-' .:

REVISED FORCE m.T_~ i-:O:ct.K-UP

FOR ll-IrlC3 'mH~iEL

NoverJber 29, 1966

. , , !

If .

.. . ~ ..

Part I.

Part II.

TABLE OF CC?lTElrTS

SYMBOLS

PROCEDURE FOR SENDING DATA TO DATA REDUCTION

I. II.

III. ~v. v.

Provided by engineer· •••••.•••••••••.•••••••. 7094 Load Sheets •....•.••.•••..••..•••.•...• Initial Tare Loads •••••.•.•••••..••••.•..•.. Attitude Tare Loads ••.•••••.•••••••.••.•.•.• Data Sheets •••.....•.••••.•• ~ •••.•.•••••••••

Part III. . CHECKING DATA FROB DATA REDUCTION BRANCH

I. II.

nI. IV.

Listings Ret~ned from DRB •••••••••••••••••• Checkpoint Computation •••••••••••••••••••••• Interaction Computaticn ••••••••••••••••••••• Additional Calculations •••••••••••••••••••••

....

Page

1-1

2-1 2-2 2-3 2-5 2-6

3-1 3-1 3-8 3-11

r , '.

) .

. '

Part I - SYHS)I.S .,

.'

....

I

I r·

)

;.!

• I

SYHBOr.S

Ct.: normal force coefficient

C, ax:.al force coefficient· h

C pi tC:'1ing morr.ant coefficient m

r::>lling moment coefficient

C yawing moment coefficient n

Cy side force coefficient

C_ lift coefficient L

ct D

d!'ag coefficient

CAB base drag. coefficient

N normal force, lb

A axial force: Ib

axial force on base, lb

m pitching moment, in.~lb

Z rolling moment, in.-lb

::l ymlir..g moment, fn.-lb

Y side force, lb

b span or lateral reference len~th, i~~

c mean aerodynamic chord or pitch refere~Ga length~ !ae

Kl -* 27 interaction conste.nts

L Reynolds nur:.ber cha.ract€ri:;tic

M Each nwr.ber

1-1

.. ' .

. \

. f

I '. l'

. !

C. ~~ue 3~o~~ zero re&dic[

. ~ . 1.

p • 1:)

OJ

:.> "0

q

free st~e&m static preEs~~e)

base pressure, in.hg •

stagnatio~ pressure, in.r.g. Ib

clynam:tc pressure, ft2'

lleynolds number based on L

reference area, ft2

base area, ft 2

.5 .~. , etc.} balance sensitivity constants

S Iil

TLXl free stream static tempera::ure, oR

st~gnation tamperature, of

distance from moment'ref€::"cnce to c'::!'ltcl" of pressure

y lateral moment transfer distance, lno

z vertical mo~ent transfer dist~n~e, in~

a true model angle of attack, ceg In

a. 1.

~m

~' o

y

misalignment betwaen model and bf.lsnc6 in mod.;;;}' e.ngle of att.9.(:~-: plane (see sketch on page l-L.. for positiv8 2.::t.;cticns), deg

misalign.llent bet-,/een model and b3.1ance i r. pi d-:;3lip plana (s!"!E: sketch on page 1-4 for pcsi~ive d:'re~ti.ons). deg

true model sideslip plane~ deg

ini tial YS1tl angle betHeen balance and strut (usually zero), deg

ratio of specific hc~ts 5/3 for 11<31i :.l!!l)

r interaction3

., ~

.L-~

..

~ roll angle, positive clocT..:ise :!.ooking from rea:'. 0° OCCU!'S

~hen model or balance is ~?~~6n~.

Subscripts

At attitude loads .

B balance ;

~

II .. ' initial loads

m? .. ;~: maximum

ref reference

s stability axes

'W wind axes

r.rO'.rE: No subscript on coefficisnts der.ote~ body axes data.

)

, '

, '

_ r.

~-;

'.,

i .: ~ .

"

' .. , ..

:. ~

.'

) ~ .' !

. J

. j

!

