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 Decade: 1940-1949
 Year: 1940
 Collection: National Advisory Committee for Aeronautics Collection
Aerodynamic heating and the deflection of drops by an obstacle in an air stream in relation to aircraft icing

Aerodynamic heating and the deflection of drops by an obstacle in an air stream in relation to aircraft icing

Date: October 1, 1940
Creator: Kantrowitz, Arthur
Description: Two topics of interest to persons attempting to apply the heat method of preventing ice formation on aircraft are considered. Surfaces moving through air at high speed are shown, both theoretically and experimentally, to be subject to important aerodynamic heating effects that will materially reduce the heat required to prevent ice. Numerical calculations of the path of water drops in an air stream around a circular cylinder are given. From these calculations, information is obtained on the percentage of the swept area cleared of drops.
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
Design charts relating to the stalling of tapered wings

Design charts relating to the stalling of tapered wings

Date: January 1, 1940
Creator: Soule, H A
Description: An aid in airplane design, charts have been prepared to show the effects of wing taper, thickness ratio, and Reynolds number on the spanwise location of the initial stalling point. Means of improving poor stalling characteristics resulting from certain combinations of the variables have also been considered; additional figures illustrate the influence of camber increase to the wing tips, washout, central sharp leading edges, and wing-tip slots on the stalling characteristics. Data are included from which the drag increases resulting from the use of these means can be computed. The application of the data to a specific problem is illustrated by an example.
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
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
Flame speeds and energy considerations for explosions in a spherical bomb

Flame speeds and energy considerations for explosions in a spherical bomb

Date: January 1, 1940
Creator: Fiock, Ernest F
Description: Simultaneous measurements were made of the speed of flame and the rise in pressure during explosions of mixtures of carbon monoxide, normal heptane, iso-octane, and benzene in a 10-inch spherical bomb with central ignition. From these records, fundamental properties of the explosive mixtures, which are independent of the apparatus, were computed. The transformation velocity, or speed at which flame advances into and transforms the explosive mixture, increases with both the temperature and the pressure of the unburned gas. The rise in pressure was correlated with the mass of charge inflamed to show the course of the energy developed.
Contributing Partner: UNT Libraries Government Documents Department
The unsteady lift of a wing of finite aspect ratio

The unsteady lift of a wing of finite aspect ratio

Date: January 1, 1940
Creator: Jones, Robert T
Description: Unsteady-lift functions for wings of finite aspect ratio have been calculated by correcting the aerodynamic inertia and the angle of attack of the infinite wing. The calculations are based on the operational method.
Contributing Partner: UNT Libraries Government Documents Department
Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Effect of exit-slot position and opening on the available cooling pressure for NACA nose-slot cowlings

Date: January 1, 1940
Creator: Stickle, George W
Description: Report presents the results of an investigation of full-scale nose-slot cowlings conducted in the NACA 20-foot wind tunnel to furnish information on the pressure drop available for cooling. Engine conductances from 0 to 0.12 and exit-slot conductances from 0 to 0.30 were covered. Two basic nose shapes were tested to determine the effect of the radius of curvature of the nose contour; the nose shape with the smaller radius of curvature gave the higher pressure drop across the engine. The best axial location of the slot for low-speed operation was found to be in the region of maximum negative pressure for the basic shape for the particular operating condition. The effect of the pressure operating condition on the available cooling pressure is shown.
Contributing Partner: UNT Libraries Government Documents Department
Aerodynamic characteristics of horizontal tail surfaces

Aerodynamic characteristics of horizontal tail surfaces

Date: January 1, 1940
Creator: Silverstein, Abe
Description: 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.
Contributing Partner: UNT Libraries Government Documents Department
Static thrust and power characteristics of six full-scale propellers

Static thrust and power characteristics of six full-scale propellers

Date: January 1, 1940
Creator: Hartman, Erwin P
Description: Static thrust and power measurements were made of six full-scale propellers. The propellers were mounted in front of a liquid-cooled-engine nacelle and were tested at 15 different blade angles in the range from -7 1/2 degrees to 35 degrees at 0.75r. The test rig was located outdoors and the tests were made under conditions of approximately zero wind velocity.
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
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
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