1、., ,. ,-.,! .! a71f ACR MOV . 1940,. . .k:kNATIONAL ADVISORY COMMITTEE FOR AEROWAIWIME IuwollrWlND-TUNNELWITHORIGINALLY ISSUEDNovember 1940 asAdvance CcmfidentialReportlIWRSTIGATIONOF AN NACA 23012 AIRFOILTWO SIZES OF BALANCED SPLIT FLAPBy Thomas A. Harris and Paul E. PurserLangley Memorial Aeronaut
2、ical LaboratoryLangley Field, Va.,., .! : !, ,:, . .;WASHINGTONNACA WART REPORTS are reprints of papers originally issued to provide rapid distkbution ofadvance research results to an authorized group requiring them for the war effort. They were pre-viously held under a security status but are now u
3、nclassified. Some of these reports were not tech-nically edited. All have been reproduced without change in order to expedite general distribution.L -“441,.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.i 3 117601 W5247.- .TIHD-TUNEEL IWESTIGATIO19
4、 OF M? Z?A)OA23012 AIEEOILWITH-TWO SIZES ”03BALANCED SPLIT BLAP, -f- . .,- .3y Thomas A. Harris and Paul E.-“uree-r “ m. .SUkXARYmAn investigation has been made in the I?ACA 7- by 10-foot wind tunnel of an NAOA 23012 alrfoll with a 15-percent-chord and a 25-percent-chord balanced spilt flap of theCl
5、ark Y profile. The inveatigaton wag made to determinethe aerodynamic section characteristics of the airfoil asaffected by the Et%e, nose location,flap.and deflection of theComplete aerotynamlc section characteristics wersdetermined for several nose locatlocs of each flap and arepresented for four ty
6、pical locations for each flap. A .comparison of the drag aud lift characteristics is madewith two other medium-chord flaps previously investi%ated-The optimum arr.ngement Of either of the balancedsplit flape, from consideration of maximum lift coeffi-cients and minimum profile-drag coefficients for
7、take-offand climb, was a combination comparable to the Fowler flap.Then compared on n bmsis of flnp deflection for equal mnx-imum lift coefficiong, there TRS little difference in thepitching-mor.ont coefficients for .ny of tho arrangementstested. Any leak octwoen the nose of the flap and thelower cu
8、rface of ths ing wag harmful from considerationof maximun lift coefficient, but if tho gap was increasedt“oform a suitable slot the naxium lift coefficient wasIncreased. The results of this investigation furntsh datasultnhle for application to the design of any proba%lesplit-flap arrangement.INTRODU
9、CTIONAn investigation of various hlqh-lift devices has beenundertaken by the lUCA to provide designers with aerody-nnnic and structural data fGr the design of wing-flap con-“.Blnntlons for Inproved safety and porfornance of airplanes.Aerodzanic data for sinle-slotted flaps on airfoils ofvnrious thil
10、tnesses have been nmde aailable in references1 throuqh 6, for Fowlor and plain flaps on 12-percent thick.airfoils 1P reference 1, nnd for split flaps on airfoilsof various thicknesses tn reference 7. Structural datafor the single-clotted flaps are presented in references8 and 9, for the plain flap i
11、n reference 8, for the splitflap in referenco 9, and for the Iowler flap in reference1-10.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 . . . . . . “ . . . . . .Since .st df the flapu in geaerel use today are someform of spilt flap, the investiga
12、tion was extended toflaps 0$ the.balanced split te and the present reportpresents aerodynamic data for two sizes of balance splitflap on an NAOA 23012 alrfotl.APPA3ATITSAND TESTSModelsThQ basic airfoil was built to the lIAOA 23912 profile,the ordinates of which are given in table 1 .It has a spanof
13、7 fact and a.chord of 3 feet, and is the same basic qir-foil used in reference 2. The rear po=tion of the airfoills”remoable so that flFLpS of var:oue sizes can be used.Ths 15-peroent-chord and the 25-percent-chord flapswere built OS lamlzzated ma.hozany to the Clark T profile(ta%le I). The spn of e
