Date of Award
Doctor of Philosophy (PhD)
A dynamic inflow model is used to calculate minimum induced power for a helicopter in high-speed forward flight with infinite and finite number of blades. Comparisons between analytical and numerical results are shown and they show good agreement. Different flow conditions (such as with and without reverse flow or inflow feedback) are used to show how each condition affects optimum induced power. Several results confirm the findings of earlier investigations such as a singularity in rotor power in reverse flow and induced power reduction with increase in blade number. Some of the new findings are that greater inflow feedback (due to greater solidity) reduces the induced power for an infinite-bladed rotor. For a rotor with a finite number of blades, the addition of inflow feedback can either increase or decrease optimum power depending on the flight conditions. Results obtained using higher harmonic blade pitch control show that induced power can be thereby reduced for all conditions.
David A. Peters
Philip Bayly, Humberto Gonzalez, Swami Karunamoorthy, Mark Meacham,