1、.I,“1+ “+J.F , A% July 1942Tl!mw!w! “ -g-.:.;.-._.L-7_. ,L1 !NATIONAL ADVISORY COMMITTEE FOR AERONJWFICS0RlG4NALLY ISSUEDJuly 1942 asAdvance RestrictedReprtKIND-TUNNEL INVESTIGATIONOF CONTROL-SURI?ACXcHARAc!TERIsmcsVIII - A IARG3 AERODYNAMICWCE OF TWO NOSE SHAPES7EED KITE A 30-PmC,.,L.-4k:J: -4U1,:J
2、.-T.,:. .-,-i, :-. . . r- -q(. -NACA J“mmJF?.:.,. , , : ;. . .?,.: -. . ,. ,. -_h,. . -,. ,. , , . . 1 ;. . , . . . .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-9 . . tho overbalance and the range through which it extendedwas greater for the blun
3、t-noso flap. Unsealing the gap atthe noso of the flap caused an increase positively of,bothcf; and ChfGf a result that is in agreenont with theresults for the thin airfoil (reference 3).3ecuso the flap with 0.50cf overhang was overlalancodthroughout sor,e rnnge of deflection, it cannot ba usedwithou
4、t notifications. A trailing-edge tab deflected intho sano direction as the flap nay be used in conjunctionvith this flap nrrangencnt to ovorcone the overhalnc ofthe flap (roferonce 3). Such an unbalancing tab will in-crease the lift effectiveness of the flap, with the resultthat the deflection requi
5、red to obtain a given incrementof lift will not he so great as that for a conventional.fla of the same chord. Bec,ause chf is positive, theaflap will float against the relative wind, a factshould cause the static stability of the airplanecontrols free to exceed that with controls fixed.Rudders with
6、a large positive value of chathatwi”thand con-a71siderahle fr.iction”al damping have lean reported to causeundesirable flying qualities on a num%er of airplanes hav-ing small directional stability. These airplanes showed atendency to oscillate in yaw but the undesirable characteristic has been corre
7、cted by making ha and Morec%fnegative. Ylight tests of one airplane at Langley I!emorialAeronautical Laboratory in which the rudder had a positivevalue of ,c and the airplane had a large amount of di-arectional stalility indicated that the behavior of the air-plane was satisfactory.” A theoretical a
8、nalysis currentlybeing made at the Laboratory shows that a positive valueof ch is desirable provided that other factors are prop-aorly controlled.Pitching IlomentsCm() qThe values of the parameters ma and ()act Sflisted in ta%le III indicate the position” of the aerodynam-ic center of the airfoil. W
9、hen the lift is varied bychanging the angle of attack, at a flap deflection of 0Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-“1othe aerodynamic center of the airfoil is at the 0.235c ;,point for both flap-nose shapes with the gap sealed and atthe
10、0.225c point for bcth flap-nose shapes with the 0.005cgap. When the lift is var ed by changing flap deflection,iat an angle of attnck of O , the aerodynamic center is atthe 0,41c point foz both nose shapes with gaP sealed andat the 0.42c point fGr oth nose shapes with the 0,005cgay , Tho positions o
11、f the aerodynamic center for the pres-ent tests are in good agreement with those for the airfoilwith plain flap (reference 7). The position of the aero-dynamic contor for the flap deflected is a function ofaspect ratio (refarence 1) and will move toward the trail-ing edge as the aspect ratio is decr
12、eased. DzagThe measured vnlues” of dr.g cannot be considered abso-lute because of a relatively large unknown tunnel correc-tion. The increments of profile-drag coefficient causedby flap deflection (fig. 4), however, should be independentof tuynel effect. The medium-nose flap gave i=.nincrease inmini
13、.um profile-drag coefficient of shout 0.0022 over thatof the plain flap on the same airfoil (reference 7). Viththe l)lunt-nose flap the increase was within the experi- .marital accuracy of the tests. .Tab CharacteristicsIn general, the tal characteristics for the balancedflap are similar to those fo
