AE 6070 4070 Home Work Set 2 Due on Tuesday October 3 2006 Given a rotor with the following characteristics 0 1 tw 8 degrees B 0 97 k 1 1 Cutout 7 Cdo 0 01 for simple performance estimate a 5 7 per radian 1 For the case where the collective pitch angle is 10 degrees compute and plot the inflow ratio v R using a momentum theory b empirically corrected momentum theory where the disk area has been redefined as BR 2 c combined blade element theory with no twist and d combined blade element theory with twist Solution Inf low D istribution 0 10 Empirical 0 08 0 06 Ideal 0 04 0 02 No twist Twisted 0 00 0 0 2 0 4 0 6 x r R 1 0 8 1 2 Compute the hovering performance plot for this rotor using a simple estimate C P k CT 3 2 2 C do 8 b Blade Element Theory c Combined Blade Element Momentum Theory Use k 1 1 and Cd 0 01 for the simple estimate Assume a tip loss factor B 0 97 for the blade element theory and combined BEM In other words assume that the last 3 of the rotor produces no lift For blade element theory and combined blade element theory both use Cl 5 7 Cd 0 0087 0 02167 0 4 2 Here the effective angle of attack is in radians You may compare your results with figure below 2