Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 30, 2016 - December 02, 2016
Helicopter has an emergency landing function that is called autorotation. Autoratation is a maneuver that we can land safely in case of engine failure. It is carried out by pulling down collective pitch (average pitch angle of blade) in order to keep mainrotor’s rotational speed. However, autorotation is said to be very dangerous because failure is equal to an accident. So it is considered that automation of it leads to grow helicopter’s safety. In this paper, aiming at automation of autorotation, flight dynamics of a small scale helicopter during autorotation is analyzed to improve our dynamics model. For that, 2 mainrotor downwash models are focused on and precision of them are analyzed by 2 types of analysis: one is by autortation flight data, and the other is by the calculation result of downwash distribution using CFD tools. In the former analysis, dynamics of thrust and attitude is considered with developing an approach to remove wind influence, and succeeded to improve the precision of dynamics model. In addition to that, the latter analysis showed that the effect on adding downwash distribution to dynamics model is large enough to change the downwash model.
