1、.-. /4s- . - /-3 q w-a+/K!?CH3 ICAL MEPiRAMI)UliS,.“,”*.i- .),4y. .,. -:.”.bi,.d. .;.No. 9101.AHD COM?ARISOH WITH FLIGHT MEASURZMZI?TSBy W. BaderLuftfahrtforschungVol. 16, Ho. 2, February 20, 1939Verla,g von R, Oldtsribourg, Miizxhen und aerlin“ ,.WashingtonSeptenber 1939I!JBRARY COPYIr,.,b.;.,.:,.,
2、: ,.-.- ,.IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-“;Illlllilllmmmllllllllll31176014165782*=. :-.h-d-.I$A!T!IOITALADVISORY COMMITTEE l?ORAERONAUTICSKTO, 91.oIifTHE ROTATING JETMEASUR3!MIIITTS*six-component measure-ments in the small tunnel of
3、 the DVL on a model of theBIW-M 27bl, which were made to determine the effect ofrolling and yawing on the air forces and moments. The ex-periments were carried out in a rotating air stream. Theviind was given a spiral motion by nee,ns of a rotatingscreen, the model being suspended in the conventiona
4、l man-LnergIron the findineCt ratio of A = 9.5$ alllc of tJiStProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-of O,hollt 40 anti 2 5 0 dihedral. In the first third of thescr.lispo.n(counted fron plane of synnetr) the airfoil isa G8ttinCcn G13681; the
5、 othor profiles over the ncan linocycorrcs:,ond. to the latest IALU stao.dard of nonenclo,turo-The ,?,ri,.:iesin fiuro 2 are plotted. positive; the arrowsifLicnte the TOillt frOU whic! th anglUS are counted. .!positive wgle of yaw indicc.tes an advace of the star-board win; thus a positive value of
6、anlc of yaw in aright SJin indicates ta.tivc Zn or xadirection, the l;ter,force is positive if in directionof the positive y axis. !Xlcrloric71ts, L, M, and N,ore :;ositive for positive rotation about their respectiveaxes .where s .is hnlf SiO.n;z:nr 1, nean wing chord.A positive contol witla arcOnt
7、r.,rea of around 38 percent the vnlue is around*This ILi-,“wre is readily deduced from a relation for theO.:IGIC of yaw l)c.scd on the steady spin.vProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a (XH0.7 .38 = 0.43 for with elevator hart up; the fac
8、 -aqtor 0.7 for fully d.cflectet. contrcl corresponds to thousu.1 r,ssunption rcspectin the inciyicnt loss of COQ-trol offcetivoness. teIicnce nornal force COCffi.CiCili isslip) in fiGurcs 10 and 11. For the non-stalled ran;:e,ihc r.ieasureneats give a La.npin:;value in roll ofa CTe =- 1.0. Tlhecalc
9、ul.atior. of the pertinent t.ni:credw:qs t, .aTrProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-1,n,4.A conio.risen 01fijures 10 and il discloses the well-c:20w:1increase in ,nutorotatioll velocit;r for outward slip.I.feel.scrcucntsat 50 inwc.rfi.sli
10、p (not reproduced here) hrinGClut the spin-rctarclin5 effect of the inward slip and hencethe Inportanee Of tliejraWill;r*OEiCllts.Fi:ure 12 ivcs the ya.wini;-noncnt curves without ro-tation; note, with rud.clcrdeflection. tho hlaiketinfl effectof the rmiq.er ty the elevator and stabilizer in the sta
11、lledrcme. This l,anketiieffect is intensified if accon-pmiccl l)ypUShC?C1-dC)Wilelevator (not shown) C?VOilat smallflOw a:l;les,so that t!hc rucl.d.ereffect r?.reps60 percent:IrLa si:.ewind at very sI?all m.les of o,ttack, a slit;htrcstori:l; ycuwinflr.loncnt(curve = 10, = O“) is createil.in consequ
12、ence of the wind vme st,lility,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-0:1approq.chine the stall the unstahilizinc win yaw-ing noncnt increases consiclerally, and the directionalstability is lost; the flow on the shoved-%,aclc win tiptrcn.ks
13、awo: sooner as a result of the inccunnlation ofioundr.ryla;er naterial th,an on t.ehalf shoved forwa.rdAt fJ.rtherincreasing alc cf attack the anplificd win;yo,winf;:oleitis gradually superseded by the lateralcontrol surface noneni tursiaG into the wincl, althouhweakc:led as a result of the blanketi
