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  Partner: UNT Libraries Government Documents Department
 Decade: 1930-1939
 Year: 1931
 Serial/Series Title: NACA Technical Reports
 Collection: Technical Report Archive and Image Library
Aircraft accidents : method of analysis

Aircraft accidents : method of analysis

Date: January 1, 1931
Creator: unknown
Description: The revised report includes the chart for the analysis of aircraft accidents, combining consideration of the immediate causes, underlying causes, and results of accidents, as prepared by the special committee, with a number of the definitions clarified. A brief statement of the organization and work of the special committee and of the Committee on Aircraft Accidents; and statistical tables giving a comparison of the types of accidents and causes of accidents in the military services on the one hand and in civil aviation on the other, together with explanations of some of the important differences noted in these tables.
Contributing Partner: UNT Libraries Government Documents Department
Aircraft woods: their properties, selection, and characteristics

Aircraft woods: their properties, selection, and characteristics

Date: January 1, 1931
Creator: Markwardt, L J
Description: Strength values of various woods for aircraft design for a 15 per cent moisture condition of material and a 3-second duration of stress are presented, and also a discussion of the various factors affecting the values. The toughness-test method of selecting wood is discussed, and a table of acceptance values for several species is given.
Contributing Partner: UNT Libraries Government Documents Department
Airfoil pressure distribution investigation in the variable density wind tunnel

Airfoil pressure distribution investigation in the variable density wind tunnel

Date: January 1, 1931
Creator: Jacobs, Eastman N
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. The distribution of pressure over an airfoil having a Joukowski section is compared with the theoretically derived distribution. A further study of the distribution of pressure over all of the airfoils resulted in the development of an approximate method of predicting the pressure distribution along the chord of any normal airfoil for all attitudes within the working range if the distribution at one attitude is known.
Contributing Partner: UNT Libraries Government Documents Department
Comparative flight performance with an NACA Roots supercharger and a turbocentrifugal supercharger

Comparative flight performance with an NACA Roots supercharger and a turbocentrifugal supercharger

Date: January 1, 1931
Creator: Schey, Oscar W
Description: This report presents the comparative flight results of a roots supercharger and a turbocentrifugal supercharger. The tests were conducted using a modified DH-4M2 airplane. The rate of climb and the high speed in level flight of the airplane were obtained for each supercharger from sea level to the ceiling. The unsupercharged performance with each supercharger mounted in place was also determined. The results of these tests show that the ceiling and rate of climb obtained were nearly the same for each supercharger, but that the high speed obtained with the turbocentrifugal was better than that obtained with the roots. The high-speed performance at 21,000 feet was 122 and 142 miles per hour for the roots and turbocentrifugal, respectively.
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The design and development of an automatic injection valve with an annular orifice of varying area

The design and development of an automatic injection valve with an annular orifice of varying area

Date: January 1, 1931
Creator: Joachim, William F
Description: The purpose of this investigation was to provide an automatic injection valve of simple construction which would produce a finely atomized oil spray of broad cone angle and would fulfill the requirements of fuel injection in aircraft oil engines. The injection valve designed has only six parts - i. e., two concentric nozzle tubes flared at one end, two body parts, and two nuts. Analysis and engine tests indicate that the fuel spray from this type of injection valve has characteristics which reduce the time lag of autoignition and promote efficient combustion in high-speed oil engines.
Contributing Partner: UNT Libraries Government Documents Department
The design of airplane wing ribs

The design of airplane wing ribs

Date: January 1, 1931
Creator: Newlin, J A
Description: The purpose of this investigation was to obtain information for use in the design of truss and plywood forms, particularly with reference to wing ribs. Tests were made on many designs of wing ribs, comparing different types in various sizes. Many tests were also made on parallel-chord specimens of truss and plywood forms in place of the actual ribs and on parts of wing ribs, such as truss diagonals and sections of cap strips. It was found that for ribs of any size or proportions, when they were designed to obtain a well-balanced construction and were carefully manufactured, distinct types are of various efficiencies; the efficiency is based on the strength per unit of weight. In all types of ribs the heavier are the stronger per unit of weight. Reductions in the weight of wing ribs are accompanied even in efficient designs by a much greater proportional reduction in strength.
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The design of plywood webs for airplane wing beams

The design of plywood webs for airplane wing beams

Date: January 1, 1931
Creator: Trayer, George W
Description: This report deals with the design of plywood webs for wooden box beams to obtain maximum strength per unit weight. A method of arriving at the most efficient and economical web thickness, and hence the most suitable unit shear stress, is presented and working stresses in shear for various types of webs and species of plywood are given. The questions of diaphragm spacing and required glue area between the webs and flange are also discussed.
Contributing Partner: UNT Libraries Government Documents Department
The effect of reduction gearing on propeller-body interference as shown by full-scale wind-tunnel tests

The effect of reduction gearing on propeller-body interference as shown by full-scale wind-tunnel tests

Date: January 1, 1931
Creator: Weick, Fred E
Description: This report presents the results of full-scale tests made on a 10-foot 5-inch propeller on a geared J-5 engine and also on a similar 8-foot 11-inch propeller on a direct-drive J-5 engine. Each propeller was tested at two different pitch settings, and with a large and a small fuselage. The investigation was made in such a manner that the propeller-body interference factors were isolated, and it was found that, considering this interference only, the geared propellers had an appreciable advantage in propulsive efficiency, partially due to the larger diameter of the propellers with respect to the bodies, and partially because the geared propellers were located farther ahead of the engines and bodies.
Contributing Partner: UNT Libraries Government Documents Department
Effect of turbulence in wind-tunnel measurements

Effect of turbulence in wind-tunnel measurements

Date: January 1, 1931
Creator: Dryden, H L
Description: This paper gives some quantitative measurements of wind tunnel turbulence and its effect on the air resistance of spheres and airship models, measurements made possible by the hot wire anemometer and associated apparatus in its original form was described in Technical Report no. 320 and some modifications are presented in an appendix to the present paper. One important result of the investigation is a curve by means of which measurements of the air resistance of spheres can be interpreted to give the turbulence quantitatively. Another is the definite proof that the discrepancies in the results on the N. P. L. Standard airship models are due mainly to differences in the turbulences of the wind tunnels in which the tests were made. An attempt is made to interpret the observed results in terms of the boundary layer theory and for this purpose a brief account is given of the physical bases of this theory and of conceptions that have been obtained by analogy with the laws of flow in pipes.
Contributing Partner: UNT Libraries Government Documents Department
Effect of variation of chord and span of ailerons on rolling and yawing moments at several angles of pitch

Effect of variation of chord and span of ailerons on rolling and yawing moments at several angles of pitch

Date: January 1, 1931
Creator: Heald, R H
Description: This report presents the results of an extension to higher angles of attack of the investigation of the rolling and yawing moments due to ailerons of various chords and spans on two airfoils having the Clark Y and U. S. A. 27 wings. The measurements were made at various angles of pitch but at zero angle of roll and yaw, the wing chord being set at an angle of +4 degrees to the fuselage axis. In the case of the Clark Y airfoil the measurements have been extended to a pitch angle of 40 degrees, using ailerons of span equal to 67 per cent of the wing semispan and chord equal to 20 and 30 per cent of the wing chord. The work was conducted on wing models of 60-inch span and 10-inch chord.
Contributing Partner: UNT Libraries Government Documents Department
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