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  Partner: UNT Libraries Government Documents Department
 Decade: 1920-1929
 Collection: National Advisory Committee for Aeronautics Collection
The determination of the effective resistance of a spindle supporting a model airfoil

The determination of the effective resistance of a spindle supporting a model airfoil

Date: January 1, 1921
Creator: Davidson, W E
Description: An attempt was made to determine the effect of spindle interference on the lift of the airfoil by measuring moments about the axis parallel to the direction of air flow. The values obtained are of the same degree as the experimental error, and for the present this effect will be neglected. The results obtained using a U.S.A. 15 wing (plotted here) show that the correction is nearly constant from 0 degrees to 10 degrees incidence and that at greater angles its value becomes erratic. At such angles, however, the wing drag is so high that the spindle correction and its attendant errors become relatively small and unimportant.
Contributing Partner: UNT Libraries Government Documents Department
Loads and calculations of army airplanes

Loads and calculations of army airplanes

Date: February 1, 1921
Creator: Stelmachowski, Ing
Description: By comparing airplanes of known strength that have resisted all the usual and even extreme air loads with those that under like conditions were found to be insufficiently strong, the researchers, aided by scientific investigations, developed standards which are satisfactory for the calculation of airplane structures. Given here are standards applicable to loads on wing trusses, load factors for use in stress analysis, load factors required in sand testing, loads on control surfaces, loads on wing ribs, loads on landing gear, and rigidity of materials.
Contributing Partner: UNT Libraries Government Documents Department
Progress made in the construction of giant airplanes in Germany during the war

Progress made in the construction of giant airplanes in Germany during the war

Date: December 1, 1920
Creator: Baumann, A
Description: The construction of giant airplanes was begun in Germany in August, 1914. The tables annexed here show that a large number of airplanes weighing up to 15.5 tons were constructed and tested in Germany during the War, and it is certain that no other country turned out airplanes of this weight nor in such large numbers. An examination of the tables shows that by the end of the War all the manufacturers had arrived at a well-defined type, namely an airplane of about 12 tons with four engines of 260 horsepower each. The aircraft listed here are discussed with regard to useful weight and aerodynamic qualities.
Contributing Partner: UNT Libraries Government Documents Department
The photographic recording of small motions

The photographic recording of small motions

Date: November 1, 1920
Creator: Norton, F H
Description: Methods and equipment for recording small and sometimes rapid motions by photographic means are described, and the efficacy of photographic recording in such instances is evaluated. The optical system consisting of the light source, the mirror or prism for transmitting motion to the emergent beam, and a means of bringing the rays into focus on the film are discussed. Attention is given to the critical issue of mirror mounting. The film holder and the driving motor for the recording drum are described in detail. The authors conclude that the optical methods they describe are far more satisfactory than the recording pen, in compactness, in high natural period, and in elimination of friction. Costs are similar to mechanical methods. The development and reproduction of the record is an added complication, but the ease of duplicating the records is a decided advantage.
Contributing Partner: UNT Libraries Government Documents Department
The problem of the turbo-compressor

The problem of the turbo-compressor

Date: August 1, 1920
Creator: Devillers, Rene
Description: In terminating the study of the adaptation of the engine to the airplane, we will examine the problem of the turbo-compressor,the first realization of which dates from the war; this will form an addition to the indications already given on supercharging at various altitudes. This subject is of great importance for the application of the turbo-compressor worked by the exhaust gases. As a matter of fact, a compressor increasing the pressure in the admission manifold may be controlled by the engine shaft by means of multiplication gear or by a turbine operated by the exhaust gas. Assuming that the increase of pressure in the admission manifold is the same in both cases, the pressure in the exhaust manifold would be greater in the case in which the compressor is worked by the exhaust gas and there would result a certain reduction of engine power which we must be able to calculate. On the other hand , if the compressor is controlled by the engine shaft, a certain fraction of the excess power supplied is utilized for the rotation of the compressor. In order to compare the two systems, it is there-fore necessary to determine the value of the reduction of ...
Contributing Partner: UNT Libraries Government Documents Department
Remarks on the Pressure Distribution over the Surface of an Ellipsoid, Moving Translationally Through a Perfect Fluid

