Recent developments in rotary-balance testing of fighter aircraft configurations at NASA Ames Research Center

' ' _"_ ' ' NASATechnical Memorandum 86714

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NASA Technical Memoratidum 86714 _

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: _ Recent Developmentsin Rotary- _

!: Ii BalanceTestingof FighterAircraft ,' , Configurations at NASA Ames I ,

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Gerald N. Malcolm and Lewis B. S chiff, Ames Research Center, Moffett Field, California ii

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July 1985

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i_ . R E C E N T DE V EL OP _ NT8 ZN R _ A RY- BA L ANC _ I _ST ZNOO V P ZOH'r _ R AZRC R A _ C ON F IGURATI O N S AT NASA AH _ R£ S £ARCH C£NTE R Ger a ! d N, M a l es lm a n d bow ie B, S Q hlf f N k gA k gS e Rane a rL h Cen te r, Xo f r o t , t l ; 'le l d , Calif o r ni a 8UI,94AR¥ NASA Ame s R es e arc h C _ n t er ha s an on g oin g r esea r c h pP o gP am to inv es kipt, e high-an gl e - o f - a ttack a s r od y - mmio pheno m ena ss s o o is t, ed w i t h hi g h-p e r f o rm anc e ai r c r aft, , A s p a r t o f this rese ur oh e ff o r t', t, w o r ot,s Py - b alance ap par el,u s e s have r e oent,ly been de v eloped P er t,est in g ai r p l a ne models in a coning mo t, io n . A _ e w • larie - so a le ap pa r at u s, developed f o r u s e i n t,he 12-Foo t P r e ss u r e M ind Tunnel prl m ril y t o p er :i t, t, est i ng _ t, high R eynolds number s , w a s r ecen t l y u s e d t o i n v eet,lgat,e the a e r odyna mi cs o f a O.05- an ale m odel o f t,h e F-15 f igh teP a ircr aft. Ef f e cts o f R e ynold s nu m b er , spin-P a t, e para m et,e r, m od61 at t it ud e , presence o r a nose b oo m, . an d m od e_ / e t, ln _ m oun t, ln g an g le us re l n ve st, lp t, ed.

A s m aller a ppa rat us, w hich i s a m ode P nized versi on o f a es nln8 ri g d evelo pa d ae v e Pa l y ea rs a S S to lnve s t,i g a t, e the a erod y na mic s o f bod i es o f P e V OlU t, ion i n a c on ing m o ti on, has b e e n u s ed in t,he 6- b y 6-Foo t, SupOr s onio M ind T unnel to in v esti ga te t, he a er od yna m i c beh a vior o r a s i m pl e represent, a t i on o f a m odern fi g ht e r, t h e Standard Dyn am i us Mod el (SDM). Effe ct s o f s pin-rat e p ara me t e r and mode l a tt i t u de w e r e ln ves tl - p t,e d. T his pap er pr e sents a d e scription of th e t w o r ig s and a dis c u ss ion o f s om e o f the r e sults obt ai ned i n the re spec t i v e tests.

sno o ts !

A referen ce ar e a , P -15 (0 . 1 _ 72 m 2 , 1 . 52 f t2 ), _ (0 . 017 _ m2 , 0.187 f t, 2) i b win ipspan, P -15 (0.652 m, 2.1q f t'), SDH (0.2286 m, 0.75 f t' ) w i ng m ean a erodyna m i c oll or d, P -15 (0.2 _ 3 m, 0.7 9 7 i t ) , S DH (0.0 8 62 m, 0.28 3 f t) CA axia l f oroe / q A J C£ r ollln _ m om e nt / qAb _ C_ w dC L / d ( _ b / 2V), sl ope o f r olling m o m ent, c o eff i c ien t v ers u s w b / 2V at w - 0 Cm pltohlnsmoment, / qA _ ( ce n te r o f mo men t, at 0 . 25 _ ) ++I_ C n ya w lns m o m ent / qA b (c e nter o f m o m ent at 0 . 25 o ) : " ; _ . Cnu d C n l d( w b l 2V), slope o f ya w ing m o me n t c oe ff i c ient ve rs u s wb / 2V at.. w - 0 " ' _ _ normal f o ree / qA N f ree- s t ream Has h nu m b e r q f r ee- s t re a m dyn am i c pre s su re . . B Reynolds n-mber based on _ !_ V t ree- s t r eam velocit y i! C _ side f o r oe / qA i__ . o anEle o f attack I : ' o s s tin g angle (Pig . q) '+ +: I # 1,2,3 rotational posi t ion a x es ( P ig. 3) w angular ve l o c ity or rota r y appa r atus about the w ind axi s +°iJ _ _ _ angl e of s ide s lip ', . Note th a t P or e s and m o m ent coef f ici ent s ar e w ith respect to body -fi xed a xes, : / ! I : °; : • c ' .

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I, INTRODUCTIO N NA SA A m e s R as ea r ofl C e nt e r s po ns o r s a r e aasr c n pro g ra m to u nd er s t a n d a n d exploi t the as r odynam io ph en o m - ena w h ich sc o ur on hi g h-p e r for m a nc e f i g hte r a ircr af t, p arti oulurl y at high an g l es o f a tt a ck. A nu m ber of r a e ete aom p r i ns t his re sear ch prog r a m , i nc lu ding f urfdm aanta l r lui d - ae o he n i o e e t u d l es , der i v a t io n and verifi- ca t ion of' aer od yn a mic m a th ema ti c al m odel s , e ns e e e m en t o r the a erod y n m lo e e ff eo te on f li g ht drn a mios, a nd the d e velop me n t o f ne w test app a r a tuse s f o r p e r r or m in8 t h e n eems e a ry w ind-tunnel experi me nts, One o r the require d expe r i ment s is t o measur e the a erod_ m omi o properti e s o f a vehi c l e in a con ti n uous e pin m o ti on a b ou t t he veloc it y v e c t o r , som e t i m es re f er r e d t o as a co n i n g mo t ion. Thi n experi m ent r a n be p erf o r m e d w i t h a ro tary -b a l a nce a pp arat u s o r , s i m ply, a rot a ry ri g. Ro ta ry ri gs h a v e b ee n dsve lopud in t h e Uni t ed States a n d a numbe r o r o t he r coun tr ie s in t he p ast f e w yea rs . Soar o r t hese r ig s h a ve been d e s c ri bed in a r e c e nt A O A RD le ct ure ae r ie s (l _ e r . 1).

T w o rotary r i g s ha v e b een develop e d at NASA Amos Re esa roh C e n t e r . The f irs t r ig t o b e dis cu s s ed Is a l a r ge-s c a l e a pp a r a tus f o r t e sting a irpl a n e con f i g ur a tio n s in the A m es 12- F oo t P r es su re W ind Tunnel. This rig wa s d ev e loped t o pr ov i d e a ca p a bili t y f or h ig h- Reyn old s -numbe r ro ta r y-ba l a nc e te s ts. A p re li m in a r y r ep or t on t he de v e loixn an t o f thi s ri g i s giv en in R ef. 2 . T he f i rs t w ind -t unnel t e st us in g this ri g was r ec en t l y com ple t e d on a O.05-eo a le m odel o f t he F -15 f i g h t e r a ircr aft . A v a il a bili t y o f f li g h t - t ea t data f r om N AS A D r yd e n R e e es r oh F_o ili t y wa s t h e m a in rea s on f or c hoos i n g t he F-15 co n f igu rat ion. The f li g h t t es t s wer e conduc t e d on a 0.375-sc a le F-15 Spin R e nsa reh V b hlele (S R V) a nd provided ex t e n sive d ata on s tea dy a rfd n ea rly s tea d y spins. Al th ough t h is p a pe r a ddr e ss es only t he w ind -t unnel t e at a p parat u s a n d d ata , a lon g - t erm o b je ct iv e o f t he rus e ar o h pro g r a m is t o co m p a r e w ind- tun nel an d f l ig h t - t e s t d ata f o r s t e a dy e p l n o & 8 e a ° Th e s econd rlg is a sm a ll- s c a le r o tar y rl l _ t h at wa s o r igin a ll y con s t ruc t ed f o r t ea t s on bod i es o f r e vd lu t lon In t he Ames 6- by 6- F oo t Sup e r sonic W lnd Tunnel ( B E T . 3), and l at e r was m odi f ied f o r e xp lor at o r y test a in t he 12 - T oo t t unnel ( R a r e . Ii a nd 5) o n si mp le a ir p l an e co n f i g ur at ion s . Th i s r ig h a s r ecen t ly b ee n r e t urbish ed w i t h a ne w hydr au lic d riv e s y s t e m an d a s s oci at ed h a rd w are a nd a m ode r n contr ol s yst e m . Th e fir s t t es t o f this a p parat u s w as r ec e n t ly c omp le ted I n t he Am e s 6- b y 6- f oo t tunnel us in g a s i mp li f ied v er si on o f a s_ Dde r n l 'lgh t er a i r cr a f t , r e f er r ed t o a s t he S tan d a rd D y na m ics Hodel ( S DM).

Th i s pa pe r I s a r e p or t o f r ecen t p r o gr ess i n t he developmen t an d us e o f r o ta ry rig s at NA S AA m es. So a r ex a aplea o f d _ta r ecen t ly o bta ined on bo t h a p pa r atus es a re p re sen t ed. Th e de ta ils o f e a ch ap p a r at u s , ar e a ddre s sed in Sec t ion 2. Si m il a rl y, t he r e su l t s o f t he Indi v idu a l rind- t unnel ex p e r i m en ts a re dis c us sed I n Section 5. Bot h r i _ e use a oo _ on data-acquisi t ion system an d share a co ,m oon da t a-reduction technique, a nd they a re di sc us sed in Sect i ons 3 and _1.