~rnen m = 00

'I'll'.

when rn - 1800 'I'm -;-

II. ~i

'Wnen cp = 270 0

m

Sign Direct:o~S fo~ and ~ .. ~

reference line

balance fixture

reference line

'"

)'

. Part II PROCEDURE FOR m-:~mING DATA TO DATA REDUCTION

",

)

'I

:i

'. ~ ;

.....

'.~ .

.... :". ~. .'

'.1. • ~ • TetOot

). :-"

.1 .. '

"

~ "

PRCCEDlBE FOR SENDING FO::CE D.~'l\A TO DA1".~ REDUCTION

I. 'Provided by engineer

A. Force Data Infor~~tion Sheet - applicable to one or more runs.

B. Tunnel Run Sheet.for each run.

C. Brown Records for each component ma~ked for run, test, data component, before and after ~~ zeros1initial loads, attitude loads and test angles of attack •

Following is a sample Brown Record:

e."".d Of ~ltn 'J;..

2-1

. a I -!t r, .... :.o,..-!,~'t_1 .:n'l_!Jr~...:J. ') ~ r~M~ o~'! ... Il' __

. I . ~. 1 J "'" '5 n .-.-,o.~ t.'V"~Q

II. 7094 Load Sheet

A. Balance - precede balance nmnber by Si (e.g. Si-1113).

B. Calibration Date - date of interactions to be used - usually the must recent ones found in the BalancQ Book. Check with the engineer.

C. Run(s) - Run ~ Nurnber(s) to vpich load constants apply.

D. Test - provided by engineer

E. Engineer - last name.

F. J.O. - given by engineer.

G. Balance'Sensitivities - value of senitivites for each component foth~d in Balance Book. Check ~ith engineer' for correct ones to use.

H. Test questions

1. Type 4 Data - check vThether or not runs have Type 4 data.

2. Type 1 Data - If Type I Brown readings "rere recorded with no change, check "Unchanged II ; otheri-lise, check changed.

3. Balance can or cannot be rolled - check vath engineer.

4. Axial corrected or uncorrected for base pressure - force data information sheet.

5. Balance is 3 or 6 component balance.

I. Delta W _ found in Balance Book for balances that can be rolled, othE:T1,.Tise is zero.

J. Alpha I - force data information sheet.

K. Checkpoint run and point nU!Jlbers check with engineer.

L. Base pressure area - must record S for each base pressure. n

M. S area

c chord

x longitudinal-;.

y lateral

z vertical

L length ~

force data infor~4tion sheet

2-2

"

"

N. Delta A - Full scale axial r:ru.ltiplied by percent of accuracy for axial (Balance Book).

O. Delta N - Full scale normal multiplied by percent accuracy for normal (Balance Book).

p. Delta PB - Full scale of base pressure gage multiplied by percent

accuracy of gage (engineer).

Q. Delta < - Estimatederror in setting of angle of attack - provided m by engineer (usually ± .2 deg.).

III. Initial Tare Loads

A. Definition - the change in reading due to the "reight of the

B.

model at a • Initial tare loads are identical for any series mref of runs where the starting angle of attack (a ), balance roll mref angle (<p ), and configuration are constant..

m

IBM Record Sheet to be completed

l. Balance

2. Configuration - Example: 800 Delta \iing

3. Date

4. Type 1

5. Test N1..L."'llber

6. Run - one or more runs "dth S~"'lle configuration and code.

7. Sensitivity number used - indicate the number for each component for Pt. I row only.

8. The engineer takes a reading for each configuration 1.-11 th the model mounted on the balance and the balance roll angle, CPS' set at the value for Hhich the model will be tested. This value is the upright reading and the value for Pt. 0) on the record sheet. The model and balance are then rotated 1800

and another reading is taken. Ynis is the inverted reading • ....

2-3.

- 0"

... --;

":'.'1 •. - •

~ : . , i,- ... ,· .i: .: . -L--

f , ~ ...

, .: ~ " .. ":.'

, .-

r',.- . ... : .... '

-; :..:

.! , ..•.

o .-

.,

.j ..