Remarks on the Pressure Distribution over the Surface of an Ellipsoid, Moving Translationally Through a Perfect Fluid

Date: June 1, 1924
Creator: Munk, Max M
Description: This note, prepared for the National Advisory Committee for Aeronautics, contains a discussion of the pressure distribution over ellipsoids when in translatory motion through a perfect fluid. An easy and convenient way to determine the magnitude of the velocity and of the pressure at each point of the surface of an ellipsoid of rotation is described. The knowledge of such pressure distribution is of great practical value for the airship designer. The pressure distribution over the nose of an airship hull is known to be in such good agreement with the theoretical distribution as to permit basing the computation of the nose stiffening structure on the theoretical distribution of pressure.
Contributing Partner: UNT Libraries Government Documents Department
On the distribution of lift along the span of an airfoil with displaced ailerons

On the distribution of lift along the span of an airfoil with displaced ailerons

Date: June 1, 1924
Creator: Munk, Max M
Description: The effect of an aileron displacement on the distribution of the lift along the span is computed for an elliptic wing of aspect ratio 6 for three conditions. The lift distribution caused by the aileron displacement is uniform and extends normally beyond the inner end of the ailerons. Hence, the displacement of an aileron with constant chord length may bring about passing the stalling point of the adjacent wing sections, if these were near this point before. Hence, such ailerons can become ineffective at low speeds. Tapering the aileron towards the inside suggests itself as a remedy.
Contributing Partner: UNT Libraries Government Documents Department
Pressure distribution on the nose of an airship in circling flight

Pressure distribution on the nose of an airship in circling flight

Date: August 1, 1925
Creator: Fairbanks, Karl J
Description: In recent tests on the pressures occurring on the envelope and control surfaces of the naval airship C-7, it was noted that the pressures on the nose of the airship, while flying in level circling flight, were symmetrically distributed. Such a condition can only occur when the nose of the airship is pointed directly into the wind, and to accomplish this in circling flight, the axis of the airship must then be parallel to the direction of the motion of the nose. The question was raised as to whether the same conditions occur generally on all airships in circling flight. It appears that airships flying in a constant, level, circling flight path will generally head very closely into the wind, and any deviation will be so slight that the distribution of pressure over the nose will be but slightly, if at all, changed from a symmetrical distribution.
Contributing Partner: UNT Libraries Government Documents Department
Micarta propellers I : materials

Micarta propellers I : materials

Date: August 1, 1924
Creator: Caldwell, F W
Description: Here, values for tension, compression edgewise of laminations, and transverse flatwise of laminations are given for Micarta made with various kinds of sheet material. The corresponding values for white oak are given for comparison. It was found by destructive and service tests that Micarta made with a good grade of cotton duck will give satisfactory service with most designs. In propellers having detachable blades, it is desirable that the root of the blade be of a small cross section to decrease the weight of the metal hub. Here the use of the special fabric or wood veneer offers advantages due to greater tensile strength. These materials, especially the wood veneer, produce stiffer blades than duck. This is also a value in controllable and reversible pitch designs where it is desirable that the plan form of the blades be symmetrical.
Contributing Partner: UNT Libraries Government Documents Department
Structural weight of aircraft as affected by the system of design

Structural weight of aircraft as affected by the system of design

Date: November 1, 1924
Creator: Hall, Charles Ward
Description: Various details of design or arrangement of the parts of airplane structures are shown and discussed, the use of these devices having resulted in the production of structures of adequate strength, yet of a weight less than one-half of the usual construction.
Contributing Partner: UNT Libraries Government Documents Department