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Aircraft Behaviour in a Vertical Gradient of Wind Velocity

Published online by Cambridge University Press:  07 June 2016

J. K. Zbrożek
J. K. Zbrożek*
Affiliation:
Royal Aircraft Establishment, Bedford
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Summary

The stability of the phugoid motion of an aircraft in the presence of wind shear is investigated. The effect of the wind shear on the phugoid frequency increases with increasing aircraft speed and can be stabilising or destabilising, depending on the aircraft orientation relative to the wind shear. The destabilising effect of wind shear is alleviated by the stabilising effect of the density gradient of the atmosphere. At the most critical combination of speed and altitude a strong wind shear may lead to divergence, with a time to double amplitude of the order of 10-15 seconds.

A numerical study of the aircraft motion with controls fixed when descending through a wind profile similar to that in a jet stream indicates that the increase in the aircraft indicated speed can be of the same magnitude as, or larger than, the maximum wind velocity increment in the jet stream core. However, as the time to reach the excess speed is of the order of one minute, the actual behaviour of the aircraft strongly depends on the pilot's action and thus is not fully predictable by theoretical analysis.

Type
Research Article
Information
Aeronautical Quarterly , Volume 14 , Issue 3 , August 1963 , pp. 265 - 278
Copyright
Copyright © Royal Aeronautical Society. 1963

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References

1. Grosso, V. A. Analytical Investigation of the Effect of Vertical Wind Gradients on High Performance Aircraft. Air Research and Development Command, AFFTC-TR-61-11, March 1961.Google Scholar
2. Oddie, B. C. V. Sources of Data for the Derivation of Vertical Gradients of Wind Velocity Over Great Britain. A.R.C. 21,008, May 1959.Google Scholar
3. Vaughan, W. W. Idealized Wind Profiles Applicable for the Study of Vehicle Performance Between 60 km and 80 km Altitude, Cape Canaveral, Florida. N.A.S.A. T.N. D-560, December 1960.Google Scholar
4. Crossley, A. F. Extremes of Wind Shear. Meteorological Office, Scientific Paper No. 17, Her Majesty's Stationery Office, 1962.Google Scholar
5. Neumark, S. Dynamic Longitudinal Stability in Level Flight, Including the Effects of Compressibility and Variations of Atmospheric Characteristics with Height. A.R.C. 11, 726, May 1948.Google Scholar