1、NATIONAL ADVISORY COMMITTEE FOR AERONAUTICStrllRTIMl: REP()RTJanuaryMemorandum ReportTESTS OF THE NORTHROP MX-33_ GLIDER AIRPLANEIN THE NACA F01L-SCALE TUNNELBy Gerald W. BrewerLangley Memorial Aeronautical LaboratoryLangley Field, Va._I _I _0._ 4 _,_:i:WASHINGTONNACA WAI_TIME REPORTS are reprints o
2、f papers originally issued to provide rapid distribution ofadvance research results so an authorized group requiring them for the war effort. They were pre-viously held under a security status but are now unclassified. Some oi these reports were not tech-nically edited. All have been reproduced with
3、out change in order to expedite general distribution.L - 628Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR I;ERONAUTiCSc_c_MEMORANDUM REPORTfor theArmy Air Forces, Materiel Cor,mandTESTS O.F T_E NORTHROP _!IX-_. GLIDE
4、R _._ _IN THE NACA FULL-SCALE TUNNELBy Gerald W. BrewerINTRODUCTIONTests of the Northrop MX-_I_ airplane have beenmade in the NACA full-scale tunnel at the request of theArmy Air Forces, Materiel Command. The results of thisinvestigation are of oarticular interest since the r._iX-33Lis an all-wing g
5、lider-t_fpe airplane having neither a con-ventional fuselage nor vertical surfaces.The primary purpose of these tests ws.s to obtainsufficient data with which to determine the longitudinaland lateral stability and control characteristics of theairplane. In addition to the stability and controlstudy,
6、 this memoranum report contains the results oftests that were made to (i) determine a suitable wing-tip leading-edge slat arrangement which would improvethe static longitudinal stability of the airplane as wellas increase the maximum lift coefficient; (2) establisha value of the minimum drag coeffic
7、ient for the basicwing and determine the additional drag caused by theleading-edge slats; (3) determine the effects on thedirectional Stability characteristics of the airplane ofthe addition of vertical fins_ (_) measure the effective-ness of the air-operated directional control system.SY_,._BOLSCD
8、drag coefficient (X/qoS)Cy lateral-force coelflc_ent (Y/qo S)Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-b abt_eJ_/Voq_ileron span (9.7 feet)elevon tab st:an 2 leet;)root-mean-square .elevator cLord (_J.8_3 foot)roo_-mean-square“ aile?on chord ()
9、o,bp3r_foo_.)root-mean-square tab chord (0.167 foot)relative air-flow quanti_vo!l_ile ra-be of ,q“ _.i_ flOWpb/2V helix anglePVFeFaApCd oHoHIYFCL6 arollins velocity, radians per secondindicated airspeedelevator stick forceaileron s_ick forcedifference in static pressure between tl_einsideand ou_side
10、 of the rudder bellowssection profile-drag coefficientfree-stream sotal pressuretotal pressure in the field of nne airfoilvertical distance from the wake centera correction factor, usually about 0.8 to 0.angle of attack of thrust axis, degrees_. (_ _ oositive when the rightangle of yaw, de_,r_,_ ; _
11、. _.wing is retardedelevstor deflection (with respect to the wingchord), degrees; _)ositive when bhe trailing edgeis deflected downwardaileron deflecion, degrees_ oositive when thetrailing edge is deflected downwardProvided by IHSNot for ResaleNo reproduction or networking permitted without license
12、from IHS-,-,-D7_-4given in figure 3. It was necessary to install a,uSi-tional seals at the hinge, s and at the inboard and or,t-board ends of the elevons prior to the tests to obtain acompletel7 sealed control surface,The inboard surfaces are the air-operated bellowstype and provide both dive brakin
13、g and directional con-trol. Each surface was divided into two parts to simplifythe structure at the joint between the wing and centersection. The mechanical linkage between these two sur-faces is such that the upper and lower surfaces haveidentical angular travel. _either surface can be oper-ated in
14、dividually. The ducting for this system consisCsof a passage from a leading-edge inlet through a venturisection to a trailing-edge outlet and a second ductleading from the venturi throat to the be!lo,;,s. Thepressure and air flow for the bellows are regulated bymeans of a butterfly control valve pla
15、ced in the venturisection.NETHODS AND TESTSDuring preliminary tests of the airplane _-iththeslats removed the wing tips stalled at high angles ofattack. Due to the high sweepback of the wing this tipstall caused a serious longitudinal instability. Thedevelopment was theref, ore undertaken of a leadi
