1、. -, ,4c)4z =-%,.%. , . J-V.LVA Uuvuuv . . .- . 4 llllllllllllllllllllllllll!llllllllllllllllllllllllln 4._. . .;. -,. .- -_ _:ll me=xy11111111111111111lllulll!lllllllllllllllllllllll1176 00113 6564RESEARCH MEMORANDUMSUMMARY OF SPIN AND RECOVERY CHARACTERISTICS OF 12 MODELSOF FLYING-WING AND ImC ONV
2、ENTIONAL -TYPE AIRPLANESBy Ralph W. Stone, Jr. and Burton E. Hultz.Langley Aeronautical LaboratorycLAsg.qQ:; ; :!y,y:,;.:a”., ,. .,tJ;.$,.-tw_L-_ti-IJN(XASSIFILD-_/96+AI?,(. -”-“-“”!lLllJtho?i,y of b. K;77-,.%9f,+e,J whereas elevator-down and aileron-againstsettings were conducive of the slowest rec
3、overy; for mass distributedchiefly along the wings, the converse was true. The influence of massdistribution on the effect of directional controls was dependent notonly on the yawing moment produced but also on the accompanying rolling-moment if the rolling moment was appreciable. Recovery technique
4、srequired were similar to”those of conventional configurations exceptwhere unconventional-type control surfaces set up unusual moments whenmoved for recovery. The models generally recovered from inverted spins as readily as from erect spins and it was indicated that wing-tipparachutes are an effecti
5、ve means of terminating spins in an emergency.Although the results were not sufficiently extensive for evaluation inthe form of a design criterion for satisfactory recovery, the.datapresented should help designers of flying-wing and unconventional-typeairplanes anticipate probable spin and recovery
6、characteristics.-. 4, MK%ASSIFIED. ,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2INTRODUCTIONNACA RM L50L29The results of investigationsof the spin and recovery characteristicsof numerous models tested in the Langley is-foot free-spiriingtunnel a
7、ndthe Langley 20-foot free-spinningtunnel during the years 1935 to 1946have been used to establish empirical criterions for satisfactory spinrecovery (references1 and 2) which are generally applicable to airplaneshaving mass distributions typical of this time period and which areconsidered of conven
8、tional design (that is, having both horizontal and vertical surfaces at the tail end of the airplane). The results ofseveral designs which may be generally termed unconventional or flYing-wing.ty configurationswere also available and, because of increasedinterest in unconventional high-speed airplan
9、e configurations,it appeareddesirable to evaluate these available results to determine criterionsfor satisfactory spin recovery similar to those evolved for conventionalairplanes. Because the flying-wing and unconventional-typedesigns oftenutilized unusual and differentmethods of obtaining direction
10、al control,it was not possible to evaluate their spin-recoverycharacteristicsinterms of a vertical-tail design parameter (tail-dampingpower factor)in the manner used for conventionaldesigns (reference1). Also, becauseof rather limited data available for these configurations,an alternateeffective par
11、ueter could not be developed at this time. Resultsavailable for 12 designs of unconventional and flying-wing-typeconfig-urations have been summarized, however, and the more important spin andrecovery characteristicsare presented in this paper.The effects of mass distributionand center-of-gravityloca
12、tionwere determined for many of the models as were the effects of geometricmodifications designed in an attempt to improve the spin-recoverycharacteristics. The investigations included the determination of theeffectiveness for spin recovery of Several types of controls which arepeculiar to flying-wi
13、ng and unconventional-typeairplanes.The spin and recovery characteristicsof each model are presentedfor the various control configurations,mass distributions,anddimensional configurationstested. Dimensional data, mass data, and athree-view drawing of each of the various free-spinningmodels areinclud
14、ed. The data presented are intended to help designers of uncon-ventional and flying-wing-typeairplanes anticipate probable spin andrecovery characteristics.SYMBOLSbswing span, feetwing area, sqwre feetWUSSIFIE3 . positive when center-of-gravityposition is rearward of leading edge of Eratio of distan
15、ce between center of,gravity and thrustline or fuselage reference line to length of meanaerodynamic chord; positive when center of gravityis below thrust line ,m mass of airplane, slugsP air density, slug per cubic footP airplane relative density (m/pSb)Ix) Iy) Iz moments of inertia about X, Y, Z bo
16、dy axes, respectively,slug-feet2. .1X “ Iymb2inertiaIy - Iz2 inertiambIz - Ix inertiamb2yawing-moment pmameterrolling-moment parameterpitching-moment parametera angle between thrust line or fuselage reference lineand vertical, degrees, approximately equal to absolutevalue of angle of attack at plane
