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The Aerodynamics of the Helicopter in Forward Flight

Published online by Cambridge University Press:  28 July 2016

Extract

Existing methods of estimating the blade loadings on a helicopter rotor in forward flight have suffered from the necessity of using false simplifying assumptions in order to make possible an analytical approach. The following list gives the most usual of these assumptions:

  1. (i) Blades have no twist or taper, or are twisted and tapered in a particular way.

  2. (ii) The coning angle is small enough to neglect the resulting changes in velocities, angles, and so on.

  3. (iii) The disc is horizontal.

  4. (iv) The components of velocity parallel to the blade length may be neglected, and forces are calculated for and act with reference to the velocities normal to the blade length.

  5. (v) There is no variation in downwash over the disc, or the variation is capable of simple expression.

  6. (vi) The blades extend from hub, and tip losses are neglected.

  7. (vii) The blades have pure flapping hinges and the analogy between flapping and feathering enables loadings calculated for flapping blades to be referred to a “hingeless” rotor system.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1956

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References

1. Squire, H. B. The Flight of a Helicopter. R.& M. 1730.Google Scholar
2. Glauert, H. A General Theory of the Autogiro. R. & M. 1111.Google Scholar
3. Gessow, A. and Myers, G. C. Aerodynamics of the Helicopter. Macmillan.Google Scholar
4. Wald, Q. (1943). Rapid Estimation of Helicopter Performance. Journal of the Aeronautical Sciences. April 1943.Google Scholar
5. O'hara, F. A Method of Performance Reduction for Helicopters. A.F.E.E. Res. 26.Google Scholar
6. Keith-Lucas, D. (1952). The Shape of Wings to Come. British Association Meeting, Belfast, September 1952.Google Scholar
7. Meyer Drees, J. A Theory of Airflow through Rotors and its Application to some Helicopter Problems. Journal of Helicopter Association of Great Britain, Vol. 3, No. 2.Google Scholar
8. Collingbourne, J. R. The Estimation of Lift-Curve Slope at Subsonic Mach Numbers. Tech. Note Aero. 2145.Google Scholar
9. Weber, J. and Brebner, G. G. A Simple Estimate of the Profile Drag of Swept Wings. Tech. Note Aero. 2168.Google Scholar
10. Lock, C. N. H. and Yeatman, D. Tables for Use in an Improved Method of Airscrew Strip Theory Calculations. R. & M. 1674.Google Scholar
11. Multhopp, H. On the Maximum Lift Coefficient of Aerofoil Sections. A.R.C. 12, 115.Google Scholar
12. Jacobs, E. N. and Sherman, A. Aerfoil Section Characteristics as Affected by Variations of Reynolds Number. N.A.C.A. Report 586.Google Scholar
13.Hoerner, S. F. Aerodynamic Drag. Otterbein Press.Google Scholar
14.A Simplified Theoretical Method of Determining the Characteristics of a Lifting Motor in Forward Flight. N.A.C.A. Report 716.Google Scholar
15. Marshall, J. Investigation into the Effects of Tip-losses on the Thrust and Torque Loadings on a Helicopter Rotor in Forward Flight. S. B. & H. Ltd. Aerodynamics Report No. 69.Google Scholar
16. Squire, H. B., Fail, R. A. and Eyre, R. C. W. Windtunnel Tests on a 12 ft. Diameter Helicopter Rotor. Report Aero. 2324.Google Scholar