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The Aerodynamics of the Helicopter in Forward Flight

Published online by Cambridge University Press:  28 July 2016

E. N. Brailsford
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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
Information
The Aeronautical Journal , Volume 60 , Issue 548 , August 1956 , pp. 523 - 542
Copyright
Copyright © Royal Aeronautical Society 1956

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