REG NACA-TR-528-1936 Reduction of hinge moments of airplane control surfaces by tabs.pdf

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1、Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORT No. 528REDUCTION OF HINGE MOMENTS OF AIRPLANECONTROL SURFACES BY TABSBy THOMAS A. HARRISLangley M

2、emorial Aeronautical Laboratory140293-35,-1 IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICSHEADQUARTERS, NAVY BUILDING, WASHINGTON, D. C.LABORATORIES, LANGLEY HELD, VA.Created by act of Congress approved M

3、arch 3, 1915, for the supervision and direction of the scientific study ofthe problems of flight. Its membership was increased to 15 by act approved March 2, 1929. The members areappointed by the President, and serve as such without compensation.4bJOSEPH S. AMES, Ph. D., Chairman,President, Johns Ho

4、pkins University, Baltimore, Md.DAVID W. TAYLOR, D. Eng., Vice Chairman.Washington, D. C.CHARLES Go ABBOT, Sc. D.,Secretary, Smithsonian Institution.LYMAN J. BRIGGS, Ph. D.,Director, National Bureau of Standards.BENJAMIN D. FOULOIS, Major General, United States Army,Chief of Air Corps, War Departmen

5、t.WILLIS RAt GREGG, B. A.,Chief, United States Weather Bureau.HARRY F. GUGOENHEIM, M. A.,Port Washington, Long Island, N. Y.ERNEST J. KING_ Rear Admiral, United States Navy,Chief, Bureau of Aeronautics, Navy Department.CHARLES A. LINDBERGH, LL.D.,New York City.WILLIA M. P. MAcCRACKEN, Jr., Ph. B.,Wa

6、shington, D. C.AUGUSTINE W. ROBINS 9 Brig. Gen., United States Army,Chief, MatGriel Division, Air Corps, Wright Field, Dayton_Ohio.EUGENe. L. VIDAL, C. E.,Director of Air Commerce, Department of Commerce.EDWARDP. WARNER, M. S.,Editor of Aviation, New York City.R. D. WEYERBACHER, Commander, United St

7、ates Navy,Bureau of Aeronautics, Navy Department.ORVILLE WRIGHT, Sc. D.,Dayton, Ohio.GEORGE W. LEWIS, Director of Aeronautical ResearchJOHN F. VICTORY, SecretaryHENRY J. E. REID, Engineer in Charge, Langley Memorial Aeronautical Laboratory, Langley Field, Va.JOHN J. IDE, Technical Assistant in Europ

8、e, Paris, FranceTECHNICAL COMMITTEESAERODYNAMICS AIRCRAFT ACCIDENTSPOWER PLANTS FOR AIRCRAFT INVENTIONS AND DESIGNSAIRCRAFT STRUCTURES AND MATERIALSCoordination of Research Needs of Military and Civil AviationPreparation of Research ProgramsAllocation of ProblemsPrevention of DuplicationConsideratio

9、n of InventionsLANGLEY MEMORIAL AERONAUTICAL LABORATORY OFFICE OF AERONAUTICAL INTELLIGENCELANGLEY FIELD, VA. WASHINGTON, D. C.Unified conduct, for all agencies, of Collection, classification, compilation,scientific research on the fundamental and dissemination of scientific and tech-problems of fli

10、ght, nical information on aeronautics.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REPORT No. 528REDUCTION OF HINGE MOMENTS OF AIRPLANECONTROL SURFACES BY TABSBy THOMAS A. HARRISSUMMARYAn investigatio_ was conducted in the N. A. C. A.7- by lO-.foo

11、t wind tunnel of control sur,faces equippedwith tabs for reducing the control,forces or trimming theaircraft. Two sizes of ordinary ailerons with severalsizes of attached and inset tabs were tested on a Clark Ywing. Tabs were also tested in combination with aux-iliary balances o,f the horn and paddl

12、e types, and with aFrise balanced aileron. A tail-surface model of sym-metrical section, equipped with tabs, was tested with 40percent of the area movable (elevator) when used as a horizontal tail and 60 percent of the area movable (rudder)when used as a vertical tail. The half-span tail-surfacemode

13、l was tested with and without a reflection plane.Complete detailed results of the tests are tabulated instandard nondimensional coe y_cient form. The ailerontest data are discussed for one aileron movement andgraphs of control,force against rolling-moment coefficientare included. Curves showing the

14、effect of the tabs astrimming or as serve-control devices are given. For. thetail surfaces, the effectiveness of tabs in reducing thecontrol -force and in trimming and serve operation isdiscussed and figures are included.The effect o,f angular velocities on the application o,f thedata to complete ai

15、rplanes is considered and also theeffect of the difference in the wind-tunnel test set-up,fromthe actual arrangement on an airplane.The results of the tests indicated that inset tabs weresuperior to attached tabs for the same ratio o,f tab control-surface deflection. The greatest reduction in contro

