Technical Report Archive and Image Library (TRAIL) - 184 Matching Results

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Accelerations in Landing with a Tricycle-Type Landing Gear

Description: In connection with the application of stable tricycle-type landing gears to transport airplanes, the question arises as to whether certain passengers may not experience relatively great accelerations in an emergency landing. Since the main landing wheels are behind the center of gravity in this type of gear, a hard-braked landing will cause immediate nosing down of the airplane and, when this motion is stopped due to the front wheel striking the ground, there will be some tendency for the rearmost passengers to be thrown out of their seats, The provided rough calculations are designed to show the magnitudes of the various reactions experienced in a severe landing under these circumstances.
Date: February 1937
Creator: Jones, Robert T.
Partner: UNT Libraries Government Documents Department

Aerodynamic characteristics of NACA 23012 and 23021 airfoils with 20-percent-chord external-airfoil flaps of NACA 23012 section

Description: Report presents the results of an investigation of the general aerodynamic characteristics of the NACA 23012 and 23021 airfoils, each equipped with a 0.20c external flap of NACA 23012 section. The tests were made in the NACA 7 by 10-foot and variable-density wind tunnels and covered a range of Reynolds numbers that included values corresponding to those for landing conditions of a wide range of airplanes. Besides a determination of the variation of lift and drag characteristics with position of the flap relative to the main airfoil, complete aerodynamic characteristics of the airfoil-flap combination with a flap hinge axis selected to give small hinge moments were measured in the two tunnels. Some measurements of air loads on the flap itself in the presence of the wing were made in the 7 by 10-foot wind tunnel.
Date: 1937~
Creator: Platt, Robert C & Abbott, Ira H
Partner: UNT Libraries Government Documents Department

Air propellers in yaw

Description: Report presents the results of tests conducted at Stanford University of a 3-foot model propeller at four pitch settings and at 0 degree, 10 degrees, 20 degrees, and 30 degrees yaw.
Date: January 1, 1937
Creator: Lesley, E P; Worley, George F & Moy, Stanley
Partner: UNT Libraries Government Documents Department

Aircraft accidents.method of analysis

Description: This report is a revision of NACA-TR-357. It was prepared by the Committee on Aircraft Accidents. The purpose of this report is to provide a basis for the classification and comparison of aircraft accidents, both civil and military.
Date: January 1, 1937
Partner: UNT Libraries Government Documents Department

Aircraft compass characteristics

Description: From Summary: "A description of the test methods used at the National Bureau of Standards for determining the characteristics of aircraft compasses is given. The methods described are particularly applicable to compasses in which mineral oil is used as the damping liquid. Data on the viscosity and density of certain mineral oils used in United States Navy aircraft compasses are presented. Results of flight tests are presented."
Date: January 1, 1937
Creator: Peterson, John B. & Smith, Clyde W.
Partner: UNT Libraries Government Documents Department

Alternating-current equipment for the measurement of fluctuations of air speed in turbulent flow

Description: From Summary: "Recent electrical and mechanical improvements have been made in the equipment developed at the National Bureau of Standards for measurement of fluctuations of air speed in turbulent flow. Data useful in the design of similar equipment are presented. The design of rectified alternating-current power supplies for such apparatus is treated briefly, and the effect of the power supplies on the performance of the equipment is discussed."
Date: March 1937
Creator: Mock, W. C., Jr.
Partner: UNT Libraries Government Documents Department

An analysis of the factors that determine the periodic twist of an autogiro rotor blade, with a comparison of predicted and measured results

Description: Report presents an analysis of the factors that determine the periodic twist of a rotor blade under the action of the air forces on it. The results of the analysis show that the Fourier coefficients of the twist are linear expressions involving only the tip-speed ratio, the pitch setting, the inflow coefficient, the pitching-moment coefficient of the blade airfoil section, and the physical characteristics of the rotor blade and machine.
Date: April 14, 1937
Creator: Wheatley, John B
Partner: UNT Libraries Government Documents Department

An analytical and experimental study of the effect of periodic blade twist on the thrust, torque, and flapping motion of an autogiro rotor

Description: An analysis is made of the influence on autogiro rotor characteristics of a periodic blade twist that varies with the azimuth position of the rotor blade and the results are compared with experimental data. The analysis expresses the influence of this type of twist upon the thrust, torque, and flapping motion of the rotor. The check against experimental data shows that the periodic twist has a pronounced influence on the flapping motion and that this influence is accurately predicted by the analysis. The influence of the twist upon the thrust and torque could be demonstrated only indirectly, but its importance is indicated.
Date: 1937
Creator: Wheatley, John B
Partner: UNT Libraries Government Documents Department

