1、. .,.I - ., - ,., NATION,AL ADvWy fOMMITE . .-. /FOR AERONAUTICSWAlrnpm IUWOMIORIGINALLY ISSUEDMarch19+4asAdvanceConfidentialReportkCUWIND-TUNNELINVESTIGATIONOFSHIEKDEDHORNBKGANCESANDTABSONA O.7-SCALEMODELOFXF6FVZRTICALTAILSURFACEBy John G. Lowry, JamesA.Maloney,and1.ElizabethGarnerLangleyMemorialAe
2、ronauticalLaboratoryLangleyField,Va.,- -. - # ., NACA-N .,. A CA LH3RARYLANGLEYMEMOW AERONAC,LABORATORYDy Fielthe design of shielded horns in general and to obtaindata useful for the XF6F vertical tail in particular.”: Additional tests were made to determine tab character-istics for two different ta
3、bs and flow characteristicsover several ofthe shielded horns- .:The various shielded horn balances tested includedmodels of the original horn on the XF6F airplane and ofshielded horns of four chords, each of which was testedwith two different spans and nose shapes. The variation” “in horn size cover
4、s the range from no balance to over-balance. Flow characteristicswere determined by tufttests of”two of the smaller horns and pressure-distributiontests of two of the larger horns. The pressure-distribution data show the local velocity distribution ofthe two nose shapes tested. For convenience, the
5、term!fshieldedhornl*will generally be referred to as fhornj”followed by a designation to indicate the horn size andnose shape. .“.Tests were made of an unshielded horn balance todetermine whether any correlationbetween shielded andunshielded horns was poss?ble. These tests tire alsothe logical exten
6、sion of those of the short-span shielded “horns.Characteristics of the tab were determined in orderto have tiformation useful In the design of any balancingor unbalancing device that uses tabs, as well as to havethe characteristics of the particular trhming tabstested. A round-nose tab of the same p
7、lan form and sizeas the orlghal tab was tested to determine the varia-tions In characteristics, if any, from the original tab.The round-nose tab represented the type of tab usuallyused on wind-tunnel models. Both tabs were testedsealed and unsealed.APPARATIR AND METHODS .The model was mounted vertic
8、ally in the LMAL 7- by10.foot tunnel with one end adjacent to the floor of theProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. .,; 3tunnel which acted as a reflection plane. (See figs. 1and 2. The model was supported entirely by the bahanoe. fr.ame(
9、fig,l).wt,ha-small clearance at the tunnel floorin order that all the forceshnd.iiiets aotng on themodel could be measured. Provisions were made forchanging the angle of attack of the model and the.defleo-tlon of the rudder while the tunnel was in operation.The hinge moments ofthe moving surfaces we
10、re measured bymeans of eleotrlcal strain gages mounted within the model,and the rudder deflections were measured by an eleotrioalposition Indicator attadaed to the rudder and mounted.within the surface. For the pressure-distributiontests,the pressures were reoorded photographically from amultiple-tu
11、be manometer looated outside the tunnel.“The 0.7-scale model of the XF6F vertical tail sur-faoe wps built b the National AdvisorT Committee forAeronautics and conformed to the dimensions cf figure 3.Theairfoil secttons used (fig. ) were modified?ACA16-series airfoils with the portZon rearward of the
12、rudder hinge line faired to a flat oontour. The tipcontour was changed somewlmtfrom tn shape used on theairplane in that It was built with semicircular sectionsthrolh the tip to allow for changing the horn shape andsize easily. The trailing edges of the cover plateswere 0.61 inch ahead of the rudder
13、 hinge line from theroot section to station 47.93 and tapered from 0.61 inchat station 47.93 to 0.35 inch at the tip. The rudderwas sealed with a flexible seal fcr most of the tests;the hinges, however, were not sealed. Some geometriccharacteristics of the model.are given in the table Infigure 3.Sev
14、eral different arrangements of shielded hornbalances were made for the model and are shown In fig-ure 4. Horn 2-a (fig!+(1)represents the hdrn on theXF6F airplane with the exception of the tip fairing.The other shielded horns were tested with two differentnose shapes. The blunt-nose horns are of air
15、foil con=tour fram the hinge line to the point of tangency withthe leading-edgeradius. The medium nose shapes weremade to the ordinates given in table I. The.variationstested included horns of four chords and two spans andoover the range f%om no balance, plain rudd6r, to a con-dition of overbalance.
