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Flutter of Wings with Localised Masses

Published online by Cambridge University Press:  28 July 2016

W. G. Molyneux*
Affiliation:
Royal Aircraft Establishment, Farnborough

Summary

From a general consideration of the available data on the flutter of wings with localised masses certain deductions are made as to the possible types of flutter that can occur. On the basis of these deductions it is shown that there is an optimum choice of modes for use in flutter calculations for wings with localised masses. These modes are obtained with artificial constraints imposed on the wing at the localised mass section fixing the wing at this section in translation and/or pitch. It is deduced that for certain mass locations types of flutter are obtained that are insensitive to increase of localised mass, beyond a certain value, with flutter speeds considerably greater than that of the fixed root bare wing. It is also deduced that for the majority of aircraft configurations the maximum flutter speeds for these types of flutter will be realised when the localised mass is in the region of two-thirds semi-span from the root. A limited theoretical investigation is made for a rectangular unswept uniform wing with symmetric and antisymmetric body freedoms, to illustrate and confirm the conclusions derived from general considerations. At the same time the investigation shows that an ill placed localised mass can reduce the wing flutter speed to a very low value.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1957

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References

1. Lambourne, N. C. and Weston, D. (1944). An Experimental Investigation of the Effect of Localised Masses on the Flutter and Resonances of a Model Wing. Unpublished N.P.L. Paper, A.R.C.Google Scholar
2. Gaukroger, D. R. (1953). Wind Tunnel Tests on the Effect of a Localised Mass on the Flutter of Swept-back Wings with Fixed Root. Unpublished M.O.S. Report, A.R.C.Google Scholar
3. Nelson, H. C. and Tommassoni, J. E. (1949). Experimental Investigation of the Effects of Sweepback on the Flutter of a Uniform Cantilever Wing with a Variably Located Concentrated Mass. N.A.C.A. RML9F24.Google Scholar
4. Runyan, H. L. and Watkins, C. E. (1948). Flutter of a Uniform Wing with an Arbitrarily-Placed Mass According to Differential Equation Analysis, and Comparison With Experiment. N.A.C.A. T.N. 1848, March 1948.Google Scholar
5. Woolston, D. S. and Runyan, H. L. (1949). Appraisal of a Method of Flutter Analysis Based on Chosen Modes by Comparison With Experiment for the Case of Large Mass Coupling. N.A.C.A. T.N. 1902, June 1949.Google Scholar
6. Sewall, J. L. (1951). Experimental and Analytical Investigation of the Flutter of a Non-Uniform Sweepback Cantilever Wing With Two Concentrated Weights. N.A.C.A. RML51H09a.Google Scholar
7. Gaukroger, D. R. (1953). Wind Tunnel Tests on Antisymmetric Flutter of Swept-back Wings with Rolling Body Freedom. R. & M. 2911.Google Scholar
8. Gaukroger, D. R. and Nixon, D. (1955). Wind Tunnel Tests on Antisymmetric Flutter of a Delta Wing With Rolling Body Freedom. Unpublished M.O.S. Report.Google Scholar
9. Gaukroger, D. R. (1952). Wind Tunnel Tests on Symmetric Flutter of Swept Back Wings, Including the Tailplane Effect. R. & M. 2911.Google Scholar
10. Gaukroger, D. R., Chapple, E. W. and Milln, A. Wind Tunnel Flutter Tests on a Model Delta Wing Under Fixed and Free Root Conditions. R. & M. 2826.Google Scholar
11. Gaukroger, D. R. and Chapple, E. W. (1956). Wind Tunnel Tests on the Effect of Body Freedoms on the Flutter of a Model Wing Carrying a Localised Mass. Unpublished M.O.S. Report.Google Scholar
12. Lambourne, N. C. (1947). An Experimental Investigation on the Flutter Characteristics of a Model Flying Wing. Unpublished N.P.L. Paper.Google Scholar
13. Smith, F. and Hicks, W. D. T. (1953). An Electronic Simulator for the Solution of Flutter Problems in Six Degrees of Freedom or Less. Unpublished M.O.S. Report.Google Scholar
14. Gustafson, P. N., Stokey, W. F. and Zorowski, C. F. (1954). The Effect of Tip Removal on the Natural Vibrations of Uniform Cantilever Triangular Plates. Journal of the Institute of the Aeronautical Sciences, September 1954.Google Scholar
15. Minhinnick, I. T. and Yarwood, J. (1943). Interim Note on the Theoretical Effect of an Engine Mass on Wing Flutter. Unpublished M.O.S. Report.Google Scholar
16. Frazer, R. A. (1943). Interim Note on a Theoretical Investigation of the Influence of Mass on Wing Flutter. Unpublished N.P.L. Paper.Google Scholar
17. Seal, D. M. and Broadbent, E. G. (1956). Flutter Calculations Using Arbitrary Modes on a Wing With Tip Mass. Unpublished M.O.S. Paper.Google Scholar
18. Houbolt, J. C. (1945). Investigation of Antisymmetrical Body Freedom Flutter for Swept Wing Aircraft. Unpublished M.O.S. Report.Google Scholar
19. Seal, D. M. (1954). A Note on Wing Flutter of the Meteor 8 Carrying Underwing Bombs. Unpublished M.O.S. Report.Google Scholar