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  Partner: UNT Libraries Government Documents Department
 Decade: 1920-1929
 Year: 1929
 Collection: National Advisory Committee for Aeronautics Collection
Condensed data on the aircraft engines of the world

Condensed data on the aircraft engines of the world

Date: April 1, 1929
Creator: Fliedner, C S
Description: This compilation of the outstanding characteristics of the available aircraft engines of the world was prepared as a compact ready reference for desk use. It does not pretend to be anything but a skeleton outline of the characteristics of engines reported in the technical press as being in either the experimental, development, or production stage.
Contributing Partner: UNT Libraries Government Documents Department
A new method for the prediction of airplane performance

A new method for the prediction of airplane performance

Date: February 1, 1929
Creator: Lesley, E P
Description: A new method for the prediction of airplane performance in level and climbing flight, together with complete information regarding propeller speeds, is described in this report. Developed from Bairstow's system and making use of American absolute coefficients, this method has advantages of simplicity and brevity.
Contributing Partner: UNT Libraries Government Documents Department
Corrosion embrittlement of duralumin VI : the effect of corrosion accompanied by stress on the tensile properties of sheet duralumin

Corrosion embrittlement of duralumin VI : the effect of corrosion accompanied by stress on the tensile properties of sheet duralumin

Date: May 1, 1929
Creator: Rawdon, Henry S
Description: The effect of corrosion on the tensile properties of duralumin while stressed is shown in graphical form. According to the test results, duralumin sheet, coated with aluminum, maintains its initial properties unimpaired for corrosion periods as long as 60 days with an applied tensile stress as high as 20,000 lb/sq.in., which is approximately one-half the stress corresponding to the yield point as defined here. In these tests, that material which had been heat-treated by being quenched in cold water, though far inferior to similar material having the aluminum coating, was superior to the sheet material which was heat treated by being quenched in hot water. These results are in excellent agreement with the results of previous laboratory and exposure tests.
Contributing Partner: UNT Libraries Government Documents Department
Corrosion embrittlement of duralumin V : results of weather-exposure tests

Corrosion embrittlement of duralumin V : results of weather-exposure tests

Date: February 1, 1929
Creator: Rawdon, Henry S
Description: In a series of weather exposure tests of sheet duralumin, upon which accelerated corrosion tests in the laboratory by the wet-and-dry corrosion method in a sodium chloride solution has already been carried out, a close parallelism between the results of the two kinds of tests was found to exist. The exposure tests showed that the lack of permanence of sheet duralumin is largely, if not entirely, due to corrosion. A corrosion attack of an intercrystalline nature is very largely responsible for the degree of embrittlement produced. The rate of embrittlement was greatly accelerated by a marine atmosphere and by the tropical climate. Variations in corrosion and embrittlement are noted in relation to heat treatment, cold working, and types of protective coatings.
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Wind tunnel tests on airfoil boundary control using a backward opening slot

Wind tunnel tests on airfoil boundary control using a backward opening slot

Date: October 1, 1929
Creator: Knight, Montgomery
Description: This report presents the results of an investigation to determine the effect of boundary layer control on the lift and drag of an airfoil equipped with a backward opening slot. Various slot locations, widths of opening, and pressures, were used. The tests were conducted in the Five-Foot Atmospheric Wind Tunnel of the Langley Memorial Aeronautical Laboratory. The greatest increase in maximum lift was 96 per cent, the greatest decrease in minimum drag was 27 per cent, and the greatest increase in the ratio, maximum lift coefficient/minimum drag coefficient, was 151 per cent.
Contributing Partner: UNT Libraries Government Documents Department
Wind tunnel tests on an airfoil equipped with a split flap and a slot