2. DESCR IPTION OF WI N D-TU NN ELF A CI L ITIES A N D A PP A R A TUS ES 2. 1 1 2- F oot P re ss ure Wi nd T un nel A ppa r atu s Th e objecti v e s f o r t he f i r st test o f thi s ap par atus in the tun nel were three- f old. Th e f i rs t was to i ns tall an d cheek t he a p paratus an d all asso c iated equip m ent an d i ns tru m entatio n i n t h e w in d -tunnel en v iron- men t . The s econ d was to a c quire ae r ody nsm ic _ ata on a f i g hte r ai rcr a f t m odel in a s p in m otion at v ario us attitudes (¢1 - -5 • to 90% B " -15 ° to + 15 °) at Reynolds numbe r s r_ nBlng fr o m 1 to 5.5 million based on w in8 m e an ae rod yna m ic cho rd . Th e third was to acq u ire wi n d-tunnel data t ha t co u l d be ns_ d for oo m parl an n w it h t h e Dryden S R V f l ig ht-teat data. Sin c e t he SR V had a rather lar s e nose boo m to m easure model at t itude and speed I n f li g h t , the w ind-tunnel m odel was t es ted both w ith an d w ithout a nose boo m . _ - , 2.1.1 12- F OOt P re ss ure W ind Tunnel T he 1 2- F oo t Pre ss ure Wi nd T unnel i s a var i a b le- p r ese m ' e , lo w - t u rb ulence fa cili t y w i t h a t o ta l pr essure capa b i lity ranBe o f 5.0 at t n. Math number ran be varied f rom 0.1 to 0.981 ho w ever, beoa un e o f the solid-wall t es t se ctio n and li mi ted po w er , operation o f the tunnel beyond a Haoh nu m ber o f 0.5 y ie lds q uas tlonable i!

results. A un i t Reynolds nu m ber up to app r ox ima tel y 25 m llllo n/ m can be obtained at H - 0.2 _ . !_ 2.1.2 Ap p arat us a nd Hodel Th e r o tar y a p parat u s _ ,nd t he m odel w i t h t he nose b co m atta ched ar e sho w n I nsta lled on a l a b o rat o r y t es t s ta nd in F i g . 1. A pr o t e cti ve enclos u re su r ro un d s t he a pp a r at us f o r s af e t y p ur poses w hil e i t is r o tat i n g.

Th e r ig a nd m odel (minus t h e no s e boom) i nsta lled in t h e 1 2 - r o o t t unnel t es t sec t ion are sho w n In F i g . 2 . A ske t ch o f t he a p p a r at u s i s s ho w n in F ig. 3. F or e f f ici e n t ope rat i o n in a p r essu re t urmel, i t Is ms aen t i a l t o m inimiz e t he n umb e r o f t unnel e ta r t up e a nd shu t do wns nea ee e a ry t o c ha n ge m odel att itude. To a cc o m pli s h t his , t he r ig wa s desi g n e d w i t h elec tr ic a lly d r i ven mo vab le ar m s w hich p ermi t r emo t e c h a nge of' t he a ngl e s o f attan k a nd sides l i p . Th e de s i re d a ngl es ar e ob ta ined by ro tat ing tw o a r ms on t h e r i g ( wh ile i t i s s ta tion- a ry) a bou t t h e a xes 0 1 a nd t 2 as sho w n In F ig. 3. ? he s s a xe s in t e rns o t t h e s p in a xis at t h e desi gnat ed longitudinal loca tion on the m odel rep r e se nt i nE the ns nte r o f g r av ity of a f ull - a esir, free-flying vehicle . By using a straight, base- m ounted sting, the a ._ le of lnoi ds noe oF the mod el w ith respec t to the f lo w can b e va r ied from -30 to 30 ° . By top- m ount i n g the mod el on bent etir _ e ( Q a " _ S e and 7Or) , th e an g les o r atta c k and side s lip can be var i e d over the envelope sho w n in F ill. q ( u fr o m - 3 0 • to +1 00 • w i th b et w een _ 30o). F igu r e 5 sho ws a p hoto g ra p h o f th e m odel m ounted on r as h o f the three at i r _ e. _ r e m otel y I _ | driv e n eount e rw els h t ( Fi g s. 1 -3) was po_i t i o ns d to s tdt io al l y ba l a nc e t he m ass distrib utio n of' th e s yst em about the np i n axis p _ l ur to r ota _ lhS t he r i g. Po tent iom et e r a m ounted on the a rms Save remo t e indiom tio ns _l o r th e posi t ion s o r t h e arms an d o r t he coun t er w eigh t p us l t ion, The a _ pore t un i s ro ta t e d a bou t • n a x i s pa ra ll e l t o t he w ind- t_ n ns l •i r e _re am at speeds ra n g ing f r ee 0 t o 37 re d / s e e (0- 3 50 r p m ) in e it h er a clock w i s e o r esu n tor ol on k w l es di re c t ion u s i ng a se r qo -os n tr oll e d hyd rau lis drive s y s t e m , _ 1o attem p t was m a de t o dyn M le al l y bal anc e t h e s y s tem . The ma gni t u d e o f t h e e en - tri f up ll y induc ed d yn a u u lo mom en t was, in t h e w urs t a es e , as mu sh as _ 5,200 ) l . m ( _ 00,000 l n.-lb), Be ususe O r t he large d y na mi c loads exper i en c ed b y t h e f i x e d par t o f t he ro t dr y rig an d t h e tunnel s u p po rt s y s t e m , apa el a l p r ovi s ions were u d b to se cur e th e s ys tem a s r igidly as pa ssi b le. Th e o e n tur bo dy o f t h b OUl _ P urt s y st e m is no rma lly t raverse d and pi t ched on the ver t i ns l b l a de str ut t o vary the mo d b l a tt i t u d e. F or t_a t es t, t h e cen te r bo d y was r i g i dly f as ten e d t o t h e s t ru t w ith th r eede d p i ne t o p re v d n t a ny mot ion b et w ee n t he r i g/ oen ter bod y a nd t he tu nn e l s tr u t . To eliminate p os sibl e r es o na nce o f t he r otar y - apparatus / t unn e l a upbort sy stem, i t w a s de s isned to h a ve a n at u ra l f re quen c y a t l east t h ree t i m e s the maximum r ot ati on • l f re qu e ncy o f 37 P a d / s ee.

" Th k model i s a O . 05 1os le v ere x o n of an F- 15 f ighte r es n fi l _ ' a tlon w i t h tw o nos e con f i g ur at ions a _a ll - able, one with a n o se boo m and one with out. Th e cen ter o _ moment a is at 0.25 o f the mean aerodynamic eh ur d el" th e w in _ . Th i s location i s also the oen t e _ o f ro t• ties o _ " t he mo del a bou t the s pin axi s . Contro l de f lec t ions s an b e chansed manual l y. The ho r izontal tails e _ ln be v aried at a n y desired angle in 5 • in ur e- ma nta. Th e ail e ron and rudd e r s ur f aces c an be set •t 0 • or a t the max im um angles o f _ 20 • fur t h e a il er ons a n d ±3 0 _ f or the r udders, i . i The furos s an d m um_ n t e are m easured u s ing a 5 . 08-m _ (2 in.) diameter, six-so=portent , sir•In g a _ hal- i1 ari es m ounted in the mod el . Since the spin •xis o f the ri g i s pa ra llel to t h e _ lnd strea m , co ns tan t an g le s o f • it•ok and sid es lip are mai ntained d ur in8 a r o t atio n c ycle. Th us, th e r esult i r _ bal anos output i s son- i: : slant _ t an y g iven rota ti onal speed , ex c ep t _ur c yclical v ar ia t io ns due to model w eig ht and aerodynamicall y i_ 11 ind u ced unstead i nes s . Th e one-pie c e balanc e, co nstr ucted es peci a lly f o r use w ith thi s a p paratus and m odel , os n be at t a ched to the sting through the rear or th e to p o f th e model. Electrical po _er and all _ L l p a t hs f r _ n th _ balance ar e provid e d b y a ellp-r i_ as semb ly m ou n ted I n t h e oir etLl ar ho um ln _ near t h e strut _ . : mo unt . The slip-ring assemb l y al s o car ries the po w e r le ad s t o th e el ectr i cal ly driven mova b le arms and th e ,' slSnals f rom the arm-pos i tion potentl on eter s , a resolv• r is mo unted on the rear o _ th• s li p -ri ng unit to _ m e as ure the angular po s i t i o n oF the r i g about t he spin axis. A tachomete r to d etermin e ei _i n rate Is mounte d o n the hydraulic drive motor s haft. _ " _ eoa _ e o _ th• ext r emely l arg e oent r l f usall y ind u ced o s cillatory loads on the appa r atu s an d t he t un nel !

su i _ po r t sy s tem ( os u _ ed by the l arg e d _, na _l o I m balance o _ th e ri g ) , an extens i v e amo un t o f data w a rn collected ; _ continuously duri ng t h e tes t to monitor the struct ur al integrity o f the appar atus an d s up po r t. Numerous _ • loo •t lo ns on the ap p ar a t us and the tunn e l s ul _p o r_ s_tem _ e r e ins trumented w ith s train s a _ e s to mo hll : ur ampli t ud es and fre q ue n c ie s . In a ddition, pr es s ur e i ns tr um enta t ion w as used to mo nito r the important pr es- . ' _ t st r e s s es, e ddy-current pr ox i mity p rob es to m e asur e de f lec ti ons, and ao os l urume t ar a to m ea sur e the v i b r ation c ure s wi thin the hydr a ulic dr iv e system . Although es s ential to acr e ope ra tion o f the ap par a tus , t he _ onl- _!_ _ - .I . toti ng instru _ -ntatlon I s not di s cussed fur ther in this pa per. I i_ _ 2 . 2 6- by 6-Foo t Super s onic Mind Ttulnel Ap p arat us

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- -_I ' 2.2.1 6 - by 6-F on t Supe r sonic W ind Tunnel 4 " The 6- b y 6-) ' oa t _ ul _ e reun io W in d Tunn e l is a v ar iabl e -l _ reb• ure t un n e l w ith a tot _ il pre s sure rang e o _ ! 0. 3 t O _ .0 a t m . The Hash n unber can be v ar ied f r em 0.25 to 2.2 continuously. R e yriol ds num bers to _ , 1 5 • 10V i m can b e a c hiev e d . The t unn e l has an es y m_• trie s li d i ng- blo _ k no zz le f ur o hs n _ ln8 H mo h nu m ber end • _ , a test section w ith per f orated f loor and o eilln8 to pe rm it t es tin _ •t transo n ic _ ae h s u gars , .!

