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  Partner: UNT Libraries Government Documents Department
 Decade: 1920-1929
 Collection: National Advisory Committee for Aeronautics Collection
Experience with geared propeller drives for aviation engines

Experience with geared propeller drives for aviation engines

Date: September 1, 1920
Creator: Kutzbach, K
Description: I. The development of the gear wheels: (a) bending stresses; (b) compressive stresses; (c) heating; (d) precision of manufacture. II. General arrangement of the gearing. III. Vibration in the shaft transmission. An overview is given of experience with geared propeller drives for aviation engines. The development of gear wheels is discussed with emphasis upon bending stresses, compressive stresses, heating, and precision in manufacturing. With respect to the general arrangement of gear drives for airplanes, some principal rules of mechanical engineering that apply with special force are noted. The primary vibrations in the shaft transmission are discussed. With respect to vibration, various methods for computing vibration frequency and the influence of elastic couplings are discussed.
Contributing Partner: UNT Libraries Government Documents Department
Tests of the Daimler D-IVa engine at a high altitude test bench

Tests of the Daimler D-IVa engine at a high altitude test bench

Date: October 1, 1920
Creator: Noack, W G
Description: Reports of tests of a Daimler IVa engine at the test-bench at Friedrichshafen, show that the decrease of power of that engine, at high altitudes, was established, and that the manner of its working when air is supplied at a certain pressure was explained. These tests were preparatory to the installation of compressors in giant aircraft for the purpose of maintaining constant power at high altitudes.
Contributing Partner: UNT Libraries Government Documents Department
Italian and French experiments on wind tunnels

Italian and French experiments on wind tunnels

Date: November 1, 1920
Creator: Knight, WM
Description: Given here are the results of experiments conducted by Colonel Costanzi of the Italian Army to determine the influence of the surrounding building in which a wind tunnel was installed on the efficiency of the installation, and how the efficiency of the installation was affected by the design of the tunnel. Also given are the results of a series of experiments by Eiffel on 34 models of tunnels of different dimensions. This series of experiments was started in order to find out if, by changing the shape of the nozzle or of the diffuser of the large tunnel at Auteuil, the efficiency of the installation could be improved.
Contributing Partner: UNT Libraries Government Documents Department
Relation of rib spacing to stress in wing planes

Relation of rib spacing to stress in wing planes

Date: May 1, 1920
Creator: Zahm, A F
Description: The stress relations to the fabric and the rib consequent upon a change of spacing between ribs in a wing plane are discussed. Considering the wing plane as a static structure, and ignoring the question of aerodynamic efficiency, it appears that the unit stress in the rib and fabric will remain constant for constant p if the linear dimensions of both rib and fabric are increased alike, viz., if wing and fabric remain geometrically similar. Since the bulge and the structural dimensions remain geometrically similar, the whole distended plane remains so, and hence should have the same pressure distribution and efficiency. If therefore the Burgess rule of making the rib spacing always one-fifth of the chord of the plane be valid, it must be valid for all others that are mechanically similar in structure and covering.
Contributing Partner: UNT Libraries Government Documents Department
Soaring flight in Guinea

Soaring flight in Guinea

Date: August 1, 1920
Creator: Idrac, P
Description: The term soaring is applied here to the flight of certain large birds which maneuver in the air without moving their wings. The author explains the methods of his research and here gives approximate figures for the soaring flight of the Egyptian Vulture and the African White backed Vulture. Figures are given in tabular form for relative air speed per foot per second, air velocity per foot per second, lift/drag ratio, and selected coefficients. The author argues that although the figures given were taken from a very limited series of observations, they have nevertheless thrown some light on the use by birds of the internal energy of the air.
Contributing Partner: UNT Libraries Government Documents Department
The effect of longitudinal moment of inertia upon dynamic stability

The effect of longitudinal moment of inertia upon dynamic stability

Date: October 1, 1922
Creator: Norton, F H & Carroll, T
Description: Free flight tests were carried out to show whether the longitudinal oscillations of a standard S.E.5A airplane are noticeably affected if its longitudinal moment of inertia is increased. These oscillations were taken by means of a self-recording instrument, the airplane having first its ordinary moment of inertia and then one increased by 14 percent. The period of oscillation was slightly longer after the increase of the moment of inertia, but the damping was not affected. Presented here are test results from an investigation to determine the relative performance of a single-cylinder, high-speed, compression-ignition engine when using fuel injection valve nozzles with different numbers, sizes, and directions of round orifices. A spring loaded, automatic injection valve was used. It was centrally located at the top of a vertical disk-type combustion chamber formed between horizontally opposed inlet and exhaust valves of a 5-inch by 7-inch engine. A series of fuel injection valve nozzles with different arrangements of round orifices were tested, starting with orifices so small that impingement on the combustion chamber walls was impossible and increasing beyond the start of impingement. a :A table and curves are presented showing the performance of the engine with different nozzles. The test results are ...
Contributing Partner: UNT Libraries Government Documents Department
Airplane performance as influenced by the use of a supercharged engine

Airplane performance as influenced by the use of a supercharged engine

Date: May 1, 1920
Creator: De Bothezat, George
Description: The question of the influence of a supercharged engine on airplane performance is treated here in a first approximation, but one that gives an exact idea of the advantage of supercharging. Considered here is an airplane that climbs first with an ordinary engine, not supercharged, and afterwards climbs with a supercharged engine. The aim is to find the difference of the ceilings reached in the two cases. In the case of our figure, the ceiling from 25,000 feet is increased to 37,000 feet, the supercharging maintaining the power only up to 20,000 feet. This makes, in comparison with an engine without supercharging, an increase of about 50 percent.
Contributing Partner: UNT Libraries Government Documents Department
Notes on the design of supercharged and overdimensioned aircraft engines

Notes on the design of supercharged and overdimensioned aircraft engines

Date: July 1, 1920
Creator: SCHWAGER
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Static testing and proposed standard specifications

Static testing and proposed standard specifications

Date: July 1, 1920
Creator: Warner, E P
Description: Static tests fall into two groups, the first of which is designed to load all members of the structure approximately in accordance with the worst loads which they carry in flight, while the second is directed to the testing of specific members which are suspected of weakness and which are difficult to analyze mathematically. The nature of the loading in the second type is different for every different test, but the purpose of the first is defined clearly enough to permit the adoption of some standard set of loading specifications, at least for airplanes of normal design. Here, an attempt is made to carry through an analysis leading to such a standard, the goal being the determination of a load which will simultaneously impose on every member of the airplane structure a stress equal to the worst it will carry in flight.
Contributing Partner: UNT Libraries Government Documents Department
Notes on longitudinal stability and balance

Notes on longitudinal stability and balance

Date: April 1, 1920
Creator: Warner, E P
Description: None
Contributing Partner: UNT Libraries Government Documents Department