• !r> ••••

i °

NOTE TO ENGINEERS: To obtain tJ.U fer any bale.nce, '/i th balance at a B :: 0 0 measure difference in normal force between roll angles of 00 and 1800 • Divide by 2. S'l1btrilct this result from axial force net reading when balance is at aR :: 900

• (lilien axial force beam is behind normal force beam tJ.W is positive.)

9. Code - a three digit number tells the ?-tach number, and the the roll conditions of the model and the balance.

a • The first ciigi t refers to the l{ach number of the run.

If M :: 6:8-1 . a~r

9.6

Code digit:: I

2

10.5 or 18 (helium) 3 b. The second digit gives the roll of the model.

If tp :: 00 Code digit :: 1 m

900 2

1800

3

270 0

4

c. The third digit gives the balance roll angle: ~B' in " relation -";0 cp.

m If CD :: 00 and cp :: 0 om B

90 0 90"

1800 1800

270 0 270~

If tp :: 900 and o :: 0-:1 m "S

180" 900 .....

2700 1800 Code digit::: :2

0 0 270;)

2-4

.j

i.,

, ':,. , . , '\1

. ! i

. "L . c.

f ·T:> .;: ,

!.

,.' '. t', ,

':"':.

' .. ,',

r,'"

!.

~ .

If co 'm = 1800 and ~ - 00 S -

2700 900 Code digit = :3

00 i800

900 2700

If cp = 2700 and QS = 00 m

.00 900 Code digit =4

900 1800

1800 2700

The cede is recorded on the rew for Pt. 1 only.

IV. Attitude Tare Loads

A. Definition - attitudeta~e loaa carrections to the final d~te are necessary because the cOl::?Q::1ents of the we.ight of the model sensed b~' th9 balance change with angle of attack.

B. Attitude tare loads must be t9.ken for each configuration and for each set of runs in "which the balance roll angle, (jiB' is changed •.

C. IBH Data Sheet for attitude tare leads - rrype 44 \.olhen Type 1+ en:tries are made l the attitude loads al">3 computed by DRB. T~rpa 4 entries may be made on:!.y ;,..rhen the follot;ing test sot up is used. It is the one nost frequently L..sed in the section and occurs when the initial ya'rl a~gle of the balan~e is zero (0 0 = 0 0

);

CPm ::'.00 , 900 , 1800 ~ or ~700 ~ az:~ tpS =. any v~lue. Vr(le~ te:t. Sfrt,­

up dlffers from th~s I the spe::~aliz.8d procadUl".3' dascribed III the appendix is followed.

1.' Balance

.2. Configuration

3. Date

4. Type 4 - DRB COillpU.tss .~ttitllda lc~lJs

5. Test ""

6. Run

7. Sansi ti vi ty m!r:lo;;!'

8. Code - Se3 section I!I. en i~iti61 lo~ds.

2-5

. ),.

~ -j' .

.. ', ... :',

. . ; ,

. ; .". ".:' .

., ~ . . :-

)

...•

j'

" .,

a J • The engineer will

extreme angles of

amref

when 0 :: 'm

~ :: 90 0 or 270°. m

p!'ovide attitude load readings at t'..J'O

attacEo. These angles will be am ' and

00 1800 , ~m and p maxh or or w en m f max re

At Pt. 0 list the r'eference angle from

the brc~s,' (a or ~ ). At Pt. 1 list the maximum mref mref

angle (a or A ). As a check, when ~ :: 0° the m r'm m' max max

maxinum value of am will, in general, be positive and

when <Pm:: 180°, the lr.aximTh-:l .... alues of am will be negative •

'l-lhen <Pm:: 90 0 the maximThll value of ~m will be positive,

and at ~m:: 2700 the maximThn value of ~m will be negative.

10. For each corr..ponent, record the 1:;:-mmreading at the reference angle (usually CI :: 00 ) at Pto 0 and the bro\ffi reading at m .

ref the maxim~~ angle at Pt. 1.

