RESEARCH OF CONNECTION OF VERTICAL SPEED OF MI-8 HELICOPTERS DESCENT WITH ENGINE ADJUSTMENT PARAMETERS AND FLIGHT SPEED IN SELF-ROTATION MODE
The article presents the results of the research of the reasons for the difference between the vertical speed of descent of the Mi-8T and Mi-8MTV helicopters in the self-rotation mode of the rotor from the design one presented in the corresponding sections of the RLE. Research was carried out using correlation and regression analysis based on data arrays obtained in helicopter flights performed according to special control flight programs. The results of the research revealed that the number of estimates obtained out of the range corresponding to the estimated vertical reduction speed ± 1 m/s for Mi-8T helicopters is approximately 5 %, and for Mi-8MTV helicopters - 25 %. During the research, it was revealed that the main reasons for the mismatch of vertical reduction speeds at the self-rotation mode with the RLE data are: the mismatch of the rotor pitch to the minimum value and presence of residual power on a shaft of engines. Both of these factors are the result of methodological errors made by the crew when setting the helicopter to self-rotation mode. Also, the change in the vertical reduction rate may be due to the adjustment of the pitch-to-gas system. In this case, helicopters of both types can see a change in cruise flight speeds relative to the calculated values.