Wind tunnel tests on an airfoil equipped with a split flap and a slot

Date: October 1, 1929
Creator: Bamber, Millard J
Description: The investigation described in this report is concerned with the changes in the aerodynamic characteristics of an airfoil which are produced by a gauze-covered suction slot, located near the leading edge, and connected by an air passage to a split flap at the trailing edge. The tests were conducted at the Langley Memorial Aeronautical Laboratory. At the larger values of lift coefficient where the action of the slot might be expected to be most effective, the pressure differences were such that the air flowed out of the slot rather than in through it, and in consequence, the maximum lift coefficient was decreased.
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Remarks on airplane struts and girders under compressive and bending stresses : index values

Remarks on airplane struts and girders under compressive and bending stresses : index values

Date: February 1, 1929
Creator: Wagner, Herbert
Description: In this paper the behavior of straight, centrally loaded compression struts is discussed and values computed.
Contributing Partner: UNT Libraries Government Documents Department
A preliminary investigation of supercharging an air-cooled engine in flight

A preliminary investigation of supercharging an air-cooled engine in flight

Date: January 1, 1929
Creator: Ware, Marsden
Description: This report presents the results of preliminary tests made on the effects of supercharging an air-cooled engine under airplane flight conditions. Service training airplanes were used in the investigation equipped with production types of Wright J engines. A N.A.C.A. Roots type supercharger was driven from the rear of the engine. In addition to measuring those quantities that would enable the determination of the climb performance, measurements were made of the cylinder-head temperatures and the carburetor pressures and temperatures. The supercharging equipment was not removed from the airplane when making flights without supercharging, but a by-pass valve, which controlled the amount of supercharging by returning to the atmosphere the surplus air delivered by the supercharger, was left full open. With the supercharger so geared that ground-level pressure could be maintained to 18,500 feet, it was found that the absolute ceiling was increased from 19,400 to 32,600 feet, that the time to climb to 16,00 feet was decreased from 32 to 16 minutes, and that this amount of supercharging apparently did not injure the engine. (author).
Contributing Partner: UNT Libraries Government Documents Department
The comparative performance of Roots type aircraft engine superchargers as affected by change in impeller speed and displacement

The comparative performance of Roots type aircraft engine superchargers as affected by change in impeller speed and displacement

Date: January 1, 1929
Creator: Ware, Marsden
Description: This report presents the results of tests made on three sizes of roots type aircraft engine superchargers. The impeller contours and diameters of these machines were the same, but the length were 11, 8 1/4, and 4 inches, giving displacements of 0.509, 0.382, and 0.185 cubic foot per impeller revolution. The information obtained serves as a basis for the examination of the individual effects of impeller speed and displacement on performance and of the comparative performance when speed and displacement are altered simultaneously to meet definite service requirements. According to simple theory, when assuming no losses, the air weight handled and the power required for a given pressure difference are directly proportional to the speed and the displacement. These simple relations are altered considerably by the losses. When comparing the performance of different sizes of machines whose impeller speeds are so related that the same service requirements are met, it is found that the individual effects of speed and displacement are canceled to a large extent, and the only considerable difference is the difference in the power losses which decrease with increase in the displacement and the accompanying decrease in speed. This difference is small in relation to the net ...
Contributing Partner: UNT Libraries Government Documents Department
A study of wing flutter

A study of wing flutter

Date: January 1, 1929
Creator: Zahm, A F
Description: Part I describes vibration tests, in a wind tunnel, of simple airfoils and of the tail plane of an M0-1 airplane model; it also describes the air flow about this model. From these tests are drawn inferences as to the cause and cure of aerodynamic wing vibrations. Part II derives stability criteria for wing vibrations in pitch and roll, and gives design rules to obviate instability. Part III shows how to design spars to flex equally under a given wing loading and thereby economically minimize the twisting in pitch that permits cumulative flutter. Resonant flutter is not likely to ensue from turbulence of air flow along past wings and tail planes in usual flying conditions. To be flutterproof a wing must be void of reversible autorotation and not have its centroid far aft of its pitching axis, i. e., axis of pitching motion. Danger of flutter is minimized by so proportioning the wing's torsional resisting moment to the air pitching moment at high-speed angles that the torsional flexure is always small. (author).
Contributing Partner: UNT Libraries Government Documents Department
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