Autorotation application analysis for the safe-landing field-tests

Aeronautical and Space-Rocket Engineering

Dynamics, ballistics, movement control of flying vehicles


Morozov A. A.1*, Ilyukhin S. N.2**, Khlupnov A. I.1***

1. Moscow helicopter plant named after M.L. MiL, 26/1, Garshina str., Tomilino, Moscow region, 140070, Russia
2. Bauman Moscow State Technical University, MSTU, 5, bldg. 1, 2-nd Baumanskaya str., Moscow, 105005, Russia



This article is devoted to the topical issue of applying the autorotation phenomenon in emergencies while helicopter engine malfunctioning to ensure safe landing. In the beginning of the article, the basic theoretical data on the physics of the helicopter rotor autorotation process is presented, and the conditions for the occurrence of a stable autorotation mode are considered. The objective of the overrunning clutch is described on the example of the MI-8 helicopter. Further, the characteristic sets of initial conditions and spatial zones of the autorotation commence are considered, staying in which ensures or does not ensure a safe landing. It was emphasized that the key for the correct entry performing into autorotation is maintaining the rotor rotations. Two techniques for the rotor speed drop terminating in emergencies are presented. Besides, the article considers the pilot’s actions in case of an emergency associated with engine malfunctions in Mi-8, 24, 28 helicopters, ensuring stable autorotation mode and a safe landing. Based on the results of a series of field tests, a scientific substantiation was also presented for the main parameters selection, allowing the helicopter landing with idle engines, as well as recommended landing profile for the rotor self-rotation was elaborated. By the results of processing of video recording of ten landings, the values of the height of the helicopter pitch increasing commence are presented. The pitch angle value and height, at which this pitch angle was reached, as well as vertical and horizontal components of landing velocities are presented as well. In conclusion, the landing technique while autorotation mode performing, formed as the result of flight test data analysis with the listing numeric parameters of the flight is presented.


rotor self-rotation, emergency helicopter landing, autorotation modes, control algorithm


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