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  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Collection: National Advisory Committee for Aeronautics Collection
Knocking in an internal-combustion engine

Knocking in an internal-combustion engine

Date: January 1, 1940
Creator: Sokolik, A & Voinov, A
Description: The question remains open of the relation between the phenomena of knocking in the engine and the explosion wave. The solution of this problem is the object of this paper. The tests were conducted on an aircraft engine with a pyrex glass window in the cylinder head. Photographs were then taken of various combinations of fuels and conditions.
Contributing Partner: UNT Libraries Government Documents Department
Longitudinal stability and control with special reference to slipstream effects

Longitudinal stability and control with special reference to slipstream effects

Date: January 1, 1940
Creator: Katzoff, S
Description: Report presents the results of a study of data obtained in the NACA full-scale wind tunnel concerning the effects of interference and of propeller operation on longitudinal stability and control. The data include pitching moments for various power conditions for airplanes with tails removed and with tails set at various stabilizer and elevator angles. A number of surveys of the dynamic pressure and the flow direction in the region of the horizontal tail surface are also included. Results are given for eight airplanes, including a model of a four-engine airplane tested both as a tractor and as a pushed and a model of two-engine pusher. The effects are shown of propeller operation on the downwash angles and the dynamic pressures at the tail and on the pitching-moment contribution of the propeller and the wing.
Contributing Partner: UNT Libraries Government Documents Department
Mechanical Properties of Flush-Riveted Joints

Mechanical Properties of Flush-Riveted Joints

Date: January 1, 1940
Creator: Brueggeman, W C & Roop, Frederick C
Description: The strength of representative types of flush-riveted joints has been determined by testing 865 single-shearing, double-shearing, and tensile specimens representing 7 types of rivet and 18 types of joint. The results, presented in graphic form, show the stress at failure, type of failure, and d/t ratio. In general, dimpled joints were appreciably stronger than countersunk or protruding-head joints, but their strength was greatly influenced by constructional details. The optimum d/t ratios have been determined for the several kinds of joints. Photomicrographs of each type show constructional details and, in several instances, cracks in the sheet.
Contributing Partner: UNT Libraries Government Documents Department
Mechanical Properties of Flush-Riveted Joints

Mechanical Properties of Flush-Riveted Joints

Date: January 1, 1940
Creator: Bruggeman, Wm. C. & Roop, Frederick C.
Description: The strength of representative types of flush-riveted joints has been determined by testing 865 single-shearing, double-shearing, and tensile specimens representing 7 types of rivet and 18 types of joint. The results, presented in graphic form, show the stress at failure, type of failure, and d/t ratio. In general, 'dimpled' joints were appreciably stronger than countersunk or protruding-head joints, but their strength was greatly influenced by constructional details. The optimum d/t ratios have been determined for the several kinds of joints. Photomacrographs of each type show constructional details and, in several instances, cracks in the sheet.
Contributing Partner: UNT Libraries Government Documents Department
Mechanism of flutter.a theoretical and experimental investigation of the flutter problem

Mechanism of flutter.a theoretical and experimental investigation of the flutter problem

Date: January 1, 1940
Creator: Theodorsen, Theodore & Garrick, I E
Description: The results of the basic flutter theory originally devised in 1934 and published as NACA Technical Report no. 496 are presented in a simpler and more complete form convenient for further studies. The paper attempts to facilitate the judgement of flutter problems by a systematic survey of the theoretical effects of the various parameters. A large number of experiments were conducted on cantilever wings, with and without ailerons, in the NACA high-speed wind tunnel for the purpose of verifying the theory and to study its adaptability to three-dimensional problems. The experiments included studies on wing taper ratios, nacelles, attached floats, and external bracings. The essential effects in the transition to the three-dimensional problem have been established. Of particular interest is the existence of specific flutter modes as distinguished from ordinary vibration modes. It is shown that there exists a remarkable agreement between theoretical and experimental results.
Contributing Partner: UNT Libraries Government Documents Department
Piston temperatures in an air-cooled engine for various operating conditions

Piston temperatures in an air-cooled engine for various operating conditions

Date: January 1, 1940
Creator: Manganiello, Eugene J
Description: As part of a program for the study of piston cooling, this report presents the results of tests conducted on a single-cylinder, air-cooled, carburetor engine to determine the effect of engine operating conditions on the temperatures at five locations on the piston.
Contributing Partner: UNT Libraries Government Documents Department
Preliminary investigation of the flying qualities of airplanes

Preliminary investigation of the flying qualities of airplanes

Date: January 1, 1940
Creator: Soule, H A
Description: The National Advisory Committee for Aeronautics is undertaking an investigation of the flying qualities of airplanes. The work consists in the determination of the significant qualities susceptible of measurement, the development of the instruments required to make the measurements, and the accumulation of data on the flying qualities of existing airplanes, which data are to serve as a basis for quantitative specifications for the flying qualities of future designs. A tentative schedule of measurable flying qualities has been prepared and the instruments needed for their measurements have been assembled. A trial of the schedule and the instruments has been made using the Stinson SR-8e airplane. The results showed that, although the original schedule and instruments are basically satisfactory some further development is required to eliminate nonessential items and to expedite flight testing. The report describes and discusses the work done with this airplane.
Contributing Partner: UNT Libraries Government Documents Department
Preliminary wind-tunnel investigation of an NACA 23012 airfoil with various arrangements of venetian-blind flaps

Preliminary wind-tunnel investigation of an NACA 23012 airfoil with various arrangements of venetian-blind flaps

Date: January 1, 1940
Creator: Wenzinger, Carl J & Harris, Thomas A
Description: Report presents the results of an investigation made in the NACA 7 by 10-foot wind tunnel of a large-chord NACA 23012 airfoil with several arrangements of venetian-blind flaps to determine the aerodynamic section characteristics as affected by the over-all flap chord, the chords of the slats used to form the flap, the slat spacing, the number of slats and the position of the flap with respect to the wing. Complete section data are given in the form of graphs for all the combinations tested.
Contributing Partner: UNT Libraries Government Documents Department
Principles, practices, and progress of noise reduction in airplanes

Principles, practices, and progress of noise reduction in airplanes

Date: January 1, 1940
Creator: London, Albert
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Propeller rotation noise due to torque and thrust

Propeller rotation noise due to torque and thrust

Date: January 1, 1940
Creator: Deming, Arthur F
Description: Sound pressure of the first four harmonics of rotation from a full-scale two-blade propeller were measured and are compared with values calculated from theory. The comparison is made (1) for the space distribution with constant tip speed and (2) for fixed space angles with variable tip speed. A relation for rotation noise from an element of radius developed by Gutin is given showing the effect of number of blades on the rotation noise.
Contributing Partner: UNT Libraries Government Documents Department