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Experimental verification of the theory of oscillating airfoils

Description: Measurements have been made of the lift on an airfoil in pitching oscillation with a continuous-recording, instantaneous-force balance. The experimental values for the phase difference between the angle of attack and the lift are shown to be in close agreement with theory.
Date: January 1, 1939
Creator: Silverstein, Abe & Joyner, Upshur T
Partner: UNT Libraries Government Documents Department

Analytical investigation of icing limit for diamond-shaped airfoil in transonic and supersonic flow

Description: From Introduction: "The results presented herein were calculated for a symmetrical diamond airfoil at zero angle of attack for a range of airfoil-thickness ratios from 0.02 to 0.10, pressure altitude from sea level to 45,000 feet, and free-stream static temperatures to -.40^o F."
Date: January 1953
Creator: Callaghan, Edmund E & Serafini, John S
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of a number of modified NACA four-digit-series airfoil sections

Description: Report presenting theoretical pressure distributions and experimental aerodynamic characteristics at low speeds for a group of NACA four-digit series airfoil sections. Results regarding lift, drag, and pitching moment are provided.
Date: June 1948
Creator: Loftin, Laurence K., Jr. & Cohen, Kenneth S.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of wings with cambered external airfoil flaps, including lateral control, with a full-span flap

Description: From Summary: "The results of a wind-tunnel investigation of the NACA 23012, the NACA 23021, and the Clark Y airfoils, each equipped with a cambered external-airfoil flap, are presented in this report. The purpose of the research was to determine the relative merit of the various airfoils in combination with the cambered flap and to investigate the use of the flap as a combined lateral-control and high-lift device."
Date: 1935
Creator: Platt, Robert C
Partner: UNT Libraries Government Documents Department

Airfoil lift with changing angle of attack

Description: From Summary: "Tests have been made in the atmospheric wind tunnel of the National Advisory Committee for Aeronautics to determine the effects of pitching oscillations upon the lift of an airfoil. It has been found that the lift of an airfoil, while pitching, is usually less than that which would exist at the same angle of attack in the stationary condition, although exceptions may occur when the lift is small or if the angle of attack is being rapidly reduced. It is also shown that the behavior of a pitching airfoil may be qualitatively explained on the basis of accepted aerodynamic theory."
Date: September 1, 1927
Creator: Reid, Elliott G
Partner: UNT Libraries Government Documents Department

Airfoil-contour modifications based on (epsilon)-curve method of calculating pressure distribution

Description: From Introduction: "Certain alternations of a qualitative nature may be performed in spite of the fact that a pressure change cannot be prescribed. It is the purpose of this paper to indicate a method by which qualitative alternation may be performed. It will be noted that the present method of contour modification will serve the intended purpose of the inverse method."
Date: July 1, 1944
Creator: Theodorsen, Theodore
Partner: UNT Libraries Government Documents Department

Air force tests of sperry messenger model with six sets of wings

Description: From Summary: "The purpose of this test was to compare six well-known airfoils, the R.A.F 15, U.S.A. 5, U.S.A. 27, U.S.A. 35-B, Clark Y, and Gottingen 387, fitted to the Sperry Messenger model, at full scale Reynolds number as obtained in the variable density wind tunnel of the National Advisory Committee for Aeronautics; and to determine the scale effect on the model equipped with all the details of the actual airplane. The results show a large decrease in minimum drag coefficient upon increasing the Reynolds number from about one-twentieth scale to full scale. A comparison is made between the results of these tests and those obtained from tests made in this tunnel on airfoils alone."
Date: 1928?~
Creator: Shoemaker, James M
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of airfoils at high speeds

Description: From Summary: "This report deals with an experimental investigation of the aerodynamical characteristics of airfoils at high speeds. Lift, drag, and center of pressure measurements were made on six airfoils of the type used by the air service in propeller design, at speeds ranging from 550 to 1,000 feet per second. The results show a definite limit to the speed at which airfoils may efficiently be used to produce lift, the lift coefficient decreasing and the drag coefficient increasing as the speed approaches the speed of sound. The change in lift coefficient is large for thick airfoil sections (camber ratio 0.14 to 0.20) and for high angles of attack. The change is not marked for thin sections (camber ratio 0.10) at low angles of attack, for the speed range employed. At high speeds the center of pressure moves back toward the trailing edge of the airfoil as the speed increases. The results indicate that the use of tip speeds approaching the speed of sound for propellers of customary design involves a serious loss in efficiency."
Date: 1925~
Creator: Briggs, L. J.; Hull, G. F. & Dryden, H. L.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of several airfoils of low aspect ratio