16、 The gap between the horn noseand fin extensf.onwas similar to the one on the airplanefor horn 2-a and was maintained for all other horn ar-rangements. The gap.betbeen tlieInboard end of the horn Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-., ,-
17、, -,-, . . .14andthe, ., - ., . . . . . . . . . . . . - , .,= . .,. ,fin was 0.22 Inoh, which corresponds to the gap onXF6F vertical tall.The unshielded horn tested Is shovm In figure 5 andmade to the same span as horns 1. 2. 3. and 7. Theshape of the horn Is the same as the-al;fl tipshapeand has-th
18、e same gap between the horn and fin as theshielded horns.The plan form and geometric characteristics of thetabs tested are given In figure 3 and the sections of thetabs ere given in figure 6. The original tab representsthe tab on the XF6F rudder. The leakage through the.piano hinge was simulated by
19、a piece of gauze. Theround-nose tab was constructed as shown in figure 6 andhad provisions for sealing. Both tabs were sealed witha flexible seal for some tests.Horns 8-a and 8-b were modified for pressure-distribution tests by placing a row of orifices . ;9:i:e; from the inboard end of the horn, as
20、 shownThe chordwlse locations of the orificesare given i; figure 7 and are the same for both horns,except that orifice 1 on horn 8-a was eliminated fromhorn 8-b. These orifices”wereconnected to copper tubesthat were in turn connqcted to leads from the manometer.The copper tubes were kept within the
21、model until theywere a few Inches from the tunnel floor. When pressure-diatribution tests were made, time was allowed forconditions in the tunnel and for the manometer to becomestable before the pressures were photographed.A damic pressure of 16.37 pounds per square foot,which corresponds to a veloc
22、ity of about 80 miles perhour and to a test Reynolds number of about 2,300,000based on the model mean chord of 3.16 feet, was main-tained for nearly all tests. In some cases it was notpossible to maintain the dynamic pressure at 16.37 pomds per square foot because of the hiph drag at large anglesof
23、attack and rudder deflections, for which the dynamic -pressure was decreased and corresponding corrections weremade in the computations.J. IProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. . .5RESULTS Am DISCUSSIONCoefficxlentsand Sols. The ooefflci
24、entsand-symbols used indefined as follows:CLCDcDicmChPLnMHsq.bc?zBPPoPlift coefficient (L/qoS)drag coefficient (D/qoS)induced-drag coefficientthe report arepitthing-moment ooefficient (M/qoSc)hinge-moment coefficient (H/qob )pressure coefficient (P-Po)/qolift of modelag of modelpitching moment about
25、 mounting-axis center linemoment about oontrol-surfacehinge lineareadynamic pressure of free air stream()*02spanchord (formovable surfaces, measured fromhinge line to tratling edge)mean chordroot-mean-square chordbalance coefficient (* H l/%cr 1)static pressure at an orifioestatic pressure of free a
26、ir streammass density of air -,.- . . . . . . - - . . .- .- . . - . - . - .- . . -Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. . . - . - .-e . mfi+ -. - . . . . . . -. :+ :+!. :e-.:”- -:,.,-Provided by IHSNot for ResaleNo reproduction or network
27、ing permitted without license from IHS-,-,-IF1. .9attack through the unstalled range. A comparison ofthe tidividual ourvea of figures 12(a) and 12(b) indi-oat-e”althouglr+he -use of some of the larger hornsgives a large positive Inorease In c+ over the%? small deflection range, the values of C% for
28、these horns In the stalled r-e with large ruder deflectionare Inoreased.In order to obtan a more oomprehenslve comparisonof the shielded horns, the Values of ACha and AC% 8nwere plotted against belanoe coefficient *B ofreference 1 in figure 13. . The curves for the unshieldedhorns of reference 1 hav
29、e been included for comparison.The data of figure 13 Indicate that the values of AC“ad c% in some oases gave a valueof L b sed on deflections of “ about 5 to10 perc all of the horns except 3, 6, and Couldbe further balanced by use of balanolng tabs withoutgoing out of the region of complete damping.
