Analysis of Effects of Spanwise Variations of Gust Velocity on a Vane-controlled Gust-alleviation System
Analysis of Effects of Spanwise Variations of Gust Velocity on a Vane-controlled Gust-alleviation System

Author: L. Keith Barker

Publisher:

Published: 1971

Total Pages: 36

ISBN-13:

DOWNLOAD EBOOK

An analysis has been made of the effects of spanwise variations of gust velocity in isotropic turbulence on a gust-alleviation system which employs an angle-of-attack vane mounted ahead of the wing to sense the vertical gust velocity. The wing flaps were moved in response to the vane deflection by a linear second-order servosystem to produce a lift opposite to that produced by the gust. Consideration of spanwise variation of gusts has indicated design parameters (gain and natural frequency of flap servosystem and vane location) that give substantial reduction of the lift due to gusts.

Analysis of a Vane-controlled Gust-alleviation System
Analysis of a Vane-controlled Gust-alleviation System

Author: Robert W. Boucher

Publisher:

Published: 1956

Total Pages: 45

ISBN-13:

DOWNLOAD EBOOK

A theoretical study using an electronic analog computer has been made of the response to step gusts of an airplane equipped with a system in which modified wing flaps and a modified elevator are operated to reductions accelerations in rough air. These surfaces are actuated by an automatic control system in response to the indications of an angle-of-attack vane. The effect of interconnection of the flap operating mechanism with the pilot's control system is also included in the study.

Effect of Limited Amplitude and Rate of Flap Motion on Vane-controlled Gust-alleviation System
Effect of Limited Amplitude and Rate of Flap Motion on Vane-controlled Gust-alleviation System

Author: L. Keith Barker

Publisher:

Published: 1972

Total Pages: 52

ISBN-13:

DOWNLOAD EBOOK

An airplane (light transport type) is assumed to be in level flight (no pitching) through atmospheric turbulence which has a mean-square vertical gust intensity of 9.3 (m/sec)sq. The power spectral density of the vertical acceleration due to gusts is examined with and without a gust-alleviation system in operation. The gust-alleviation system consisted of wing flaps that were used in conjunction with a vane mounted ahead of the airplane to sense the vertical gust velocity. The primary purpose of this study was to examine the change in the effectiveness of the gust-alleviation system when the flap motion is limited in amplitude and rate. The alleviation system was very effective if no restrictions were placed on flap motion (rate and amplitude). Restricting the flap amplitude to 0.5 radian did not appreciably change the effectiveness. However, restricting the flap rate did reduce the gust alleviation, and restricting the flap rate to 0.25 rad/sec actually caused the alleviation system to increase the vertical acceleration above that for the no-alleviation situation. Based upon this analysis, rate limiting appears to be rather significant in gust-alleviation systems designed for passenger comfort.

An Experimental Study of a Vane Controlled Jet Flap Gust Alleviation System
An Experimental Study of a Vane Controlled Jet Flap Gust Alleviation System

Author: Leonard Joseph Deal (Jr)

Publisher:

Published: 1974

Total Pages: 77

ISBN-13:

DOWNLOAD EBOOK

An experimental effort to demonstrate the feasibility of an active gust alleviator using a fluidically actuated jet flap control system was undertaken. The wing model had a variable deflection jet at the trailing edge and was free to move in pitch only. A vane mounted ahead of the wing served as gust sensor and provided the signal which controlled jet angle. Experimental results showed the system capable of alleviating up to 92% of the motion caused by a sinusodial gust at constant amplitude. RMS values of wing rotation angle were found to be 0.68 degrees with control off and 0.29 degrees with control on when excited by a random two-dimensional gust. (Author).