NASA NACA-TN-715-1939 Wind-tunnel investigation of an N A C A 23012 airfoil with two arrangements of a wide-chord slotted flap《带有宽弦开缝襟翼两种形式的NACA 23012机翼的风洞研究》.pdf
《NASA NACA-TN-715-1939 Wind-tunnel investigation of an N A C A 23012 airfoil with two arrangements of a wide-chord slotted flap《带有宽弦开缝襟翼两种形式的NACA 23012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-715-1939 Wind-tunnel investigation of an N A C A 23012 airfoil with two arrangements of a wide-chord slotted flap《带有宽弦开缝襟翼两种形式的NACA 23012机翼的风洞研究》.pdf(24页珍藏版)》请在麦多课文档分享上搜索。
1、;i I 3 -i : I TECRNICAL NOTES NATIONAL ADVISORY COMMITTEE: FOR AERONAUTICS No. 715 - - _ - .- - i .- , - WIND-TUNNEL INVESTIGATION OF AN N.A.C.A. 23012 AIRFOIL , -+ r. .Jg WITH TWO ARRANGEMENTS OF A WIDE-CHORD SLOTTID FLAP By Thomas A. Harris Langley Memorial Aeronautical Laboratory Washington June
2、1939 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS . TECHNICAL NOTE NO. 715 WIND-TUNNEL INVESTIGATION OF AM N.A.C.A. 23012 AIRFOIL WITH TWO ARRANGEMENTS OF A WIDE-CHORD SLOTTED FLAP By Thomas A. Harris SU
3、MMARY An investigation has been made in the N.A.C.A. 7- by lo-foot wind tunnel of a large-chord N.A.C.A. 23012 airfoil with several arrangements of a 40-percent-chord slotted flap to determine the sectfon aerodynamic char- acteristics of the airfoil as affected by slot shape, flap location, and flap
4、 deflection. The flap positions for maximum lift, the polars for arrangements considered favorable for take-off and climb, and the complete set- tion aerodynamic characteristics for selected optimum arrangecnents were determined. A discussion is given of the relative merits of the various arrangemen
5、ts. A corn- parison is made of slotted flaps of different chords on the N.A.C.A. 23012 afrfoil. The best 40-percent-chord slotted flap is only slightly superior to the 25-percent-chord slotted flap from considerations of maximum lift coefffcient and-low drak for take-off and initial climb. . INTRODU
6、CTION The National Advisory Committee for Aeronautics has undertaken an extensive investigation of varfous wing- flap combinations to furnish information applicable to the aerodynamic and the structural design of high-lift devices for improving the safety and the performance of airplanes. A high-lif
7、t device capable of producing hgh . lfft with variable drag for landing and high lift with low drag for take-off and Initial climb is believed to be desirable. Other desirable aerodynamic features are: no increase in drag with the flap neutral; small change in pitching moment with flap deflection; l
8、ow forces required to operate the flap; and freedom from possible hazard due to icing, Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-2 N.A.C.A. Technical Note No. 715 It is planned in this investigation to test both simple and multiply slotted flap
9、s of different chords on airfoils of different profile. Some promising arrange- ments of medium-chord slotted flaps have been developed for the N,A.C.A. 23012 and 23021 airfoils. The aerody- namic data for these arrangements are reported in refer- ences 1 and 2. Further improvement from consideratio
10、ns of high lift coefficients and low drag at high and inter- mediate lift coefficients was obtained with the combina- tion of a modium-chord and a small-chord slotted flap (reference 3). Pressure-distribution data are also avail- able for the medium-chord slotted flap on the N.A.C.A. 23012 airfoil,
11、(See reference 4.) In the present report, the section aerodynamic char- acteristics are given for the N.A.C.A. 23012 airfoil equipped with a 40-percent-chord slotted flap in combina- tion with two slot shapes, MODELS Plain Airfoil The basic wing, or the plain airfoil, used in these tests was built t
12、o the N.A.C.A. 23012 profile and has a chord of 3 feet and a span of 7 feet; the ordinates for the section are given in table I. The model was built of solid laminated pine and had been previously used in the investigation of the medium-chord slotted flap reported in reference 1. The trailing-edge s
13、ection of this model is easily removable so that the model can be quickly al- tered for tests of dif-ferent flap arrangements. Slotted-Flap Arrangements . The slotted flap and the slot shapes were built of solld laminated beech. The slotshapes were bolted to the main airfoil in place of the solid tr
14、ailing edge, The flaps were mounted on special hinges that permittod considerable latitude in the location of the flaps with respect to the main airfoil. Flaps.- Only one flap shape was tested; it is de- , signated flap 1 (fig. 1 and table I). , This flap has a small nose radius and was designed to
15、give only a small . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-N.A.C.A. Technical Note No. 716 3 . break inthe lower surface of the airfoil when undeflect- 0d. It also lends itself to use with a door to seal the break in the lower surface of the
16、 airfoil with the flap undeflected. mt shaoes.- The two slot shapes shown in figure 1 were used with the flap and are designated a and b. Slot ahape a was designed to give a minimum break in the lower surface of the wing and, consequently, to have the smaller effect on the drag wfth the flap neutral
17、. Slot shape b is simflar to slot shape h of reference 1, which gave the lowest drag at intermediate and high lift coefficients for take-off. The models were made to a tolerance of f0.015 inch. TPISTS 4 The models were so mounted in the closed test sec- tion of the N.A.C.A. 7- by 10.foot wind tunnel
18、 that they completely spanned the jet except for small clearances at each end. (See references 1 and 5.) The main airfoil was rigidly attached to the balance frame by torque tubes, Prrhich extended through the upper and the lower boundarias of the tunnel. The angle of attack of the model was sut fro
19、m outside the tunnel by rotating the torque tubes wfth a calibrated drive. Approximately two-dimensional flow is obtained with this type of installation and the section characteristics of the model under test can be determined. A dynamic,prossurs of 16.37 pounds per square foot was maintained for al
20、l the tests, which corresponds to a velocity of 80 miles per hour under standard atmospheric conditions and to an average test Reynolds Number of about 2,190,OOO. 3ecause of the turbulence in the wind tunnel, the effective Reynolds Number Re (reference 6) was approximately 3,500,OOO. Par all tests,
21、R, is based on the chord of the airfoil w%th the flap retracted and on a turbulence factor of 1.6 for the tunnel. Plain airfoil,- Tests were first made of the plain airfoil over the complete angle-of-attack range from -60 to the stall. Slotted flaosti- 31th each slotted-flap arrangement, tests were
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