1、.nin“.,.- - - _ _T_.=,NATIONAL ADVISORY COMMITTEE FOR- 4w ,AERONAUTICORIGINALLY ISSUED LApril 1945 asConfidential Bulletin 5B05COMPUTATION OF HINGE-MOMENT CHARACTERISTICSOF HORIZONTAL TAILS FROM SECTION DATABy Robert M. CraneAmes AeronauticalMoffett Field,LaboratoryNOT TO BE TAKENFROMTHIS ROOUWMHING
2、TONNACA WARTIME REPORTS arereprintsofpapersoriginallyissuedtoproviderapiddistributionofadvanceresearchresultstoanauthorizedgrouprequiringthemforthewareffort.Theywerepre-viouslyheldunderasecuritystatusbutarenowunclassified.Someofthesereportswerenottech-nicallyedited.Allhavebeenreproducedwithoutchsmge
3、inordertoeweditegeneraldistribution.A-H c,.-.-.,t. . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-*-.w.ifACA CB No. 5305NJITIC.NALADVISORY (J()JtITTE. .-FOR AERONAUTICSCONFIDENTIAL BULLETIN-CCKPUTATICN 03HINGE-IICPIE!NTCHARACTERISTICS03 HORIZONTAL
4、 TAIIJS FROM SECTION DATABy Robert M. CraneSUMMARYA study of data fron various wind-tunnel tests of hori-zontal tail surfaces was made to determine the accuracy withwhich section data can be used to estimate the hinge-momentcharacteristics of control surfaces of finite span. The studyconsisted of a
5、compal*ison between the variation of elevatorhinge moments with elevator deflection and with airplane pitch-ing moment, as estimated from data obtain.ed in two-dimensional -flow, and that variation measured. experimentally on 16 differ-ent horizontal tails mounted on wind-tunnel models of completeai
6、rplanes, The method used in applying section data to theevaluation of three-dimensional characteristics is outlined,and summary curves showing the variation of the maJor param-eters with control-surface chord, balance chord, and trailing-edge angle are presented. It is deifionstrated that the three-
7、dimensional hinge-moment characteristics of tail surfaces canbe derived from existing section data with an accuracy whichis within the tolerance required in preliminary design.INTRODUCTIONConsiderable data on the characteristics of large-chordflaps hnvc been obtained (references 1 to 11), which esta
8、blishthe effect of the major variables (flap chord9 balance chord,nose shape, nose gap, etc.) on the section aerodynamic charac-teristics ofairfoils, The question has arisen on occasion,as to the degree of accuracy with which these data can heapplied to the estimation. of the characteristics of cont
9、rol6 surfaces in three-dimensional flow. This question is partic-ularly pertinent as applied to the horizontal or vertical”tail surfaces of complete airplanes, since these surfaces.Mi.-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA C3 NO, 51105
10、 2.(as distinguished from ailerons) are subjected to mutualinterferences, fuselage interference, and are of relativelylow aspect ratio, so that the differences caused by theset.secondaryleffects might be so large as to preclude theuse of section data for anything but the most approximatef%timates,In
11、 order to sh some lit on this problem, the ex-perimentally measured hiuge-moment and pitching-moment char-=acteristics of 16 different horizontal tail surfaces mountedon couq?lote airplane models have %eon compiled and are com-parod with charactertstic estimated from data obtained intwo-dimensional
12、flow, his, study has taken the form of thecomparison of hinge-momant characteristics as defined bythe variation of elevator hinge mwnts with elevator angle,with tail angle of attack$- aud with airplane pitching moments.The types of aerodynamic ba$neo .eqaidered in the presentinvestigc.tion include i
13、ntorzually seled nose balance and un-shrouded nose overh,ang balance,No consideration has been given to shielded or unshieldedhorn-type balances. The data pyesen%ed have been confined tothose obtained at zero aiig.lso? att,ck of the tail, but aretypical ofthe range of nng”les otattack encountered by
14、 a tailin noriaal flight, Considerations were limited to elevatordeflections where stall is absent (characteristics remainlinear), ad all the experimental data were determined in theabsence of operating propellers. These restrictions, however,do not prevent application of the conclusions to the flig
