Technical Report Archive and Image Library (TRAIL) - 22,044 Matching Results

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Reduction in efficiency of propellers due to slipstream

Description: In the slipstream behind a propeller there is a considerable amount of kinetic energy which has been imparted to it by the engine without producing any corresponding propeller thrust. The increased absorption of power reduces the propeller efficiency. Attention has been previously directed to this question by Bendemann and Madelung and other writers. Their contribution serves to verify a simple method of calculating the reduction in the propeller efficiency due to the slip stream. That method of calculation is given here. Explanations and examples are given for as single propeller and for two propellers mounted in tandem.
Date: December 1, 1923
Creator: Munk, Max M.
Partner: UNT Libraries Government Documents Department

Reduction Mills in Montana in 1925

Description: List of reduction mills in Montana, compiled in the course of investigations of mineral resources of Montana. It includes information about each loaction including: the process, character of ore, when the mill was operated, and custom work; equipment and power used; and capacity in tons.
Date: March 1927
Creator: Gerry, C. N.
Partner: UNT Libraries Government Documents Department

The Reduction of Aileron Operating Force by Differential Linkage

Description: It is shown that the control force of ordinary ailerons may be reduced to zero over a range of deflections and at a given flight condition by the use of an appropriate differential movement. Approximations to the ideal motion obtainable with a simple linkage are discussed and a chart that enables the selection of an appropriate crank arrangement is presented. Various aspects of the practical application of the system are discussed and it is concluded that a small fixed tab, deflected to trim both ailerons upward, would be advantageous.
Date: December 1, 1936
Creator: Jones, Robert T & Nerken, Albert I
Partner: UNT Libraries Government Documents Department

Reduction of Air Pollutants from Gas Burner Flames: Including Related Reaction Kinetics

Description: From Abstract: "The concentrations of air pollutants and the flame temperatures were measured, and the effects of ingress of secondary air into the primary and secondary combustion zones, flame stability, burner port surface, and simulated recycling of combustion gases were noted."
Date: unknown
Creator: Harris, Margaret E.; Rowe, Valeria R.; Cook, E. B. & Grumer, J.
Partner: UNT Libraries Government Documents Department

The Reduction of Airborne Dust Generated by Roof Bolt Drill Bits Through the Use of Water

Description: Abstract: In the vast majority of American coal mines, roof bolt holes are drilled dry, mainly because of mine operator concern with the spent water creating adverse working conditions. Wet drilling, however, can increase drilling rates and the effective lifetime of the drill bits used. This study, carried out as part of an ongoing cooperative research program between the U.S. Bureau of Mines and the University of Missouri-Rolla, shows that the large volumes of water conventionally used in wet drilling are not necessary, and the performance benefits from wet drilling can be achieved with total volume flows on the order of 0.4 L per hole. This conclusion is validated based on the measured respirable dust generated in drilling Berea sandstone. The results are confirmed using a variety of bit shapes, which are also shown to have a significant effect on penetration rate.
Date: 1995
Creator: Sundae, Laxman S.; Summers, David A.; Wright, Douglas & Cantrell, Bruce K.
Partner: UNT Libraries Government Documents Department

The reduction of airplane flight test data to standard atmosphere conditions

Description: This report was prepared for the National Advisory Committee for Aeronautics in order to supply the need of practical methods of reducing observed performance to standard conditions with a minimum of labor. The first part gives a very simple approximate method of reducing performance in climb, and is particularly adapted to work not requiring extreme accuracy. The second part gives a somewhat more elaborate and more accurate method which is well suited to general flight test reduction. The third part gives the conventional method of calibrating air-speed indicators and reducing the indicated speeds to true air speeds. An appendix gives working tables and charts for the standard atmosphere. (author).
Date: January 1926
Creator: Diehl, Walter S. & Lesley, E. P.
Partner: UNT Libraries Government Documents Department

Reduction of Coal by Lithium-Ethylenediamine and Reaction of Model Compounds with Metal-Amine Systems

Description: From Introduction: "This report describes Bureau investigations on the effects and significance of treating coal and model compounds by lithium-ethylenediamine and some other metal-amine systems."
Date: unknown
Creator: Reggel, Leslie; Zahn, Charles; Wender, Irving & Raymond, Raphael
Partner: UNT Libraries Government Documents Department

Reduction of Data for Piston Gage Pressure Measurements

Description: Report issued by the U.S. National Bureau of Standards discussing piston gage pressure and reducing errors of measurement. Sources of error are described and evaluated in order to "reduce the magnitude of overall error of measurement" (p. 1). This report includes tables, and illustrations.
Date: June 17, 1963
Creator: Cross, J. L.
Partner: UNT Libraries Government Documents Department

Reduction of Data for Piston Gage Pressure Measurements

Description: Report discussing pressure measurements made with piston gages that are affected by gravity, temperature, pressure, and several other variables. For accurate determinations of pressure the calculations must take these variables into account. A general equation is developed and simplified procedures for calculating pressure are illustrated.
Date: June 17, 1963
Creator: Cross, J. L.
Partner: UNT Libraries Government Documents Department

Reduction of fuel-vapor loss by omitting some of the fuel constituents normally lost during flight

Description: Report discussing an investigation to determine the effect of omitting some of the fuel constituents in AN-F-28 Amendment 2 fuel that are normally lost in flight on fuel-vapor loss. Removing the components was found to decrease the fuel-vapor loss and increase the critical altitudes.
Date: August 27, 1945
Creator: Stone, Charles S. & Kramer, Walter E.
Partner: UNT Libraries Government Documents Department