The apparent width of the plate in compression

Description: This report discusses an investigation that treats the load capacity of a rectangular plate stressed in compression on one direction (x) beyond the buckling limit and the plate is rotatable (i.e., free from moments) supported at all four sides by bending-resistant beams.
Date: July 1937
Creator: Marguerre, Karl
Partner: UNT Libraries Government Documents Department

Asbestos

Description: From Introduction: "This report covers the essential features of the asbestos industry, including occurrence, production, mining, milling, utilization, international trade, and marketing."
Date: 1937
Creator: Bowles, Oliver
Partner: UNT Libraries Government Documents Department

Auto-ignition and combustion of diesel fuel in a constant-volume bomb

Description: Report presents the results of a study of variations in ignition lag and combustion associated with changes in air temperature and density for a diesel fuel in a constant-volume bomb. The test results have been discussed in terms of engine performance wherever comparisons could be drawn. The most important conclusions drawn from this investigation are: the ignition lag was essentially independent of the injected fuel quantity. Extrapolation of the curves for the fuel used shows that the lag could not be greatly decreased by exceeding the compression-ignition engines. In order to obtain the best combustion and thermal efficiency, it was desirable to use the longest ignition lag consistent with a permissible rate of pressure rise.
Date: October 5, 1937
Creator: Selden, Robert F
Partner: UNT Libraries Government Documents Department

Ball-Mill Grinding

Description: Report issued by the Bureau of Mines discussing the ball-mill grinding technique. Different methods of mill grinding are presented and compared with ball-mill grinding. This report includes tables, illustrations, and photographs.
Date: 1937
Creator: Coghill, Will H. & DeVaney, Fred D.
Partner: UNT Libraries Government Documents Department

The behavior of thin-will monocoque cylinders under torsional vibration

Description: Curves of forced frequency against amplitude are presented for the conditions where the forced frequency is both increased and decreased into the resonant range. On the basis of these curves it is shown that the practical resonance frequency is the point where wrinkling first occurs and that the resonance frequency will be subject to considerable travel once permanent wrinkles appear in the vibrating shell. The decreasing mode of striking resonance is found to be by far the most destructive condition.
Date: August 1, 1937
Creator: Pekelsma, Robert E
Partner: UNT Libraries Government Documents Department

Bending tests of circular cylinders of corrugated aluminum-alloy sheet

Description: Bending tests were made of two circular cylinders of corrugated aluminum-alloy sheet. In each test failure occurred by bending of the corrugations in a plane normal to the skin. It was found, after analysis of the effect of short end bays, that the computed stress on the extreme fiber of a corrugated cylinder is in excess of that for a flat panel of the same basic pattern and panel length tested as a pin-ended column. It is concluded that this increased strength was due to the effects of curvature of the pitch line. It is also concluded from the tests that light bulkheads closely spaced strengthen corrugated cylinders very materially.
Date: March 1, 1937
Creator: Buckwalter, John C.; Reed, Warren D. & Niles, Alfred S.
Partner: UNT Libraries Government Documents Department

Blower cooling of finned cylinders

Description: Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches.
Date: January 1, 1937
Creator: Schey, Oscar W. & Ellerbrock, Herman H., Jr.
Partner: UNT Libraries Government Documents Department

Burning of Coal and Coke Treated with Small Quantities of Chemicals

Description: Report issued by the Bureau of Mines over studies conducted on the use of chemicals to enhance the burning of fuels. Methods and results of the studies are presented and discussed. This report includes tables, illustrations, and photographs.
Date: 1937
Creator: Nicholls, Percy; Rice, W. E.; Landry, B. A. & Reid, W. T.
Partner: UNT Libraries Government Documents Department

Calculated and measured pressure distributions over the midspan section of the NACA 4412 airfoil

Description: Pressures were simultaneously measured in the variable-density tunnel at 54 orifices distributed over the midspan section of 5 by 30 inch rectangular model of the NACA 4412 airfoil at 17 angles of attack ranging from -20 degrees to 30 degrees at a Reynolds number of approximately 3,000,000. Accurate data were thus obtained for studying the deviations of the results of potential-flow theory from measured results. The results of the analysis and a discussion of the experimental technique are presented.
Date: January 1, 1937
Creator: Pinkerton, Robert M
Partner: UNT Libraries Government Documents Department

Characteristics of six propellers including the high-speed range

Description: This investigation is part of an extensive experimental study that has been carried out at full scale in the NACA 20-foot tunnel, the purpose of which has been to furnish information in regard to the functioning of the propeller-cowling-nacelle unit under all conditions of take-off, climbing, and normal flight. This report presents the results of tests of six propellers in the normal and high-speed flight range and also includes a study of the take-off characteristics.
Date: January 1, 1937
Creator: Theodorsen, Theodore; Stickle, George W & Brevoort, M J
Partner: UNT Libraries Government Documents Department