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Airship Model Tests in the Variable Density Wind Tunnel

Description: This report presents the results of wind tunnel tests conducted to determine the aerodynamic characteristics of airship models. Eight Goodyear-Zeppelin airship models were tested in the original closed-throat tunnel. After the tunnel was rebuilt with an open throat a new model was tested, and one of the Goodyear-Zeppelin models was retested. The results indicate that much may be done to determine the drag of airships from evaluations of the pressure and skin-frictional drags on models tested at… more
Date: January 27, 1931
Creator: Abbott, Ira H.
open access

The drag of two streamline bodies as affected by protuberances and appendages

Description: This report presents the results of wind tunnel tests of two airship models conducted to determine the drag coefficients at zero pitch, and the effect of fins and cars and of flat and streamlined protuberances located at various positions along the hull. During the investigation the stern of one model was rounded off to produce a blunter shape. The extreme range of the Reynolds number based on the over-all length of the models was from 1,300,000 to 33,000,000. At large values of the Reynolds nu… more
Date: September 26, 1932
Creator: Abbott, Ira H.
open access

Tests in the variable-density wind tunnel of the NACA 23012 airfoil with plain and split flaps

Description: From Summary: "Section characteristics for use in wing design are presented for the NACA 23012 airfoil with plain and split flaps of 20 percent wing chord at a value of the effective Reynolds number of about 8,000,000. The flap deflections covered a range from 60 degrees upward to 75 degrees downward for the plain flap and from neutral to 90 degrees downward for the split flap. The split flap was aerodynamically superior to the plain flap in producing high maximum lift coefficients and in havin… more
Date: January 21, 1938
Creator: Abbott, Ira H. & Greenberg, Harry
open access

The Pack Method for Compressive Tests of Thin Specimens of Materials Used in Thin-Wall Structures

Description: "The strength of modern lightweight thin-wall structures is generally limited by the strength of the compression members. An adequate design of these members requires a knowledge of the compressive stress-strain graph of the thin-wall material. The "pack" method was developed at the National Bureau of Standards with the support of the National Advisory Committee for Aeronautics to make possible a determination of compressive stress-strain graphs for such material" (p. 133).
Date: August 23, 1938
Creator: Aitchison, C. S. & Tuckerman, L. B.
open access

Calculation of the chordwise load distribution over airfoil sections with plain, split, or serially hinged trailing-edge flaps

Description: From Summary: "A method is presented for the rapid calculation of the incremental chordwise normal-force distribution over an airfoil section due to the deflection of a plain flap or tab, a split flap, or a serially hinged flap. This report is intended as a supplement to NACA Report no. 631, wherein a method is presented for the calculation of the chordwise normal-force distribution over an airfoil without a flap or, as it may be considered, an airfoil with flap (or flaps) neutral. The method e… more
Date: 1938
Creator: Allen, H. Julian
open access

The experimental and calculated characteristics of 22 tapered wings

Description: From Summary: "The experimental and calculated aerodynamic characteristics of 22 tapered wings are compared, using tests made in the variable-density wind tunnel. The wings had aspect ratios from 6 to 12 and taper ratios from 1:6:1 and 5:1. The compared characteristics are the pitching moment, the aerodynamic-center position, the lift-curve slope, the maximum lift coefficient, and the curves of drag. The method of obtaining the calculated values is based on the use of wing theory and experiment… more
Date: November 17, 1937
Creator: Anderson, Raymond F.
open access

A study of the torque equilibrium of an autogiro rotor

Description: From Summary: "Two improvements have been made in the method developed in NACA Reports nos. 487 and 591 for the estimation of the inflow velocity required to overcome a given decelerating torque in an autogiro rotor. At low tip-speed ratios, where the assumptions necessary for the analytical integrations of the earlier papers are valid, the expressions therein derived are greatly simplified by combining and eliminating terms with a view of minimizing the numerical computations required. At high… more
Date: January 10, 1938
Creator: Bailey, F. J., Jr.
open access

Spinning characteristics of the XN2Y-1 airplane obtained from the spinning balance and compared with results from the spinning tunnel and from flight tests

