AIAA-92-4EI

The Use of The Captive Trajectory System for Computation of Trajectories to The Impact Point Moshe Zilberman and Moty Shay Israel Aircraft Industries Ben-Gurion Airport. Lod . Israel

AlAA 17th ace Ground Testing Co

July 6-8, 1992 1 Nashville, TN For psrmlmbn to copy or mpubllth, contact tho *mbrloln lnrtllute of 370 L'Enfant Promenado, S.W., Wmhlngton, D.C. 20024

THE USE OF TEE CAPTIVE 'IZAJECTORV SYSTEM

FOR COMPUTATtON W TIUIECrORIES to THE IMPACT POINT

M. WkmMrn and M. S b y "

* Mamew RM), kmbm AIAA m* Senior Eng. Aerodyrromk: Wr t ion

Copyright c 1992 by the American lnstitue of Aeronautics and Astronautics

-1-

Mk-82 store being released from a "generic" aircraft. It was shown t ha t thse parameters related to the store separation accounted for W A of the total miss dmtance at 450 knots snd to 21% a t 860 knots. h a btw study4 it b demonstrated that one will need to release 15 stores for 20% CEP wcwscy at a confidence levd of 85%. Mddox. in hi. plpw5. concIUdBd k t the aircraft/store interference is important to the cskdatioors o f down range trajectories. h a previous studys. it was

y shown that the separation effect CP&d for the eCW8Cy of cdculations of the ground distances. The peSmt b m 6tf8%1)69 aerodyrrsmic interference

Ve 8 &gi f~sol t tance of a store.

calculates the trajectory o f a store to the img8ct point.

Figure 1: Mk-82 on tbe C.T.S at Irrael Aircraft Industria

The red time cakuiations of the CTS ere

ANGUM5 h4OTlQNs 1 3 0 ° ~ ~ ~ ~ t i 8 YAW

I ~ ~ R O L L

we 2: A Sshcmirtic Chart of the C.T.S

3. The Test Program

3.1 Test Ccnfiguration

Two stores were tested in the present study: 1) A Mk-84 which was released from a single pylon, located a t station 3. 2) A Mk-82 store which was released from all three shoulders of a triple ejection rack (TER) and was also located at station 3.

During the release of the Mk-82 the parent aircraft was loaded tank at station 5. stations 4 and 6. a and 9 and Mk-82 stores at stations 7

Table 1

[Config. # Store Stat. 1 -9 Stat .2-8 Stat .3-7 Stat. 4 -6 Stat 5

I I I I 1 Mk-84 A-9 Clean

i 2 Mk-82 A-9 Clean 37 I

I 3 Mk-82 A-9 Clean 37

I 4 M k - 8 2 A - 9 Clean 370G t

P - I - Single pylon. - TER. @ - Dummy store. @ - Metrlc store.

3.2 Test Conditions

The dores were tested in sirnula following blight conditions:

4. Tests Results d Dkussbn

4.1 The Procedure

Two trajectories were Ntr lbted for each CTS test. h om. th. BDOF poqn, cotrsideted only t k e j e c t h forces, &ed on the atom and the crlcubtkrw were performed uder the ftee rtrewn wdtbnrr. h the second, the program wrsd the d point of the tnhctory, which nna obtrCnsd by the CTS (rimed uepntbn effect), m the stwtkrg point o f i ts crlcuktbrrs.

h the first p u t of t)ris worlt, two CTS teats were conducted with the Mk-84 atore whkh w r s l a d frwn abtkn number 3 (see tabkt 1). The testa were simulathg flight conditions at Mach 0.7 and at Mach 0.85 (see table 2, teuts no. 1 nd 2). The trajectory f9r the test w)r'n=h was conducted for the Mk-84 at Mldr 0.7 with the sa~wrti in effect re ths initid conditions ewtJbited a ground wrar ahotter h 7m thur tb gro which was obtained for the which was c W a t e d udet free a h a m conditions. The difference in the ground distance between the trajectories which were computed at Much 0.85 was 25m. h both Mach nrunben, there was b good agreement between the reports from preukw Mt teatu md tho W t a which

of tho Mk-84.

In the ascond p r t of this work the Mk-82 was tested with the CTS by

its relsaee from three podtiins TER md at three Mlch numbers:

0.7, 0.8 end 0.8 (aae tables 1 and 2). At MIch 0.7 the store wee released from the

lddere of tb TER ( teats # The OW simulation cdcdations

r both bhoulders diffsrences of 17m in ground distances between the

trojsCtwiss which were cslzukted with the separation effect md those which were calculated without it. Figwe 3 presents the the I j s twb of the m@k of pitch (e) and

neb of ?PI for o mkse from the H#ud TER ahddtw CI test # 39. see top md b o t h fw, mspctivelv).