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2.2.2 A p parat us and Model : _ • i Figu r e 6 Is a diag r am o f t he small-scale rotary- be lan os a ppa rat us . A h yd rm ulio mo tor is used to t ur n • i!

shaft aUgne d no m inally pa ra ll el to the wi nd-tunn el alrm tr as m . Any one of a s er ies of int er o hs n g eable bent '_ : e _ inl _ ca _ b e a tt ac hed to the r otati ng shaft to vary th e ar _ l e of l ne ids noe with r espe ct to th e alr at re m .

" Th e sti ngs a r e designed to suppo r t a model off a s t rai n-s ag e balance at p i tch angles ranging f ro m 0 to 3 0 • _ w h i le keeping the s ame axial mod el station on th e ax i s of r ot at ion. Th e ri g f oll on e th e _e b esi e concept , _i _i• en d us e s the s am e bent a l i ne s, as an earlier r ot ar y-t _a l an oe a ppar a tus (4 emor ibed i n R e_ . 3), but it i s consid er abl y more s ophi s ticated in that it uses s pe e d and po s ition as ns ur o and t h e esrrospo ndin8 fes db mo k i!

_ . control loops (si m ila r to th ose o f the 1 2- f t t un nel a p parat us ) to give t h e ope r ator cl os e control o f e i ther il the s p eed or ansular pos i tion o f the rotat i n g s ha _ .

Th e b al anoe us e d Was a standard six-compo nen t ? a sk Co rpor a ti on _ .81 o m (1.5 i n.) dl em eter I _ ( X _ XA i , b alan c e, with all p c _ e r a nd s ignal l i ne s routed th _ o ng h the bent sting and the sha f t of th e hy dra d l i e -i motor. A s et o f gold slip ring s and b r ushes w a s used to t r ans fe r the si gn al s to the n onrot a tin s portion Of • t h e ri g . H od el attit u de w as s et by adjus tment o r the pitch and roll a ng les of the mo del, Pl _ oh an g les w ere dete rm ined b y t h e choice o f bent s tieS, and r oll ansl es b y c h oice of • f ixt ure located bet w een the b al enos

I

_ : and t he mod el w hic h m aintained a s et roll angl e . A set of such roll l'ixt uras w as a v a ilable, inol u din8 one { f o r u se u i t h all b e nt stin gs giving ze ro si de slip angle, a nd one f o r e a ch of the b e nt sti ng s to o b tain I.

_ ' _ The rig I s oapabl u o f be l n8 d rive n s t r otat iorl ra t es f rom 0 t o 6 3 ro d / se e (600 r pe) in althar 4 tr eo- _ lio n . S i ne s t he rot st i n 8 parts _ s n e i th er s tat io s lly nor d yn em L oa ll _ b alanced, the oantr t f ug al l Y in d u oa d i s d es ilPte d t o w | thota nd t he se load s , bu t s o m e add it io ns , m easu r es we re flee esas ry t o p r even t axo o asl vo _!_ : o an llla t ory loa d s _ n ara t ed on the n o n r o t sti ng st ruo t u r " . t ..ximu_ rot.,lon rst . a t. q ui t. l ar S . . Th . P ig de f lec t ion or t he rig s u pport, s t r uctur e in t he t unnel. The tu nnel's bod y o F revol ut io n , wh |o h i s v o rt i oa ll y _ _ s upport ed by lead sa r e w s an d laterally restr ai ned by roll ars , wa s O lBPO d ri s l dly t o th e v ar t l o8 1 stru t i n _ this ease . Br as s pad s war s ins ta ll e d b stwas n tha body of r e v olu t ion an d t he v e r t i oa l ot r ut t o dis t ribu t e El t he load an d p re veri t damage to t h e s t rut , s ur r a oe. I n add iti o n, a p ai r o r di u on al br anas, sx tan dlng f r a n • - t he L se din 8 sdSe o f t he v art l oa l stru t t o t he t unnel f loor , we e ir wtal l od t o restra i n laterdl mov U sn t o f _ th e rL8 suppor t . Vi b ra t ion em pli t u d o s , in bo t h v art i oa l an d lst ar al pllin as , ware m o nL tar sd b y a oo alar om- -_ s t eps mou n ted on t h d bo d y of' revolu t ion, an d t hes e oon f lrmod t ha t no exo ass Lvs v lb ran io n le v els oo ourro d • : :-- w hile the rig w as runn i na.

hol d ini _ 8 mi nia t ure vid e o or m ovie on= or s, w i t h po w er an d al a na l line s ro ut ed throu sh t he p r ev ious l y m en- _ t i o n ed slip ri m8 set . Th e armor s view r. t hs uppe r sur f's e e o r t h e m o d el , and sin es t h s oamer a and m odel ro tata t og ethe r the mo d e l imase re= d i ns s tead y regardl ess o f' the mo t i on of' th e ri8 . This f eature w a _ inol u ds d t o ena b le vapo r-sor se n In ve s t iga t ions o f. t he beha vi or o f' t h e vo rt ex w ake of' ths mod al lh # as [ _ n ab t o oon | ng mo t i on.

_E '/ _ _ Fii ur e 7 is a photo g raph o f' th e m od el (d se iKnated ths S ta ndard Dynamios 1 4 _ )d el , Si) N ) u s ed In this i n ves- o i-_ . tlgation. Th e basle planf'o _ i8 that of a o urrent hi _ - p erf'ol _ nanoe a _ rora f t oon f ll _ atlon. I t w as d el iber- at el y d es igned for m anu _ aot ur e by s i m ple mach i nise t an hnl q uea to enoouraae Its w idespread use 88 a standard m_ e _ )d al Fo r tsst i n8 In 41f. _ er e nt wind tdnn al s and on dl f. f.eren t d ynamlo tes t rll _ s. The mod e l mus d as l _ nod and _oi! " "; manufaoturs d by the Ha t lon al &er onau t l o al E _ tabl i shmeht (H _) , Canada. A more o ompleto deaor ip t _ on o f. it s _ _ e _ st r y an d ehara ct s _ 'l s ti e s 18 no nta l ned I n Re f's . 6 and 7. Th e oente r O f' _ o _ en ta was looatsd at 0.35 o F the w in8 mea n asr od ynaml o chord, whloh was oo i nolden t w i l l1 the renter of' rotation oF the mod al abou t the _ spin axis.

:_i_;_ " i • ; 3. D ATA A C _ UISITIO _ M I D EZDUC _ IOHS¥STE _ _ :. The data fo _ " b oth rotary-bal an oe a p parat _ ss s wer e t ak en and r od u od d with a oo _ n O n stand- al one o _ loro- _ _ oo _ ut ar system. Co n vsn t lonal analog 8i _ n al -o o nd tt ionlng equ l lm an t w as _ ssd to p r oo em s an d f' ll t e r t _ le b alan oe an d tao bo_ ete r s ign al s, l.o _ - pan 8 f' il tar ln8 o f' the balanoe s ign al s elim inated the o so lllat ar y s la- _ rial s due to model wei g ht. A sp eo lal data-aoqu _ slt i on unit proo es Sed th e signal s f' r o _ th e I _ Llanoe. shaf t - _ . _ tach em et ar , r ig anaul ar pos _ tlon snootier , an d (i n the o an s of' the 12- _ t tu n nel _ lpparat ue ) t h s a _ -po al tlon po t an t i c _ et ars . Tunnel conditions, l n o lu dl ng tunnsl t em p s r at ur e an d pras s urse , w ere routed t o the S yste m by

:_

, , _' par al l el in _ the oon v ( _ ntlon al tunnel senso r s.

: .i_ In addition to the data-aoqulsl tl on unit an d the main oan t r al pr ooe sal nK unit, the da ta sy s t em inoludsd ; o! , a d ue l f' lop p y disk dr i ve, external printer, an d a m ult l oolo r on-line plotter. Th e da _ a s y s t em pr ovided no,p lots on-l i ne listln88 an d plots o f' the 81x f' o r oe an d mome n t ooe f'f'l oLe nta as a fun ct i on o f' the a p w atus o_ * spin rate.

! : _i 1;. ROTAR'_ AND ST A TIONAR Y TARE MgASUREMI_ IT S - '_/ Th e re ar e three types oi" f. o rose and mo m d nt s a ct ing on t he balarioe wh e n the a Pl _ ' a t ue and _ od al are i .. _' :' rotated in the wind tunnel. The f. ir s t are t he inertial f. oro es and _ ent s due t o the mom e n ts o f' l _ ertla OF : the rotat i n _ model. Th ese v _ ry w ith mod el attitude arid rotatio n 8 pood , an d may he oo _ p an sat od f'or by mo o- ! _ s ur i _ w ind-o F f r otatln _ tares an d s ub traotlng the _ f. ro_ the w i n d-on data. The seoond ar e osolllato r y ' f.ur o em o aasod by the ohanas in o ri entat i on of' t h e mode l _and re l a t ive to i _ . avit y, k X t houah i t i s Ix _s Lblo _ : _ t o aooo un t f o r these f. o r oe e an alytl oa ll y , th e y were eli m ina t e d i n a more s tr a laht f. ore ar d e _ ahner by lo _-_ uts f. il tar in8 the h elan oe eiKn al s. Th e remainin g Fo r o as an d m_ ents ar e ths ae rod ynamlo l oa ds of ' interest.

/> i .

°_ / " The maan i t u de o f ' the inertial l oad s o _ n b e oslotlla ted in a s tral a ht f. o rw_ L _ d _ e r l _ the _ aent8 oF i : ' _ ' i inertl4 about the p r l no ipal axes o r the m odel and the lo oa_i on of. the mod el o ent ar of' muss w ith r aspo ot t o .... i th e rotat i on ax i s ar e k nown and do not v ar y w ith r otstio n rat _ . He , e v e r + th s model / a lin e oc _ bt n a tl on " " I d e fl e ots durin g rot a tLon, an d wi ll oa ue e ths aot ue l ln _ tl al loa ds to var y f. rem _ h e a nal ytl .oall _ det eralned " " _ valu e s, Th e r e f. o r e, i t i s n e o e ss ar y to me as urs w ind-o f t t are loa d s at th e mod e l attltu da an d rot a tio n rates -- ' _ ' i pl an ned Fo r the w in d -on testa. The se m e asurem ents ar e stored In the d a ta -an qut al t i on sy s t em and later " _ _ 8 ub t r a o te d f'r om the w ind-o n m e as u r ements.

