National Advisory Committee for Aeronautics (NACA) - 1,437 Matching Results

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Investigation of a Rateau supercharger for a 700-horsepower airplane engine

Description: The Rateau supercharger investigated had, under normal operating conditions, an adiabatic efficiency of 52 percent, the CINA constant-pressure altitude being 6,240 m and the corresponding CINA compression ratio being 2.22. In order to understand the flow conditions in the supercharger, the air velocities at various points, the theoretical delivery heads and a few characteristics were calculated.
Date: March 1, 1934
Creator: Oestrich, Hermann
Partner: UNT Libraries Government Documents Department

Experiments with three horizontal empennages

Description: The main objective of these experiments was to determine how the air forces on the whole empennage are affected by varying the size of the elevator without changing the size of the whole empennage. The secondary objective was to determine how the magnitude of the air forces acting on the elevator (or the elevator moments) are affected by varying the angle of attack of the whole empennage, or of the elevator alone.
Date: July 1, 1927
Creator: Seiferth, R
Partner: UNT Libraries Government Documents Department

The interdependence of profile drag and lift with Joukowski type and related airfoils

Description: On the basis of a systematic investigation of Gottingen wind-tunnel data on Joukowski type and related airfoils, it is shown in what manner the profile drag coefficient is dependent on the lift coefficient. The individual factors for the construction of the profile drag polars are given. They afford a more accurate calculation of the performance coefficients of airplane designs than otherwise attainable with the conventional assumption of constant drag coefficient.
Date: March 1, 1935
Creator: Muttray, H
Partner: UNT Libraries Government Documents Department

Instrument for measuring the wall shearing stress of turbulent boundary layers

Description: It is shown that at a smooth wall in a turbulent boundary layer the velocity profile next to the wall is dependent, aside from the material constants of the flowing medium, only on the shearing stress transmitted to the wall, even with pressure rise or with pressure drop. Consequently, the heat transfer of a small element that is built into the wall and has a higher temperature than that of the flowing medium is a measure of the wall shearing stress. Theoretical considerations indicate that the wall shearing stress of the boundary layer can be defined by means of a heat-transfer measurement with an instrument mounted in the wall. Such an instrument is described. The calibration curve and its directional sensitivity curve are indicated. It permits the determination of the wall shearing stress in magnitude and direction.
Date: May 1950
Creator: Ludwieg, H.
Partner: UNT Libraries Government Documents Department

Inherent stability of helicopters

Description: The equilibrium, in still air, of a "stationary" helicopter (i.e., of one having neither vertical nor translational velocity, but a tendency to remain practically motionless within restricted limits of space) presents some difficulty in practice and justifies a theoretical investigation of its "inherent stability," i.e., independent of the pilot.
Date: October 1923
Creator: Crocco, G. Arturo
Partner: UNT Libraries Government Documents Department

Investigations and tests in the towing basin at Guidonia

Description: The experimental methods at the Guidonia towing basin are discussed including specifications. Some of the components examined are the bridge towing carriage, side towing carriage, catapult installation, and dynamometer systems. Tests were performed on hulls and floats, as well as motor boats and torpedo shaped bodies. Theoretical investigations were also performed to determine pressure distributions on geometrically simple bodies, propagation of small wave motions, and planing and submerged surfaces.
Date: April 1, 1939
Creator: Cremona, C
Partner: UNT Libraries Government Documents Department

Investigations and experiments in the Guidonia wind tunnel

Description: This paper is a presentation of the experiments and equipment used in investigations at the Guidonia wind tunnel. The equipment consisted of: a number of subsonic and supersonic cones, an aerodynamic balance, and optical instruments operating on the Schlieren and interferometer principle.
Date: July 1, 1939
Creator: Ferri, Antonio
Partner: UNT Libraries Government Documents Department

A method for the direct determination of wing-section drag

Description: In order that the method may be more easily understood, we will first consider the simpler case when there is no lift, but only drag, and when the streamlines at the measuring point behind the obstacle are nearly parallel. Moreover, the flow is assumed not to deviate much from the two-dimensional flow.
Date: November 1925
Creator: Betz, A.
Partner: UNT Libraries Government Documents Department

Method of characteristics for three-dimensional axially symmetrical supersonic flows

Description: An approximation method for three-dimensional axially symmetrical supersonic flows is developed; it is based on the characteristics theory (represented partly graphically, partly analytically). Thereafter this method is applied to the construction of rotationally symmetrical nozzles. (author).
Date: January 1947
Creator: Sauer, R.
Partner: UNT Libraries Government Documents Department