16、lforce occurred at 0 angle o,f attack. The tabs couldbe used satis,factorily as trimming dewices and also toreduce the control -force .for control moments as large asthose ordinarily obtained by deflecting the control surface15 or less. The reduction of hinge moments due totabs could be added direct

17、ly to the reduction due to paddle,horn, or Frise types o,f balance. Angles o,f yaw up to20 had no appreciable effect on the reduction o,f hingemoments due to tabs.INTRODUCTIONFor large airplanes, designers have found it necessaryto provide some means of balancing the excessiveaerodynamic forces on t

18、he control surfaces. Aero-dynamic methods of balance such as horns, paddles,and inset-hinge arrangements have been used to aconsiderable extent. A mechanical device is notdesirable because the hinge moment varies with thespeed of the airt)lane; whereas balancing force isindependent of speed.In recen

19、t designs, auxiliary airfoils attached to thecontrol surfaces have been used for balance and alsofor trimming the airplane. This type of aerodynamicbalance is a development of the “Flettner rudder,“which has been in use for a number of years on largevessels. Such an auxiliary airfoil has been referr

20、edto in this paper as a “tab“ and may be inset, attached,or mounted on outriggers from the trailing edge ofthe control surface. The tabs, when linked, move inthe opposite direction to that of the control surfaceand thereby decrease the hinge moment for a givendeflection of the control surface. Vario

21、us arrange-ments of inset tabs are shown in figure 1. When thetab is used to actuate the control surface, it is referredto as a “serve-control tab.“In reference 1 the theoretical expressions for thehinge moment about any hinge position have beendeduced for flaps on a rectangular airfoil of finite sp

22、anand applied to an airfoil fitted with a serve-operatedflap. The theoretical discussion by Kirste (reference2) also includes complete tests of a symmetrical rec-tangular airfoil with a flap and a tab.The results of wind-tunnel tests of a tab attachedto the aileron are reported in reference 3. Calcu

23、la-tions based on airfoil theory have been made, in refer-ences 4 and 5, for the tab deflections required to holdthe rudder over for different combinations of tab andrudder settings. The results of these calculationswere checked by wind-tunnel tests (reference 6) aswell as in flight (reference 7).A

24、more recent series of tests (reference 8) coversseveral attached tab arrangements on a symmetricalrectangular wing with a flap. These tests were madewith both ordinary and balanced flaps.The data presented in the present report are theresult of a systematic series of wind-tunnel tests on a1Provided

25、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICScommonly used wing profile with several arrangementsof ailerons and tabs, alone and in conjunction withother types of balance. The tests were also extendedto i

26、nclude a tail surface of assumed average propor-tions with several different tabs. Although the testsdo not include all possible tab arrangements, it ishoped that the data are sufficiently general to fulfillmost design requirements.MODELS AND APPARATUSWING-AILERON ARRANGEMENTSThe models used for the

27、 aileron balance tests wererectangular 10- by 60-inch laminated mahogany wingsFixed tr/mming _abControllable trknrning fclbBalancing tab“To trlmm/ng controlBalancing ond control/ob/e frimmin 9 fobTo control stickServo-contro/ lobFIGURE 1.-Diagram showing various tab linkage systems.of Clark Y sectio

28、n constructed to the specified ordi-nates with a precision of d: 0.005 inch. The right-handwing tip of each wing model was equipped with a con-ventional aileron to which the various tabs were fitted.Two sizes of ailerons were tested, one being of 40percent wing chord by 30 percent wing semispan andr

29、eferred to as the “short wide aileron“; the otherbeing of 25 percent wing chord by 40 percent wingsemispan called the “medium-size aileron.“ Eachaileron was mounted on a different wing.Attached tabs.-The short wide aileron withattached tabs is shown in figure 2. In the followingtable the various att

30、ached tab arrangements are listed:Tab chord Tab spanPercent c a Percent b a5 iO010 . 10010020. 505O5O30 . , 100ISpan designationFull-span.OutboardCenter Half-span.Inboard Full-span.Where c a is the chord and ba the span of the aileron.“Outboard“ refers to outboard end of tab flush withoutboard end o

31、f aileron, “center“ refers to tab sym-metrically located with respect to aileron span, and“inboard“ refers to inboard end of tab flush withinboard end of aileron.The attached tabs were constructed of _%-inch flatsteel and were screwed to a brass trailing-edge pieceof the aileron so that when neutral

32、 the lower surface ofthe tab was flush with the lower surface of the aileron.The angle of the tab was adjusted by bending aboutthe trailing edge of the aileron and all openings betweentab and aileron were sealed with plasticine.Inset tabs.-The short wide aileron is shownequipped with inset tabs in f

33、igure 3. In the followingtable the various inset tab arrangements are listed:Tab chordPercent e A5 .10.20 .Tab spanPercent b a1001001005O505OSpan designationFull-span.Outboard /Center Half-span.Inboard Outboard, center, and inboard have the same mean-ing as for the attached tabs. The brass inset tab