-_ Fo r aoo ur aoy, t he i ne rtial tare lo a ds should be measure d with the m odel ei th ar in a oo _ plete vao uue or I _ sur rounded by an enolosure that rotates w ith it. T hi s w ill pr s van_ any i nt e r aotion of; the surr oun d i n 8 still a i r with t h e model ns it r otat es . Ho w eve r , in a r ms o ases, d epo ndinS on s un h r an to ro as mo d el e ls e, ro ta tion ta r e values m eas ur ed i n the olo _ k w l s e and o ounte r ol no k w iss dir an t i or _ w e r e av er aged. Fo r the eas e w here the " ' _i! rat e s, a nd e xp e ot od w ind-on l oa ds+ the no nt r ib u tion f.ro e thLo e f. f o ot ann b e 1s no red . In thoas test s, the sid es lip ambl e is s e t to zero, ths e FFe ct s o f. th s s urr oundln8 air on s i de f. or oa, ya w ins meman t, an d roll i n s _ : : "_ m oment should be equal and opposite in 8San. In this o se s , a var_l n _ the m eas ur e d valu as Is nearly th e same : o- _ ' . ii an mo ae uri n8 the tares in a v acuum. Ho _ eve r , the offsets on normal r a re s, p i tohlni; m_an t , an d ax i al tar os _ : ! ar e not e liminated by a v e r a Ein8 the m eas ureme nts f ro m both ro ta tional d i re ct ions. It is f elt that t h e I; OF P( ., .:_ . . : [ , ! L . , .... " k , st ill- a i r loa ds a r e sm all enou gh t o i g n o re , pa r t l o ul arly r ot thes e exp e r i ments whe r e the Ine r t i a l l oads an d the air io a d n are v ery l arge ;n s em p er | s on.

Ty ploall y , w i n d- o f' r r o r oee a n d mome nts w or e d e&ermi ne O s t se v eral f i x ed ro tati on rat es ra n g in g f r om 0 t o t h e m axi mum r o t eec h ro ta r y rig. Th e r s e p _ot i v e r o r o e n end m om e n t s _er e ti t w i th a ri ve - t e _ pol ynom i a l o r t h e f o rm F - A 0 * Alw _ A2 _ * A3.3 * A _ . g w here F t a t h e fores or mom en t a n d w is t he r o tati on rate. T he Q o er ft oi en ts A 0 t h r o ugh Aq ve , ' e th en sto red . The e em e proo ed ure w as u s e d f'or ro tat ion i n th e oppo s i te dlreo t ion. Th e tw o s e t s of' eoe f.f. i o i an t s we r e t hen av era g e d t o orea te a com bi ned t ar e f. i)e o f one set o f. oo e f. fle l e nt s t h at w as ap pllo ab le t o a 11 • ro ta tion ra _ e8 fo r t hat pa r tiou L er angle of' att a ok and si de s lip.

T h e o r i gin a l Ln t en t was t o m e as ure all the rotatin g tars loads in t he 1 _ ) r ato r y prior t o l no ta lXin s t h e a pp arat us Ln t he t unn e l, a n d store t h em f o l ater use dur in8 t he t unnel t es t . T h e p ur po s e w as to s li m i - i " na _a th e e xpend it ure o r val ua b l e t unnel oo oupe n _y time t o per f orm th e tar e m eas ur em ent s . T ares unr e, In f. ao t , m eas ur ed pr io r t o tun nel L na tella t ion , bu t i t yam s oon re c o g nized, a f t er repeatin g some tar e m eas ur e - m e n t s I n t he t unnel, t ha t t h ere was enough varl at io r . Ln t he m eas urem en ts ( wh en com pare d t o th ose prev i o us l y acq u ired in the laborato r y) tha t ne w t ar es wou l d have to be m e as ured i n t he t un nel. The d i morepa _ o y was o aum ed by a mll di r f. aran oe bet t ed t h e etl rr n ass o r th e su ppor t ayetm i n the tunnel and t h e laborato r y w hl o h r em ult e d In a dl ff.aranoa i n th e de _ 'l e ot i on o f th e mod e l oa n tar o f. mas s r s la t lve to the rota t lo n a xi s fo r the t w o suppo r t sys te _a . ._ An add i tional o ff set o f dsf. leo t lon is the ehe n g e i n po si tio n o f t h e model w it h r as peo t to the rotatio n axi s o aUsed by th e w ind-on loa d as oo m pa r e d to the w ind-o f f condition. This o f. f ee t oannot e as il y be a oo ounted f. o r and, si n e s i t y es f. el t t o be mll , no a t tempt w a s made to s o ft es t t h e w i nd -on data .

W hen data ar e t ak e n w ith t he m odel s t at ion ar y ( w - O) i n the w ind tunnel w it h th e w t n d on , the w eight _ of the m odel mus t be a oo o unt ed r o _. (Fo r t h e eas e wh er e the m odel I s r ot at i n g, the w e i gh t I s a v e r aged to

t

a r t 's o v er a o y o le b y us ing lo w - pe as analo g filte r s.) Hods1 w ei g h t is a ooo un ted f. o r by pe rf o _ l ng a e , m rl em o r v lnd-oi' r sta tlo t ar e m eas ur emen ts at v a riou s kno w n an g ular pos it ion s a r o un d the r otation a x is and d et e r- m in i ng t h e w e i g ht e rf eot on t h e bal s n oe. The m m Xa h t compon e n t on the balan c e w i t h th e w ind o n i s th e n ._ oalo u dated , us i ng t h e ang u la r pos ition o r th e r i g wi th re s peot to the tun nel and the atti t u de o f t he m odel | w i t h ras peot to f. h 6 _ i8.

• i

: , 5. _ P£RIHE _ I'JU , R F, SULTS _ _. 1 1 2-Foo t T un n e l Experi me n ts • r The offse ts of. a nu m ber o f. var i able s o n the a e r odynem tos w er e ex emin ed d uring this experi m ent.

! { lnoludsd ar e var iations in R e y n old s nu m ber, angle s of att a ck an d sides l ip, sting an g le , and the p_e senee of.

a I1os e boo m . A Hash nu m ber o f. 0.28 w as 8sle e ted _ or t he e _ Jor i ty O f. the t est s , sin es thi s _ x im iz es the Itsynol da nu m b er os pa bl l i ty o r t h e tunn e l, late r i n t h e test pro g ram, i n o rder to obtain lar g e r values o f.

]

the spin-rate para m eter _ b / 2V (wher e b Is the span and I / t h e tun n el f ree-st r e ss val ooi t y) , s o m e r un8 i s er e o on duote d at a d e c reased velo o it _em u l t l n g In a 4 eureana o f the Naoh su mner to 0 . 2. Ccmpar lso na w ar e negli g i ble. T h e s erod yn em lo se e r.r e. . ants deter m ined ln o lude d _ no rm al f or e& , pltohl ng mom ent, s ide bo_ . w een the res ults m ea sur ed a t Has h nd 0.28 Indl oa ted that e lf. sot s due to t h e ohange in Hash nu m b e _ ! ( fo re s , y a w i ng moment, an d r olli ng mom en t a. _ xlal t er se w as also m eas ured , b u t I t wee not de t r a in ed w l t h L b_ . - _ a o o a ' _oy oo mpe rab l e to th e ot her o ompo n ants , nor w as i t f. e lt t o be pe rt io ul an l y imp o rta nt _ 'o r t h e s e teats.

: " Th e _ 'ollo w i ng di s s ua sion viii int rod u c e some examples o f th e da ta obtained d ur ing this tes t an d will h i , h - i l i g h t s ome o f. the more int er e s ti ng r es ults. :: " • 5.1 .1 Static Ae r od ynamic Data i The varlatior _ of. the surre al- f ore s and pitoh i r _ -em _ ent oosf. _ lol _ nte w ith ang l e o f. atta o k are eho_n _ 'o r !

th e oor _l auration wit ho u t the n o s e boo _ i n F 18 . 8. Results are s bow n f. o r R eynolds nu m b e r s o f. 1.5 m illion - an d f _ _ .0 o r 5. $ million. Also 8 no un for oom p erta o n ar e the da ta obtained at m ush lO W er ae y nolds nu _ b ar 8 i i (0.2 m illion) on a r ot ar y r i b i n the N A SA l a lna l ey R ase a ro h Cen t er spin t_ nn al ( R e f. . 8). As ex pl ained i e arl ier i n th e d eeo ri ptio n o f. t he a ppara t us , data wer e aoqu i re d w l _ h t hr ee d i f.fe r ant st i n g s but at soms s t r a i gh t base-mo un ted sting and t he to p -mount ed _5_ s t in_ . Bet w een m of. §0 • an d 70 • da t a were obtained on - both the _ 5 • and TO • _ lng s . Th e over l apping s et s o r data are s ho w n in Pi g . 8. A s san be ae o n _ 'r om F ig . 8, _ ii ang l es of. attaok there 18 an over l ap or the d a t a . Fo r e xample, data w ar e ob t ained at • - _ 0 _ o n bo_ h the : i , th e n o .el- f or es see r.fast es t pe ak s b e t w e e n _ of 35 • a n d liO • an d rm ml na a lmo s t oo na tan t f. er ! , t _ 0 e £ d S 90% exoept rot a s light d e o _e ase betwee n a o f. 50 0 an d 60 % Theme is som e var i a tio n w ith il • Reynolds n umbe r and, l nte ras tl r _ l y_ t h e t r end in di r sotlon w it h R ey n ol ds n t _ be r i s o on sl st e n t w i th t hs d ata i' ) f rom the Langlsy r ot ar y r i g , The r e ar e n o t io as ble dl rr e e an o es , a s well, d u e to t he d i ff erent st i _ " )_ angl es . The mom e n t aent ar f. ur _he pitchi ng -m om ent ooa rr i ol an t data Is t he 0,25 po sition o r the w in8 m ean " 1 as rodyn em ia ahord, The v aria t ion w ith Rey n olds n um ber i e pri m arily oaused b y the beha v ior O f. t he flow over t h e fore bo dy and f us ela g e an d not by variation s of the flO W over the w in g and t _ il surf. aa es , l_ i e is pe r - tio u l ar ly tru e at t he h ig he r an g les o r attaok s i ne s the f. lo w alm ost as s ur edl y se p arat es at th e wi t _ leading edge re ga r dl ess o f. th e R ey n ol d_ nu m ber. Con v er as l y, t h e Plo w s ep ar a t i on ar o und t he f.er e bo d y and th e round e d v 'w j c orne rs o f the in le ts, and the r ns u l tt ng va ri a tio n o f th e forc ed e nd moments , a r e kn ow n to b e se n s i t iv e t o ' Rey nolds n um ber .

_ 7 Th e v ar i at i o n o f t h e ya . tnK- 8n d r o llin _ o man t ooe fft e t ento w i t h en s | e of a ttac k , fo r a ran ge of Reyn o l ds number _ var i at io n o n the ya w i ng - mom ent c oeffici en t fo r a _ _ OO e and v ery l itL l _ e ffec t o n t h e rolli ng -mo men t c oeffi c i e nt at al l angles of att ack . At anglos of a t t ac k .he ro si | ntfl es n t e r nss flow s e p ara - tion exi s ts, R e y nolds nu abar v ar ia ti on mainl y a ff ac t s t he f low ov e r the fore hody an d t he fus e l age . T hs r ac u Z ti ng d iff e r e n o t s i n th e fo rce d and m om e nts w ould be e_ p eete d p r i eaw i Zy i n t h e y a w i n g me m ant . I n add i- tion, the e ff ects of di ff eren t s t i n g an s Z en a r e a l s o s i zab l e, pe t i te "ear l y at R - 1.5 m illi on . The p r im ary e ff ect of chang i ng the s t i ng a n g l e i8 t o [nfl us ns o t h e l e e w ar d fl o w fi e ld a n d t h e resulti nB in tera c t ion o f ,: t h e l oan i da v ert i ces over th e f usal aa e a n d v er tic a l an d ho r izo nta l tal l sur f aces , lttn y o f t he st udi es that have b e en don e t o inv estt p to th e as y m et r i e v o r t ex phen omen a on ogiv e -e y l i nd ar bo d ie s at h igh a n g l es of attack ha ve s hown t ha t th e m ax i mum u _ ee t r y and r e s ult in g valu es of a i d e f ores and y a w i n g m oment o d our b e tw e e n a of 50 • a n d 700. The re s aZ _ s of t his experi m en t ar e o o ns ie ts nt with that ob se r v at ion. There a pp ea rs t o b e a sli gh t bias in th e dire ct ion of t he roll tng -mola ant co e f fici en t at all t _g l ns of a tta c k althou gh t he si de s lip le suppo s edly zero. I t is possi b l e t h at the r e I s s ali g h t an ymmtr y i n the m odel o r p e r ha p s a ve r y s mall sid eslip a ng le ususe d by mt an ll j pmaen t of t he m odel in t he al r s t r ea m .

, t st m il ar pr tm an ta t i on of the y a w in g - and r olli _ - e mmm t d ata is a l _ m in Fi g . 10 f or t h e m o ds l wi th th e nos e boo m i nstal l ed. Ag a in, th e v ar iation with a _ y ne ld s num b er i s f a irl y sl _ nifi eant fo r e ntri e s of _ a t t a ck g r e et e r t han _ 00. Even m ore i n t eres t ing, ho w eve r , Is the c ha nge in the co effici ents , par t i c ular l y t h e y awi ng -momen t ooeffi s L an t , w hen c o m p ar ed t o th e b o a -off can e show n In Fi g . 9. kt hi ghe r a ngle s of i ; _i ] _" a t tack , t he pre,sen o e s t the no s e hoom os n si gnifica n tl y alter t h e v o r t e x flo w fi e ld on the fo r ebod y and i_1 notloe a bl _ l n f l usnos th e resul ting m_ ent s. F or e x am pl e, a t a - 60 ° with a s tin g a nlrl c of _ 5° , _he ya uln8 ] mome nt sho wn In Fi g. 10 at R - _. 0 million has th e opposite 818 1 1 to that 8 he w n In Fig . 9 . H o we ve r , i t to al e s app ar ent that the st ln 8 a n g l e ha8 a ma jor I nf l U ence o n the re s ult. Thi s san be s een b y _ pari ng the data at a o 6 0 • and R o q . O eLlll i on fo r s t ing an _ea of _ 5 • and ? 0 e (Fi g. 10).

_ " The I mplication o f the r es ult s s ho wn a _ e o er ta{nly o f s om e oono ar n f o r determ i n i ng the a ar o d yn anlus of _ oo n r _ r - _ ' atlons at h igh an _le s of at ta ck. The dl f f ar e no - _ caused b y the p rese n ce o f a no86 bOOm I l lus t ra t e - _ th e ;l tlv l ty of the aerod ynami es to the for eho dy oon _ i _ 'a t lon. Since many fl i ght - te s t ai rcr a f t employ a _ -. _j . _ ; nos e _ o _ to acqui re air da ta, the r e san be s i g nific an t dl f f er en es 8 bet. sen th e ae r ody ns d i_ of the fli gh t- _ teat ai ror a r t an d th e o pe r a tional ai rer a _t whi c h, t _ pi es lly, do n ot have a nod e bo om . The d|ff e r ano da i _ ob serve d due to the stin g an g le also ill us trate th e pr ob l em s of su p porti n g a m odel In a wind tunn e l a t large _ - _ . in c id e nces wi t ho ut alt eri ng the lee ward -sid e flo _ f ie ld.

5. 1 . 2 Rotary Aer od y n a mi c Da ta The da t a i n this s e ction er e shown a s varia t ions of ya w l n a-m c_ n en t and r ollln g -m _en t co e f f ic ie n t s w it h the no n di m en _ lonal r otation ra te o r s pin-rate p aram eter , _ b / 2V. Fi gur e 11 s ho w s r esul t s fo r an81 en o f att ank fr um 0 • to 90 • a nd a R eyflolds nu m b e r of 1.5 mi llion for th e oo n _i_ atlo n w it ho ut t he nose bo _ . Per angl es of at tso k ran g in g fr om 0 • to JlOe , the va r ia tio n of Cn with sp i n rat4 Is r ea s onably li near . Above k a - qO• t he be ha vior is f _ :rly n onlinear , and f _ t h e _ ase o f a - 6 0 °, there ls a sizabl e offset I n the ya b ln _ o _ e n t at zero P otation rats. I n all oa s es the ov er all slopes of the Cn c ur v e s e x h i b i t an an t i- s pi n be ha v i or. I)e _ p lte th is , the offset i n t he nor _ ' otatid K v alue of t he ya _ l _an_ _ oe _ flol en t a t a - 60* o ausns a signific ant pr o-s p in t en d enc y fo r all val ue s o f _ b / 2V le a s than zero . Th e be1 _ tvlor o f the rollin g -moment co effici ent w ith ln _ee aing a n g l e of a tt a ck Is w _ th e x a mini ng . Th e rolling mom e _ tt is anti -spin for a n81 en o f attaek up to 20% b ut f or a f r om 25 • to q O • an d f or • o f 80 • to 90% the rollld8 aoman t is ganara lly pro - spin. _ ladre 12 Shows sim il ar r es ults for lteyr _ oldS nu=b ar 8 of q . O a nd 5 . 6 m ll- : ; _ lion . Compa r i ng thb r es ults to tho se s ho wn in Fig. 11, s a ne dlff eranes a are obser v e d d ue to Ite ynold _ number i : w r i ati oo , ps_ tie ular l y a t a ng l es of a tt ack abov e 30 o .

Figur es 1 _- 15 show the y aw ing t_ n en t co e ff i ci en t f or a d81 es of a t tac k of 30% §0% an d 70% res peo- ,i_ i t .ely, fo r t h e model with an d wi t ho u t th6 n os e bo _. The d i f f e r en t c ur v es o _ pa _ e res ul t s obtai n ed at hlah " the 8 _ e Re ,me l ds num b er. F i gure 13, f o r a - _ 0°, shoes l i ne ar b e havio r o f the _om ent w_t h t h e sp i n-r a te _ . !! _ n d 10 _ _ e _ O lda n_her S for a g iv e n s ting an_ le , and for r . ulth o,ta l_ed w ith dif f erant s ting _ . a _ _ p arame ter f or both t he bo _ -oFf _ nd bo o , -on enn fiaur a tiorta. S k _e diff e r en ces due t o Ite ydold e n umhe r _a n b e obse r ve d at t h e high er r ot a tion r _ t ee, ns ; _ eci a l ly for t h e os ae with th e bo_ on. T han e Is a 8li g ht e _ f e o t _ * ,_' of sting anal a o n the data a _ well , pri m aril y at t he h i _ e r r o _at i o n rat es. S im il ar data obtai _ k _ fOP a - 50* are s ho wn in F l a. I _. ?he r es ults, In g e n e r al , a ho_ a hig her de ar e r o _ ; nohl |nea ri t y th a n for ,_ a ., 3 0 % 1, o_ / The m o s t int e r esti ng cas e i8 sho. n i n P i E, 15 f or a - 70% Looki ng fi r st at the _ on _ tahrat i on wi t hout the no s e bo _ i n F i g. 15a , there I s very little a f fect o f the Br ine angle a t t h e hi g h e r It eynol d s dum b(,, , Ho we v e r , at the lo _ e r R e ynold s n um b er , a s ig n i f i cant a ffact of t h e s t ing ang l e i s o he e _v ed e t the hi gher rotat i on r at e s. T here I s al so a oo ns [ d ar able d ifferanos bet . een the results obt ai ned fo r the t w o Reynolds numbers usi ng t he s a _ e s ti n g.

The e f f ect s o f adding the no s e boom at th i s an _ le of a ttack are rather dre a at t e, as ae o n i n F ig . 15b.

