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 Collection: Technical Report Archive and Image Library
Results 15351 - 15360 of 18,906
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Investigation of the boundary layer about a symmetrical airfoil in a wind tunnel of low turbulence

Investigation of the boundary layer about a symmetrical airfoil in a wind tunnel of low turbulence

Date: August 1, 1940
Creator: Von Doenhoff, Albert E
Description: None
Contributing Partner: UNT Libraries Government Documents Department
The maximum delivery pressure of single-stage radial superchargers for aircraft engines

The maximum delivery pressure of single-stage radial superchargers for aircraft engines

Date: August 1, 1940
Creator: Null, W Von Der
Description: With the aid of simple considerations and test results, an attempt is made to clear up some obscure points that still exist. The considerations are restricted to those cases where it is in fact of advantage to"force" the large delivery heads required for high altitude and high supercharge with a single-stage supercharger.
Contributing Partner: UNT Libraries Government Documents Department
A simple approximation method for obtaining the spanwise lift distribution

A simple approximation method for obtaining the spanwise lift distribution

Date: August 1, 1940
Creator: Schrenk, O
Description: The approximation method described makes possible lift-distribution computations in a few minutes. Comparison with an exact method shows satisfactory agreement. The method is of greater applicability than the exact method and includes also the important case of the wing with end plates.
Contributing Partner: UNT Libraries Government Documents Department
Stemming in Metal Mines. Progress Report 2

Stemming in Metal Mines. Progress Report 2

Date: August 1940
Creator: Johnson, John A.; Agnew, Wing G. & Mosier, McHenry
Description: Report issued by the U.S. Bureau of Mines on the progress made in metal-mine stemming. Different types of stemming methods and testing procedures are presented. This report includes tables, illustrations, and photographs.
Contributing Partner: UNT Libraries Government Documents Department
Transient Effects of the Wing Wake on the Horizontal Tail

Transient Effects of the Wing Wake on the Horizontal Tail

Date: August 1, 1940
Creator: Jones, Robert T & Fehlner, Leo F
Description: An investigation was made of the effect of the wing wake on the lift of the horizontal tail surfaces. In the development of expressions for this effect, the growth of wing circulation and wing wake, the time interval represented by the tail length, and the development of lift by the rail were considered. The theory has been applied to a specific case to show the magnitude of the effect to be expected. It is shown that, for motions below a certain frequency, the development of lift by the tail may be represented by a simple lag function. The lag is, however, somewhat greater than that indicated by the rail length.
Contributing Partner: UNT Libraries Government Documents Department
Correlation of knocking characteristics of fuels in an engine having a hemispherical combustion chamber

Correlation of knocking characteristics of fuels in an engine having a hemispherical combustion chamber

Date: July 1, 1940
Creator: Rothrock, A M & Biermann, Arnold E
Description: Data are presented to show the effects of inlet-air pressure, inlet-air temperature, and compression ratio on the maximum permissible performance obtained with having a hemispherical-dome combustion chamber. The five aircraft-engine fuels used have octane numbers varying from 90 to 100 plus 2 ml of tetraethyl lead per gallon. The data were obtained on a 5 1/4-inch by 4 3/4-inch liquid-cooled engine operating at 2,500 r.p.m. The compression ratio was varied from 6.0 to 8.9. The inlet-air temperature was varied from 110 to 310 F. For each set of conditions, the inlet-air pressure was increased until audible knock occurred and then reduced 2 inches of mercury before data were recorded. The results for each fuel can be correlated by plotting the calculated end-gas density factor against the calculated end-gas temperature. Measurements of spark-plugs, cutting off the switch to one spark plug lowered the electrode temperature of that plug from a value of 1,365 F to a value of 957 F. The results indicate that the surface temperatures of combustion-chamber areas which become new sources of ignition markedly increase after ignition.
Contributing Partner: UNT Libraries Government Documents Department
The effects of engine speed and mixture temperature on the knocking characteristics of several fuels

The effects of engine speed and mixture temperature on the knocking characteristics of several fuels

Date: July 1, 1940
Creator: Lee, Dana W
Description: Six 100-octane and two 87-octane aviation engine fuels were tested in a modified C.F.R. variable-compression engine at 1,500, 2,000 and 2,500 rpm. The mixture temperature was raised from 50 to 300 F in approximately 50 degree steps and, at each temperature, the compression ratio was adjusted to give incipient knock as shown by a cathode ray indicator. The results are presented in tabular form. The results are analyzed on the assumption that the conditions which determine whether a given fuel will knock are the maximum values of density and temperature reached by the burning gases. A maximum permissible density factor, proportional to the maximum density of the burning gases just prior to incipient knock, and the temperature of the burning gases at that time were computed for each of the test conditions. Values of the density factors were plotted against the corresponding end-gas temperatures for the three engine speeds and also against engine speed for several and end-gas temperatures. The maximum permissible density factor varied only slightly with engine speed but decreased rapidly with an increase in the end-gas temperature. The effect of changing the mixture temperature was different for fuels of different types. The results emphasize the desirability of ...
Contributing Partner: UNT Libraries Government Documents Department
Experimental investigation to determine the relative magnitude of vertical and horizontal gusts in the atmosphere

Experimental investigation to determine the relative magnitude of vertical and horizontal gusts in the atmosphere

Date: July 1, 1940
Creator: Donely, Philip
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Experimental results with airfoils tested in the high-speed tunnel at Guidonia

Experimental results with airfoils tested in the high-speed tunnel at Guidonia

Date: July 1, 1940
Creator: Ferri, Antonio
Description: The results are presented of a triple series of tests using force measurements, pressure-distribution measurements, and air flow photographs on airfoil sections suitably selected so that comparison could be made between the experimental and theoretical results. The comparison with existing theory is followed by a discussion of the divergences found, and an attempt is made to find their explanation.
Contributing Partner: UNT Libraries Government Documents Department
Experiments on ball and roller bearings under conditions of high speed and small oil supply

Experiments on ball and roller bearings under conditions of high speed and small oil supply

Date: July 1, 1940
Creator: Getzlaff, Gunter
Description: This report describes a testing machine on which 35 millimeter bearings (bore) can be run at speeds of the order of 21,000 rpm, while the following factors are recorded: 1) oil circulation through bearing and oil temperature. 2) maximum temperature of outer bearing ring, 3) radial and axial load on bearing, 4) radial, axial, and angular clearance of bearing, 5) power consumption of bearing. The experiments show that the lubrication was most reliable and oil consumption lowest when the oil was introduced through a hole in the outer or inner ring of the bearing.
Contributing Partner: UNT Libraries Government Documents Department