V. Da ta Sheets

A. A separate sheet must ba made for each r~~

B. Record Sheets

1. Balance

2. Configuration

3. Date

4. Type - 3

5. Test

6. Run

7. a. l'JB.ch 6.8 data. - In this cohu.m.;J record tha ti."11e, in seconds, for aacb test angle" Do not raoord fra.~tion:5 of seconds.. For points less than 10 seconds, record 10 s·econds.

b. }fg.ch 9.6 data - F~ecord true }fac}::, numc3r fc:· "th;3 rU.!1. Average tha P IS and divide by 29.92 to c.O!H"ar-:O to atmospheres. °L:)·;~~ up HdCh nll.'ri02r fro'..! plot of H~-l.ch numb9!' VerS'l!3 P in Ccm?Utsr' s :!oteb:,Cl:~~

o

c. Hach 10.5 and :':5.ch 18 - (helium) record Hach to 3 decimal places.

2-6

\ .. !.

)

8. In this col~~~ recorc? in inches of mercury absolute •. 'P • .~. d f t' o ~l . ( d ~ th . 15 oOvalne Tom ne wa~ gage recor 8u on e run sfieet for every 10 seconds) or pressure film. f.sk eng­ineer which to use. If the wall gac;e is used, 30 inches of mercury must .be added to make the pressure ab50ltrt.;~ and interpolation bei'.-reen tha lO-second intervals is 1'19-

ouired to obtain pressures corresponding to the time at ~hich the· data is recorded.

9. am' Bm

'.

The follmling instructions apply only to the test set-up previously described under Type 4 attitude loads. ~llien set-up differs, refer to the appendix.

~rnen G = 0° or l800,~: will vary and ~ will be constant. 1m 'm m Since a = a + a. when ,... = 0° or 180°· m s 1 'I'm •

If In :: 00 'I'm ' am will, in general, be positive.

G'm = l8Co, am willJ in general, be negative.

I-lhen ';J = 900 or 2700 , fl· \-Till vary, -< will be constant. 'm m III

Since A = a + B. Pm S 1 ,,:hen

~ will, in g<;;:nc:ral, be positive. t-'m

<p :: 270 0, A 'Will,. in g~merall be negative. m t-'m

10. Sensitivity number - recorded On brovns t:.nd. run sheet for each component.

11. The readings for the six compo::lents (or 3 cOI:lponents for a fe'.l balances) are to be read fro:-:: the brm:r., records. Point 0 is the raference readinG batore th~ Fun starts. To obtain this refere~~e ra~dingj 8vsrzge th8 rc&dings ~~rzed 0t' am ' and °1 • If howe-.rer i a~~:; tuo cf these reedings

ref ....

differ by ~ora t~an 4 co~nts, the ~Jr! may be invalid. The

2-7

, ....

)

only reason, aside from balance malf1Ll1.ction, for this to occur is \-lhen, for some reason, the model is not returned to the reference position after calibrating or after attitude loads. If more th~~ a 4 count difference is obtained, Ch8Ck with project engineer to determine the cause. If engineer canr..ot explain the discrepancy or sho'.-,s indecisiveness, reject the run.

The reference reading after the run, Of' must be considered befor'e recording data values. Because of balance heating, this Of may be different from the average reference reading computed before the run starts. If this difference is less than or equal to 4 counts, ignore the difference. If greater than 4 counts, hOi,rever, a haa t shift correction, 0, given by the follmTing equation, must be added to the data c readings at each test angle.

where

(0 - O",)(time of data reading) o .1.

(total run time)

o = average reference reading before the run o

Of = reference reading after the run

NOTE: As a check, the average reference readings before the run, listed as Pt. 0, on the Type 3 sheets should be identical to the Pt. 0 listing on Type 4 sheets.

At Points 1, 2,3, etc., enter the respective data values corrected for heat shift (if necessary).

12. PB, base pressures, will be read from B.COi.fll records and

recorded in inches of mer-::ury ~li th !r decimal places. If there are two or more base pressure.:.', record all the base pressures on a Type 5 IR-'l Rec0rd Sheet.'

