The Influence of Vertical Wind Gradients on the Longitudinal Motion of Airplanes
The Influence of Vertical Wind Gradients on the Longitudinal Motion of Airplanes

Author: Joseph Gera

Publisher:

Published: 1971

Total Pages: 28

ISBN-13:

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The present study is an attempt to make an assessment of the influence of wind shear on the longitudinal motion of airplanes. It was assumed that the wind is completely horizontal and its speed varies linearly with altitude. It is shown quantitatively that both glide and climb performance are influenced by wind shear and that trimmed flight at constant airspeed, attitude, and with fixed controls is along a parabolic path relative to the ground. The problem of the landing approach in a wind shear is examined in some detail. Small disturbance theory indicates no wind-shear effect on the short-period motion and the time for the phugoid to damp to half amplitude but the phugoid frequency and damping ratio vary considerably with wind shear. A nondimensional quantity which depends on the wind shear and airspeed is shown to be a fundamental parameter influencing the longitudinal dynamic behavior of the airplane.

Aeronautical Engineering
Aeronautical Engineering

Author:

Publisher:

Published: 1971

Total Pages: 580

ISBN-13:

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A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA)

Influence of Wind Shear on the Aerodynamic Characteristics of Airplanes
Influence of Wind Shear on the Aerodynamic Characteristics of Airplanes

Author: Dan D. Vicroy

Publisher:

Published: 1988

Total Pages: 78

ISBN-13:

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The aerodynamic effect of shear flow through a series of sensitivity studies of the wind velocity gradients and wing planform geometry parameters is investigated and characterized. The wind shear effect is computed using a modified vortex-lattice computer program and characterized through the formulation of wind shear aerodynamic coefficients. The magnitudes if the aerodynamic effects are demonstrated by computation of the resultant change in the aerodynamics of a conventional wing and horizontal stability configuration on a fixed flight path through a simulated microburst. The results indicate that as much as 20 percent of the control authority of the airplane may be required to counteract the wind-shear-induced forces and moments in the microburst environment.