Description: From Summary: "This paper presents the results of wind-tunnel tests of several airfoils of low aspect ratio. The airfoils included three circular Clark Y airfoils with different amounts of dihedral, two Clark Y airfoils with slots in their portions, and three flat-plate airfoils. Lift, drag, and pitching-moment characteristics of the slotted airfoils with slots open and closed; pitching moment characteristics of one of the slotted airfoils with slots open and closed; and lift characteristics of the flat-plate airfoils are included. The results reveal a definite improvement of lift, drag, and pitching-moment characteristics with increase in dihedral of the circular Clark Y wing. Lift characteristics near the stall were found to depend markedly on the shape of the extreme tip but were not greatly affected by slots through the after portion of the airfoils. Changes in plan form of the flat-plate airfoils gave erroneous indications of the effect to be expected from changes in plan form of an airfoil of Clark Y section. The minimum drag characteristics of the circular Clark Y airfoils were found to be substantially the same as for a Clark Y airfoil of conventional aspect ratio."
Date: August 1935
Creator: Zimmerman, C H
Partner: UNT Libraries Government Documents Department

The aerodynamic characteristics of six commonly used Airfoils over a large range of positive and negative angles of attack

Description: From Summary: "This paper presents the results of tests of six commonly used airfoils: the CYH, the N-22, the C-72, the Boeing 106, and the Gottingen 398. The lifts, drags, and pitching moments of the airfoils were measured through a large range of positive and negative angles of attack. The tests were made in the variable density wind tunnel of the National Advisory Committee for Aeronautics at a large Boeing 106, and the Gottingen 398 airfoils, the negative maximum lift coefficients were found to be approximately half the positive; but for the M-6 and the CYH, which have less effective values were, respectively, 0.8 and 0.6 of the positive values."
Date: November 1931
Creator: Anderson, Raymond F
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of four NACA airfoil sections designed for helicopter rotor blades

Description: From Introduction: "The purpose of the present work is to extend the previous investigation and to derive additional airfoil sections designed to minimize the undesirable characteristics of the previously tested airfoils. The tests of these additional airfoils were made in the Langley two-dimensional low-turbulence tunnel (LTT)."
Date: February 1946
Creator: Rice, Fred J., Jr.
Partner: UNT Libraries Government Documents Department

The aerodynamic characteristics of airfoils as affected by surface roughness

Description: From Summary: "The effect on airfoil characteristics of surface roughness of varying degrees and types at different locations on an airfoil was investigated at high values of the Reynolds number in a variable density wind tunnel. Tests were made on a number of National Advisory Committee for Aeronautics (NACA) 0012 airfoil models on which the nature of the surface was varied from a rough to a very smooth finish. The effect on the airfoil characteristics of varying the location of a rough area in the region of the leading edge was also investigated. Airfoils with surfaces simulating lap joints were also tested. Measurable adverse effects were found to be caused by small irregularities in airfoil surfaces which might ordinarily be overlooked. The flow is sensitive to small irregularities of approximately 0.0002c in depth near the leading edge. The tests made on the surfaces simulating lap joints indicated that such surfaces cause small adverse effects. Additional data from earlier tests of another symmetrical airfoil are also included to indicate the variation of the maximum lift coefficient with the Reynolds number for an airfoil with a polished surface and with a very rough one."
Date: April 1933
Creator: HOCKER RAY W
Partner: UNT Libraries Government Documents Department

Aerodynamic forces and loadings on symmetrical circular-arc airfoils with plain leading-edge and plain trailing-edge flaps

Description: From Summary: "An investigation has been made in the Langley two-dimensional low-turbulence tunnel and in the Langley two-dimensional low-pressure tunnel of 6- and 10-percent-thick symmetrical circular-arc airfoil sections at low Mach numbers and several Reynolds numbers. The airfoils were equipped with 0.15-chord plain leading-edge flaps and 0.20-chord plan trailing-edge flaps. The section lift and pitching-moment characteristics were determined for both airfoils with the flaps deflected individually and in combination."
Date: 1953
Creator: Cahill, Jones F.; Underwood, William J.; Nuber, Robert J. & Cheesman, Gail A.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of the NACA 64-010 and 0010-1.10 40/1.051 airfoil sections at Mach numbers from 0.30 to 0.85 and Reynolds numbers from 4.0 x 10(exp. 6) to 8.0 x 10(exp. 6)

Description: Report presenting an investigation in the low-turbulence pressure tunnel to determine the aerodynamic characteristics of NACA 64-010 and 0010-1.10 airfoil sections. The investigation covered a range of Mach and Reynolds numbers.
Date: August 1954
Creator: Loftin, Laurence K., Jr.
Partner: UNT Libraries Government Documents Department