15、htconditions where the elevator stick forces are normally mostcritical; namely, accelerated maneuvers at high syeed (wherethe elevator deflections are normally small and the slipstreameffects are negligi%le)oIn order to facilitate the application of section datato control surfaces on which the impor
16、tant geometric variableswere different from the basic data available, a systematicmethod of application was develoycd. This method and an il-lustrative example on ono of the tail surfaces are outlinedin the section Methodj and tho results of application of thismethod to 16 tail surfaces are consider
17、ed in the sectionDiscussion.SYMBOLSThe symbols used in this paper are defined as follows:.“.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NA,C.ACB NO. 5BG5 3.*“.c1CLCh%cmwhere1LhHMcM.A.COCfCeCeSwseqIno1airfoil section lift coefficient -qc(L)airfoil
18、 lift coefficient l%)control-surface section hinge-rpoment coefficient(h/qcf2)()elevator hinge-moment coefficient -QqqsecetMairplane pitchingmoment coefficientSW(MOAO CO)“)airfoil section liftairfoil liftcontrol-surface section hinge momentelevator hine momentairplane pitching moment about center of
19、 gravitychord of airfoil with control surface neutral, meangeometric Choi-d of horizontal tailmean aerodynamic chord of wingchord of control surface aft of hinge linemean geometric chord of elevator aft of hinge lineroot-mean-squarearea oiwingarea of slevatordynamic pressurechord of elevator aft of
20、hinge lineaft of hinge lineof air s.rea-(;PV)addition to these tb.e fllollinz svrbols have beenemployed:.,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA - “ -.U.M110. !5.BU5 4angle of attack of horizontal tail or airfoilcontrol-surface deflecti
21、on with respect to the airfoilelevator t,ail length (horizontal distance from centerof gre.vity of airplane to the center of pressureof the tail load due to elevator deflection)horizontal tail are?. affected by the elevatoraspect ratio of horizontal tailtrailingedge angle of control surface!hesubscr
22、ipts outside the parentheses indicate thefactors held constnn- fi.uringthe inezsurement of the parameters,METHODThe influence of the foliowing factors has been includedin the calculation of the paraeters Ch8s hat and (bCJtn (1) The elevator chord aft of the hinge line(2) The elevator balance chord f
23、orward of the hinge line(3) The elevator nose gapProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-a71“.-NACA CB NO. 5B05 5.(4) The elevator nose shape(5) The airfoil siction of the horizontal tail, e:3Pe-ci.ally as it affects the included angle betwee
24、n thoupper and lower surface: at the trailing edge of the airfoil(6) The aspect ratio of the horizontal tailThe data of references 1 to 11 are used to establishthe effects of the first five of the above variables on thesection characteristics, These data were collected subse-quently and presented in
25、 reference 120 To facilitate theuse of these section data they have been fully correctedfor tunnel-wall effect and are presented in figures 1 to 8in a form suitable for the present application. In theapplication of these data the following assumptions havebeen made:(1) The variation of the section c
26、haracteristics a ,ch and h. with percent chord will be independent o$the section pofile. This assumption permits the variationgiven in reference 1, which was determined from tests of anNACA 0009 airfoil with various chord flaps, to be appliedto any othor section profile,(2) The hinge-moment paramete
27、r increments due to changesin trailing-edge angle are independent of flap-chord ratioand have the following value:AcIL-J,- = 0,0050claA.Ach6- = 0.0078c18AThe data of figure 2 of reference 11 have been rcproducod infigure 7 of this report in a form more suitable for the presentapplication. Data fro a
28、dditional tests on beveled control ,surfaces (references 13, 14, and 15) have been included todemonstrate the scatter of the experimental points around thepl*oposed correlation curve, It is obvious that all the factorswhich influence the effect of the trailing-edge angle on thehinge-moment parameter
29、s have not been inc.uded in these curves.Since the increments in trailing-ed;e angle needed in thisIProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. .”NACA CB NO* 5305 6report are small (no beveled trailing-edge control surfacesconsidered herein), n