17、 of symmetry$ angle between span axis and horizontal, degrees; on thecharts U or D means inboard wing (right wingin aright spin) up or down, respectively, with relationto the horizontalv full-scale true rate of descent, feet per secondc1 full-scale angular velocity about spin axis, revolutionsper se
18、cond-.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4ACnlWICARM L50U9*.deflection of rudder=,degrees,.deflection of elevator, degreesdeflection of ailerons, degreeselevator upelevator neutralelevator downrolling-moment coefficient due to control de
19、flection( /)Rolling moment *.,-,. .“charts 13 and 14, respectively. The results of tests with dimensionalmodifications on the various models are listed with their indicatedeffectiveness in table III and in general are presented in the corre-sponding charts 1 to 12.Erect SpinsThe spin and recovery ch
20、aracteristicsof models 1 to 6 (charts1to 6) were found to be in general agreement with references 1 and 6 asregards the influence of the mass distribution.onthe effectiveness ofthe controls during the spin and the recovery. When the mass of themodels was distributed primarily along the wings, for ex
21、ample, aileronsettings against the spin (stick left in a right spin) and down-elevator settings (stick forward)were generally favorable. For thesecontrol settings, steeper spins with more rapid recoveries were generallyobtained than were obtained for other control settings. These controlsettingswere
22、 also conducive of no-spin conditions. For this massdistribution,reversal of rudders-whichprimarily gave a yawing momentonly were ineffective;whereas movement of the elevator down appe=edto be the most effectivemethod of obtaining recovery. Such controlmovement for recovery is consistentwith that in
23、dicated for conventionalairplanes for similar loadings. When the mass of the models was distri-buted primarily along the fuselage, aileron-with settingsand elevator-up settingswere generallymost effective in causing steep spins fromwhich recovery was most easily obtained. For this mass distribution,
24、movement of the rudder against the spin, when the rudder primarily gavea yawing moment only, generally appeared to be the most effectivemethodof obtaining recovery. These results of control effectivenessare alsoconsistentwith those indicated for conventionalairplanes for similarloadings (references1
25、 and 6).Some exceptions to the general effects ofcontrol settingsandmovements on the spin and recovery were obtained, however. When, forexample, model 6 had its loading distributedmainly along the wings(chart 6)full-down elevator and full ailerons against the spin sometimescaused a relatively flat s
26、pin from which recovery was unsatisfactory.For this model and other similarmodels, combination of the longitudinaland lateral controls in a single surface caused unusually large deflectionsof the surfaceswhen both full elevator and aileron controls were applied.When the elevator was full down and th
27、e ailerons were full against thespin, the inboard control surface (that on the right wing in.a right spin)had a large downward deflection;whereas the outboard-controlsurfacewas nearly neutral. It is believed that this large downward deflectionof the inboard control causedunusually large pro-spin yaw
28、ing momentswhich overcame the possible favorable effect of the rolling moment dueto the aileron-against setting. For loadings for which the mass wasdistributedprimarily along the fuselage, control settings of the elevatora71.Provided by IHSNot for ResaleNo reproduction or networking permitted withou
29、t license from IHS-,-,-2 NACA RM L50L29c. a71 “ 9full up and the ailerons full with the spin tended to be similarly.detrimental.Models 1 to 4 (charts 1 to 4) had rudders which did not primarilyprovide yawing moments only but also provided appreciable rolling moments.The rudders for models 1 to 4 are
30、 shown in figure 6. Typical of these.rudders are those of models 2 and 3, similar models with differentrudders. The rudder of model 2 is a spoiler-like surface which on theairplane protruded downward and forrd through the lower surface ofthe wing; a pitch flap moved upward in conjunction with downwa
31、rd move- .ment of the spoiler surface. On model 3 two split flap-like surfaces,one on the upper surface and one on the lower surface of the wing, wereboth deflected for rudder movement. For both models, the rudders onthe right wing functioned and those on the left wing remained neutralfor a right tu
32、rn. These rudders may generally be termed scoop-typeand split-type rudders, respectively.A comparison of the aerodynamic yawing- and rolling-moment character-istics of the two general types of rudders (measured on,the free-flight-tunnel balance, described in reference 7) is shown in figure 7. Theres
33、ults indicate that, for angles of attack above 34, setting the rudderagainst the spin (left rudder pedal forward in a right spin) for thea71 scoop-type rudder produced a rolling-moment increment in the ssme direc-tion as would be obtainedby setting the ailerons against the spin(left stick in a right
