Research On Trimming,Flight Performance Calculation Method Of Coaxial Helicopter

In this paper, the single rotor slip flow model is generalized to the coaxial double rotor, using the inflow model of the first-order harmonic static non-uniform forms and interference factors of coaxial double rotor establish the model of aerodynamic characteristics, combined with the blade element-momentum theory calculate coaxial double rotor aerodynamic load; According to the balance of moments around wave-hinge, establish wave motion equation of up and down rotor blade; Referring the shape of ka-28 coaxial helicopter,build the body geometry model, then, using ICEM gains the fuselage flow field grid, import the grid to calculation fluid software to solve the fuselage aerodynamic characteristics, and get the fuselage aerodynamic characteristics change curve with the airflow Angle of attack; Based on this establish balance equations of coaxial helicopter, objective function minimum value optimization method is used to solve the balancing equations, and write a matlab program. Research fuselage attitude angle, manipulated variable, waving coefficient and average induced velocity of up and down rotor change curve with the forward speed in a stable flight.On the basis of balancing calculation get coaxial double rotor required power curve, and use it to calculate coaxial helicopter vertical flight performance, level flight performance and climbing performance, finally,the calculated performance results was compared with the performance data of the ka-28 coaxial helicopter, verify that, the established calculation model and method in this paper is effective.