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Aerodynamic characteristics of circular-arc airfoils at high speeds

Description: From Summary: "The aerodynamic characteristics of eight circular-arc airfoils at speeds of 0.5, 0.8, 0.95, and 1.08 times the speed of sound have been determined in an open-jet air stream 2 inches in diameter, using models of 1-inch chord. The lower surface of each airfoil was plane; the upper surface was cylindrical. As compared with the measurements described in NACA-TR-319, the circular-arc airfoils at speeds of 0.95 and 1.08 times the speed of sound are more efficient than airfoils of the R. A. F. or Clark Y families. At a speed of 0.5 times the speed of sound, the thick circular-arc sections are extremely inefficient, but thin sections compare favorably with those of the R. A. F. family. A moderate round of the sharp edges changes the characteristics very little and is in many instances beneficial. The results indicate that the section of the blades of propellers intended for use at high tip-speeds should be of the circular-arc form for the outer part of the blade and should be changed gradually to the R. A. F. or Clark Y form as the hub is approached."
Date: 1932~
Creator: Briggs, L. J. & Dryden, H. L.

The aerodynamic characteristics of eight very thick airfoils from tests in the variable density wind tunnel

Description: Report presents the results of wind tunnel tests on a group of eight very thick airfoils having sections of the same thickness as those used near the roots of tapered airfoils. The tests were made to study certain discontinuities in the characteristic curves that have been obtained from previous tests of these airfoils, and to compare the characteristics of the different sections at values of the Reynolds number comparable with those attained in flight. The discontinuities were found to disappear as the Reynolds number was increased. The results obtained from the large-scale airfoil, a symmetrical airfoil having a thickness ratio of 21 per cent, has the best general characteristics.
Date: 1932~
Creator: Jacobs, Eastman N.

The aerodynamic characteristics of four full-scale propellers having different plan forms

Description: From Introduction: "Its main purpose is to present propeller data for four full-scale propellers of Navy design, three of which have somewhat unusual plan forms and the other one has a normal (usual present-day type) plan form. These data may give some clue as to what may be expected from fundamental changes in blade plan form."
Date: 1938~
Creator: Hartman, Edwin P & Biermann, David

The aerodynamic characteristics of full-scale propellers having 2, 3, and 4 blades of Clark y and R.A.F. 6 airfoil sections

Description: Aerodynamic tests were made of seven full-scale 10-foot-diameter propellers of recent design comprising three groups. The first group was composed of three propellers having Clark y airfoil sections and the second group was composed of three propellers having R.A.F. 6 airfoil sections, the propellers of each group having 2, 3, and 4 blades. The third group was composed of two propellers, the 2-blade propeller taken from the second group and another propeller having the same airfoil section and number of blades but with the width and thickness 50 percent greater. The tests of these propellers reveal the effect of changes in solidity resulting either from increasing the number of blades or from increasing the blade width propeller design charts and methods of computing propeller thrust are included.
Date: 1938
Creator: Hartman, Edwin P & Biermann, David

Aerodynamic characteristics of horizontal tail surfaces

Description: From Summary: "Collected data are presented on the aerodynamic characteristics of 17 horizontal tail surfaces including several with balanced elevators and two with end plates. Curves are given for coefficients of normal force, drag, and elevator hinge moment. A limited analysis of the results has been made. The normal-force coefficients are in better agreement with the lifting-surface theory of Prandtl and Blenk for airfoils of low aspect ratio than with the usual lifting-line theory. Only partial agreement exists between the elevator hinge-moment coefficients and those predicted by Glauert's thin-airfoil theory."
Date: 1940
Creator: Silverstein, Abe & Katzoff, S

Aerodynamic characteristics of NACA 23012 and 23021 airfoils with 20-percent-chord external-airfoil flaps of NACA 23012 section

Description: Report presents the results of an investigation of the general aerodynamic characteristics of the NACA 23012 and 23021 airfoils, each equipped with a 0.20c external flap of NACA 23012 section. The tests were made in the NACA 7 by 10-foot and variable-density wind tunnels and covered a range of Reynolds numbers that included values corresponding to those for landing conditions of a wide range of airplanes. Besides a determination of the variation of lift and drag characteristics with position of the flap relative to the main airfoil, complete aerodynamic characteristics of the airfoil-flap combination with a flap hinge axis selected to give small hinge moments were measured in the two tunnels. Some measurements of air loads on the flap itself in the presence of the wing were made in the 7 by 10-foot wind tunnel.
Date: 1937~
Creator: Platt, Robert C & Abbott, Ira H

