’s Cajon Summit. The PSSFestival, held over the Memorial Dayweekend, attracted more than 50pilots, some from as far away asHawaii and New York, looking forgood wind and pleasant weather.

They weren’t disappointed. In the 5previous years that the ISR havehosted the Festival, they have neverhad to postpone due to lack of wind,and this year was no exception. Plentyof lift all weekend allowed the pilots tomake impressive flights with a collec-tion of planes that numbered into thehundreds. Excellent weather sawshorts worn by many and a slight

PSS Festival 2003

Page 11July 2003

(L) Brian Koester’s Sukhoi Su-35Super Flanker, his own scratch builtdesign. Brian turned to designing

his own Su-35 when he wasunsatisfied with the flight

performance of a commerciallyavailable kit. It’s interesting to seethis unfinished third prototype in

the air, a tribute to Brian’s tenacity.The plane flew very well.

Jack Cooper’s huge EPP SR-71Blackbird takes flight for the first

time. Photo by Jack Mullen.

Steve Greenfield’s new “MonsterTigershark.” A 60-inch span slope jet

carved from EPP-foam, this plane flies verywell and will be made available as a kit by

California Sailplanes.

Jeff Fukushima flew a prototype 33-inchspan Curtiss P-40 Warhawk, with moldedfuselage painted in the mold. Jeff kits the

Mini Warhawk along with a Mini Zero, andyou can order either slope or electric power

versions from Vortech Models.

afternoon cooling added to our com-fort, making a sweatshirt or wind-breaker a welcome, but not necessary,addition.

Power Scale Soaring (PSS) sailplanes,for those unfamiliar, are slope glidersmodeled after full-size power planes.A wide range of planes are available tobe modeled, from military bombersand fighters to civilian passenger jetsand props. World War II fighters arevery popular with the PSS crowd sincethe large wing planforms of the daywork well when used as a slope glider.

Cajon Summit is situated about anhour east of Los Angeles in the SanBernardino National Forest. Duringthe summer months, daily heating ofthe High Desert north of San Bernar-dino causes an on-shore flow in theafternoon that draws cooler air fromthe ocean towards the desert. Thatwind, funneled through the Cajon Passon its way to the desert, gives CajonSummit its normally abundant windthat can usually be counted on to keepthe PSS Festival from being a bust.

With the Cajon flying site overlookingthe pass along a large ridge line, thereare multiple locations that are slopablewith the incoming wind. As in yearspast, the Rebels set up two separateflight locations so that they couldseparate the planes into two groups.By separating the planes into slow andfast groups, having a ballistic slopesled ripping huge half-pipes through agroup of slower planes was prevented.At times, between the two locations,nearly twenty planes were ripping

R/C Soaring DigestPage 12

Jack Cooper’s Patriot, a combat-rated EPP-foam plane that flys exceedingly well. Jackkits several advanced EPP-foam planes at

Leading Edge Gliders, including BrianLaird’s new designs in EPP-foam, the

Mustang and the Me-109.

Brian Koester ’s flies a Sukhoi Su-35 Super Flanker, his own scratch built design.Joe Chovan works behind the camera.

Cajon Summit 2003 Winners

Expert Class:1st Carl Maas / Messerschmitt Me-109, Cavazos Sailplane Design Kit2nd Brian Laird / Me-262 Stormbird, Scratch built3rd Jeff Fukushima / F9F Panther, Vortech Models Kit

Best Foam:1st Ren DiLeo / Messerschmitt Me-109, Scratch built2nd Jack Cooper / Lockheed SR-71 Blackbird, Scratch built3rd Brian Koester / Sukhoi Su-35 Super Flanker, Scratch built4th Jack Mullen / Bell X-1 FSW variation, Scratch built5th Rick Schwemmer / P-51 Mustang, Leading Edge Gliders Kit

Best Prop:1st Jeff Fukushima / F4U Corsair, Vortech Models Kit2nd Jeff Vosburg / Me-109, Scratch built3rd Tim Neja / Kawasaki Ki-61, Dave’s Aircraft Works Kit4th John Beaver / Corsair, Scratch built5th Tony Matyi / F6F Hellcat, Cavazos Sailplane Kit

Best Jet:1st Dan Sampson / Aeromachi MB339, Scratch built2nd Mitch Schwartzburg / F-20 Tigershark, Cavazos Sailplane Kit3rd Thomas Fowler / F-20 Tigershark, Cavazos Sailplane Kit4th David Cairns / Boeing B-52 Superfortress, Scratch built5th Steve Greenfield / F-20 Tigershark, Canterbury Sailplane Kit