16、ng-edgeslat configuration that would eliminate the inherentlongitudinal instability of the wing.The three slat arrangements that were tested in-clude (i) the original slat (fig. _,_), (2) the originalslat moved closer to the wing leading-edge contour(fig. _), and (5) a large-span slat with the revis
17、edslot. The original and the large-span slats ex_ended20 and 35.6 percent of the wing span, respectively(figs. ! and 5). Force and moment measurements weremade through a large range of angles of attack for thebasic wing and for the three slat configurations. Tosupplement the force tests, tuft observ
18、ations were madeto determine the stalling characteristics of the wing asaffected by these slat configurations.In order to provide a check on the force-test re-sults, the mlnimum drag of the airplane was also obtainedby measuring the loss of total pressure in the wake behindProvided by IHSNot for Res
19、aleNo reproduction or networking permitted without license from IHS-,-,-7RESULTS AND DISCUSSIONAerodynamic Characteristics of the AirplaneLift and pitching moments.- The lift and pitching-momen_-c-h-aracteristlcs of the airplane_ with the leading-edge wing slat removed and with the original and larg
20、e-span slats installed, are given in figure 8. The resultsof tuft observations, which supplement the force test data,are shown in figures 9 and !0. The pitching-moment varia-tion for the basic wing shows approximately neutral sta-bility for lift coefficients up to the stall with thecenter of gravity
21、 located at 27.5 mercent mean aerodynamicchord. At the stall the loss of lift at the wing tipsincreases the positive pitching-moment coefficient andcauses serious longitudinal instability. It was evidentthat before further investigation of the aerodynamiccharacteristics of the airplane were justifie
22、d, improve-ment of the static longitudinal stability of the wingnear the stall was necessary.The most effective method for eliminating the insta-bility appeared to be the control of the stalling patternwith suitable wing-tip slats and_ accordingly, the threeslat configurations previously described w
23、ere tested.Each slat _on_zguratzon progressively improved the stallingcharacteristics of the wing, as shown by the continuousdecrease in wing-tip stall in the tuft surveys, and bythe decrease in positive pitching moments at angles ofattack near the stall in figure 8. The large-span slatswith the rev
24、ised slot retarded the flow breakdown a_ thetip section until after the center section had stalled_thus eliminating the cause of the instability. Theyalso increased the maximum lift coefficient from a valueof 1.15 to 1.26. The unstable pitching-moment variationat low lift coefficients for this condi
25、tion is probablydue to the interference effects of the slats oD the airflow over the wing at low angles of attack.Drag.- The drag data from these tests are presentedin figure II. The minimtml drag coefficient for the basicwing was 0.0100. The original slats with the revisedslot increased this value
26、to 0.0118_ the large-span slatswith the revised slot, to 0.0146.In order to determine the section drag coefficientsand to check the minimum drag of the basic wing, wakeProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-L 9L , Static Longitudinal Stabil_
27、ty and ControlElevator effectiveness.- The results of test_ madewith _e s-_a_e%_6_S operated as elevators are giwullin figures I_ and I_ which show the variation of CL,Cm, and Che with elevator deflection. The data are,presented for the basic wing and for the wing with thelarge-span slats i_sta!led.
28、 At low angles of attackthe elevator effectiveness dCm/d6e_ measured atCm - O_ is -0_00_ 7 with the slats removed and is -0_00_Iwith the large-span slats _ _n_talled. Although dCm/d_5 eis decreased at high lift coefficients for the slats-removed condition to -0_00_, the value of dCm/d6 e forthe slat
29、s-installed condition remains unchanged. Sirai-larlv,_, the values of dCh_/d6e,_ measured at Che = O_are lower at low lift coeffic_ents and higher at highlift coefficients with the slats installed than with theslats remow_d. For the slats-removed condition dChe/d_ eis -0.0055 at a CL of 0,_!_ and -0
30、.0055 at a CL of0.90; with the slats installed, dChe/d6 e is _-0.0050 ata CL of 0o33 and -0o00_3 at a CL of 0.92_In order to compa_e the stick-fixed longitudinals_ability of the airplane with and without slats_ curvesshowing the variation of elevator deflectio_Is for trimwith lift coefficient have b