14、ng effect. The accu-racy in the yawing nonent ner.surenents left much to tc t!e-sired in eonsequonce of the cases previously describedFor tho purpose5. comparison with the flight tests infiguro 13, the Yawing Honent coeffi.cicnts about the nor-11.1 i.1jlcilaxis are, therefore ylotted for several and
15、lesof attnck between 15 and 40 with spin proaoting controldeflections aainst the spinninc factor A e,nd Be = 0;if accompanied by a positive angle of slip (outward) thepoints of intersection of the curves with the C:7 zero,axie shift tpward the right.ilconplete reprofluction of the test cl,atawas for
16、e-ry detcrnination of the yawing no-nent islthe rotating tunnel jet with reater instrunento,laccur,zcy (higher dynmic pressure, use of larger nodel),For, while the existence of a static pressure gradient naycause a n.ove:cnt of the boundary layer nass, it cannotcreate a wing yawing nonent with linea
17、r superposition.The scuenay be assuncd to hold true for the fuselage andcontrol surface yawing nonat: the drag nay perhaps befalsified at hicr ae as a result of an air force to-ward. the jot center but not the drag difference of theport and starboard siclc.loco:plcte nunerical a.greenent can obtain
18、betwoonthe nodel test data and those at full scale because ofthe scale effect. Even sol it has been proved in theforeGoiafl: that the effect of the five factors a, p, h,n) and ila.sbeen reprduced substantially correctly inthe wind-tunnel tests. With a view to establishing the,a71a15. .a71,Provided b
19、y IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N.A. C.A. !lech.nical Menortandun No. 910 15-12. .a71a77wIlurinG these tests a so-called ls.utonatic ol)server”develOL?dhy the DVL was iilsto,lled in tho airplane, Itrccorc.edthree anar velocities o,lout the thre
20、e. princi-p:ll Cl,xcsof inerti,o.,tho three normal nccclerations inthe direction of the three axes, the sinkins speed andthe on(:ine r.p,n.IQ a stad.y sii(to which is solely referredherei:) the oquo,lity of the resultant air force with thoresultvltnass force givesvi +- G sin Y= ()tho flit-po.th a!lg
21、lo in the spiil cuttetween -75 and -90and the lateral force consistently small numerically, itfollows that the drag is approxinatoly equal to the grosswei;ht aid the lift eq.rul to the centrifugal force.As stre=sed in the discussion of the lateral forcencasure:.onts,the angle of the yawed flow in a
22、stecl spinis in ;enern.1very ;reat and approaches a ri;.ht,aale;owi; to tk.is, the anGle of attack and the absolute anountof the Ci.ilLli2of pitch fireconylclzontary with, here, satis-factory accuracy to a riht fiillo,even if the ant;le ofthe fli;ht path does not zmourit to -90. “Hence tho aillcof a
23、ttack “u is given byThe c.:lt;lcof yaw can be ccnutocl hy means of tho equa-tions af notion. A sinpler way is, as was done in these?flijilts,to neo.suro ky r.leansof a tent nozzle; accorcl-in to tho flifiht records raned at Ietwcen 0 and 50outwa.rflslip.With ?3X, l)y, Ci:ld oZ denoting the neasured
24、nornnlProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-x axisY a,xi sz axisTliflht 1 Fliarefi:o 5) ; because, since infirst approximation it nay be assuned that+-1A rCP40(CXO+- CW)COS cfw+ CvJo(aO+ Gd)sin w (3) YcJq r I 1 1 1 1$uMode )4274 Refl-z$ 41S
25、K%.-. a 0 40 a 0$ 3Figure 3.- Systemof axes.Figure 6.- Change of drsgduring rolling.?igure 4,- Effect ofy6iw on liftand drM.c.GLla1 1 1fO o 10” I20a; M I- 4jc.ClubI I-40 io I40 I I20 :30 40Yigure 5.- Lift /-lb o do 20 30 wFigure9.-Rollingmomeatin yawagainstangleofattackae.W,.-4I 1 1 I10 04 20 3 (1;
26、dFigure8.-Coefficientof pitchingmomentat diffeentcontroideflection.,. I I I I0 40 20 I30GWFigure 12.- Coefficient ofyawiagmoment at differentcontrol setting8.Figure10-ll.=Coefficientof rollingmomentagainst-s , for77- = 00 and#Je= 100.?igure13.-.CoefficientofYawing momentqQsagainst at#e=OoOProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