14、r a tab on th plain flaP(reference 7). At a flap deflection of O , the effective-ness of the tab in changing the flap hinge-moment coeffi-cients was greatest when the tab was defleoted in conjunc-tion with the angle of .attaak. This result is oppositeto that for a tab of tho same size on an NACA 000
15、9 airfoil,for which the effectiveness of the tah was greatest whenthe tab deflection and the angle of attck wero in opposi-tion. AS previously discussed, the overbalance of theflap that occurred when the large overhang was used on theflap may be overcome by the use of a differentially oper-“ atod un
16、balancing tab deflected in the same direction asthe flap.BaI.ancing Effectiveness of Various Overhangs .The values of the hinge-moment parameters for blunt- . .-.= . , .,. ,., :- y-y - .,”. ,- ”, -.-, - -:- :.7,:. ., .,.- .* : .“: . . :.,.,:. -“.”, ; .-.,-:, ,-. ” :, .-.,:,- ., : . . .J .Provided by
17、 IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-11nose flaps on the NACA 0009 and NACA 0015 airfoils are pro-sentod as a function of aerod:?nanic balance in figure 7.Tl:e data are summarized from the investigations reportedin roforonces 2 to 8, with the exclusi
18、on of reference 6,.”3 vhich does not deal with overhanging lalances . The unsealedPPa gap was 0.005c in all cases except that it was 0.0015c forA the largest overhang on the NACA 0009-airfoil. Tho plainunbalanced flap, because it is hinged at the center of itsncso radius, has an overhang, This overh
19、ang, however, cancontribute no lalancing affect because all forces normalto the surface of the ovorhang act through the hinge axis. .Figure 7 shows that, for both airfoils, the hinge nO-nents of a balanced flap were reduced by unsealing the gap.Tho rate of change of hinge-moment parameters with incr
20、eas-ing aerodynamic balance was greater for the thinner airfoilthan for the thicker airfoil. On both airfoils, the flapwith 0.35cf overhaag did not produce overbalance, but with0.50cf overhang the flap was overbalanced. Tho paraneterc becane positive with a 0.35cf overhang on the thicker“faairfoil b
21、ut, on the thinner airfoil, a 0.50cf overhang was-eqvirad to produce a sinilar effect.COITCLUSIONSThe,results of the tests of the NACA 0015”airfoilwith a balanced flap having a chord 30 percent of the air-fcil chord and a flap-nose overhang 50 percent of theflap chord compared with tho results of pr
22、evious tests ofa sinilar flap on the NACA 0009 airfoil indicate the fol-lowing conclusions:1: The slope of the lift curve for the NACA 0015 air-fci.1 was slightly less than that for the NACA 0009 airfoiland decreased when the gap at the flap nose was unsealed.2. The lift effectiveness of the flap wi
23、th largebalance on the NACA 0015 airf.il was practically the saneas that of the plain flap on the same airfoil and as thatof the sinilar flap.on the NACA 0009 airfoil.3. The blunt-nose balance was more effective in re-ducing flap hinge monents and caused gredter overbalancethan tho nediun-nose balan
24、ce, but the effectiveness of theProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- . . .“12blunt-nose balance was not naintainad to so high a flap df3-flection when the flap was deflected in conjunction withthe angle of attack as that of the uedium-nos
25、e balance.4. The nediuz-nose flap caused an increase in mini-Hum profile-drag coefficient of 0.0022 over that of theairfoil with lnin flap, whereas tho blunt-nose flap gaveno noasl.lr.nble”increase .5. The tal), when dofleced in conjunction” with theangle of attack, gae greater increments of lift an