The aerodynamic characteristics of seven frequently used wing sections at full Reynolds number

Description: This report contains the aerodynamic properties of the wing sections U.S.A. 5, U.S.A. 27, U.S.A. 35 A, U.S.A. 35 B, Clark Y, R.A.F. 15, and Gottingen 387, as determined at various Reynolds numbers up to an approximately full scale value in the variable density wind tunnel of the National Advisory Committee for Aeronautics. It is shown that the characteristics of the wings investigated are affected greatly and in a somewhat erratic manner by variation of the Reynolds number. In general there is a small increase in maximum lift and an appreciable decrease in drag at all lifts.
Date: 1927~
Creator: Munk, Max M. & Miller, Elton W.

The aerodynamic characteristics of six full-scale propellers having different airfoil sections

Description: From Summary: "Wind-tunnel tests are reported of six 3-blade 10-foot propellers operated in front of a liquid-cooled engine nacelle. The propellers were identical except for blade airfoil sections, which were: Clark y, R.A.F. 6, NACA 4400, NACA 2400-34, NACA 2rsub200, and NACA 6400. The range of blade angles investigated extended for 15 degrees to 40 degrees for all propellers except the Clark y, for which it extended to 45 degrees. The results showed that the range in maximum efficiency between the highest and lowest values was about 3 percent. The highest efficiencies were for the low-camber sections."
Date: 1939
Creator: Biermann, David & Hartman, Edwin P

Aerodynamic characteristics of twenty-four airfoils at high speeds

Description: From Summary: "If a propeller is mounted directly on the of a modern high-speed airplane engine, the outer airfoil sections of the propeller travel at speeds approaching the speed of sound. It is possible by the use of gearing and a somewhat larger propeller to reduce the speed of the propeller sections, but only at the expense of additional weight and some frictional loss of power. This report presents the results of this work."
Date: 1930~
Creator: Brigg, L. J. & Dryden, H. L.

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

The aerodynamic effects of wing cut-outs

Description: From Introduction: "The information now available concerning wing cut-outs or applicable to the analysis of their effects is plentiful (references 1 to 7) but too disconnected and unorganized to be of the greatest possible usefulness. In connection with the interference program being conducted in the N.A.C.A. varible-density wind tunnel, an analysis was therefore made of existing material to determine the qualitative effects of the different features of wing cut-outs, and to obtain means of calculating wing characteristics as affected by them."
Date: 1934
Creator: Sherman, Albert

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

The aerodynamic forces and moments exerted on a spinning model of the NY-1 airplane as measured by the spinning balance

Description: From Summary: "A preliminary investigation of the effects of changes in the elevator and rudder settings and of small changes in attitude upon the aerodynamic forces and moments exerted upon a spinning airplane was undertaken with the spinning balance in the 5-foot vertical tunnel of the National Advisory Committee for Aeronautics. The tests were made on a 1/12-scale model of the "NY-1" airplane. Data by which to fix the attitude, the radius of spin, and the rotational and air velocities were taken from recorded spins of the full-scale airplane."
Date: February 7, 1933
Creator: Bamber, M J & Zimmerm, N, C h

The Aerodynamic Forces on Airship Hulls

Description: This report describes the new method for making computations in connection with the study of rigid airship, which was used in the investigation of the navy's ZR-1 by the special subcommittee of the National Advisory Committee for Aeronautics appointed for this purpose. It presents the general theory of the air forces on airship hulls of the type mentioned, and an attempt has been made to develop the results from the very fundamentals of mechanics without reference to some of the modern highly developed conceptions, which may not yet be thoroughly known to readers uninitiated into modern aerodynamics, and which may, perhaps, for all time remain restricted to a small number of specialists.
Date: 1924
Creator: Munk, Max M.

The Aerodynamic Forces on Airship Hulls

Description: The new method for making computations in connection with the study of rigid airships, which was used in the investigation of Navy's ZR-1 by the special subcommittee of the National Advisory Committee for Aeronautics appointed for this purpose is presented. The general theory of the air forces on airship hulls of the type mentioned is described and an attempt was made to develop the results from the very fundamentals of mechanics.
Date: 1979?~
Creator: Munk, M. M.