31、een obtained from the testresults and are given in figure 15. _ith the s!a_sremoved_ the airplane is unstable from a CL of 0.I to0_L and is neutrally stable from a CL of O._ to O. 9.At higher lift coefficients there is a large degree ofinstability since increases of down-elevator deflectionsare requ
32、ired to reduce the forward speed of the airplane._ith the large-span slats installed, however, the air-plane is stable at all lift coefficients above 0_6 but isapproximately neutrally stable at lower lift coefficients.A criterion for satisfactory stability requires astable stick-free pitching-luomen
33、t variation. The re-sults in figure 16 show that the airplane with slatsremoved is very unstable, stick free. With the airplanetrimmed at the same lift coefficient, it is shown thatthe large-span slats decreasGd this instability slightlyand that the large positive pitching-moment variation achigh li
34、ft coefficients was reduced.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-!.i 2 ,%GE . “- .,._,_ ifS, U.-L _.,_ O_,. 6 . u O-tivelces , tsus _“-qP-: “ - m_._.t top tab deflections of _q_O .,._ 220 _,Jl-th tb_e _-a_-,“_.-suan._ slats l,t_,_.le,_.“ _
35、-“ q ,q 8Pe _ve,-, in _“_.:.-2re Pl. These c_rves slow the v,._“it,.:_ _z,.,n D._f CL, “-q_.:,az,_d Che with 6 e for three an_L%es of attac;!t. ?h.e(n “_ “ f_ : value s of ._Crp/da and -,C.Ohe/d6 e s.,e bothaPpPo.Ttiliient C) 6 _he nose-upf.oatinF-_ .an_!e is less with the tab de-fTected -20 thanrq
36、“ _ 7z orion of -i0 “ Deflectin% T:he _-“ _“o. ai2- ._._“_2,eof-7 . :, -_XT_t.G(_ le for, ,_,_Ls ucrlG zo, ,th _s stick-free lonsi, tudir:al inst?.bi_if_ty is (isoPGso.0258J.0 L,_pO-o ,ozL6- .01o0- ,oz3o-.oz6o-0 _ _C _/- 0027o_Sqoo33o.0520 On0360 On.0560 on_u7p- .o23o- .0200-, ,.,_p p-O _!_,J_; 0-oz
37、T).03600220iFins 1t0ff !0Full chord.4a=f chord IIIu_ O:f lOn Off I0n iFull chordlOn iKa!r chordJ iI ii OffOn0n IFul_ chordlProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Figure i.-(a) Three=quarter front view.The iViX-334 airplane mounted for tests
38、in the NACA full-scale tunnel.Original slats installed.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-“popnlouOO -I _n_!_I, . i . ,_ i i _Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N_DBGNATIONAL
39、ADVISORYCOMMITIEE FORAEBONAUTICSF79ure 2 - Three-view drawing of/he kIX-334 _#rfilone. . . -., . .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-L-628NATIONAL ADVISORYCOMMITIE.E FOR AEBONAUTiCS_#ure3;Dio_m _,Jn,_rno/_/once ,6o./)ee/epo.v of ._e A1,I
40、-3“54o_,o/o,_e.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-% % % 1NAIIONAL ADVISORYCOMMITTEE FOR AERONAUTICS_co/e!ona i._,chProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for R
41、esaleNo reproduction or networking permitted without license from IHS-,-,-Tullchordt_/pe-_CG01J4- / _ “/fchordl_,peNATIONALADVISORYCOMMITTEE FOB EBONUTIC$,Sect on of cenfcr/ine of the ojrp/clnngure 6.-Arrongemenf of fin_ on the hlX-334 o/rpIone.Provided by IHSNot for ResaleNo reproduction or network
42、ing permitted without license from IHS-,-,- !IJ i _I _i : _o: _L “i. :,4_26#-diringRcviseoI in/e faceOr/gina/ n/el faceHorizon_o/.section fhrodg/_ the wing c/_ord/neOr/gina / in/e / lace -,- Revl_ed /n/ef faceVerlicu/ 3cc?/on of the duct/n/e?NATIONALADVISORYCOMMITTEE FORAERONAUTICSF/gure 7 -/n/ef mo
43、dif/cGlion for/-he MX-334 o/rp/eneProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,_D/NATIOflk,L ADVISORYCOMMIITEE FOR AERONAUIICSd,/9.8 _, 20._oC, _1.6
44、 _“, 2/.6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-i_ : _!_iiiNAIIONAL ADVISORYCOMMII1EE FOR AERONAUIICS_/o5 oProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-T q_ -:j :-:-:_z_iZ . ,-.; F *_.- _
45、,_:_- 7“aZZL=I :_222I_trz_a_2_-7.-i2.-=-N_- 227_ 5=iPt 2222 .- .899“IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-L-628Provided by IHSNot for ResaleN
46、o reproduction or networking permitted without license from IHS-,-,-,!(_.O0 ,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_o0I1_ L_-I. 1t:_ _:!_ii; !t:it:,;,t_:i_!i:it_:_ :-1 ._4_- _1 _ _ : i_ _ :t ,il, ;_ _:_4-H H I_ _H-H4f:- “l“Ja .I:2,!tIi,1:Pr
47、ovided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-,H +_L_ _ Hi 4 z_ Ifli- _ , p L Ii: _: ,h, lit i;i:ii _ii_iiv-._ q ii!_ l,_ir-_ ,!i,!I,.,lr“-“4 _, _ _ F II. _% _ ., , _ ,:i_!i:i_i:iK-l:!I Iii!itii!i:I!_!ilii_i-;li_d_iil!iiiliii_.i!_i_i!iii i:ii,i,i_ii:,-i_ii_h_ _._ !d.,:
