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  Partner: UNT Libraries Government Documents Department
 Decade: 1940-1949
 Year: 1940
 Month: April
A full-scale investigation of the effect of several factors on the shimmy of cantering wheels

A full-scale investigation of the effect of several factors on the shimmy of cantering wheels

Date: April 1, 1940
Creator: Howard, Walter B , Jr
Description: A full-scale investigation has been conducted to determine the effect of various factors on the shimmy of castering wheels. The factors considered were the geometric arrangement, the tire types, the variations of load, the spindle moment of inertia, and the tire inflation. A comparison of the results of the present investigation with those calculated from existing theory was made. The constants needed in the calculations to determine the damping required for a castering wheel were measured. The results indicate that solid friction appears to be impracticable as the sole damping agent for castering nose wheels on large airplanes. Also it was concluded that the existing theory is adequate for calculating the damping required to prevent shimmy. The caster angle and the spindle moment of inertia were found to influence the solid friction required to prevent shimmy. The effect of variations in the type and the pressure of the tire was insignificant.
Contributing Partner: UNT Libraries Government Documents Department
High-Speed Tests of a Model Twin-Engine Low-Wing Transport Airplane

High-Speed Tests of a Model Twin-Engine Low-Wing Transport Airplane

Date: April 1, 1940
Creator: Becker, John V. & Leonard, Lloyd H.
Description: Force tests were made of a 1/8-scale model of a twin-engine low-wing transport airplane in the NACA 8-foot high-speed wind tunnel to investigate compressibility and interference effects at speeds up to 450 miles per hour. In addition to tests of the standard arrangement of the model tests were made with several modifications designed to reduce the drag and to increase the critical speed. The results show serious increases in drag at critical speeds below 450 miles per hour due to the occurrence of compressibility burbles on the standard radial-engine cowlings, on sections of the wing as a result of wing-nacelle interference, and on the semi-retracted main landing wheels. The critical speed at which the shock occurred on the standard cowlings was 20 miles per hour lower in the presence of the fuselage than in the presence of the wing only. The drag of the complete model was reduced 25% at 300 miles per hour by completely retracting the landing gear, fairing the windshield irregularities, and substituting streamline nacelles (with allowance made for the proper amount of cooling-air flow) for the standard nacelle arrangement. The values of the critical Mach number were extended from 0.47 to 0.60 as a result of ...
Contributing Partner: UNT Libraries Government Documents Department
The lead susceptibility of fuels and its dependence on the chemical composition

The lead susceptibility of fuels and its dependence on the chemical composition

Date: April 1, 1940
Creator: Widmaier, O
Description: The fact that by the use of tetraethyl lead a number of otherwise unsuitable fuels could be made to meet engine requirements was not sufficiently appreciated. While use of tetraethyl lead is limited, the addition of special leaded fuels that increase the octane number is a requirement for many fuels. In this connection, the extent to which the action of tetraethyl lead through the addition of knock-resistant hydrocarbons to the base gasoline is influenced, is quite important. To the elucidation of this problem and of the storage stability of leaded fuels, the present report is dedicated.
Contributing Partner: UNT Libraries Government Documents Department
Measurements and analysis of the motion of a Canard airplane model in gusts

Measurements and analysis of the motion of a Canard airplane model in gusts

Date: April 1, 1940
Creator: Donely, Philip; Pierce, Harold B & Pepoon, Philip W
Description: None
Contributing Partner: UNT Libraries Government Documents Department
Powdery mildew of ornamental plants.

Powdery mildew of ornamental plants.

Date: April 1940
Creator: Weiss, Freeman.
Description: Describes the powdery mildew fungus and methods for its control.
Contributing Partner: UNT Libraries Government Documents Department
A study of unsymmetrical-loading conditions

A study of unsymmetrical-loading conditions

Date: April 1, 1940
Creator: Pearson, Henry A
Description: The force variation along the wing span under combined normal and angular accelerations is considered. Non dimensional curves of section load, shear, and moment are given for: (1) the air load that produces a normal acceleration; (2) the accompanying wing weight and normal inertia loads; (3) aileron and gust air loads that produce angular acceleration; (4) the angular inertia load of the wing. The required aerodynamic load distributions have been obtained by use of wing theory, and the wing inertia distributions are based on an analysis of wing-weight data. Several examples are included to illustrate the effect of wing taper and aileron span on the total shears and moments at any section along the span.
Contributing Partner: UNT Libraries Government Documents Department
Theory of ballooning.

Theory of ballooning.

Date: April 25, 1940
Creator: United States. War Dept.
Description: A general guide to piloting a free balloon.
Contributing Partner: UNT Libraries Government Documents Department
The torsion of box beams with one side lacking

The torsion of box beams with one side lacking

Date: April 1, 1940
Creator: Cambilargiu, E
Description: The torsion of box beams of rectangular section, the edges of which are strengthened by flanges, and of which one side is lacking, is analyzed by the energy method. The torsional stresses are generally taken up by the bending of the two parallel walls, the rigidity of which is augmented by the third wall. The result was checked experimentally on duralumin and plywood boxes. The torsion recorded was 10 to 30 percent less than that given by the calculation, owing to self-stiffening.
Contributing Partner: UNT Libraries Government Documents Department
Work of the United States Forest Service.

Work of the United States Forest Service.

Date: April 1940
Creator: United States. Forest Service.
Description: Discusses forest depletion and provides a history of forest conservation efforts by the United States government. Describes the work of the the Civilian Conservation Corps and other emergency projects, and discusses forest and range research.
Contributing Partner: UNT Libraries Government Documents Department