Tha first c ha ract er istic to not e is that t he data o b ta ine d w ith t he 7 0 • s tin g at It - 1. 5 _ illion (ci r c l es ) show a ya w ifla-mom en t co e fficient th a t to mul t iv al us d ov e r a wid e r _ nae of v al u es of th e spin - r a te para m- eter . This m ulti .sl ue d v a r i a_ ton an d t he ao c os p a n y ing h y et are al e loop indicate th a t t wn flo w fi e ld stat e s J san e x l nt a r o u n d the mod el f o r s i l v en s pi n rat e . W h lo h o f t h e two po ss i b l e std tes t h at ann e x i st d e pe n ds on th e pa qt h i sto ry o f t h e f lo w , t hat i s, w hether tha t spin rat e is e ppr o a oho d from s rat e th a t I _ hLilh er o r _ .

lo wer . (A de n orip ti on o r t he hys ter e s is loop e nd de tai l s or t h e d ep endono e o r i ts oh era o ta r / s t i o s on !

R e y n olds n um be r ore d t s o unsed A s tor Xn t h i s ooQ ti o n in oo n n eo t ion w i t h ViE. 1 6.) T he h y s teres is e #f )m t is quit e sens it ive t o m od el suppo r t i n t o r f e r an o e . Al t ho u g h tw o f lay states er e al es evidd nt for t h e r esu l t s ob te ined unl n d th e ,S e _tln l l st R - 1.5 mill i o n , t he h y s ter esis le alm os t n e S1illible. Th i s dif f o r es oo i n hy s t o r ani s o f f set and t he l er g o d i ff oran c o b otwes n ya wi nE _ en t oo o f r i o l en_ v a l ues at n q ativo s pin rat e s d am or,)t ra to t he o onsL t ivi ty o r t he 8o r odynam ios to s t i ni a nll d di r r _ re noes and r esu ltin8 suppor t infer r er- en os e rr, o rs, zt I s s pp a #en t f r om these re su l t s that t here is a n ls ab l e i n t lu an os o r t he t wo o tl nss on the lee war d f low f ield wh in h, i n t ur n, af _ e ota the y awins m omen t . For t h e m e an ure m en ta made s t a • 70% t he _ 7 0" o tin l i s p eral l el t o t h e tunn el s L r s t ro om . Conv er s e, # 6 f or a - 70% t h e 4 5 ° st i r s is Lnol in ed w it h rnp e o t to t he ei r st r e am and p r obably c r eat e s more o r a d i st u r be noe I n Its wake, t hus l n r l.en o ins t he flo w fi e ld more severel y , At t he h i ghe r Reynold s num be r , _ .0 m ill i on, n o hy s t er es i s wj - obs er ved in the m e as ure- me ats ma de with ei t h e r e t l n s, a nd the re s ults ob tai n e d w i t h both s t a rtle are In re as ona b ly clos e aip . esm en t .

• , W i g ure 1 6 ill ue tr atas , in m c _.e d e t a il then Fi l . 15b , the e f f eo t o r Re y n olds numb er v _ ir ia t i o n on t he ya wi nE-m d bent aoe ff ioient ve r su s the s p in-rate para:et ar . The ease sho w n in f or m - 70". a n - TOe , a h d Reynol ds numbe rs r an s i n g fr om 1.0 m i ll i on t o q.O mi ll i on, the m o s t ob v i o as e ff e ot o f Reynol ds n umhe r varia- tion is t he o hans e i n t he value o r the sp in-rate par am eter st w h i oh a "Jt _ p" i n the yawin % -m om ent oo e rfi - . i el an F , assure, sass e d by a w it _ i r q _ f r om one f lay s t a te to another. At R - 1 .0 m ill i on there i s no J _) o r !)

s ign ifies nt h y s t e r es i s exempt f o r a sm al l hys t er es i s loo p at t he l er ger p o si t i ve val u e s o f the s p i n-ra ta Para m eter. At a s lightl y larger Reynolds n um b e r , t.2 m illion , t he J um p a ss ure at • v al ue o f _ 4) / 2V nea _ -0.08. H Lt h f urt h er l n or ease i n Re y nold s n umber , to 1.3 million , t he J ump p , a nt i s o b s e r ved a t a value o f s pi n - r a ce para m eter ne ar -0.0 _ . A smal l hy st er esis loop i s observed i n both th as o oase s s urrou _ d i n8 t h e t t he ourv e s) secur e a t a _ / 2V - -0.01. th e r lo _ w_ rel at ivel y uns ta b le and s o o n f e t e ' n ed to the o r i g inal sta te (2) un t il t h e s p in-rate p arame t e r tr as he d -0 .0 _ , w h er e the mome n t J um pe d a g ain (3). i / lt h an ln er e as e in Reynol ds nu m be r t o 1.5 m illion, t he ya w i n _um en t ooe _ f i olent heoo_as m ultiv a lued, as d esor i bed J ump oo nd it ion. Fo r It - I. _ m i llion i t is int er estln8 to note th at th e f irst J ump (indl a ated b y _ ( 1 ) on i*; p re viously i n F I E. 15b, and s i Sn ifies nt h yster esi s looi)8 are obs er ved , th e f ollowing d asor lb as t h e se _ uenoe or enq u i ri ng t he data i n the hys t eres is loop.

For th e e ase s ho_ n at R = 1. 5 million, t he init ial v al ue o f the yawlns-mca ant ooeffi ol an t was n e sa- t i re. th e i nitial rotat i on direc t ion was in t he neBattve dlreotion, and the yawins _um ent oo e f f iole _ t r e m ained ne g ative un til _ b / 2V - -0 .036, t he n it Ju m ped to I ( positive value (1). The mom ent remained p o s i ti ve as t he rotation rate wa s slo w ly ln ore ased In the n e gative dl r e o tion to _ b / 2V o -0.12. th e r otation rate was then slo w ly de or ease d to zero and ln or e as ed in t he oppo s ite o r po si tive dlreotion, th e oo rr espon ding y a m ah a -m omen t coef f i o l an t r espo nse remained pos i tive until the m odel reached a v al u e o f sp i n- rate pars : as ter o r 0 . 09 then J um ped (2) to a nesatlve value, k s th e spi n -r a te pe rs is te r w as slo w ly in or eaned t o its maximum value an d then de or ea es d t hr ou g h zero , the ya _ lng- _um en t oo e f f iol ant a _ al n J _pe d to a po_ i - tir e value a s _ b / 2V de or e as ed through -0 . 03 ( ) ). How e ver, as t he sp i n-rate paramete r was ds c res sed to its m_ l mum nega t i ve v al ue an d then ln or ea es d through ze _ o f o r th e s econd time , t h e , J un p i n the yaklfl&- _ n _ ent oo e r f l o l an t to a neEati ve v al ue see .v.': ' .ed at _ b / 2V - 0.01 (q) rather than a _ d) / EV - 0.09 as be f o r e. It is a pp arent, f ella h in8 this path a s s ho _ n , that t her e i s hydr a ' eel s in the val u _ o r the va g ina- mom e n t ooe _ - V i o lent w ith variation o f the spin-rate par l ,,et er . This type o f variation indloat as t h e de _ nde n oy o f the f lo _ f ield es_e tr y, not onl y on t h e dl r eotion o f rotation, bu t on the hi s tor y o r t h e rotation dlreotlon.

It is l nt eres_ ln l_ that thi s oh ar a o t er l a tlo o f a m ultival ue d y a w ln E - mum ent _ oe ff iolent w as obs _v ed only at this an _ le o r a ttaok an d a smlll tense o f Reynold s nu m bers on the oo r _ i sur atlo n w it h the n ose bo _ .

Hol_e a tad r uns at these s a=e oo ndltio ns p rod uoed ¢ _ s e ntl al ly the sa m e r e s ult s with onl y a all va r iation i n the value of _ b / 2V w h er e the J _pe oo o ur r ed, th e r epeatabilit y o f the Ju m p o o nditlon is ver y sensiti ve to the Reynolds n um ber . : Data o b tai n ed f or I t - 2 ._ million and I t - q . O million do n ot indl os t e t w o f lo _ sta te s and are es sent ial l y s in _ l b - valusd , th e onl y exemption i s obser v ed at t i t s 4xtr um e n e_ atl _b v alued o _ _ b / 2V. the variation Is relatively line er and. f or the hi gh est He ) i nside number, R - _ .0 million, th er e l e little offset " in the ya _ inl _ - _om ent es ef f iolent a t s er e spin rate. At the hi E he r Reynol ds n um be r s the f lc _ on t he f orebo4y a nd i nl et 8ur f aoe s i s lik41y to b e tur b ulent , a n d t he f lay se p aratio n i s no t es _ e ns lt ive to t he P ot a t i o n - indues d loc al f lay anE ula r ity.

th e e ffe o t o f v_ ,i a tion o r s ideel ip _ n _ le on t h e h p teren l e i s llluetrated i n _ l l . 1_. Di r e are s ho _ n f o r R • !. 5 m il l ion at a • 70 • f or the boo . -on oon _ i E ur at ion , w i t h 6 ran _ in _ _rom -5 _ t o - 5 • an d iS - -5 • the Jumps in t he yawi n 8 1oman t ooer f iolent sco ur a t v al u e s o f sp i n - ra te par am eter on e ither side o f the v al u e a t whloh th e J um p w as o b se r ved a t iS - 0% Fo r iS - 10% th e f lo w a n sGl er ity on the model r es ultin8 from the oo_ b i natio n o r side s lip and r otat i on anllles I s apparentl y no t 8 t _ f i o ian t to osun e a Jump i n the f lay o ri entat i on as s een i n the ot her a sses . Fo r c _ npa ri eon, the data are s h _ f o r t h e mod el wi thout a nose boom at iS - 0 ° a t the s ame oond i t i o ns . As s een i n F lS . 1.a s, t her e i s l i t t le l ndioa- t i on o f as _ et ry , wh i oh L8 a n i sn ifi o an t contrast to t he d a t a obta i ned w i t _ _e boom on.

5.2 6- b y 6-F oo t T un nel Experiment s . " The tests o o n duoted on the S i )H in the 6- by 6 - r t t unn el wer e all per fo _ ed at Hash 0.6 an d a Reynolds n um be r o f 0.88 m illion based on th e wi n e m e an a erod yn ami o s har d, th ese te s t oond iti on s w er e o ho sen to ma r s h " those or oompl am ent er y f oro ed- os oilletlo n tests performed at the NAg (Eels. 6 and 7). The se r od yn m io : oo e f f iolen ta m ea s ured in the 6 - by 6- i t tun n el an d reported i n He r. 9 inoluded n o rm al r ares , pitohin8

4 V

m_an t, sid e r o r o o, ya wi n g m _en t, r ollin g m_an t e n d axia l f m.e e . The m od el o a nt_ o r r o tati on we, looat od s t 0.3§ o f th e w inji m o a n a erod y n mi o s hard . T h i n poin t was a l s o o h o nafl as the mQ m ant r o r er en eo e a st er .