Method of curved models and its application to the study of curvilinear flight of airships. Part I

Description: In the first part of this paper we shall present the theoretical side of the problem of constructing curved model forms and the method of testing the model. In the second part we shall present a detailed account of the first experiments according to the given method, carried out with a curved model of the nonrigid airship V-2, and a comparison of the experimental results with some data of full-scale tests made with this airship in 1933.
Date: June 1, 1937
Creator: Gourjienko, G A
Partner: UNT Libraries Government Documents Department

Method of curved models and its application to the study of curvilinear flight of airships. Part II

Description: This report compares the results obtained by the aid of curved models with the results of tests made by the method of damped oscillations, and with flight tests. Consequently we shall be able to judge which method of testing in the tunnel produces results that are in closer agreement with flight test results.
Date: June 1, 1937
Creator: Gourjienko, G A
Partner: UNT Libraries Government Documents Department

A method for the instantaneous determination of the velocity and direction of the wind

Description: The laboratory instruments, which we often constructed with makeshift means, gave encouraging results and showed that they could satisfactorily meet the required conditions. By limiting ourselves to the employment of hot wires of 0.05 mm (0.002 in.) diameter, we obtained instruments which faithfully followed all the wind fluctuations of over 0.1 second and even much more rapid variations without any very great error.
Date: June 1, 1924
Creator: Huguenard, E; Magnan, A & Planiol, A
Partner: UNT Libraries Government Documents Department

The oscillating wing with aerodynamically balanced elevator

Description: The two-dimensional problem of the oscillating wing with aerodynamically balanced elevator is treated in the manner that the wing is replaced by a plate with bends and stages and the airfoil section by a mean line consisting of one or more straights. The computed formulas and tables permit, on these premises, the prediction of the pressure distribution and of the aerodynamic reactions of oscillating elevators and tabs with any position of elevator hinge in respect to elevator leading edge.
Date: October 1, 1941
Creator: Kussner, H G & Schwartz, I
Partner: UNT Libraries Government Documents Department

Optico-photographic measurements of airplane deformations

Description: The deformation of aircraft wings is measured by photographically recording a series of bright shots on a moving paper band sensitive to light. Alternating deformations, especially vibrations, can thus be measured in operation, unaffected by inertia. A handy recording camera, the optograph, was developed by the static division of the D.V.L. (German Experimental Institute for Aeronautics) for the employment of this method of measurement on airplanes in flight.
Date: March 1, 1931
Creator: Kussner, Hans Georg
Partner: UNT Libraries Government Documents Department

Optimum flight paths of turbojet aircraft

Description: The climb of turbojet aircraft is analyzed and discussed including the accelerations. Three particular flight performances are examined: minimum time of climb, climb with minimum fuel consumption, and steepest climb. The theoretical results obtained from a previous study are put in a form that is suitable for application on the following simplifying assumptions: the Mach number is considered an independent variable instead of the velocity; the variations of the airplane mass due to fuel consumption are disregarded; the airplane polar is assumed to be parabolic; the path curvatures and the squares of the path angles are disregarded in the projection of the equation of motion on the normal to the path; lastly, an ideal turbojet with performance independent of the velocity is involved. The optimum Mach number for each flight condition is obtained from the solution of a sixth order equation in which the coefficients are functions of two fundamental parameters: the ratio of minimum drag in level flight to the thrust and the Mach number which represents the flight at constant altitude and maximum lift-drag ratio.
Date: September 1, 1955
Creator: Miele, Angelo
Partner: UNT Libraries Government Documents Department

The organization of airways

Description: An aircraft freed from all contact with the ground during most of the period of its operation, is nevertheless dependent on the provision of proper ground organization. The provision of landing fields scattered over the country for the benefit of civil or military pilots who may arrive from any direction constitutes the first step in making commercial flying possible.
Date: November 1, 1922
Creator: Warner, Edward P.
Partner: UNT Libraries Government Documents Department

Nomogram for correcting drag and angle of attack of an airfoil model in an air stream of finite diameter

Description: In experimenting with airfoil models in a wind tunnel, the magnitude of the forces acting on the model is affected by the fact that the air stream in which the model is suspended, has a restricted cross-section. In order to utilize the results for an airplane in an unlimited quantity of air, a correction must be made. The magnitude of this correction was determined by Prandtl by the application of his wing theory.
Date: December 1924
Partner: UNT Libraries Government Documents Department