NASA NACA-TN-763-1940 Wind-tunnel investigation of two airfoils with 25-percent-chord Gwinn and plain flaps《带有25%弦的Gwinn和普通襟翼两个机翼的风洞研究》.pdf
《NASA NACA-TN-763-1940 Wind-tunnel investigation of two airfoils with 25-percent-chord Gwinn and plain flaps《带有25%弦的Gwinn和普通襟翼两个机翼的风洞研究》.pdf》由会员分享,可在线阅读,更多相关《NASA NACA-TN-763-1940 Wind-tunnel investigation of two airfoils with 25-percent-chord Gwinn and plain flaps《带有25%弦的Gwinn和普通襟翼两个机翼的风洞研究》.pdf(14页珍藏版)》请在麦多课文档分享上搜索。
1、“ .#a .* - .-. . .-. .,-:A ,- J + , .#.;. . _- - -+-S:J!JS -: :.: - . / “llllll!lllllllll!llll!llil“- -i:-:”-z-:ii:rfi- := ,. .:. .=- ,., :.,; - _ L +z:. :y-L., :. ; i ,. .:=!- . _yd:- ., .- _-. - ,. -,:. -./# .-TECHNICAL NOTESNATIONAL ADVISORY COMMITTEE FOR AERONAUTICSNO. 763 .-WIND-TUNNEL INVESTIG
2、ATION OF TWO AIRFOILS WITH25-PERCENT-CHORD GNINN AND PLILIN FLAPSBy Milton B. Aries, Jr.Langley Memorial Aeronautical Laboratory, /WashingtonEay 1940 .Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NAT IoNAL ADVISOR”y tiONMITTEE FCYR”AERONAUTICSTECH
3、NICAL NO,TE“NO. 763 ,WIND-TUNNEL INVESTIGATION OF TWO AIRl?OIGS WIT “25-PERCENT-CHORD GWSNN AND PLAIN FLAPSBy Milton 3. Ames, Jr”.,SUMMARY.,Aerodynamic force tests of an N.A.C.A. 23018 airfoilwith a Gwinn flap having a chord 25 percent of the over-all chord and of an N.A.C.A. 23015 airfoil with a Pl
4、afflap having a 25-percent chord were conducted in theN.A.C.A. 7- by 10-foot wind tunnel to determine the rela-tive merits of the Gwinn and the plain flaps.!Chetests indicated that, based on speed-range ra-tios, the plain flap was more effective than the Gwinnflap. At sqall flap deflections, tePlain
5、 flQP h the.lowe drag coefficients at lift-coeffici,ent ,values lessthan 0.70. For lift coefficients greater than 0.70,however, the Gwinn flap at all downward flap deflections hadthe lower drag coefficients,INTRODUCTIONImprovement in airplane performance has dependedsomewhat on the development and t
6、he use of high-lift de-vices. “As an aid to designers, the N.A.C.A. has conductedmany experimental investigations of various types of flapand has reported the effects of these different flaps Orihigh or low drag at high lift (gliao-ath control), low cdrag in the cruising-speed conditiohr and high li
7、ft andlow arag at the”take-off.The present investigation, conducted in the .NAoC*A.7- by 10-foot wind tunnel, was of a high-lift deviceidentified as the Gwinn flap and included for comparisontho te5.ts of a plain” flap. “The Gwinn flap is essentially,.a flat plate mounted at a point very near the tr
8、ailingedge “of the wing. In its neutral posit$on, the flap eX-tends past the traillng edge of the wing, there%y resultingProvided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 -N.A.C.A !?edhntcal .lJoto.lJo.763. . .,in an increased over -all .chord and wi
9、ng. area. In somerespects the Gwinn flap is similar to the plain flap.Both flaps deflect upward or downward so that either ofthem may ho Used “as a high-lift, device and the nodels used, however, were not comparable withthe Gwinn flap nodel used in this investigation. Thenodels of the airfoils with
10、the Gwinn wad the plain flopsused in these tests had the sane over-all chord., span,aspect ,ratio, and approxirmte naxtnum thickness.APPARA!l!US AIJD TESTSModelsTwo airfoil models were teited: An 8-inch-chordIJ.A.C.A. 23018 airfoil section with a Gwinn flap havinga chord 25 percent of the over-all c
11、hord (fig. 1) anda10-inch-chord N.A.C.A. 23015 airfoil section with a.plainflap having a 25”-percent chord (fig. 2). Each model hasa span of 60 inches and an over-all chord of 10 inches.The maximum thickness of the model with the Gwinn flap,based on over-all chord, is 14.4 percent of the chord and,o
12、f the model with the plain flap, 15 percent., Both air-foils and the plain flap are made of laminated beech; theGwinn flap is made of aluminum. In order to mount theGwiun fla-p; 5 percent of the over-all chord was removedfrom the trailing .adgo of the i?.A.C.A. 23018 airfoil sec-tion. The flaps are
13、arranged to move up or down alouttheir respective hinge axes Qr.to lock rigidly in a givenposition. Flap deflections were measured with respect tathe airfoil chord line, and all gaps between the airfoilsand the flaps were sealed with plasticize to prevent airleakage., .Wind Tunnel and BalanceThe tes
14、ts wero made in the N.A.C.A. 7-by 10-foot,tunnel, which has a closed throat and return passage. T.hetunnel and the ragular 6-component balance aro describedin references 2 and 3.F.Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. . :. ”.,. . . N.A.C.
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