Investigating trim algorithms for a utility helicopter

Demirel, Anıl.
Obtaining trim positions of an aircraft is an issue of importance. In this thesis, the aim is to develop a procedure that can achieve the trim points with reasonable assumptions for the entire flight of a helicopter. In order to achieve this goal an autopilot is used to determine the trim points. A high-fidelity flight model is used. The structure is based on GENHEL model. Helicopter trim states are calculated for specified flight conditions. The parameters that are sensitive to trim convergence are determined. A simplified set of trim equations are solved to generate a proper input set for fast convergence of Nelder-Mead (NM) Simplex runs. A NM Simplex algorithm is used to find accurate trim points. The procedure is tested for the UH-60 helicopter model in hover and forward flight conditions. A comparison of the trim results with flight test data available in literature is used to. Thereby the utility of the procedure is demonstrated, the reliability of the assumptions and the practicality of the model are shown.


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Citation Formats
A. Demirel, “Investigating trim algorithms for a utility helicopter,” Thesis (M.S.) -- Graduate School of Natural and Applied Sciences. Aerospace Engineering., Middle East Technical University, 2019.