Reduction of hinge moments of airplane control surfaces by tabs

Description: This report presents the results of an investigation conducted in the NACA 7 by 10-foot wind tunnel of control surfaces equipped with tabs for reducing the control forces or trimming the aircraft. Two sizes of ordinary ailerons with several sizes of attached and inset tabs were tested on a Clark y wing. Tabs were also tested in combination with auxiliary balances of the horn and paddle types, and with a frise balance aileron. A tail-surface model of symmetrical section, equipped with tabs, was tested with 40 percent of the area movable (elevator) when used as a horizontal tail and 60 percent of the area movable (rudder) when used as a vertical tail. The half-span tail-surface model was tested with and without a reflection plane. The results of the tests indicated that inset tabs were superior to attached tabs for the same ratio of tab/control surface deflection.
Date: January 1, 1936
Creator: Harris, Thomas A
Partner: UNT Libraries Government Documents Department

Reduction of lift of a wing due to its drag

Description: This analysis computes for a predetermined airfoil and given Reynolds Number the course of the "displacement thickness," i.e., the course of the layer by which the streamlines of the potential flow are pushed away from the wing through the frictional layer. The result is, to a certain extent, a new wing contour.
Date: November 1, 1935
Creator: Stuper, J
Partner: UNT Libraries Government Documents Department

Reduction of observed airplane performance to standard conditions

Description: This report shows how the actual performance of an airplane varies with air temperature when the pressure is held constant. This leads to comparatively simple methods of reducing observed data to standard conditions. The new methods which may be considered exact for all practical purposes, have been used by the Navy Department for about a year, with very satisfactory results. The report also contains a brief historical review of the important papers which have been published on the subject of performance reduction, and traces the development of the standard atmosphere. (author).
Date: January 1929
Creator: Diehl, Walter S.
Partner: UNT Libraries Government Documents Department

Reduction of profile drag at supersonic velocities by the use of airfoil sections having a blunt trailing edge

Description: A preliminary theoretical and experimental investigation has been made on the aerodynamic characteristics of blunt-trailing-edge airfoils at supersonic velocities. The theoretical considerations indicate that properly designed airfoils with moderately blunt trailing edges can have less profile drag, greater lift-curve slope, and high maximum lift-drag ratio than conventional sections. These predictions have been substantiated by experimental measurements on airfoils of 10-percent-thickness ratio at Mach numbers of 1.5 and 2.0, and at Reynolds numbers between 0.2 and 1.2 million.
Date: September 1, 1955
Creator: Chapman, Dean R
Partner: UNT Libraries Government Documents Department

Reduction of the shimmy tendency of tail and nose-wheel landing gears by installation of specially designed tires

Description: Shimmy of tail and nose wheels may be eliminated by installation of dampers and use of large trail; however, this produces construction and operational disadvantages. It is more favorable to employ, instead of the customary tail-wheel tires, tires with lesser shimmy tendency. A description of the best possible form for these tires follows: furthermore, a few general concepts regarding the effects of the condition of the tire, of the type of rolling motion, and of the landing, are discussed.
Date: July 1955
Creator: Schrode, H.
Partner: UNT Libraries Government Documents Department

Reduction of turbulence in wind tunnels

Description: A brief nonmathematical outline is given of modern views as to the nature of the effect of turbulence, and their bearing on the desirability of designing wind tunnels for small or large turbulence. Experiments made on a particular wind tunnel for the purpose of reducing the turbulence are described, to illustrate the influence of certain factors on the magnitude of the turbulence. Moderate changes in the size, shape, and wall thickness of cells of the honeycomb were found to have little effect. The addition of a room honeycomb at the entrance was also of little value in reducing the turbulence. The turbulence decreased with increasing distance between the honeycomb and the measuring station. A further decrease was obtained by using a large area reduction in the entrance cone, with the honeycomb at the extreme entrance end. (author).
Date: January 1, 1931
Creator: Dryden, Hugh L
Partner: UNT Libraries Government Documents Department

Reduction of wing lift by the drag

Description: Drag and loss of lift of a wing are attributable to the same cause, wake formation, thus indicating that there is some relation between both. The analysis of measurements on Joukowsky sections revealed a typical course of curves for the interdependence between drag and loss of lift. The shape of the curves apparently depends quite regularly on the mean camber and on the thickness of the profile.
Date: August 1932
Creator: Betz, A. & Lotz, J.
Partner: UNT Libraries Government Documents Department

A reevaluaion of data on atmospheric turbulence and airplane gust loads for application in spectral calculations

Description: The available information on the spectrum of atmospheric turbulence is first briefly reviewed. On the basis of these results, methods are developed for the conversion of available gust statistics normally given in terms of counts of gusts or acceleration peaks into a form appropriate for use in spectral calculations. The fundamental quantity for this purpose appears to be the probability distribution of the root-mean-square gust velocity. Estimates of this distribution are derived from data for a number of load histories of transport operations; also, estimates of the variation of this distribution with altitude and weather condition are derived from available data and the method of applying these results to the calculation of airplane gust-response histories in operations is also outlined. (author).
Date: January 1, 1956
Creator: Press, Harry; Meadows, May T & Hadlock, Ivan
Partner: UNT Libraries Government Documents Department