Description: Report presents the results of tests of a 1/10-scale model of the XN2Y-1 airplane tested in the NACA 5-foot vertical wind tunnel in which the six components of forces and moments were measured. The model was tested in 17 attitudes in which the full-scale airplane had been observed to spin, in order to determine the effects of scale, tunnel, and interference. In addition, a series of tests was made to cover the range of angles of attack, angles of sideslip, rates of rotation, and control setting… more
Date: April 16, 1937
Creator: Bamber, M. J. & House, R. O.
open access

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 t… more
Date: February 7, 1933
Creator: Bamber, M. J. & Zimmerman, C. H.
open access

Spinning characteristics of wings 1: rectangular Clark Y monoplane wing

Description: "A series of wind tunnel tests of a rectangular Clark Y wing was made with the NACA spinning balance as part of a general program of research on airplane spinning. All six components of the aerodynamic force and moment were measured throughout the range of angles of attack, angles of sideslip, and values omega b/2v likely to be attained by a spinning airplane; the results were reduced to coefficient form. It is concluded that a conventional monoplane with a rectangular Clark y wing can be made … more
Date: November 21, 1934
Creator: Bamber, M. J. & Zimmerman, C. H.
open access

Wind-Tunnel Tests on Airfoil Boundary Layer Control Using a Backward-Opening Slot (1931)

Description: "This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil. Boundary layer control was accomplished by means of a backward-opening slot in the upper surface of the hollow airfoil. Air was caused to flow through this slot by a pressure which was maintained inside the airfoil by a blower. Various slot locations, slot openings, and wing pressures were used" (p. 3).
Date: 1931
Creator: Bamber, Millard J.
open access

Aircraft speed instruments

Description: From Summary: "This report presents a concise survey of the measurement of air speed and ground speed on board aircraft. Special attention is paid to the Pitot-static air-speed meter which is the standard in the United States for airplanes. A bibliography on air-speed measurement concludes the report."
Date: 1933
Creator: Beij, K. Hilding
open access

Determination of the Profile Drag of an Airplane Wing in Flight at High Reynolds Numbers

Description: Report presenting flight tests to determine the profile-drag coefficients of a portion of the original wing surface of an all-metal airplane and a portion of the wing made aerodynamically smooth and more nearly fair than the original section. Tests were also carried out to determine the point of transition from laminar to turbulent boundary layer and to determine the velocity distribution along the upper surface of the wing.
Date: 1939
Creator: Bicknell, Joseph
open access

Determination of the Profile Drag of an Airplane Wing in Flight at High Reynolds Numbers

Description: "Flight tests were made to determine the profile-drag coefficients of a portion of the original wing surface of an all-metal airplane and of a portion of the wing made aerodynamically smooth and more nearly fair than the original section. The wing section was approximately the NACA 2414.5. The tests were carried out over a range of airplane speeds giving a maximum Reynolds number of 15,000,000. Tests were also carried out to locate the point of transition from laminar to turbulent boundary laye… more
Date: January 6, 1939
Creator: Bicknell, Joseph
open access

The design of fins for air-cooled cylinders

Description: From Summary: "An analysis was made to determine the proportions of fins made of aluminum, copper, magnesium, and steel necessary to dissipate maximum quantities of heat for different fin widths, fin weights, and air-flow conditions. The analysis also concerns the determination of the optimum fin proportions when specified limits are placed on the fin dimensions. The calculation of the heat flow in the fins is based on experimentally verified, theoretical equations. The surface heat-transfer co… more
Date: June 28, 1939
Creator: Biermann, Arnold E. & Ellerbrock, Herman H., Jr.
open access

Heat transfer from finned metal cylinders in an air stream

Description: This report presents the results of tests made to supply design information for the construction of metal fins for the cooling of heated cylindrical surfaces by an air stream. A method is given for determining fin dimensions for a maximum heat transfer with the expenditure of a given amount of material for a variety of conditions of air flow and metals.
Date: April 26, 1934
Creator: Biermann, Arnold E. & Pinkel, Benjamin
open access