14、ach flap WP.S 7 feet end the ohordsmero 5-4 Inches aq of 16 positions. Data were obtined at each flapposition qt flap deflestlons from 0 to 60 in 10 incre-ments. The complete aagle-f-at$ac range from -6Q tq thean%le of attack fos maximum lift mas coverdd in 2 incre-ments for each test. So Sata rere
15、obtained a30vo thestall because of %Le unstead condition of the model= m. . . . . . . .RZSUiS AND DISJSSIQY. . - m.Coofficie=ta , . -. . . . . .All tho test results arm given ia standard nondimen-sional seotlor c60fficietit form, corrected as explained$n referencci 1. - “-section iift coefficient.Cz
16、 . . . (t/qc) “cd i30ctiotip%ofilo- the value waa 2.68 and WAS sllhtlyhigher thap was reached with the 0.2566c slotted flap 2*h(Yeference 1) at.the memo defleoton -defl ec%eqc+oq.+o.eor 500, the flap stalled and the lift decreased sllghtly.The point for maxlmu.m lift moved to 0.050 ahead of thetrail
17、ing edge and C).03C below t4e chord line. At the 60deflection the lift coefficient incrensed to nearly thbvalue obtained at the 30 deflection, and there was littlechoice between locatng,the flap nose at the trailing ed%eon the cho”rd line or locating it 00.05c ahead of and 0.015cbelow that point. It
18、 is interesting to note that lccatin%the nose of the 0.15c ?lap 0.05c ahead of the alrfolltrailing edge and 0.03c below the chord line %ave, for de-flections of 40 or over, a maximum lSft coefficient near-ly as high as that given by-the usual Fowlor arrangement.(See figs. lQP within the range tested
19、, forany deflection from 0 to 30 and for any lift coefficientfrom 1.0 to 2.0 fr the .3.15c balanced split flap, and forany deflection from Co to 40 end any lift coefficient from1.0 to 2.5 for the 9.25c bal.need split flap.Pitchin% moment.- The contcurs of flap location for- -Cm(a.c. )o in figures 12
20、 thyough 18, S30V for both bal-anced sglit flaps that the negative pitching moments atthe best locations were nearly twlco those of the simpleeplit flap, and that they incrensod proqresively as theflaps approached their bgst locations. When the balancedsplit flaps were located and deflectsd to give
21、the samemaximum lift coefficients as tho split, plain, or slottedflaps of reference 1, the pitching-moment coefficientswere only sllqhtly larger than for the plain and spiltflaps and were about equal to those of the slotted flap2-h. In the seleotion of an airfoil-flap combination fora %iven airplane
22、, the pltchng-moment coefficient shouldbe determined for cobintins that give equal maximumlifts in order to obtain an unbiased comparison.?Yith contours of flap location for %l.c.)o in. -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.-. .figures 12
23、 through 18, the deeiqner can determine”thepitching-moment coefficients of both wtng-flap combina-ttons with$n the range investigated.lfffe.t af -e Qng gap.- Several tests”were made withthe 0.25c balanced spilt ?lap to determine the effect ofsealing the gap between the flap nose and the airfoil.4 Th
24、e results of these tests arq.presented with the contours“ in figures 4, 8 to 11, and 15 to 18. In nearly all cases,i seallnq the gap Increased the lift, drag, and pitching-moment coefficients. These dat will afford the designerh.,additional information on the aerodynamic characteristics% of a split
25、flap deflected downward nd moved to the rear. jK The selection of the ptlmum arrangements of the bal-.“ a“nced split flas from a consideration of the maximum. lift-+8.c coefficient,-, minimum profile-drag coefficient for take-off, and pitchinq-monent coefficient will have to be a compro-mise in whic
26、h structural sinp.llclty will play an important$Secfion/iftcoefficien+c,e,4_ Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.,NACA l?ig.31Percenf w(ngC%ordq ($f=o”.-Percent wing chord(b) +- =10:Percent wing choro( 8 =30;Percent wmq chord(e) b=40:Perceti WI+ chordq) + =60:Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA Fig4.PerCcht wiy chord .,.,eIProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