Best Civilian:1st Jeff Vosburg / Yak racer “Mr. Awesome”, Scratch built2nd Tim Neja / Bell P-63 racer, Cavazos Sailplane Kit3rd Dan Schramm / Gulfstream Jet, Scratch built4th Thor Nordstrom / Beechcraft Bonanza, Scratch built5th Ken Kopas / Beech Staggerwing, Mountain Models Kit

Carl E. Maas Craftsmanship Award: Jeff Fukushima

Page 13July 2003

(Below) David Cairns Boeing B-52Stratofortress, his own design, scratch

built from balsa. This plane wasimpressive in the air and conjured upimages of conflicts in which the plane

flew over the last 50 years.

Some of the planes at Cajon 2003 including apair of Cavazos Sailplane Design F-20

Tigersharks, California Sailplanes 60” EPP-foam F-20 Tigershark, and Jack Mullen’s

original design Forward Swept Wing Bell X-1.

Cajon Summit 2003 Sponsors

Major SponsorsAirtronics, Hitec RCD, Leading Edge Gliders, Hobby People

Other Sponsors:Air Age Publishing, Balsa USA, Bob Holman Plans, Bob Smith Industries, Bob’s Aircraft Documentation, BowmanHobbies, California Sailplanes, Cavazos Sailplane Designs, Cermark, Dave’s Aircraft Works, Dremel Tools, EdgerCo, Fox Manufacturing, Frank Cavazos Models, Lone Star Models, Micro Fasteners, Northeast Screen Graphics,Patton Aircraft, Propwash Video Products, RAM, Reese Productions, S&E Modeler, Sig Manufacturing, SRBatteries, Stan’s Fiber-Tech, Tower Hobbies, Trick R/C, Vortech Models, Wing Warrior

through the air. Even with that manyplanes in the air, the large flight zones,along with experienced pilots, keptmid-air collisions to a minimum.

Each year, the level of competitionimproves with pilots bringing betterand better aircraft in an attempt tosmoke the competition. During thejudging process, quality of workman-ship and scale outline were scrutinizedclosely with the best planes in someclasses separated by mere points. Thefiberglass models featured some of themost detailed finishes I’ve ever seen,rivaling that of the best static models.Jeff Vosburg’s scratch-built Yak racer“Mr. Awesome” was just that, awe-some. That attention to detail took 1stplace in the Civilian class.

The foam class has made great stridesin quality also. “Semi-scale” poorlycovered planes that were competitivein the past were replaced with veryscale planes with detailed coveringsand paint jobs similar to their fiber-glass brothers. Some of the bestmodels, such as Ren DiLeo’s scratchbuilt Me-109, were crafted so well thatthey appeared to be fiberglass models.Not until the model was felt, was thefact that it was a “foamie” known.

What I enjoy about the PSS Festival isthe wide selection of planes to checkout. Planes that you never get a chanceto see at your local hill show up duringthe festival. Rarely modeled scratch-built designs are plentiful, along withmore common kits that are detailed tothe hilt. Museum quality planes getthrown off the side of a hill with noguarantees that it will return in thesame condition. Many times the planesmake their first flight at the festival.Some pilots, I believe, feel that if theplane is going to crash on its maidenflight, better to crash at the Fest than tohave all that hard work destroyed aweek before the Fest in a test flight.Dan Schramm built a Gulfstream Jet

R/C Soaring DigestPage 14

Best Civilian Awards: Jeff Vosburg, scratch built Yak racer; Tim Neja, Cavazos SailplaneDesign P-63; Dan Schramm, scratch built Gulfstream Jet; Thor Nordstrom (missing

from photo); Ken Kopas, Mountain Models Beech Staggerwing.

that took its maiden flight while at the Festival. Dan mixed an EPP fuselage along with sheeted foam-core wings in orderto make the 7’ wingspan bizjet a reality.

Jack Cooper’s ambitious SR-71 Blackbird also attempted to fly at Cajon for the first time. The large EPP foam aircraftmade several test “flights” while attempting to balance the plane properly. The “lifting body” fuselage made finding theoptimum CG location hard to determine and each toss saw it closer to maintaining flight. Hopefully the proper balancewill be sorted out; the big lift that Cajon generates will help. However, even if it never flies right, sometimes there areplanes that just have to be built. If they end up flying well, that is just icing on the cake.

For those who would rather build a proven design than scratch-building their own, a few new designs flew at the Festi-val. Jeff Fukushima flew a prototype 33” fiberglass P-40 Warhawk available from Vortech Models and Steve Greenfielddemoed a prototype 60” EPP F-20 Tigershark kit now available from California Sailplanes. New 48” EPP P-51 Mustangsand ME-109s, designed by Brian Laird and available from Leading Edge Gliders, were brought out by a couple pilots.

