engleski

About the Estimation of the Required Power for a Helicopter in Forward Flight

For the performance analysis of a helicopter of conventional configuration in forward horizontal flight main rotor and its required power are the most essential elements. Since the flow around the main rotor in forward flight is very complex, estimation of the power is not an easy task. Basic analytical results for uniform inflow and with neglected tip-losses are corrected with empirical factors in order to compensate the underestimate of the induced power and profile drag power. In this paper numerical model based on the blade element theory is corrected for the empirical factor of the induced power in order to make closer estimate of the required power. The main rotor power for forward flight is analysed in dependence of advance ratio, up to $\mu=0.4$. Developed model is applied for two example rotors with known experimental results. For one example results of numerical models based on the lifting-line theory are also compared. Presented results confirm a possibility of application of the developed model with empirical corrections for induced power for fast and sufficiently accurate estimates of the main rotor required power.

Helicopter main rotor; Forward flight; Required power; Blade element theory

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