30、o attempt has been made to determine amore accurate correlation method, and an average valuebeen chosen from the existing datae(3) The hinge-moment parameters of balanced flapsin the same manner with ratio of flap chord to airfoilas do the parameters for I)lain flaps, This assumptionhasvary”chordism
31、ade for the sake of expeiencer it lacks experimental veri-fica.tion$ but the effect of the psibe error on the finalresults is not large.(4) The interference effects due to the fuselage orvertical tail do not affect %lp$ %6 $ or (bCh/Cm)aaIt was assumed that there was n: ca?ry-over of lift overthe ce
32、nter section of the horizont,sl t:kil.In the application of these section data to finite-spancontrol surfaces the iifting-line theory and the assumptionof an elliptic span loading have been used as a basis forestimating the effect of aspect ratio on the section lift andsection hinge-moment character
33、istics. These assumptionsen.ble the parameters (ba/M)ct, (3Ch/ct)t$ and (bch/ )CIto be treated as independent oflocation.Caspect ratio and spanwiseNo account has been taken of the variation of theinduced angle along tile spar duc to the actual spzmwise load-ingz L and thearefinemcnts of lifting-surf
34、ace theory have notbeen applied.-lThQ finite-SPa hinge moments for two of the represent-ative horizontal tails ccinsidered in the present analysis havebec computed by tak.ng into account the aer.odcyntamicinductiondue to the actual spanwise loading. The very small increasein accuracy of these comput
35、ations over those in which anelliptic loading was corisidered did ziot warrant the use ofthis refinement,.2Since the downwash ctualy Varj.es ong the chord$ anerror is introduced in the” calculation of the hinge momentsby lifting-line theory because the hinge moments are a.func-tion of the distributi
36、on as well as the magnitude of theresultant ressureo preliminary calculations of the chord-wise distribution of lift indicate an additional aspect-ratiocorrection which increases (algebraically) the hinge-moment-coefficient slopes. This jmitation of lifting-line theoryas applied to the calculation o
37、f finite-span hinge momentshas been previously l“eported in reference 16.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.-.N.ACA CB No. 5305The method of application divides itself into thefollowing steps:7A,B.c.DOTocarriedComputation of the effects
38、 of aerodynamic balance1. Internal seal(a) I!stimate of parameters of plain sealedcontrol surfaces (figs. 1 to 4)(b) Coilputation of hinge-moment incrementsdue to balance (fig. 5)(c) Computation of the characteristic withbalance PlUS (b)29 External overhang balance(a) Interpolation of parameters for
39、 elevatorbalance cherd, nose gap and nose shape(figs, 1 to 4)Adjustment of section parameters for effect ofcontrol-surface chord (fig, 6)Adjustment of section parameters for effect oftrailing-edge angle (fig. v)Application of final section -parameters to three-dimensional flowILLUSTRATIVE EXAMPLEill
40、ustrate the method, the following example has beenout on t!le elevator of the horizontal tail of airnlaneA, the characteristics of which are shown in figure 9, Tkishorizontal tail has a 0.12-.chord-thick airfoil section forwhich the trailing-edge angle is 14.6. The control-surfacechord ratio ias a c
41、onstant value of 0,40 and the elevator isequipped with an overhanging balance of 0e25ce= The noseshape of the balance closely corresponds to the medium noseshape of references 2 to 8 and the nose gap is 0,005c.A-2.- Characteristics of a 0e30-chord flap with aQ -.0002-.0010 -.0010-.0009 -.0006Oool -.
42、0010-.oolg -Ooog_.00;- “ ; i+ ,-.vfz “- ,., # .- -L .-1 - )-.M ,. . .,Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.“ IJACACBEO. 5B05 lug.7a71a15,.( f4 m d+ Ai,. *x+-,-_4 (W -. ._ -+ . . _ ._. ._ -_ if- - if.005 a .- i 0Aa75 1.004 E0r - , “y,U*.00
43、2-,0 I I./2 ,/6 .f?q “* c#/c .28 A .36 .fl .(aC, ,;1 1 , # I,.!; ! !;! !A-4,III .-,.I -m: I.“- ; , I I I I .I i 1 I , I I ;it.- 1 1 I I I I, a71. ixperimental&i&3 ky: !I I CalculatedvalueeIII- 1.1II. .“L 1 II l-H. .“.a+mProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
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