_e o r th e r on ul t _ ob tai ned w i ll be pr e_e n t o d i n th e r ol l o w ln g s e o tl ono.

5.2.1 Rot a ry A 4r o d yrl mi o Da te _ 11e reouZ t n wi l l b e o how fl in thie oe o ti ofl t o l ll us f.r at o tha v ariati on o r t he eer ody nmi o ooo tr i o io fl t o wi t h t he npln- r a t e parame ter , _ b / 2Y. F i gure 18 m a hewe the r o r oe end m om en t oo of r iol b n to m eaou _ ed a t II - 0 e , u - 10 % S im i l ar ras u l t o obta i n e d at It - 0 ° and a - 30° a re e ho wn in F ig , 18b, io t a t ha t i altho ugh da t a wore t _ lk an at zero opln r at e, the y ha ve no t boon l nelu ks d i n Fail, 18 b ee a une 8 e m al l mi o al ign - mo o t b e t w e en t he ro tary r l 8 op l n ax le an d the Zoo al t r ee -o t re m direotlon m ade tha ne S t O t iO do t e d e pe n den t on t h e ang u lar po_ lt i on o r t he r i g. However, wi t h the r i g rota ti ng, l ow - pose Pi l f er i ng o r the dat a s ig n al s ef fec ti v ely a vera g ed out t he o r r e e t o f f l ow an g ul ar i ty .

A t zero anglo a t si d eslip , aymle t r _ oondl ti ons d io ri t e that t he la t er a l _ r. _ dyn M lo ee e tr i ol enta (¢v, Ca, lin d Cl) sho uld b e o dd f uncti ons OF _he sp i n-r at e par m e tar , w hile t h e long i tudinal ae r o d yn as lo ae s ir {- sl ants (CN. CA. an d Cm) s ho uld be even t uno t torm o r _ he sp i n tri te. Thi s i s de m o nstr a t ed by t h e dat a pre- s en te d i n Fi g . 18. For all ang l o s o r a tta ok too t ed, t he la t e ral 8erodyn ami o ee e f r io le n t e w ere o hear ved t o be nearl y l in ear w i t h respo o t t o op ts-ra t e pa r ame t b r over t he r an ge OF spin ra t es a o hi e ve d lh th e t es t . The l on gi t udi na l a er od yn am l o oo e ft iol e n t8 w er e seen t o be e ven t unotlo na OF the s p in-r ata param eter. A t t h e A o w m _ er r.L os OF 8 tt ee k, eh aranter ize d by t he res ul ts sh o wn f. o r a - 10 ° in Fig . 18 a, t he lo n gi tudinal auirod y namto oo of tl o l ant e ar e ad m os t independen t of' spin ra t e. A t t he hil l er anil am OF st reak , t ypif.ied by _i t he r es ul t s sh ow n f. or a - 30 • In Fib. 18b, t he axi al - _ or o e an d p it ohln g -m _ en t ooa f. t lele n ta 8 heW a p ar s- b elie var ia t ion i n spin- r ate p a ram e t e r r a t e. _ =me of' t his par a bolas v a r i at i on t8 un d oub t edly r e al, and i8 p r o b abl y osuaed b y inor eased v e lo o i ties and dyn m io p res s ur e on t he ta il re ot _ 1. tl n8 f.rom t h e ee ninsmo t ion, w h l o h pr od uo es ln ore a ze d ta il li f.t . However, l i mi tat io na OF da ta res olu t ion a t t h es e l ow l evel s o f. CA and _ : Co , .d in po rtio,,t ar t he shales o f. th. m oment seat er po s i t ion , ma y al s o be r espo nsible f.or exa gger ating the i 8oalo of. the var i at ion.

J

The of.f. eot s o1" v ar iat i o n o f sid es li p angle a re shown In Fig. 19 , w hloh pr es en t s data obtai n ed at _ 6 " "5 ° and J = +5 e. Figure 19a shows data obtained at a - 9% w hile oorr espo , _ d ln i; dat a me asur e d with t a - 30 ° ar e sho w n in F i g. 19b. On ue again, the li n e ar v ar iation o f. the later al aerodynsmlo oo off. lol an t8 ' _ : with spin-r a ta par ame t e r 18 apparent. Th e nonlin e ar v ar i a tion of. the lon s it u dlnal a erodym _ to ooe f.f. i o le _ t8 ; t " with o p e n r a t e l o al s o apparent . The longi t udin al a erodyn am i es also s how a n el l' ea t due t o o id es lij _ , w hioh, ::_ k s oxp e ot ed , lnt r oduob8 a r easonably 8y _ ot r lo 8nd li n e ar oomponent w ith sp i n-rate par- a stor. In gen aral, t he res ult8 8 how a r easonable 8 Y _e t r y with d ireotion o f. side sl ip, but with some o ff. s e t s p os si bly int r oduoed i by 8 mal l a s y _a trles in the model and / or the of fs et8 of. _ :mblfled oe nt r lf.u g aI a n d aer ody n u li o loading . | ;" 5.2.2 St ati o & ar odyns _ lo Data t Static ae, ' odyna m l o data ar e p res en t ed in F188. 20 and 21. These data w ere ob ta ined f. r om the i nter- ii oept.s, at w - O, of. the l ow -spin-rat e data an al osotm to that presented in Fip. 18 ar id 19. The aotual e ta tlo da ta taken at w - 0 war e not us ed b enaue e of. the a o atter oaused by f. low a n gul ar ity rel a tiv e to the _ rotary rig's azl8 of rotation. " ?he e f.f. eo t e o f. v arll tto es in tile angle of a_ t a ok and sides l ip on the n orm al - f. o _ oe an d pltohinS-mOm en t : ooe t f. iolbnt e ar e sh o wn i n Pi g . 20, while the o o r r aspo nd _ n8 e f. l'eo ta on the yswltt _ -momeflt a nd rollinS-m _ m _ t ; _ : ooe f.f. lel anta ar e i _esan t _ d in Fl _ . 21. k lao sh ow n ar e the 8ratio data 8 1 van in R oy . 6, obtained at the NAE " : us ing the same mo _ el on a simil ar ly 81 ze d 8tint sup po rt. In m as t r u peo ta the two sets o_ ' data ar e well- _ al _ ma t o hed, with the axo e p t lon o f. the normal- t er se and pltohl n s-m omen t ooa f. f. i ole n ta m ee su _ . ed at t he larger : ar m ies o. _ at tan k . I t 18 nucl ea ted that this dlaore po noy Is p r obably attribu ta ble to w al l - and st ru t - _" lflt ar f.erenoe e r r.e at s in the sm al l 0 . 75 m x 0.38 m solid-wall tunne l us e d f.er t he NAB tksts . Sash eft' ea ts s ho uld be n e g l igi b le f or the m e asurem ents made In the 6- by 6- f.t f un sal , wh ere t h e b lookaSe b as ed on total plan r or m ar ea of. the model an d test sm otion or o es - as otlon al 8 _ ea w as approximately lJ , an d thb r dtlo of win _ shar d to tunnel t es t as ot to n holght _as approximatel y 0.05.

5.2.3 _ / na m io Rot ar y De ri vativ es Th e r o t ary de r ivatives p r ese nt ed i n Fi g . 22 w ere obtained by le est -equarEm f.i _ tl n 8 o f. etr al Sltt l i n es throu g h the data p reean t i n8 th e aerod ynaml o f. or ueo an d u _anta am f. unotion _ of' the spin-ra te p arame t er ( e.g. , rip. 18 and 19). Th e d e rivatives p rese nt e d in _ i8 . 22 are the alop ee of. these lines. The ras ul t e show a gradual o he nse w ith angl e o f a tt ao k fr om 0 to 15 • , then a m ore rapid o hanse as angle of a tta o k rea oh es an d ex oeeks 20 o . I n p ar tloud a r, th e r ollinS-moment d e rivative o ha ns es f. rom anti - spi n 4 o pro- s pin , indioatin _ a oignif.ioan t ohan g e In f. l ow o h ar aot ar i o tl es w ithin the an Sle of et ta ok ra n se f. rom 15 ° to 20 °.

This is in agreemen t with the states a ar odynamio data w hioh a l8o 8ho w a saJor oha _ o in l a t eral aer od 3mmi es within the 15 ° to 20 ° anglo o f. attaok range. In addition, vap or - s at ee n f. lo w _ lsu al ization studies lfldlos ta d a m _ Jo r oh an se in the vo r tio ee sh e d f rom th e wing le a dl n 8- e dso st r ak o. At a 15 ° angl e of. s treak, theme vortio ee passed over the win8 surf.ass an d remained intaot well downst r e am o f. the via8 t railing edp , but at 20 e an gl e of' attack, they b urst while still abov e the w in8 s ur f ao e.

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A n par t st an ongo l na r e n e a e a h pr o j[P am at tho NA SA A m_ Ro n o|r oh C _nta P to $ n v o_t L Rntd l _ ho ae rody n lmi o phen om en a af re e tlnl hllih-inoidan ee f li g h t, t wo r o ta r y -h aR ne s s a ppa _ atu e an h f lvit b een dev e l o ped r o e t, _t l n ll mo do ln o r ol r pla n e e onritl ur at, t onn in o Q nlnll mo tto ) 0. Th e r ip w a r e ron an tly u t ilise d to t I n o ulpm o l. to o th oonduo te d us inB s m o d e l o f the F-IS dtr o r n r t in the 12 " ,Foo t Pre nnuro Hi nd Turmoi l , 8_d r ot tnt n eondu ote d _ ' "nine t he Otand_r d Dyn am i e e Hod al tn the 6- by 6- F oot _ upo r e e nt o W ind Tunnel, R e sul ts o b ta ined unln8 bo t h Pi R O have d am oflntr st od the ir oa_b i l L t ies no t ools rot ln van tlp ti n m t he h / g h-lnoid an oo 8 or o dynma loo s t ii r or M 't st, a var iet y or tlm t _ ondi t lorm.