The ISR added to this year’s Fest by putting on a few instructional clinics. Brian Laird showed how the application of afew panel lines could really add to a PSS bird. Jack Cooper showed how to achieve a good tape/covering of EPP foamplanes. And Ralph Roberts gave some pointers on the art of airbrushing and weathering. The clinics were very wellattended with hopefully something learned by all who attended.

The stars of the show were the Boeing B-29 Superfortress built by Carl Maas Jr. and its companion Bell X-1 rocket planebuilt by his father, Carl Maas Sr. The B-29 was built with a fiberglass-covered blue foam fuse, and balsa-sheeted foamwings. The X-1 was built from EPP foam. With the planes having never flown in the joined configuration, the flight didnot occur until the winds had reached their maximum in the late afternoon. In a scene that reminded me of “The PiedPiper of Hamelin,” the combo was carried down to the “big” hill for the launch with most of the festival attendees in tow.

With the large crowd gathered, the huge bomber was launched with its little partner slung underneath for the first time.After a few minutes of graceful flight, the orange rocket plane was dropped from the B-29 in the same manner that ChuckYeager in his “Glamorous Glennis” was dropped from the real Superfortress in his famous assault on the Sound Barrier.A clean release brought relief to the pilots and crowd, as the pilots were now able to put on a flight show for the crowd.Carl Maas Jr. put the B-29 through maneuvers that would have surely ripped the wings off the real Superfortress. Carlkept flirting with disaster with huge loops and rolls that bottomed out just feet from the ground. Formation flying withthe two planes was so close at times that it appeared that the X-1 was trying to re-attach itself to the large bomber. Al-though a collision knocked off a wingtip from the B-29, the two planes were able to land otherwise undamaged to flyanother day.

The Slope Rebels once again showed that they can put on an excellent event. Tons of amazing planes, friendly pilots, goodweather and wind, and a large impressive raffle makes the PSS Festival an event that draws a crowd every year. Withanother great PSS Festival in the books, I’ve got to figure out what to build for next year. For more information about theInland Slope Rebels and future events like the PSS Festival and Warbird Air Races, visit the ISR website at:<www.inlandsloperebels.com>.

n

Craftsmanship Award: Four years ofwinners are Brian Laird, RalphRoberts, Carl Maas Jr., and Jeff

Fukushima. In the center is CarlMaas, Sr., donor of the awardcommemorating “100 Years of

Powered Flight.”

Page 15July 2003

(Abovbe) Best Foam Awards: RenDiLeo, scratch built Me-109; Jack

Cooper, scratch built SR-71 Blackbird;Brian Koester, scratch built Sukhoi Su-35; Jack Mullen scratch built Bell X-1

FSW; Rick Schwemmer, Leading EdgeGliders P-51 Mustang.

(Middle) Best Jet Awards: Dan Sampsonscratch built Aeromachi MB-339; MitchSchwartzburg, Cavazos Sailplane F-20Tigershark; Thomas Fowler, Cavazos

Sailplane F-20 Tigershark; David Cairnsscratch built Boeing B-52; Steve Greenfield,

Canterbury Sailplane F-20 Tigershark.

(Bottom Left) Best Prop Awards: JeffFukushima, Vortech Models F4U Corsair;

Jeff Vosburg, scratch built Me-109; TimNeja Dave’s Aircraft Works Ki-61; John

Beaver, scratch built Corsair; Tony MatyiSlope Scale F6F Hellcat.

Expert Class Awards: Carl Maas, Cavazos SailplaneDesign Me-109; Brian Laird, scratch built Me-262

Stormbird; Jeff Fukushima, Vortech Models F9F Panther.

R/C Soaring DigestPage 16

By Greg Smith of slopeflyer.comgreg@slopeflyer.com

http://www.slopeflyer.com

“The Sloper’s Resource”

So, the guy hasn’t sent in a story for awhile. Frankly, I hoped for, and expected,more chastising from the masses to help mekeep on track. I guess guilt finally got thebest of me so I took some time to get anarticle together. Actually, I am cheatingthis month because flying buddy RussWhitford had given me the article below afew months ago and all I had to do to get itto you was tidy up the drawings a bit.What a deal! So, without further ado, Igive you:

Bernoulli and the SlopeBy Russ Whitford

Most of us believe in Bernoulli’sprincipal as the theory that keeps

our planes in the air. This principal hasbeen observed to affect the amount oflift at a given slope. Thinking aboutthis effect can help determine howgood the lift conditions will be beforetossing out your favorite plane.