13. Record To in OF from tU141el run sheet.

14. a. M = 6.8, record 6...\1 in thi s co~umn. Average _ . POl ~ for. the run and find ll.N from Computerts Notebook. 'Record on row for Pt. 1 only.

b. M = 9.6, leave the column blank.

c. For helium test~ (N = 10.5 or 18) record qjP 0 in this column ..... This is found from the helium tables, knmTing the Nach number of the run. qjP = qjP t is nondimensional in helium tables (TN 4063). l1ul~iply tliis number by 102 and send 4 decimal places to DRB. For ey.a~ple: if M = 16.99, qjPt = .2581 x 10-2; 0.2581 is sent to DRB.

15. Code - See s8ction III, B-9, page 2-5.

2-8

.. ~. -',

.. . ,

:' . ·Part III - CHECKING DATA FROH DATA REDUCTION BRANCH

/

..... . ,

)

1.

CHECKING DATA FROH DATA REDUCTION BRANCH

Listings Returned From DRB

A. Input Listing.- Ever? .nu-'!lber must be compared t,.!iththe numbers sent to Data Reduction Branch on the load cards and record sheets. Tne attitude tare loads and initial tare loads Hill be printed before the runs to which they apply. Check carefully to see that each run has the cor~ect attitude ~nd initial loads before it. At the top of the input listing wri te the test number, run numbers, a..'1d balance number.

B. List of Interactions and Corrected Forces and Moments - Intial loads, atti tude loads, and data for the requested checkpoint as ,.fell as for several other points have been converted to pounds and corrected for interactions and are listed along ~/ji th the interactions used. Identify this sheet in the same manner as the input listing.

C. Final Coefficients - There t,.Till be at least tt,.lO copie~, one or more for the engineer and one for the Computer's File.

II. Checkpoint ComF~tation

In making checkpoint computat5.on, trie corrected forces and :r;:oments, final coefficients, interactions, H, q, and R must be checked for the checkpoint indicated \oThen data \o;as sent to DRB. Wnen checking the cor-rected forces and mOillents and final coefficients, assume that DRBls interaction values are correct and use them in your calculations. Because it is necessary to iterate through the interaction equations more than one time to gain the required interaction accuracy, use DRB's final interaction 7alues in your calculations. After a satisfactory check of this data is obtained, check DRE's interaction values.

-,

Eight significant figures are to be carried through all computations.

Procedure for computing checkpoint:

A. Calculation of Nach Number and Pl

1. To calculate Hach 6.8 (1st digit of code if 1)

M = mt + b + ~H

time, sec. m b

0 - 20 .001700 6.795 21 - 40 .001050 6.808 41 - 60 .000800 6.818 61 - 100 .000350 6.845

3-1

I '

) 2. PI for both H = 6.8 a!~d 9.6 is calcula'ced by the equation

P , in.hg. (.491) Ib (144)in.2

o 2 . 2. h f·2

P l' Ib/ft = -----------=~~~!,.:5-~r~J n 7~· 1:,

(1 + .21-'f)

3. For l-fach 10 or Hach 18 Eeliur2 runs (1st digit. of code is 3)

Hach nu.rnber is recorded on record sheet from tunnel calibration plot of Mach nlli~ber versus P • o

Po' in.hg. (.11-91) (144)

(1 + 1/3 lvt) 5/2

B. Calculation of a ;n (lb!ft2)

1. Hach 6.S and. 9.6 data

2. Helium runs Nach 10 or Hac~ 18

Use non-dimensional q/po as sent to DRB; Po' in.hg.

C. Reynolds NU17lber Calculation

where

R = g L x 106

L .020392 1-1 (T ) 3/2

T + 460 o T = .-::::..----00 1 + .2 H2 .

00

This Reynolds number equation is valid only for air in the range 600 R ~ T ~ 1500 R. Reynolds numbers lor gases other than air or for condi~ons outside the valid range of the. equation must be computed in the section.