?o nto w ore oondu otsd in t he 1 2-rt t unnel on J O.O§-a os io m o dal ' or th e F- 1 5 airplane, st Ha o h nu mbor o r an j i n8 fr om 0.2 t o 0.28, and at R e ynol ds numbers, heam 4 on v ine mean a orodynsmLo o he rd, rm d gl _ p be t,an n 1.0 m illion and 5.5 million. 111o an al o n o r iL _ i o k oonold er ed ranpd Pr om 0 t o 90% w i t h aides l p Shales ran gi n 8 be t ween -15* an d , 15 o. Zn addi t i o n , t he e Ftso O n on t he 8erod _ lsmi o s duo to t h e prosohos or abn anos o F a ru H leso none boo m wer e i nv oo t ip t ed. A erodynam io F or es a n d m omen t ooe t rlolon ta Yore a s sur ed a t spin Pl i e r of up t c 350 r p m (nond im on a lonal spin-ra t e pa r ame t er v al ues up t o 0.125) in bo t h t he al ookwieo and • oounter olo o k w ino d i rootiona, m e o f the m ain obeervatlom l fr om these test _ w en I. FJ' r eota o r Reynolds number var iation il anaral l y be o om e si g n l r i o an t a t an al u or at taok mbuve leo* and Reynolds numbers b al er 2.q m illion.

i ; ............... 2. V ar iatiorm o f the ao rod yn ml o oo e tr L oiant e w ith spin-ra t e pa r ame t er 8 r e ne ar ly line ar up to _ : a - 20% i .I" 3. l _f_ ets o1" the nose boca are eilml r i os n t s t anilles o r at t m o k above qOe. At a = 7 0 • a n d in al ude d t h e oo o ur r en os o r m ultiv a lu ed a er od ynamic resporm e m, an d m ooom p anyin8 ae rodynamio h _ lt eras ls, over a r ange oF t h e sp i n-ra ta parameter.

_ . T h e o ff sets ot sting-support lnterf er enoe nan he elSni J 'i os nt with s top-atounted model, ove n a t i i I R - 1.5 • 10 , the p r esence o1" the nose boom soused m ajor e f f eot s on t he ya w ing-mome n t ooe rr t o len t . Th em e -- lapp l ned d en os . The angle tha t t he top-mounte d s t ing mikes w i th r upo ot.to the model w as seen _ o have a I" . eLg nif'l os nt offset, paP t Loul ar ly at R eynolds nu m ber values belch, 1.5 , 10°.

. Teats war e 818o oonduoted in the 6- by 6- f t win d t unne l on the SDH ( a s i m plified gen el _ | o fig h te r - i ; _ rora _ t e _ ape) in Denis8 m otion at H - 0.6, at a Reynol ds s om be r , based on win8 m ean aerodyn am ic shred, o1" 0.88 m illion. The angl os o _ attaok ooneid er ed r an pd Fr om 0 t o 30** with 8tdealLp an gles ran g ing be t vee d -5 e an d 4 _ e. 11tess oondition8 m atehed t hose or ocmpl amen t ar y f or os d- os oi l l at lon test s oonduoted at t he NA _ " _' in Canada.

Aerodyn am ic Force an d m om en t ooe / ' f iol anto were m eaSured on the SDH at d p / n pat e n s t e n sing up to 600 rpm ( r _ ndi m en al ondl s p in-rate param eter v al ues up t o O.Oq) i n bo t h d i rest / stun. Over th e a n gle-o F -attack ra n ge ;' inve s tigated, the lat er al a erod yn am io o h er a o t er tsti os show a l i near v aria t io n over t he Full ren a n o1" spin- rate parame ters a o hle v ed In the test _. Althoug h no di s oont I nuou _ ohange8 In t h e a erodymmLo ohar m oteriati os oF t he S _ 4 veto oba er vod w i t h ohanae8 in atti t u ds or 8pi n rate, e v i ds n os e xi sts eF a 8ianiti os n t ollat _ e i n _ F low o h erao t ar isti os be twe en 15 ° and 20 ° an81 os oF at tao k . ?his i8 beli ev ed to b e mo o l dte d w i _ l t or us rd movement o f t he burst point of the w in8 stroke v or ti os e with In or eastnB Lnei ds n os ; from behind the w in8 at ' l a < 15 e, to a bov e the wing a t a > 20 °.

R EF E RENC E S qu 4 _ . 1. H al ool m , 0 . _. , " Rotary and Hag n us Bal anos s )" AOJ _ D beet ur o Sor i am NO . 11q, i _ / n_ lo Stability Pores - st ets, Paper 6 , Hay 1981 , pp. _ 1-26. , 2. H al_ ol m , 0. N., "Ne w Ro t a ti o n -Bal an ce Apparatus t or Haam ur i n8 Airpl an e i pl A Aer od_ n am| oa i n the Hin d ' Tunnel, " AIAA J. O t Ai ror a ft , Val. 16, No. ll, April 1979, pp. 2511-268.

+ +.. 3. _ ohi f f, L . B. and Tobak, H,, " Reault _ s from • Nw Hind-Tun nel Apparatus f or B t udyin8 CoMe8 a n d Spi nnln8 . Hotness o 1 ' Bodies o r aev61u t ion," AIAA Journ al , Vol. 8, No. 11, Nove m ber 1970, pp. 1953-1957, q. Clarkson , H. H., H al ool m , 0, N., and Chap man , O. ?., #Experimental P os t- S ta ll Rotary Alrod _ mio Coe ff L- oi anta f or Ai r pl an e-Gike Con f ig ur ations,. AIAA Journad, Vol. 13, l _ o. 8 , Au gus t 19 7 6t pp. 56 _ -5 7 0.

5. Maloolm , 0. N. and Cler kno n , M. H., "H ind-T un nel T u rin8 w ith a Rotar y -Bal an ce Jkp po rattm to 8 imul d ts A ir or ad't Spin Hotioos ) " Prooeedings oF AI AA 9Oh A drod)mlnlo Tas t l N I Con f eren os , Arlinl _to n _ Tex u , June 1976, pp. Iq3-156.

[ i . .. 6. Bey ar n, H. R. and Houlton , B. g.) "Sta bi lity Der i vatives Due to 08oillat l ona in Roll for the Bta ndlmd .- Dynamics Ho ds l at Ha sh 0.6," Report t.TR-UA-6q, Nation al A er onautlodl F a tabllaim an t, NRC , Canada, Jdnuery 1983.

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! 7. Fley er n, H. E. t K a poo r , K. B., an d H _u Zton, B. E., " Pl t o h- and Yaw -O s o iZ_a t ion Exp e r i me nts a n th e 8 t a n- ; _ na r d D y namit e Hod_ l n t H a oh 0 ,6,, R ep o rt b TR-UA-7 6 , N a t[ o n a_ Aor o nau tt o_l E at a b linhmant, N R C , C an nda, Jun e 198 _ , 8. I _rn ha rt , B., "P-l § R o t a ry E _ lonoe Da t a F o r o n Ang Ze- o P Att a o _ Ro n se of 6 De E t o 90 De_ ," NASA ¢ o n t raa- t a r R e por t 3 _ 78, H _ y1982, P r epa re d f or NA S Ah n n g l ey Re s ei roh C o ffer _ y Bihr! _ ApplLed Re seAr oh, I B o.

9. Jarmey, C. and 3ohl r r L . P.. "Anrodyn M lo Choraoterint i on o r _t and ar d Mo _ @l Ln C an i ne Mot i on n t H a oh 0.6," p r op o nod NA S A TH-85717.

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N a t i on a l A _ r o n a ut i cs a nd Sp a ce Ad mi nistr at i o n 14. s _ nw _ _

Washington , D.C. 2 05 46

15. S.pglem m u w v Nora i P oint o f C o n t ac t : Gera l d N. Malc olm , A m e s R esearch Cen t er , MS 22 7 - 6

Moffe tt F i eld, CA 9 4 035 'i

=' (4 15) 69 4 - 62 08 or FT S 464 - 6 2 0 8

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" NASA Am es Rese a rch Cen t er has a n o ngoing rese a rch program t o I nves t l-

_ ; g a te h i gh- a ng l e- o f- a t ta ck a er o dyna mi c phen om ena as soc iat ed wi t h high- • perform a nce a ircr a ft. As p a r t of th i s rese a rch eff o rt , two r ot ary-b a l _ nce = _ ' _ " a pp a r a tuses h a ve r ecen t ly been devel o ped for t e stin g airp l ane m od e ls in a , -_ con i n g m o tl o _ . A ne _ la rge-scale a pp a ra t us , develop e d for u _ e i n t he

=_i_ 1 2 -F oot Pressure Wind Tunnel primar i ly t o per mit testing a _ high Rey n o lds

used t he

_i : I numbers , was recently to i nves ti g at e a erodyn am ics o f O .05-sc a le

_ model of t he F-15 _ig h t ( _ r a i rcr a f t . Effects of Reynolds n um ber, sp l n-ra t e

• _ p a ra m eter , model att itude , presence of a n o se bo om, a nd mo del / s ti ng

o,!_, m ount i ng a ngle were i nves ti g at ed.

_ A sm all er a pp a r at us, wh i ch i s a modernized vers i on of a con i ng r i g

deve l oped several ye a rs a g o t o i nves t iga t e the aerodyna mi cs of bod i es of

_ evolut i on i n a coning motion, ha s b een used in the 6- by 6 -F o ot Superson i c _

Wind Tunnel t o i nvest i ga t e th e a erodyn _ sic behavior of a simple represe n ta-

t i on of a m odern f i ghter, t he St an dar d Dyn ami c Model (SDM). Ef f ects of ]

sp l n - rate p a r am e ter a nd model a tt i tud e w er _ i nvest i g a ted. A descr i ption o f -

t _ e two rigs and a d l scus Bi on of so m e of the results ob ta lned i n the respec-

rive test are pre _ ented.

! 1 . g _ W m mISumm _ d by A_ h _ l,))' t _ . Oistribotton Sm ten _ nt ....

R o ta ry-ba la nce t es t ing Unli m i t ed

Hi gh a ngle of a tt ack

Subject Ca tegory - 01

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