A Method to Identify Helicopter Hover Ceiling in OGE

In order to calculate the helicopter hover ceiling in OGE precisely, some aerodynamic parameters, such as tip loss effect, induced velocity distribution, the effect of rotor downwash on the fuselage and power transfer of engine into rotor, must be treated carefully. However, to precisely predict these parameters is not easy due to complicated rotor aerodynamic problems. In this paper a method to identify these aerodynamic parameters is proposed by means of vertical flight test. To the end, a mathematical model for aerodynamic parameter identification is developed. Flight tests are conducted and the corresponding data are measured and processed. The parameter identification algorithm suitable for flight test data is discussed and the identified results are obtained. Based on the identified aerodynamic parameters the tested helicopter hover ceiling in OGE is settled. The results show that the method can efficiently identify the aerodynamic parameters as well as the helicopter hover ceiling in OGE.