30、I?Yomreference 2 it appears that if the rudder is tobe closely balanced - that 1s, c% approaches zero -%c% must be held near zero if complete damping is to be.obtained. A comparison of the values of AChaand AC% at a constant value of B from figure 13indicates that AC% Increases about seven-tenths as
31、fast as “%6 ; thus, if complete balance is tober.obtained by use of shielded horn alone, the unbalanced/%control must have.the rat!O h C = 0.7. Inasmucha %?as this ratio appears to give a value of c% higher thanfound with most”control surfaces, some other type of “balance Is required to reduce c% to
32、 gtve the ratiodesired. Several types of balanolng device may be usedProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-including Internal balances, overhang, or balanolng tabs;.-.hoc?ver,any balancing devtce that reduoes c aboutthe s2.933.433.76ordinat
33、esSDanwiaestation1.olo.12J?:21ith.J:55.778.9161.0021.0 61.0501.020*.62o.071:2.193.25963?2;:l!$a71475Horns 3 and 6Chordwlse1 0rdlnate8ataton s anwisc!,1.010 0.05.20 Y:243.0.546a7155L1:z .694.8002:3; .887?.30 1.019.30 1.1112a71 30 1.1726:4; 1.2061.216i.30 1.218.30 1.2069.30 1.17210.03 1.11110.0 1.0691
34、1.28 1.020station54.620.066.132.161.258.323:?.47?.512 z:52.566.567a71 562.546.1ii:4?5Horns2 and5Chordwisestationo.02.05.12.22.721.22.722.292.72?.72.725.22i.72.727*52OrdinatesS anwi84t1.010.100.186.242.326.576.2it:92a71999:o1.13i1.1331.0901.020station54.62. .0%:0.113.152.268.541za71 93:4%.50.52J:1?:
35、75Horns7 and8 _Chordwlsestation1.101.53?1. 52. 0OrdinatesS anwiset1.010 Y:2 4a71342d:8;.8871.0191.1111.1721.2061.2161.2181.206I.lp1.1111.0691.020-lstation54.620.066.132.162.258.323z: :3.47?a71 51i%2:5.566.567.562;5$f98:475Provided by IHSNot for ResaleNo reproduction or networking permitted without l
36、icense from IHS-,-,-17TABLE II.- SUMMARY OF CHARACTERISTICS, . . OFSHIELDEO HORNS ON O-7-SCALE MODEL.3 OF XF6F VERTICAL TAIL SURFACE4-,.Horn-Nonel-al-b2-a2-C2-d3-a1-b4:?-a.-:6:b .:;i8:El2.106.106.210.210.210.lo.310151.151.50Z.505.453.453.268.268.386;.306H/sp9a71 038.038.075.075.075a71 11.111.076.076
37、.151,3.51.226.226.094.094.187a71 187.TCL= (3+ /2-16 Q )6-20 A 20-24 k 24-28 :-3236 a 36Angle of dtoctf, LX , dcg Ac of cWuch, a ,;egfigure 8.- Aerodynumlc characteristics of07-scu/e moot+ of Yf6f vctilcdiQI/ surfoce. P/QIn rudder. mhcs of QTscale model of Xf6f ven$cal izd sun?uce,P/uin sealed ru doe
38、 Y. Ougmul tibj = 0!Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NACA Fig. 10I 1 A x- ,4- IPhinseakdrudder Tmnsitionfixed 6r(deg)00V-4 A4R: El:b -/6 4 /6v -Zo A ZOv -24 k 24: MJd-36ti364.9.3.8($eulrd,YioceProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
