EFFECTS OF ROTOR CONTAMINATION ON GYROPLANE FLIGHT PERFORMANCE

Kurzfassung

This paper describes the effects of rotor contamination on gyroplane flight performance such as its influence on propeller thrust required for cruise flight and takeoff distance. It is known from flight practice that rotor contamination due to insects degrades the flight performance of gyroplanes significantly. By flight trials with an MTOsport gyroplane this degradation has been quantified: in order to maintain altitude at 60 kt airspeed the engine rotational speed has to be increased by about 200 rpm due to the rotor contamination. Considering these experimental data in the simulation model shows that this means a performance degradation of about 14 %. In order to understand this significant effect an analysis has been conducted connecting these flight test results with the degradation of the airfoil performance due to contamination. The NACA 8-H-12 airfoil characteristics have been determined using XFOIL for the clean and the contaminated case. The drag coefficient computed with a fixed transition point near the leading edge (contaminated case) is almost doubled in the relevant region of lift coefficients compared to the free transition point calculation (clean case). Utilizing these aerodynamic characteristics within the overall MTOsport flight simulation model affirms the degradation measured in flight. Hence the computational results are considered to be valid and the simulation model can be applied to investigate potential flight performance improvements of future gyroplanes. Finally a simulation study of the takeoff performance with clean and contaminated rotor is presented indicating that the takeoff distance also increases by more than 16 %.