D. Initial Loads ( :" ". -

1. Balance can be rolled I co s LJ' B) - pt 0 ] ~ - interaction

- interaction

pt 0 1 Sy - interaction

3-2

)

E. Attitude Loads

The Type 4 attitude load procedure is described in the follo\o1ing

instructions and is used whenever the initial yaH angle of the balance

is zero (f'~ = 0); <Pm::; 00 ,900 ,1800 or 270°; and~B = any value. For

other test set~ps, the specialized procedure described in the appendix

is used. , .

For Type 4 the corrected ai:.titude loads in pounds at the checkpoint

test angle are obtained by the follol,.!ing equations when 'J = 00 or 1800

1m

rcos (a - a .) -cos(a -a.)l [ 7t.O 1 mCh •pt • 1 J

fsin(a· -a. ) -sin(a -a. )] L mOh •pt • 1 mpt •O- 1

[sin (a -Ct. )-sin(a -a.-ry-·-L IDpt •1 . 1 lllpt ~ 0 1 .

- interactions

- interaction

. ' ;'r 0

mAL' l AL' nt\L' and YAL are cor~;'lu~ed by the same equatim as NAL •

If 0/ . = 900 aI' 1800 S'.lbsti tute respective values of \3 and I=> •

m ID J.

for a and a. in the above equations. In applying the equations' ID 1

use the 8-place sine-cosine tables computed on the 7094.

F. Balance Ax;s DEtta Unccrrected foY' Attitude Loads (subscript n

N.3' A3, my etc., == (Vi:L1le at che~}:p()int

(~l' SA' Sm' etc.) - intsraction

a ID Valu3 at Pt. 0)

G. Balanee Axis Data Corrected for Attitull'? Loads (subscript 4)

N4 == N.3 - NAL

A4 == A.3 - AAL

ID4 = ID.3 - fir .L

.,. . 7: = l.3 - tAL 4

H. TransfGr of Dat.':l. frcTl Ba 1 ar,ce Roll Phn€) J s'tlbscriut !~) to r·~odel

Roll Plane (subscript 5). Using third di.git 0: code •

.3-.3

)

'.

; , !

.. ~ :

"

: I

' .. '

,. ~

: ! ,

'.'

. 't

I Of ')..0'" (~?

'~~, ,

, .

;

, .'

Code 1 (9 + :)C == 9:) B

Code 2 (9B + 90 0 - 9 ) m

Code 3 (YB + 180 0 = 9 ) m

Code 4 (YB + 270 0 = 9 ) Dl

'.r - )'1 .. ~ ·'4 ~

A~ = , _'i.4 J

l!~ _ = m4 ~

N_ :> = Y4

A5 = AI"

n:5 = n4

N5 = -N4

AS = A/"

m~ = -m4 )

N, = -Y4

A =' A 54'

ID5 = -n4

Subscript 4 is balance output, 5 is model outputo

l,. J

~ I~ )'

n~ n,,,, ... , v "'5

.= Y4

l~ = l4 )

n5 = -Jr.4 Yr: = -N

) 4.

lS = Z4

n5 -= -n4

Y5 = -y 4

n~ = m4 :) '.:

Y = N . 5 4

N:J.i'E: If balance is rolled at an angle othe-..~ than 900 or r.:ul:I~:!.ph: of 90 0 , the follm.,-ing equations ar-e used for roll correc1:.ion:

7 - Z ~, - 4

Y5 = Y4cos

9' = cp '- Q > B B m

;pl + N,sin tpB' tJ 4

3-4

J.

