No commercial reproduction, distribution, display or performance rights in this work are provided. In Part II, the expression for the instantaneous induced velocity at a blade is developed by application of the Biot and Savart Law to a helical wake surface on which the circulation distribution varies both with radius and with azimuth in a manner corresponding to the actual lift distribution on the blade. Charts of the correction factor to be applied to the ordinary momentum value of induced drag are presented for ranges of flight parameters currently in use. In Part I, a method is derived for determining the induced drag of a helicopter rotor in forward flight from the distribution of circulation in the wake. V1 is roughly equal to the blade sections angular speed (r) but may will also have increments due to advancing/retreating blade speeds for forward flight.
0 Comments
Leave a Reply. |