34、s wereattached to the main part of the aileron by soft wirepins that could be bent to obtain the desired tabdeflections.The medium-size aileron (fig. 4) was tested with atab extending along the entire span of the aileron andwith a chord 10 percent of the aileron chord. The,lileron was constructed of

35、 wood with a brass trailingedge to which the brass tab was secured in a mannersimilar to that used for the inset tabs on the short wideaileron. For all tests the space between tlle tab andaileron was sealed with plasticine.Combination balanees.-Additional tests were madeat the request of the Bureau

36、of Aeronautics, NavyDepartment, of the short wide aileron and a ce#),erinset tab 20 percent of the aileron chord wide andhalf of the aileron span long in combination with twosizes of paddles. The paddies were 18.75 and 27.5percent of the aileron chord wide and 44.5 percent ofthe aileron span long an

37、d were located symmetricallywith respect to the aileron span (fig. 5). The duralu-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REDUCTION OF HINGE MOMENTS OF AIRPLANE CONTROL SURFACES BY TABS 3b = GO“L-_-b,_=o.3ob/2=S“-_FIGURE 2.-Diagram of wing sh

38、owing attached tabs on short wide aileron.NowE.- xfehord length of tab=5,10, 20, and3Opercentofca. Span of tab=100 and 50 percent of hA.Ikg!l:_ vc_IIb/2 = 30“ “_.b= GO “FIGURE 3.-Diagram of wing showing inset tabs on short wide aileron,NOTE.- z=chord length of tab=5, 10, and 20 percent of cA. Span o

39、f tab=50 and 100 percent of hA.k-b A = 0.40b/2=12“- -_J5/2 = ao“b = 60 “11fab : 60“ -FIGURE 4.-Diagram of wing showing inset tab on medium-size aileron._._-0. 445 bA -:1“- 2. 5 II g| 2k-a,_ =0.30b/2= 9 “-b/g = 30YFIGURE 5.-Diagram of wing showing center inset tab and paddle balance on short wide ail

40、eron.NOTE.- x=chord length of paddle balance=18.75 and 27.5 percent cA.iItm_c_kProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-4 :REPORT NATIONAL ADVISORYCOMMITTEE FOR AERONAUTICSiiL L.b =60“b/2 = 30“._. .,._,_,!_ 1_, 15oh i - LFIGURE 6.-Diagram of w

41、ing showing center inset tab and horn balance on short wide aileron.!/- - :_ r_ _-_-0.SObA=4.5cJ 225“_- _-bA = 0.306/2= 95“- _ _b = 60 “b/2 = 30“FIGURE7.-Diagram of wing showing center inset tab on Frise aileron.20.567 “= Spore of fob30“ = bFmua_: $.-Diagram of tail surface showing details.NOT_.- Fo

42、r elevator x=5, 10, and 20 percent cg. For rudder _=20 percent c_.IIProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-REDUCTION OF HINGE MOMENTS OF AIRPLANE CONTROL SURFACES BY TABS .min paddles had the N. A. C. A. 0012 profile and weresupported in the

43、 positions specified with _2-inchsheet steel end brackets.On this same aileron a horn was attached for addi-tional tests. The aileron was faired to a symmetricalsection in the horn, the principal dimensions of whichare shown in figure 6. The plan of the horn was madeto conform to the shape suggested

44、 by the Bureau ofAeronautics, Navy Department, the leading-edgeportion being half of an ellipse. The horn was con-structed of laminated mahogany and was fair to thesame precision as the remainder of the model.The short wide aileron was also tested with amodified FHse type of balance and a tab (fig.

45、7).The nose shape of the aileron was obtained from astudy of available Frise aileron data and was madesimilar to the Frise aileron of reference 9 with a raisednose. This type of Frise balance gives slightly lessbalance for low deflections, where overbalance usuallyoccurs, but gives about the same ba

46、lance as theordinary Frise aileron at the high deflections. Themahogany nosepiece was attached to the leadingedge of the ordinary aileron by screws and a suitablecut-out was made in the wing to provide clearance.(See fig. 7.)TAIL-SURFACE ARRANGEMENTSThe tail-surface model used in these tests is show

47、nin figure 8. The model of laminated mahogany hadan N. A. C. A. 0006 profile faired to about a ys-inchradius at the tip and was constructed to a precisionof 0.005 inch. The plan form of the model wasdesigned to be an average of either a half-span hori-zontal or a fifll-span vertical tail. The span o

48、f themodel was 30 inches and the average chord 20 inches,giving an aspect ratio of 1.5. As a horizontal tail,a portion of the model was hinged along the elevatoraxis shown in the figure. This arrangement gave anelevator area 40 percent of the total tail area. Theinset tabs of different chord lengths were made witha span equal to the span of the straight trailing-edgeportion of the elevator. The tab chords tested were5, 10, and 20 percent of the maximum elevator chord.The tabs were made from the trailing-edge portion ofthe elevator and were secured to the main part of theelevator by soft wire