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 betwee… more
Date: 1939
Creator: Biermann, David & Hartman, Edwin P.
open access

The Effect of Compressibility on Eight Full-Scale Propellers Operating in the Take-Off and Climbing Range

Description: "Tests were made of eight full-scale propellers of different shape at various tip speeds up to about 1,000 feet per second. The range of blade-angle settings investigated was from 10 degrees to 30 degrees at the 0.75 radius. The results indicate that a loss in propulsive efficiency occurred at tip speeds from 0.5 to 0.7 the velocity of sound for the take-off and climbing conditions" (p. 517).
Date: May 18, 1938
Creator: Biermann, David & Hartman, Edwin P.
open access

Tests of Five Full-Scale Propellers in the Presence of a Radial and a Liquid-Cooled Engine Nacelle, Including Tests of Two Spinners

Description: "Wind-tunnel tests are reported of five 3-blade 10-foot propellers operating in front of a radial and a liquid-cooled engine nacelle. The range of blade angles investigated extended from 15 degrees to 45 degrees. Two spinners were tested in conjunction with the liquid-cooled engine nacelle. Comparisons are made between propellers having different blade-shank shapes, blades of different thickness, and different airfoil sections" (p. 589).
Date: 1938
Creator: Biermann, David & Hartman, Edwin P.
open access

Tests of Two Full-Scale Propellers With Different Pitch Distributions, at Blade Angles Up to 60 Degrees

Description: "Two 3-blade 10-foot propellers were operated in front of a liquid-cooled engine nacelle. The propellers differed only in pitch distribution; one had normal distribution (nearly constant pitch for a blade angle of 15 degrees at 0.75 radius), and the other had the pitch of the tip sections decreased with respect to that for the shank sections (blade angle of 35 degrees for nearly constant pitch distribution). Propeller blade angles at 0.75r from 15 degrees to sixty degrees, corresponding to desi… more
Date: April 14, 1938
Creator: Biermann, David & Hartman, Edwin P.
open access

The drag of airplane wheels, wheel fairings, and landing gears 2: nonretractable and partly retractable landing gears

Description: This is the second report giving the results obtained in the NACA 20-foot wind tunnel on the drag due to landing gears. The present report gives the results of tests of nonretractable and partly retractable landing gears intended for heavier low-wing monoplanes of the transport and bomber type.
Date: June 21, 1934
Creator: Biermann, David & Herrnstein, William H., Jr.
open access

The interference between struts in various combinations

Description: This report presents the results of wind tunnel tests made to determine the interference drag arising from various arrangements of streamline struts and round struts, or cylinders. Determinations were made of the interference drag of struts spaced side by side, struts in tandem, tandem struts encased in a single fairing, a strut intersecting a plane, and struts intersecting to form a v. Three sizes of struts were used for most of the tests. These tests show that the interference drag arising fr… more
Date: June 5, 1933
Creator: Biermann, David & Herrnstein, William H., Jr.
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Cooling on the front of an air-cooled engine cylinder in a conventional engine cowling

Description: Measurements were made of the cooling on the fronts of model cylinders in a conventional cowling for cooling in both the ground and the cruising conditions. The mechanisms of front and rear cooling are essentially different. Cooling on the rear baffled part of the cylinders continually increases with increasing fin width. For the front of the cylinder, an optimum fin width was found to exist beyond which an increase in width reduced the heat transfer. The heat transfer coefficient on the front … more
Date: April 5, 1939
Creator: Brevoort, M. J. & Joyner, U. T.
open access

Experimental investigation of the Robinson-type cup anemometer

Description: This report presents the results of wind tunnel tests on a Robinson-type anemometer. The investigation covered force measurements on individual cups, as well as static and dynamic torque measurements and calibrations on complete cup wheels. In the tests on individual cups 5 cup forms were used and in the measurements on complete cup wheels 4 cup wheels with 3 arm lengths for each cup wheel were tested. All the results are presented in graphical form.
Date: October 10, 1934
Creator: Brevoort, M. J. & Joyner, U. T.
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