. ' T his wind tunnel is one of thr ee NACA Un it ary Plan Wind - PDF document

~ ~. ~- ,. UNITARY P LAN W IND TUNNELS pre sented by Unitary Plan Wind Tunnel Divi si on . ' T his wind tunnel is one of thr ee NACA Un it ary Plan Wind Tunnels, one loc ate d at each of the three Laborator ie s . Ge n er al a rr ang eme nts of the other two installations are shown on this chart (c hart 1 1) . These wind t unnels are being constructed under aut ho rity of t he Un itary Wind !unnel Plan Act of 1949 and have been designed for u se pr ima ri ly in conducting devel opmental research on airplanes, m i ssiles, and engines for the air- c raft ind u stry , .. Al t hough the primary r esponsibili ty of the N A C A is the study and so lut ion of fundamental problems in aeron auti cs, i t is al so our function ..­' t o as sis t t he aircraft industry and the military s ervices i n de velop.ent '" te s tin g when o ur r esources are needed and i t is co ns ider ed to be in the be st n ati onal interest. St r a tegic re q uireme n ts duri ng World War II caused us to emphasize develop m ental rese ar ch, arid t he ' ba l an ce between fundamental and de velopmental r esearch effort was upset. I t was a ls o apparent that wi t h th e rapid advances bein g made in a ircraft and en gi ne perfol'1ll8nce, the needs for development testing would con tinue ­ hence plans were ~e to bu il d these Unitary Wind Tunnels in ord er to re sto re th e pr op er balance of ef fo rt . nitary Plan was given the gr ee n lig ht i n 1950 w The U hen Congress appro pr iated tun ds for the const ru c ti on of these t hr ee wind t unnels and 'i- th e A ir Force's Arnold Engineer i ng D evel opment Center at Tul l ah oma, Tennessee . The Langley Unitary Plan W i nd 'Tunnel, wh ic h 1s c urr ently undergoing calibration tests, has been d esigned t o op erate ov er a Mach n umb er range of 1. 2 to 5.0 u sing two s eparate noz zles and test sections. The te st se ctions are 4 by 4 f eet in cross se c tio n. Thi s wind tunnel i s t o be de voted to aerodynamic st U d ie s of airpl an es and missi l es and it is exp ecte d tha t the fi r st inves tiga ti o ns w il l comme n ce sometime this .. samm er . The L ew is Un it ary Plan Wind Tun n el will be devo te d t o s tu d ie s of aircraf t pr op ul si ve uni t s . S tud i es w ill also be made h ere of air inlets, inle t diffuser s, in te rnal d uct i ng, je t exit s , and other a ir cra ft com- p on ents asso c ia t ed with t he pro p ulsi ve system. This wind tunnel has a " design Ma ch number ra nge of 2.0 t o 3.5 provided in a single 10­ by lO­ foo t te st sec t ion . It is now in the f i n al con structi on phases. tt Th e Am es U ni t ary Plan Wind Tunnel, like the one at Lan gl ey, will be devo ted to ae rodyn am ic investigations of airplanes and missiles . Tests can be conduc ted ov er a Ma ch number range of 0.7 to 3.5 i n three se parat e .,. test section s, an 11­ by ll­f oot transonic test section with a ranae of

~ ~ age o 00 " '\ .. T his comp re ssor i~ the largest of its type in operati on i n the world t od ay. The r o tor is 18 feet in di ameter and weighs n early 450 t ons. This ph otogra ph (c h art #2) shows one of the 11 rotor d iscs b ei ng lowe red into p lace. The sl ot s aro llnd th e edge of the d isc are for bl ade at ta chment. Also pi ct ' ured here d ur ing fin al assemb ly is the entir e ma c hine wi th the out er case open and a c lose r d etail of t he indivi d ual r otor blades. At full l oad this com presso r ci rc ul ates air at the r at e of 60 tons per minute. In order to ut i lize th i s com pres so r t o o pe r at e both supersonic circuits, it was ne c essary t o develop two extreme ly l ar ge two= way v alves:; as was men= ,. tioned previously~ one si tua ted at each end of the c ammon br anch of these ci rcui ts. This common bran ch has b een re p ro duced sc h ema tic a ll y on this next c hart (chart #3 ) . The va l ves ar e shown h ere i n positi on fo r operation of the 9= by 7­foot ci r cui t. Note that th e pa ss ages of th e 8­ by 7= foot circuit are bl ocke d. When ope rat i on of th e 8­ by 7­ foo t circuit is des i red :; the va l ves are rota t ed th us . The gui de v an es r o tate with the val ve and serve in e it he r posit io n t o gui de the a ir smoo thly aro und t he corne r . The valves are op erat ed o nly when the tun nel is not running and is open t o at mospheric pr essure. Total ro t at i on of 180 0 is accompl is hed in about 3=1/2 minutes. ( Th e photograph i s of th is val ue before in stallati on of the compressor. The vert ical strips are the c orne r gui de vanes . ) The I I­ st age compressor is driven by four tandem =m oun te d woun d r ot or m o tors wi th a com bi ned rated output of 180 :; 000 hQrsepower. For li mi te d in t e rva l s t hese mo t or s are capabl e of an ou tput of 21 6,000 horsepower. You can get s om e id ea of th e si ze of these motors by refere nce to t.his phot o gr aph of the motor as s emb ly (c hart 14 ). :rhe mo t or s and c omp r essors are ske tched here to show their re lat i ve posi t i ons. The t hree =s tage c omp r essor wh i ch o per a tes t he t r anson i c ci r cui t i s of the same gener al const ru ct i on as the l~st compres so r . Sin ce the rotor • of th is machine has only t hr ee sta ges:; it s weight i s l ess than t hat of the ll ­ stage c ompr es sor rot o r. Howeve r:; the large t r an soni c test sec t ion req ui res that the thr ee ­ st ag e c om pre ss or circulate air at t he ra te of abo ut 290 t ons per minute, or approximat ely f i ve times the ra t e of fl ow of the ll ­st age ma chine. Th i s co mp re ssor is dr i ven fro m the opp osi te end of the dr i ve motor as~mbly. D is conn ects ar e pr o vi ded on t he shaft extensions at ­>- .. both ends of t his motor assembl y:; wh ich permit co upli ng t o ei t h er co mpresso r • . .... On ly one ci r cuit ma y be ope rat ed at any on e time:; however • I n the pro c es s of co mp re ss i on as the air passes t hr o ug h th e compressor con si derable hea t is dev el oped. For example:; the temper a ture of t he air as it l eav es t he ll­sta ge compress or is 45 Heat is remov ed from the ai r i n these la rg e coo li ng s ecti ons to keep the air temperature down to 120oF o .., C oo li ng i s pr ovi ded by circula t i ng water from t his l ar ge cool i ng tower .... thro ugh finn ed coi l s or radia to rs. Pictured here (c hart #5 ) i s the c om- plete i n st al l a ti on i n the tr an sonic circuit cool er fr om which you may get t an i dea of the si ze. N o tice the man stan d ing at the bottom of t he ba nk of coo le r s. Also sh own here is one of the coil units being lifte d i nto p lace during installation . ­t­ ' ~ .