Aerodynamic coefficients for an oscillating airfoil with hinged flap, with tables for a Mach number of 0.7

Description: From Introduction: "The fundamental integral equation for the pressure distribution on an oscillating thin airfoil moving at subsonic speed has been derived by Possio in reference 1. Collocation procedures have been used by Possio, Frazer, and Skan, and others to obtain lift and moment on an oscillating first plate. An important contribution has been made by Dietze (see reference 2 and 3), who has developed an iterative procedure for numerical solution of Possio's integral equation."
Date: October 1950
Creator: Turner, M J & Rabinowitz, S
Partner: UNT Libraries Government Documents Department

Airfoil section data obtained in the NACA variable-density tunnel as affected by support interference and other corrections

Description: From Introduction: "The purpose of this report is to present the corrections for application to published results from the variable-density tunnel to give more reliable values of section profile-drag coefficient for airfoils of various thickness."
Date: 1939
Creator: Jacobs, Eastman N. & Abbott, Ira H.
Partner: UNT Libraries Government Documents Department

Airfoil pressure distribution investigation in the variable density wind tunnel

Description: Report presents the results of wind tunnel tests of pressure distribution measurements over one section each of six airfoils. Pressure distribution diagrams, as well as the integrated characteristics of the airfoils, are given for both a high and a low dynamic scale or, Reynolds number VL/V, for comparison with flight and other wind-tunnel tests, respectively. It is concluded that the scale effect is very important only at angles of attack near the burble.
Date: January 1, 1931
Creator: Jacobs, Eastman N.; Stack, John & Pinkerton, Robert M
Partner: UNT Libraries Government Documents Department

An evaluation of the characteristics of a 10-percent-thick NACA 66-series airfoil section with a special mean-camber line designed to produce a high critical Mach number

Description: Report presenting testing of the low-speed aerodynamic characteristics of the NACA 66-series airfoil section in the two-dimensional low-turbulence pressure tunnel. Results regarding the critical-speed characteristics and low-speed characteristics are provided.
Date: July 1948
Creator: Loftin, Laurence K., Jr. & Cohen, Kenneth S.
Partner: UNT Libraries Government Documents Department

The effects of variations in Reynolds number between 3.0 x 10sub6 and 25.0 x 10sub6 upon the aerodynamic characteristics of a number of NACA 6-series airfoil sections

Description: Results are presented of an investigation made to determine the two-dimensional lift and drag characteristics of nine NACA 6-series airfoil section at Reynolds numbers of 15.0 x 10sub6, 20.0 x 10sub6, and 25.0 x 10sub6. Also presented are data from NACA Technical Report 824 for the same airfoils at Reynolds numbers of 3.0 x 10sub6, 6.0 x 10sub6, and 9.0 x 10sub6. The airfoils selected represent sections having variations in the airfoil thickness, thickness form, and camber. The characteristics of an airfoil with a split flap were determined in one instance, as was the effect of surface roughness. Qualitative explanations in terms of flow behavior are advanced for the observed types of scale effect.
Date: 1950
Creator: Loftin, Laurence K., Jr. & Bursnall, William J.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of 15 NACA airfoil sections at seven Reynolds numbers from 0.7 x 10(exp 6) to 9.0 x 10(exp 6)

Description: Report presenting an investigation of the two-dimensional aerodynamic characteristics of 15 NACA airfoils at four Reynolds numbers. The results indicate that the drag coefficient at the design lift coefficient and the maximum lift coefficient are the most important aerodynamic characteristics and are most affected by Reynolds number changes.
Date: October 1949
Creator: Loftin, Laurence K., Jr. & Smith, Hamilton A.
Partner: UNT Libraries Government Documents Department

Tests of an NACA 66,2-420 Airfoil of 5-Foot Chord at High Speed, Special Report

Description: This report covers tests of a 5-foot model of the NACA 66,2-420 low-drag airfoil at high speeds including the critical compressibility speed. Section coefficients of lift, drag, and pitching moment, and extensive pressure-distribution data are presented. The section drag coefficient at the design lift coefficient of 0.4 increased from 0.0042 at low speeds to 0.0052 at a Mach number of 0.56 (390 mph at 25,000 ft altitude). The critical Mach number was about 0.60. The results cover a Reynold number range from 4 millions to 17 millions.
Date: September 1942
Creator: Hood, Manley J. & Anderson, Joseph L.
Partner: UNT Libraries Government Documents Department