Bernoulli’s principal states that a gas(air) moving at higher velocity has alower pressure than air moving at alower velocity. The curved uppersurface of our airfoils causes air tomove faster than the flat or less curvedlower surface. Lower pressure on topthan the bottom causes lift.

Yes, you in the back, how do sym-metrical airfoils create lift? Symmetri-cal airfoils must be at a positive angleof attack to the flow of air to create lift.This way, the air that hits the leadingedge separates below the front of theLE. The air that travels over the top hasa longer way to go and must go faster.The air that travels under the airfoilmoves in more of a straight line andgoes slower. See above.

Now, to the slope. We have all seen theclassic representation of slope lift (fig.1). Wind blowing into the slope iscurved upward. This vertical flow ofair is rising faster than our planes aresinking. We can fly all day in theseconditions.

What happens at the edge of the slope?Most slopers have found that there is a

calm or dead spot just behind the edgeof the slope. We seek this spot to standwhile flying in Wisconsin in January.The wind seems to go straight up atthe edge, not follow the contour of theslope (fig. 2). There is a nasty “rotor”of air behind the edge. The wind swirlslike a horizontal tornado, not the placeto land.

Our planes experience a rotor effectwhen given too much up elevatorwhile going too slow. The flow of air,

which normally follows the top of theairfoil nicely, separates and causes abig rotor on top of the wing. Can yousay, “Stall?”

The rotor behind the edge of the slopeis a stalled condition. Airflow sepa-rates from the slope curve and contin-ues up, causing a stalled rotor behindthe edge. This is a great condition forslope flying. The stalled rotor acts likethe slope is taller than it really is. Thisrotor forces the airflow to continue

Page 17July 2003

higher and the air behind it continuesin a vertical path. Good slope condi-tions.

A powered aircraft can get out of astall by applying power when a stallbegins. The increased power increasesairflow over the airfoil, causing the airto remain attached or following the topsurface of the airfoil. This same effecthappens when the wind is reallyblowing at the slope. The wind contin-ues to follow the slope instead of goingvertical above the edge of the slope(fig. 3).

For several years, we have beenobserving a phenomenon at a local 70-foot slope facing Lake Michigan. In 10to 15 knots of wind, the lift is great.When the wind gets over 20, the liftdegrades. The lift will only exist rightin front of the edge and you have tohave a fast clean plane to fly. Wetheorized that in higher wind, thewind follows the hill and little rotoreffect is felt. Bernoulli may have thereason for this.

So, when you approach a hill and tryto determine if there is enough lift tofly, observe the presence of a rotor.Throwing a handful of grass over theedge is the best way. If this grass lifts,then circles around behind you, thereis a significant rotor. If the grass blowsup and straight back, the wind may betoo strong for good lift. A taller, morevertical slope does not seem to sufferfrom this problem. I have a hard timeimagining it blowing too hard to havelift at Fermin.

Thanks, Russ! Well, there you have it.Until next time, here’s hoping there’s windin your face, unless you are a DSer, then,here’s hoping there’s wind at your back!

n

ZIKA

GONE SOARIN’

R/C Soaring DigestPage 18

Page 19July 2003

T.W.I.T.T.(The Wing Is The Thing)

T.W.I.T.T. is a non-profit organization whosemembership seeks to promote the researchand development of flying wings and othertailless aircraft by providing a forum for theexchange of ideas and experiences on aninternational basis. T.W.I.T.T. is affiliatedwith The Hunsaker Foundation which isdedicated to furthering education andresearch in a variety of disciplines. Fullinformation package including one back issueof newsletter is $2.50 US ($3.00 foreign).Subscription rates are $20.00 (US) or $30.00(Foreign) per year for 12 issues.

T.W.I.T.T., P.O. Box 20430El Cajon, CA 92021

www.twitt.org

The Eastern Soaring League (ESL) is a confederation of Soaring Clubs, spread across the Mid-Atlantic and New England areas, committed to high-quality R/C Soaring competition.AMA Sanctioned soaring competitions provide the basis for ESL contests. Further guidelines arecontinuously developed and applied in a drive to achieve the highest quality competitionspossible.Typical ESL competition weekends feature 7, or more, rounds per day with separate contests onSaturday and Sunday. Year-end champions are crowned in a two-class pilot skill structureproviding competition opportunities for a large spectrum of pilots. Additionally, the ESL offers aRookie Of The Year program for introduction of new flyers to the joys of R/C Soaring competition.Continuing with the 20+ year tradition of extremely enjoyable flying, the 1999 season will include14 weekend competitions in HLG, 2-M, F3J, F3B, and Unlimited soaring events. Come on out andtry the ESL, make some new friends and enjoy camaraderie that can only be found amongst R/CSoaring enthusiasts!

