An Experimental Investigation of the Effect of Wheel Prerotation on Landing-gear Drag Loads

An Experimental Investigation of the Effect of Wheel Prerotation on Landing-gear Drag Loads
Author: Dexter M. Potter
Publisher:
Total Pages: 19
Release: 1954
Genre: Airplanes
ISBN:

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The effect of prerotation on the wheel spin-up drag loads on a small landing gear during landings has been investigated by means of tests in the Langley impact basin. A series of simulated landings with various amounts of prerotation was made with a dropping weight of 2,500 pounds and a forward speed of 85 fps at a strut angle of 15 degrees. The results were compared with data from previous tests made with various forward speeds and no prerotation. The effect of prerotation on the maximum drag load was the smae as the effect of reducting the horizontal velocity. At low horizontal velocities any amount of prerotation reduced the drag load. The reduction became greater as the vertical velocity increased. Reductions in drag load resulting from prerotation were accompanied by reductions in vertical load. At high forward speeds somewhat beyond the range where prerotation was tested, however, consideration of existing data indicated that large amounts of prerotation would have to be used in order to assure a reduction in drag load. In this higher speed region, insufficient prerotation could actually increase the drag load. The wheel spin-up process appeared to be a small factor in tire wear and prerotation therefore should not materially increase tire life.

An Experimental Investigation of Wheel Spin-up Drag Loads

An Experimental Investigation of Wheel Spin-up Drag Loads
Author: Benjamin Milwitzky
Publisher:
Total Pages: 18
Release: 1954
Genre: Airplanes
ISBN:

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This paper presents some recently obtained information on landing-gear applied drag loads and on the nature of wheel spin-up phenomenon in landing, based on a program of tests under controlled conditions in the Langley impact basin. In particular, a study has been made of the nature and variation of the coefficient of friction between the tire and the runway during the wheel spin-up process. Also, comparisons have been made of the various results obtained in impacts with forward speed, impacts with forward speed and reverse wheel rotation, spin-up drop tests, and impacts with forward speed and wheel prerotation.

Technical Note

Technical Note
Author:
Publisher:
Total Pages: 402
Release: 1954
Genre: Aeronautics
ISBN:

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Index of NACA Technical Publications

Index of NACA Technical Publications
Author: United States. National Advisory Committee for Aeronautics
Publisher:
Total Pages: 1338
Release: 1955
Genre: Aeronautics
ISBN:

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Theoretical and Analog Studies of the Effects of Nonlinear Stability Derivatives on the Longitudinal Motions of an Aircraft in Response to Step Control Deflections and to the Influence of Proportional Automatic Control

Theoretical and Analog Studies of the Effects of Nonlinear Stability Derivatives on the Longitudinal Motions of an Aircraft in Response to Step Control Deflections and to the Influence of Proportional Automatic Control
Author: Benjamin Milwitzky
Publisher:
Total Pages: 348
Release: 1955
Genre: Aeronautics
ISBN:

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Wind-tunnel Studies of the Performance of Multirotor Configurations

Wind-tunnel Studies of the Performance of Multirotor Configurations
Author: Richard C. Dingeldein
Publisher:
Total Pages: 650
Release: 1954
Genre: Rotors (Helicopters)
ISBN:

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The power requirements measured in static thrust and in level forward flight are presented for two helicopter rotor configurations. One is a coaxial rotor arrangement having the rotors spaced approximately 19 percent of the rotor radius; the other is a tandem configuration in which the rotor-shaft spacing is 3 percent greater than the rotor daimater and in which the rotors lie in the same plane. The experimental meausrements are compared with the results of calculations based on existing NACA single-rotor theory.

Research Abstracts

Research Abstracts
Author: United States. National Advisory Committee for Aeronautics
Publisher:
Total Pages: 442
Release:
Genre: Aeronautics
ISBN:

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Report

Report
Author: United States. National Advisory Committee for Aeronautics
Publisher:
Total Pages: 44
Release: 1955
Genre: Aeronautics
ISBN:

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