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An investigation of large amplitude wing-rock

Published online by Cambridge University Press:  04 July 2016

C. Evans
C. Evans*
Affiliation:
Department of Aeronautical EngineeringUniversity of Bristol
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Summary

The large amplitude wing-rock of a ground attack aircraft was investigated by the use of a small perturbation, linear stability analysis and a non-linear simulation of the aircraft dynamics. The linear stability analysis compared the results from a complete 6 degrees-of-freedom (DOF) coupled equation set with the results obtained using a 3-DOF dynamic stability axis set. The results showed an oscillatory instability that was caused by frequency coalescence of the primary pitch and yaw modes.

The simulation produced a rolling motion similar in nature to wing-rocks experienced in flight. The large amplitude oscillation was generated by the non-linear variations of the aerodynamic loads rather than by the instability predicted by the linearised dynamics. Specifically, the appearance of nonzero lateral moments at zero sideslip as well as shock-induced jumps in the rolling moment against sideslip curves were major contributors to the motion. These features of the static aerodynamic data are thus considered better warnings of the possibility of large amplitude wing-rock than is the negatively damped Dutch roll oscillation predicted by the linearised analysis.

Type
Research Article
Information
The Aeronautical Journal , Volume 88 , Issue 873 , March 1984 , pp. 51 - 57
Copyright
Copyright © Royal Aeronautical Society 1984 

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References

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