ESL Web Site: http://www.e-s-l.org

The League of Silent Flight (LSF) is an internationalfraternity of RC Soaring pilots who have earned theright to become members by achieving specificgoals in soaring flight. There are no dues. Once youqualify for membership you are in for life.The LSF program consists of five “AchievementLevels”. These levels contain specific soaring tasksto be completed prior to advancement to the nextlevel.Send for your aspirant form, today:

League of Silent Flightc/o AMA

P.O. Box 3028Muncie, IN 47302-1028 U.S.A.

http://www.silentflight.org

SailplaneHomebuilders

Association (SHA)

A Division of the SoaringSociety of America

The purpose of theSailplane HomebuildersAssociation is to stimulate interest in full-sizesailplane design and construction byhomebuilders. To establish classes,standards, categories, where applicable. Todesiminate information relating to constructiontechniques, materials, theory and relatedtopics. To give recognition for noteworthydesigns and accomplishments.SHA publishes the bi-monthly SailplaneBuilder newsletter. Membership cost: $15U.S. Student (3rd Class Mail), $21 U.S. RegularMembership (3rd Class Mail), $30 U.S. RegularMembership (1st Class Mail), $29 for All OtherCountries (Surface Mail).Sailplane Homebuilders Association

Dan Armstrong, Sec./Treas.21100 Angel Street

Tehachapi, CA 93561 U.S.A.

Classified Advertising PolicyClassified ads are free of charge to subscribersprovided the ad is personal in nature and does notrefer to a business enterprise. Classified ads thatrefer to a business enterprise are charged $5.00/month and are limited to a maximum of 40 words.RCSD has neither the facilities or the staff to inves-tigate advertising claims. However, please notifyRCSD if any misrepresentation occurs. Personalads are run for one month and are then deletedautomatically. If you have items that might be hardto sell, you may run the ad for 2-3 months.

For Sale - Business

PARACHUTES: $12.50 (includes S&H U.S.A.)Send check or money order to Dale King, 1111Highridge Drive, Wylie, TX 75098; (972) 475-8093.

Summary of Low-Speed Airfoil Data - Volume 3 is reallytwo volumes in one book. Michael Selig and his studentscouldn’t complete the book on series 3 before series 4was well along, so decided to combine the two series ina single volume of 444 pages. This issue contains muchthat is new and interesting. The wind tunnel has beenimproved significantly and pitching moment measure-ment was added to its capability. 37 airfoils were tested.Many had multiple tests with flaps or turbulation ofvarious configurations. All now have the tested pitchingmoment data included. Vol 3 is available for $35. Ship-ping in the USA add $6 for the postage and packagingcosts. The international postal surcharge is $8 for surfacemail to anywhere, air mail to Europe $20, Asia/Africa$25, and the Pacific Rim $27. Volumes 1 (1995) and 2(1996) are also available, as are computer disks contain-ing the tabulated data from each test series. For moreinformation contact: SoarTech, Herk Stokely, 1504N. Horseshoe Circle, Virginia Beach, VA 23451 U.S.A.,phone (757) 428-8064, e-mail <herkstok@aol.com>.

Reference Material

BBS/Internet

Internet soaring mailing listserve linking hundreds ofsoaring pilots worldwide. Send msg. containing theword "subscribe" to soaring-request@airage.com. The"digestified" version that combines all msgs. each dayinto one msg. is recommended for dial-up users on theInternet, AOL, CIS, etc. Subscribe using soaring-digest-request@airage.com. Post msgs. tosoaring@airage.com. For more info., contact MichaelLachowski at mikel@airage.com.

Books by Martin Simons: "World's VintageSailplanes, 1908-45", "Slingsby Sailplanes","German Air Attaché", "Sailplanes bySchweizer". Send inquiries to: Raul Blacksten,P.O. Box 307, Maywood, CA 90270,<raulb@earthlink.net>. To view summary ofbook info.: http://home.earthlink.net/~raulb

There is a growing interest in scale soaring inthe U.S. We are dedicated to all aspects ofscale soaring. Scale soaring festivals andcompetitions all year. Source for informationon plans, kits, accessories and other peopleinterested in scale. For more information:

web site: www.soaringissa.org

InternationalScale SoaringAssociation

R/C Soaring DigestPage 20