26、d flap .hinge-moent cocfficints per unit tab deflection thanwhen doflectad in opposition to the angle of attack. lTational Advisorr Cormitteo for Aeronautics,Langley ?ied, Va.1.2.3.“4.Determi-nation of Control-Surface Characteristics fromNACA Plain-Zlap and Tab Data. itep. Ko. 721, NACA, .-1941.Seer
27、s, Richard I.: Wind-Tunnel Investigation of Control-Surfacs Characteristics. I - Effect of Gap on the .Aer5y:mc$ z Characteristics of an ITACA 0009 Airfoilw:.tk a 3G-Percent-Chord Plain Flap. NACA A.R.R.,Jwaa 1941.Sears, Richnrd 1., and Hoggard, H. page, Jr.: lind-nel investigation of Ccntrol-Surfac
28、e Characteris-tic. 11 - A large AeroclUrnanic Balance of VariouslTose Shapes with 30-Percent-Chord Flap on an ?IACA00G9 Airfoil. NAC3. A.R.P, Aug. 1941.Anes, Milton B., Jr.: Vind-Tunnel Investigation ofControl-Surface Characteristics. III - A S21allAerodynaic 3alance of Various Nose Shapes Used with
29、a 30_Percent-Chord Flap on an NACA 0009 Airfoil.UACAA.R.R., Aug. 1941. - - . . . . . -m-,- ,- ,. .- .,:. .: ._-i- . :., : .-: .-,. ,“+-.;, ?Z=T7T 7 .7.,”.+.-f. . . . . . ;, -1 .: - . . . . . . . . . . .-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,
30、-.135.(KIc-mA 6.8.9.Ames, Milton B., Jr. , and Eastman, Donald R., Jr. :lTind-Tunnel Investigation of Control-Surface Char-acteristics. IV - A Medium Aerodynamic Balance ofVarious Nose Shapes Used with a 30-Percent-ChordFlap on an NACA 0009 Airfoil. NACA A,R.R, Sept.1941,Jones, Robert T., and Aries,
31、 Milton B., Jr.: Wind- YTunnel Investigation of Control-Surface Character-istics. v - The Use of a Beveled Trailing Edge toReduce the Hinge Nonent of a Control Surface.NACA A.R.R, March 1942.Seart2, Richard 1., and Liddell, Robert B.: lind-TunnelInvestigation of Control-Surface Characteristics.VI -
32、A 30-Percent-Chord Plain Flap on the NACA 0015Airfoil. NACA A.R.R., June 1942.Sear=, Richard I., and Hoggard, H. page, Jr.: lYind-!i!unnelInvestigation of Control-Surface Character-istics. VII - A Medium Aerodynamic Balance of”TwoNose Shapes Used with a 30-percent-Chord Flapon an NACA 0015 Airfoil.
33、NACA .4.R.R., July 1942.:ienzingor , Carl J., and Harris, Thomas A.: The Ver-tical I.indTunnel of the National Advisory Comnit-toe for Aeronautics. Rep . No. 387, NACA, 1931.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-_ _. . .,.to.EmNAOATable”l.-
34、 Ordinates for HA(YA0015 Table II. - Stations andordinatesformedium-nose00500f over-.airfoil. Stationsandorditites in peroent ofairfoil ohord,.LtouwwrtaaeStathn(perwlt o) Q:1:01$.16)o *3J1:87”1.252-5-J*51520;2:37 M;5:25- .85?- .68-7.17-7.43-7bw- .25i- .62-?7- :5;.:;.;:-1:01(-.16;o25?0o11.9712.gg13*9
35、9 ;?:?17.52 19.171002.44 L. E. radius: Fair to WA 0015 profile totrailing *eNose radzus = 2.96 peroent oTable III.- Parameter values for a 0.30c flap with a50cf overhang on an NACAO015 airfoil.(Blunt nose ehme Hedlu8 nose dmm IarametomtGap“Soalod0%0o.o. 0.085-Ogg -.650 a71*o .0033.015 .027-.160 I -,
36、165(3aalse d0.0ZJ5-.48 ,.00210.095-.5k.0005-.0032.014-.157 -,. -.0030.024-.177-, =- -.z . ,., .-. .- .7.+ . . . . . . .-. ,7 -.= - , - - -,= .,- . . . . . -., -. . ., .” ,:, l:. :, J. ,-, ., :.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- , L-378I
37、 I,.1,1J,I;:,1.I,.I( * .G/ease ador .auicgap.II G/- ,:.” 8- “ “ .” :-, . . .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-t4AC/Ao.3.2.10I-HII ! I T III I 1=-47 I Y II.I It t,*IIit I Y;!v Q-/2 Io 5 /0 /s 20Tab defection, Sr degFigure 6.Tab smtion hi
38、nge-momentooeffioientand inoramentOof airfoil8eotionliftcoefficientandf OeOtionNnge-morneniiooeffiaentoaused by defbotion .ofa 0.200f.pm tab,etiwmnose0.500foverhmw with 0.W50 f= SSP;. or aqd 0.00LJ tab gap. &f= oo.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