34、 spin); whereas for the split-type rudder, a.rolling-moment increment in the same direction as would be obtained bysetting the ailerons with the spin was produced. The yawing momentscontributedby both types of rudders were approximately the same. Theresults are consistent with those indicated in ref
35、erence 6 for conven-tional designs with loadings with the mass distributed primarily along “the wings in that rolling moments caused by aileron-against settingswere favorable and rolling moments caused by aileron-with settings wereunfavorable to spin recovery. Thus for wing-heavy loadlngs, the scoop
36、-type rudders when moved against the spin gave favorable rolling momentsfor spin recovery and the split-type rudders when moved against the spinproduced unfavorable rolling moments. Conversely, it was indicated thatmaintaining the split-te rudders with the spin was favorable for spinrecovery; wherea
37、s maintaining the scoop-type rudders with the spin wasunfavorable. As is further indicated in reference 6, for loadings inwhich the mass is distributed primarily along the fuselage, aileron-withsettings are favorable. It appears probable that, for designs with theloading primarily along the fuselage
38、, scoop-type rudders when set againstthe spin would have produced unfavorable rolling moments for spin recovery;whereas split-type rudders would have produced favorable rolling moments. .Models 5 and 6 had rudder control surfaces that primarily provideda yawing moment only. Model 5 had dual rudders
39、and model 6 was testedboth with single and dual rudders. For models 5 and 6 (charts 5 and 6),Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-10 NAC!ARM L50L29when the mass distributionwas primarily along the fuselage, rudderreversal was generally eff
40、ective in producing recovery; whereas formodel 6,rudder reversal was ineffective in producing recovery when themass distributionwas primarily along the wings. These results are inaccord with the results of reference 1 for conventionalairplane designs.Thus rudders which primarily provided yawing mome
41、nt only appear to besimilarly effective in producing recovery for airplanes of the flying-wing type as for airplanes of conrentioml designs, depending primarilyon mass distribution. It has been noted for one model (model 6) thatsingle or dual vertical tails appeared equally as effective provided the
42、yhad equivalent vertical-tail volume (reference 8).aModel 7 had a delta-wing plan form and a loading for which the weightwas very heavily.distributedalong the fuselage. The results of anextensive investigation on model 7 (reference 9) indicate that spins maynot be obtained for values of the inertia
43、yawing-moment pamm-(eter Ix - Iy/mb between approximately -450 x 10-4 to -750 x 10-4and thatflat spins will generallybe obtained for larger or smaller values of theinertia yawing-moment parameter. Reversal of the rudder was generallyineffective in stopping the spin rotation except when sufficientlyl
44、argedual vertical tails and rudders were used (reference 9). These largevertical tails are shown in figure and the results m?e noted in tableMovement of the ailerons with the spin, however, was generally effec-tive for terminating the spin rotation. This effect is in agreementwith the results obtain
45、ed during an extensive investigationon a swept-wing model having a horizontal tail. This model was tested at fuselageheavy mass distributions (reference10) beyond the mass range of refer-ences 1 and 6. For all loading conditions tested on model 7 after spinrotation had ceased, the model tended to gl
46、ide at a flat attitude (veryhigh angle of attack) decreasing its angle of attack relatively slowlyexcept when the elevator was full down.Model 8 had a sweptforwardwing and generally tended to spin flatwith a wide radius, very slow rotation, and large oscillations in roll,133 :.pitch, and yaw (c wher
47、eas it did spin erect. Model 4, however, would spininverted,when the rudders were set against the spin (data not presented).Model 5 would spin inverted for most control configurations;recoveryby rudder reversal was, however, satisfactory. These results are somewhatbetter than those obtained erect, p
48、robably because more vertical fin andrudder ares,were unshielded in the inverted spin than in the erect spin.Model 6 would spin inverted only with ailerons and rudder with thespin. Satisfactory recoveries were obtained by neutralizing all of thecontrols.Model 7 would spin inverted for a loading conf
49、ition for which it wouldnot spin erect. The model spun inverted, however, only when the aileronswere against the spin and the stick was neutral or forwqrd longitudinally,The rudder of this model was above the wing and shielded in erect spins,whereas it was relatively unshielded in inverted spins. Thus for thisJ.a71HNCW=D.,Provided by IHSNot for ResaleNo reproduction or
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