Vaitla Laxman/JaeHoon Lim/SangJoon Shin/KwangHo Ko/SungNam Jung
International Journal of Aeronautical and Space Sicences, vol. 12, no. 2, pp.156-162, 2011

Abstract : The preliminary design stage of helicopter consists of various operations and in each operation design several detailed analysis tasks are needed. The analysis tasks include performance and the required power estimation. In helicopter design, those are usually carried out by adopting the momentum theory. In this paper, an explicit form of computational analysis based on the blade element theory and uniform/non-uniform inflow model is developed. The other motivation of the present development is to obtain trim and required power estimation for various helicopter configurations. Sectional and hub loads, power, trim, and flapping equations are derived by using a symbolic tool. Iterative computations are carried till convergence is achieved in the blade response, inflow, and trim. The predictions regarding the trim and power estimation turns out to be correlated well with the experimental results. The effect of inflow is further investigated. It is found that the present prediction for the lateral cyclic pitch angle becomes improved with the non-uniform inflow model as compared to that by the uniform inflow. The presently improved trim and power estimation will be useful for the future helicopter sizing and performance analysis.

Keyword : helicopter preliminary design, non-uniform inflow, trim, power estimation