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The Flutter of a Helicopter Rotor Blade in Forward Flight

Published online by Cambridge University Press:  07 June 2016

C. W. Stammers
C. W. Stammers*
Affiliation:
Westland Helicopters Ltd, Yeovil*
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Summary

The nature of flapping torsion flutter of a helicopter blade in forward flight is discussed. The essential complication in the analysis is the presence of periodic coefficients in the equations of motion; approximate solutions are obtained by use of a perturbation procedure. An unusual behaviour of the flutter equations which occurs when the fundamental frequency of flutter is a half-integer multiple of rotational speed is studied. Two different instability mechanisms can be distinguished and are related to the two energy sources in the system, namely the rotation of the rotor and the forward speed of the helicopter. It is found that forward flight can have a significant stabilising influence on flutter and that, as the tip speed ratio increases, flutter occurs predominantly at half-integer frequencies. The results are confirmed by the use of a numerical method.

Type
Research Article
Information
Aeronautical Quarterly , Volume 21 , Issue 1 , February 1970 , pp. 18 - 48
Copyright
Copyright © Royal Aeronautical Society. 1970

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References

1. Foote, W. R., Poritsky, H. and Slade, J. J. Critical speeds of a rotor with unequal shaft flexibilities, mounted in bearings of unequal flexibility—I. Journal of Applied Mechanics, Vol. 10, Transactions, American Society of Mechanical Engineers, Vol. 65, pp. A77–A84, June 1943.Google Scholar
2. Brosens, P. J. and Crandall, S. H. Whirling of unsymmetrical rotors. Journal of Applied Mechanics, Transactions, American Society of Mechanical Engineers, pp. 355–362, September 1961.Google Scholar
3. Coleman, R. P. and Feingold, A. M. Theory of self-excited mechanical oscillations of helicopter rotors with hinged blades. Chapter 3, NACA Report 1351, 1958.Google Scholar
4. Horvay, G. Rotor blade flapping motion. Quarterly of Applied Mathematics, Vol. 5, No. 2, pp. 149–167, July 1947.Google Scholar
5. Horvay, G. and Yuan, S. W. Stability of rotor blade flapping motion when the hinges are tilted. Journal of the Aeronautical Sciences, Vol. 14, pp. 583–593, October 1947.CrossRefGoogle Scholar
6. Shutler, A. G. and Jones, J. P. The stability of rotor blade flapping motion. ARC R&M3178, 1961.Google Scholar
7. Lowis, O. J. The stability of rotor blade flapping motion at high tip speed ratios. ARC R & M 3544, 1963.Google Scholar
8. Frazer, R. A., Duncan, W. J. and Collar, A. R. Elementary matrices, Section 7. 7, p. 219, Cambridge University Press, 1938.Google Scholar
9. Jones, J. P. Some investigations into the flutter and vibration of hinged rotor blades, p. 108, PhD Thesis, University of Southampton, 1956.Google Scholar
10. Ince, E. L. Ordinary differential equations, Section 15. 7, p. 381. Longmans Green, 1927.Google Scholar
11. McLachlan, N. W. Theory and application of Mathieu functions, Oxford University Press, 1947.Google Scholar