It h oh.rved I( w 3 or, to?) bt!? t)co rbsokrte o f the HOTd flocto~t)orn In 8 of bob ram #e d m k , However Umv &cay fmter d e r the free ahWI l ~ d h b d b O ~ t g(bpWWtkll effect) Um & the proKOmlty of the p u m t rkcnf?. ( 4 t h mpmaian effect). Moreover, in the I a t d direction. ( see fiaure 3 on bottom) the hitid perturbation in q~ at the rwr under the free stream conditons did not exist. Figure 4 presents the time histories of the pitch (top) lrnd yew (bottom) for Me irsboord ( test R 39) and outboard ( test n 50) TER station, retqmctively , w h the cdculetions were performed with the s n e fluctuations in pitch figwe 4 an top) but they have opposite phare in yaw ( see figure 4 on bottom).

in yaw. a t Macho the lower Mach E i numbers. II also eper f w d

CI

Ptch angle ! for the C with the t- I

" - ? F'

tt Z fpf 4 . C ' E K O Q=. :!A CI: .4E

Figure 4- Pitch ( 0 ) and Yaw ( w ) time histories from inboard ( @ -test # 39) and outboard ( A-test # 50)TER station :

inboard shoulder than in test number 4

tests and they exhibited much larger fluctuations in test numbp:r 44. At Maeh 0.9 (test# 36) when the store was released at ~ - - 4 0 ' condition (as at Mach 0.7 and 0.8) from the inner shoulder it exhibited a larger dif ferencs in the distance (43m ) . Figure 6 dornsnstrra greater fluctuations, both in pit

end outboard (test # 34) stations is presented in Figwe 7.

5. Sensitivity Study

A sensitivity study was conducted on the Mk-82 store. The main objective of this study was to explore the effect of separation ( f is t seconds after ejection) on the CEP and on the &viatiom of distances on the ground. The store was given an initid perturbation in the rate of pitch (qo) or yaw (ro) ud the 60W simulation program calculated the distance on the ground. The values for the perturbations were similar t o the veluea which wers obtained dwing the CTS tests.

Eight parameters were ctbosers t o take part

o f 0.

Table 3

Table 4 summarizes the results which were obtained for the Mk-82 when it was tested a t Mach numbers 0.7 and O.B. The first line in the t&le presents a test which was conducted without my pertwbation. The miss distance was 1.3m and the radius o f CEP was 9.5m. The second lirre in the table presents a test h which a pertwbation of - 100 degrees per second in the rate of pitch was exerted on the

not contribute

it

The co*te tn)ectotkw, f m rsk#s to i m p ~ t , of h Mk-84 d th Mk-82 atoms were cJcuktd by ut i lhg r 6001= simuhtlon pmgmn. The pgnn used the end m d t of CTS testa ma rn irput to the aerodynamic dmuktion. It wm found th8t the uwodynwnkr intwfer- wNch b wefted by the parent rlcnft on the atom, 8ffOCt8 h 0FOund dht8lWe6 d@dftcnUy. The diff(#.(\cea in @round &tam8 wNdc wen obt- for the UUt-84 were Mll;lkT ttmn Mom which were Obtw for the Mk-82, to the mJllw ballistic pwwmrter ad the w08ket ejection forco which were exertdl on the bttw atom. Theta h n krmbrl in the dlffemm of @ramid dktmce with the Mach n m b r rrd d#kant vwkt)onr betwow dhtamm wNch wc, obtrrhd for dlffam3 bcmtbon, on

t a d om@

w d wlth pnv obUrrrd In W h t teatn. A a d t l v i t y study wNdr waa conchtad on the Mk-82 by atrtkticrl mUIodr con- tho hypohala a t tho w o d m h t ~ ~ dwhg

affect8 the mlound dbtmma

m cktJkd atudy in which the amdtidty of the effect of aepmUon k mom .igdfhnt. md rmurunbk, It h ow conckrdon that t)n Cqtlv. Trajectory System can be u d u r n#ln tool In pmdicthg the com@ota W e c t o r k r of storarr from rebrim to lmQIct.

1. Anrdd R.J. nd €pest& C.S. "AGARD b h t Test Tedn'rques Ser'les VoLme 5 on Stof88 Ssprrtion Wt Testing*, AWDoggrqh No. 300.

5. Moddox A.R., "Store Separation Trajectory Anrlydrr", 3. Atcrrrft Voi. 17, No. 11 November 1880.

6.rOlknnwrM.,SOIlyM.,-A*, Shruster I. nd C b Ta. "The Olw, of the CTS for Qmdktkn of Tmjoctoriea to tho lmprct Pdnt". ProaWh@rr 8th JOCG Akcnf VStorse ComptPbOitv Qymgosiun, Oct* 1980.