Correction of Data for a. 1

(subscript 6) (used only t-rhen."l = 0° or 1800 '1ID

andcC. is in quadrants I, IV) 1

• n6 = n 5cosa i + Z5sina i

Correction of the Data for ~. 1

(s"..:bscript 7) (used only \Theno/m = 900 or 27C

Use minus P. in these 6quations: 1

K. Correction of Axial Force for Base PressUl"es

ABP = [PI - (.491) (144) PB1]Sl +

[PI - (.491) (lLr4) PB2]S2 +

~?l - (.491) (144) PB3]S3 +

[Pi - (.491) (144) PB4]S4

A6BP = A6 - ABP

3-5

L. 'Transfer of Noments from Balance Center to Model }loment Reference Point

x is positive \-rhen balance center is to "':.he rear of the desired moment reference point

Y is positive \.lhen bala..''1ce center is to the left of the moment reference point (.,hen vie',red from the rear)

z is positive when bal~!c9 center is above the moment reference

point

rnr, == m6 - xN6 + zAr o

M. Reduction of Data to Coefficie~t Form - using dyna~c pressure (~) and model reference constants (8, c, b-)--

1. Body a."<:is data

A6 C ==-­A q8

C _ mr, m ---. q8c

lA~~p 1

y C == 6

Y q8

x == Cm C cp n

VN

2. Transfer from rody axes to stability axes

Use checkpoint a in these equations regardless of the m

value of C( • m

CI == CNsin am + C;l cos a Ds

~_ m

C == C m m

s

Cz == Cz cos <.lm + G sin a 5

n m

":l ,. .,.,-0

... . ;

)

c == C nCos G ~ ~ Sln '"1

ns III v

l ~'rn

Cr s

Cy

Lin == CL /CI s D s

3,- Transfer from stability exes to \lind axe:>

4,

Use cneckpJint ~m in these 6qus.tions

C m.­w C cos

m s

~ - Cy sin 13 In :rn s

sin f3 m

== C co:.; A +.£ - Z t'm b C sin ~

== C

s

n s

In m

Gy cos ~ + Cn' sin J3 sIns m

Transfer of data from body axes to \lind 8o::.::e8

C1 == C~_cos a 1~ m

\I

CD == w

CACOS a cos A + C'T sin a cos 0. - C sin 8 m I-'m h m ~m Y 'm

Cm C ~m b ~ns:!.n ' p .L. C "':n aJ .- cos -0: G Sln • P "C''' . Z' ....... - ., ..... :;,:)

m c L'l. n m ..,1

,. Cz ~ cos + ,.

~ sin + c C sin Pm. == cos a cos a v, v

b .. In 1i1 n m til m • 1

~:orE: If t118 checkpoint anS\.1srs checy. ,,:it:-l the corrected forc6s end r:,O~ents !ind \-:ith the final data recei'.r~d :roiil DRB, g~~..,.a 8. copy of the fintll d::;.t:'l­t:) engineer. File a copy of -::~e fi:::al d-:.tc::. in the C.:rc:pt'.ter's ?ir.;:..l D'li-I! r"'lle. Then ccn:;r\lte inter"acti(:~3 3

3-7

;

\.

, . III. Interaction Computation

A. Tae Interaction Eauation

2: = N (KI + K7 N + KS A + K9 n + KIO Z + KII n + Kl2 Y) + A (K2 +

Kl3 A + Kl4 m + Kl5 Z + Kl6 n + K17 ,Y) + m (K3 + Kl8 m + Kl9 Z +

B. General. Tn~orm~tion ConcerLiL~ T~teractions

1. DRB calculates interactions on initial loads, attitude loads, and each data p0int. DRB often goes through interactions several times until they get 'VIi thin a certain accuracy. Our computations should check exactly with their first iteration because it is our first time through interactions.

2. The II-inch computer must check interactions on 2n1Y ~ of the three types of loads. If you c1:oo se to check them on initial loads, follm.; the procedure in Section :LII-C beloH; for checking attitude loads or data, follow the procedure i:l Section III-D belo',.T.

-, 3. Interactions for the var-i8Us components must be computed in the order

given on the front page of the balance calibration sheets "Thich are in the Co~puter's Balance Book.

4. The interaction constants (KI through K27) are different for each component and for each balan~e. The constants, 1.-Thich are supplied by IRD when the bala.l1ces are calibrated and do no-v change when sensitivities change, are listed on balance calibration sheets in the Computer's Balance Book.

