of the airfoils, together with the size of the ailerons and

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2 XAT I0NA.L ADVISOBY COXtIITTEZ FOR AERONAUTICS. TECHLTICAL ~ ~ E ~ NO. ~ O 437, ~ ~ T D ~ ~ ~ EX?ERIXS:BTS ON AIRFOILS WITH AILERON AND SLOT. * By A. Betz. Report 11, No. IV, 8, gives the results of '!Tests on Slotted Wingst1 (For trnsltion see EdcCook Field Uemo Report No. 124). The present report contins the results of few experiments on three irfoils to which the rer portions, hving chords respectively 1/4, 1/3, nd 2/5 of the totl chord, re hinged so s to form ilerons, especil ttention being given to the shpe of the slot between the ileron nd the min portion of the irfoil. The shpe nd rrngement of the irfoils, together with the size of the ilerons nd slots, re shown in Figure 1. The front portion ws the sme in ll three cses, s likewise the loction of the ileron hinge D. The irfoils, mde in the usul mnner from sheet metl nd plster of Pris, were reotngulr with spn of 120 cm (47.24 in.) nd respective chords of 18, 20, nd 22 cm (7.09, 7.87, nd 8.66 in.). The mnner of suspension from the three- component blnce ws the sme s for the IIExperiments with Three Horizontl Empennges" (See N.A. C. A. Technicl Memorndum - *"Untersuchungen n Fl3geln mit Klppen unci Splt,lll From "ETgebnisse der Aerodynmischen Versuchsnstlt zu Gottingen,'! Report 111, 1927, pp

3 N.X. Z.A. Technicl Uerilorndurn No No. 419, Fig. 2). The mn&xitude of the ir frces on the different irfoils t different ile,ron settings ws first determined. Complete tests were mde for only two ileron settings. In one s of tests, the upper or suction side of the irfoil remined prcticlly constnt, nd in the other series the lower or pressure side. These settings corresponded to the following ileron deflections p, which re specilly noted in the digrms nd tbles. Aileron 1: Suction side constnt t p = - 3', Pressure side constnt t f3 = -14'; Aileron 2: Suction side constnt t p = + 3' Pressure side constnt t B = Aileron 3: Eluction side constnt t p = + 2' Pressure side constnt t = The!Zero position of the ilerons is shown in Figure 1, s lso the reference line or the ngle of ttck. Perfect constncy could not be ttined on the pressure side since, due to the position of the pivot in the upwrd deflection of the ileron, its leding edge ws lowered, thus ltering the outline of the under side of the irfoil t this point. In the other ileron settings tests were mde ocly in the vicini- ty of the point of mximum lift.

4 N. A. C. A. Technicl Meinor,nd_um KO Figures 2-4 nd Tbles I-XIV contin the results of this first series of experiments. The reference surfce, tk the bsis for the clcultion of the coefficients, is the mximum projection re of the irfoil t f3' = 0. chord corresponding to this position ws tken s the irfoil chord for the clcultion of %. The reference xis for the moments is the leding edge of the irfoil or its projection on the chord corresponding to the usul definition (Pge 32 of Report I). As ws to be expected, the lift incresed with incresing deflection of the ileron ccompnied, however, by n increse in the drg. The flow lso becme detched t smller ngles of ttck for lrge ileron deflections thn for smll. ngles or for no deflection. The ileron moment ws found by nother 'series of experiments, in the sme ws s for the horizontl empennge, but in ech cse for only two ngles of ttck of the whole irfoil. The ileron moment Mk nd the moment coefficiet "k were clculted in wy siqilr to the one used for clculting the elevtor moment (See N.A.C.A. Tkchnicl Liemornduin ). In Figure 5 the C% vlues re plotted ginst the ngle of ttck nd the ileron deflectlon p. Contrry to the cse of the horizontl empennge with s7metricl profile, cons idcrble increse in the i1ero.n moment with incresing size of ileron is sogetimes found, while the mgnitude of the ngle

5 N.A.C.A. Technicl Memorndum No of ttck dioes not wke so much difference here. The numericl vlues o the moment coefficients re con- tined in Tbles XV-XVII. IiYinK, with Aileron 1 Spn b=120 em; Totl chord TABLE I. Aileron deflection p = - 3' t-18.0 em; Totl re F=2160 em2 TABLE 11. Aileron deflection p = - 14' - SUC I t em LOO c, I 100 cw ' t ; ' i I n O Aileron deflection 13 = 17' CL ]~OO 100 CW 100 Cm 13.9' TABLE TABLE IV. Aileron deflection F = 29' CL 7 \ 100 C 100 CW 100 cm 100 c 100 GW 100 ~;m 13.8' I i O so

6 11.A.C.A. TeclmictL1 Xemorndum No Wing with AileronA. Spn b=120 em; Totl chord t=20.0 em; Totl re F=2400 em2. TABLE VII. TABLE VIII. Aileron deflection f3 = 3' Aileron deflection f3 = e! ~ Q O CW -0.7' ' j i I C, c 100 cw ' 100 % -6.3' ' ,6 5.4 I I TABLE IX. TABLE X. Aileron deflection p = 45' Aileron deflection = 61' 100 % Spn Ailei O Vin with Aileron 3. b=120 ern; Totl chord t=22.2 cm; )n deflc 100 C TASLE XI. :tion 100 cvp = 20 A iler 100 Gm 4G fl Totl re F=2660 cm2. TABLE XiI* n deflec 100 c, ;ion (3 = - go 100 cw 100 cm

7 N. A. C.A. Technicl. 1lei;lorndu.m No (Cont.) I Spn 6=120 cm; Totl chord t=22.2 m; Totl re F=2660 cm2 TABLE XIII. TABLE XIV. TABLE XV. TABLE XVI. Wing with Aileron 1. Aileron Are Aileron 0 Angle of ttck 3O I! I! 18'!I It It FK = 552 cm2; 3rd tu = - Aileron def lee- - tion f3-14' ' TABLE XVII. Wing with Aileron 2. Aileron Are Aileron C Angle of ttck II If 18 II Wing with Aileron 3. Aileron Are FK = 1055 em2; Aileron Chord tk = 8.8 n. Angle of I Aileron ttck --- 3O II II 15' 11!I def leetion B 3 -go I! Trnsltion by Dwight 11. Miner, Wtionl Advisory Committee for Aeronutics. * _ * _. - FK = %~'; 3rd tu -- = Aileron def lee- --==-# no , 6 cm cx

8 &A.C.A.* Fig C K Fig. 5

9 c, f1g.2

10 Fig. 3 Alzron 2 0 /3 = 3 03Jegtive-pressure side It tt -4- /3 =-11 Positive- Qt_- p = f3 = 61 0 l- L Cm m CQJ 40 Fig. 3

11 M.A.C.A. Techicl I6emorndu;:l n o.437 Fig, 4 r2il2roi @---p = z0 0 Negtive-pressure side. -p =-9 Positie- It p =45O -0- p =53O Cm / c, 50 Fig.4