The aerodynamic forces on slender plane- and cruciform-wing and body combinations

Description: From Introduction: "Since these results were not applicable to the present problem, a theoretical analysis of the aerodynamic properties of slender wing-body combinations was undertaken. The results of this investigation were first reported in reference 5 and were later extended in reference 6 to include cruciform-wing and body combinations. The present report summarizes and extends the theory and results previously presented in these references."
Date: 1950?~
Creator: Spreiter, John R

The aerodynamic properties of thick aerofoils suitable for internal bracing

Description: From Introduction: "The object of this investigation was to determine the characteristics of various types of wings having sufficient depth to entirely inclose the wing bracing, and also to provide data for the further design of such sections. Results of the investigation of the following subjects are given: (1) effect of changing the upper and lower camber of thick aerofoils of uniform section; (2) effect of thickening the center and thinning the tips of a thin aerofoil; (3) effect of adding a convex lower surface to a tapered section; (4) effect of changing the mean thickness with constant center and tip sections; and (5) effect of varying the chord along the span."
Date: 1920
Creator: Norton, F. H.

Aerodynamic properties of thick airfoils II

Description: This investigation is an extension of NACA report no. 75 for the purpose of studying the effect of various modifications in a given wing section, including changes in thickness, height of lower camber, taper in thickness, and taper in plan form with special reference to the development of thick, efficient airfoils. The method consisted in testing the wings in the NACA 5-foot wind tunnel at speeds up to 50 meters (164 feet) per second while they were being supported on a new type of wire balance. Some of the airfoils developed showed results of great promise. For example, one wing (no. 81) with a thickness in the center of 4.5 times that of the U. S. A. 16 showed both uniformly high efficiency and a higher maximum lift than this excellent section. These thick sections will be especially useful on airplanes with cantilever construction. (author).
Date: 1923?~
Creator: Norton, F. H. & Bacon, D. L.

Aerodynamic theory and test of strut forms. Part I

Description: This report presents the first part of a two part study made under this title. In this part the symmetrical inviscid flow about an empirical strut of high service merit is found by both the Rankine and the Joukowsky methods. The results can be made to agree as closely as wished. Theoretical stream surfaces as well as surfaces of constant speed and pressure in the fluid about the strut are found. The surface pressure computed from the two theories agrees well with the measured pressure on the fore part of the model but not so well on the after part. From the theoretical flow speed the surface friction is computed by an empirical formula. The drag integrated from the friction and measured pressure closely equals the whole measured drag. As the pressure drag and the whole drag are accurately determined, the friction formula also appears trustworthy for such fair shapes. (author).
Date: May 1928
Creator: Smith, R H

Aerodynamic theory and tests of strut forms. Part II

Description: This report presents the second of two studies under the same title. In this part five theoretical struts are developed from distributed sources and sinks and constructed for pressure and resistance tests in a wind tunnel. The surface pressures for symmetrical inviscid flow are computed for each strut from theory and compared with those found by experiment. The theoretical and experimental pressures are found to agree quantitatively near the bow, only qualitatively over the suction range, the experimental suctions being uniformly a little low, and not at all near the stern. This study is the strut sequel to Fuhrmann's research on airship forms, the one being a study in two dimensions, the other in three. A comparison of results indicates that the agreement between theory and experiment is somewhat better for bodies of revolution than for cylinders when both are shaped for slight resistance. The consistent deficiency of the experimental suctions which is found in the case of struts was not found in the case of airships, for which the experimental suctions were sometimes above sometimes below their theoretical values.
Date: May 1929
Creator: Smith, R H

Aeronautic instruments. Section I : general classification of instruments and problems including bibliography

Description: This report is intended as a technical introduction to the series of reports on aeronautic instruments. It presents a discussion of those subjects which are common to all instruments. First, a general classification is given, embracing all types of instruments used in aeronautics. Finally, a classification is given of the various problems confronted by the instrument expert and investigator. In this way the following groups of problems are brought up for consideration: problems of mechanical design, human factor, manufacturing problems, supply and selection of instruments, problems concerning the technique of testing, problems of installation, problems concerning the use of instruments, problems of maintenance, and physical research problems. This enumeration of problems which are common to instruments in general serves to indicate the different points of view which should be kept in mind in approaching the study of any particular instrument.
Date: 1925
Creator: Hersey, Mayo D.