5. The interaction equaticn ~as been set up on a standard form (Bala.~ce Interaction Data S~eet) to facilitate calculation of interactions. The form is n~~ber 13 and copies may be obtained by sending a \-rork order to Printing Control in the Photographic Division.

c. Checkin£ Initial Load Intera~~ions

1. Initial loads in pounds not correct for interactions must be sub­stituted as N, A, or m, e-:o., in the Interaction Equation or in the spaces provided on the "Balance Interaction Data Sheet". To obtain the value to be ussd, add DRE's value for corrected forces and mOilisnts to their value of interaction. .

3-8

,'.

)

,. . 2. Follow the general instructions in Section I1I-B above to determine

\-lflat K' s to substitute, the order in ".-!hich components are computed, etc.

3. If using the sheet:

a.

b.

c.

d.

Compute lines (1) t,hrough (59); the answer in (59) is L or interaction on initial loads for the component you are c8mputing.

Check theanS'.~er obtained on line (59) \-lith DRB's first iterated value for initial load interaction. If it does not check exactly, go back through your calculations and try to determine if the error is in your calculation or in DRB's. Do not proceed to next component until reason for the discrepar-cy is learned. If there is no discrepancy, proceed to c.

S~ip line (60).

For line (61) subtract L (the anSi-ler in line (59) from the value that \-Tas substi tulea as N, A, or m, etc. Therefore, the answer obtained for line (61) is initial loads corrected for interactions. Use the correctGd value (line (61» as the N, A, or ID, etc., in computing the next component's interaction.

D. Checking Interactions on Attitude Loads or Data

1. Attit.ude loads or data (in polLl'lds not correct for interactions) plus initial loads (in rounds correct for last iterated value of -. interactions) must be substituted as N, A, or m, etc., in the Interaction Equation or in the space::: provided on the "Balance Interaction Data Sheet".

2. Follow the general instructions in Sectio:r: III-B above to determine what K's to substitute, the order in \-Thich components are computed, etc.

3. If using the sheet:

a. Compute lines (1) througa (59); the answer in (59) is interaction on initial loads (L ) Dlus interaction on attitude loads or data. Keep eight signific~nt· figures at all times.

b. For lin.e (60) s'.lbtract DRBls last iterated value of initial load interaction from line (59); thus the answer in (60) is attitude loads or data interaction. Check thi s answer \-/i th DRB' s first iteration of attitude loads or data. If they do not check exactly, go back through your calculations and try to determine if the error 1s in your calculation or in DRB's. Do not proceed until the reason for the discrepancy is learned.

3-9

, '\

)

c. For line (61) subtract the anS,ler in (60) from. the value that 'Was substituted as N, A, or m, etc. Therefore, the anST,o,er . in line (61) 1s attitude lo~ds or data corrected for inter­actions. Use this corrected value (line (61)) as the N, A, or m, etc., in computing the next component's interactions.

3-10

J. ~) I Ilt '0

IV. Additional Calculations

A. The folloHing values are cOr.!puted and listed for each point

PB2 = { ·421) (144} PB2

P PI

PB3 = { ·491) (144) PB3

P PI

Where PB1, Pp2' PB3

, and PB4 Rr~ supplied to Data Reduction

in inches· of mercury and p] is the free-stream static pressure as computed on page 3-2, section A-2.

3-D.

.. . j "/' " I •. ..

I ,f ,J

) ./

B. The follm.iing values are comf.'ut.ed and listed f'or each point.

2 )2 [ 2j

cos CL ,) + [~-1L sin CL • + 1 lJ. Cl ) m "'c In D nl qc D

D L/D (L/D)

D LID - PB = 1 2 3' /. - B _', Sin2, CL + f112 2 -, (LID) {[S +s +s 's ].1P j' '~J

qSC : ! m iDJ cos C! In ~ L 'J. , _ .

where M, liN, liP B' and l'ccm '\o."il1 be provided for each run and Q'm'

q, CL, CD' LID and Q'm are the quantities presently listed from the

eXisting program.

Units:

/1..4. , Ibs. ':

lIN, lbs.

llPB

, Ibs./rt2

tetm

, radians

3-12

i I

I I