The Stability And Control Analysis Of No Tail Rotor Helicopter

NO TAil Rotor (NOTAR) is a recent advance of helicopter directional control system technology.One of the characteristics of NOTAR is that the normal tail is replaced by circulation control boomand thruster, which are used to generate the side force to balance the anti-torque of the main rotor andcontrol the flight direction. With the advantages of simplicity in structure, light weight, low noise andhigh aerodynamic efficiency, NOTAR is quite suitable for light helicopters. In this case, the authorwill do an in-depth study of NOTAR from the point of circulation control boom aerodynamiccharacteristic and helicopter flight dynamics. According to blade element theory, Kutta-JoukowskiTheorem and momentum theorem, the aerodynamics of the circulation control boom and thruster areobtained. An unmanned50kg-class NOTAR is taken as a sample helicopter, and the generalparameters are identified. Then the flight dynamics model of the designed NOTAR is established,which includes the main rotor model, the horizontal stabilizer and the fuselage model. During theprocess, the non-uniform dynamic inflow model is adopted to determine the rotor induced velocityand the rotor wake interference is considered in the vertical stabilizer and horizontal stabilizer model.Then the unmanned helicopter is trimmed with Newton iteration method and the trim results areanalyzed. According to the established NOTAR flight equations, the aerodynamic derivatives andcontrol derivatives are obtained with numerical methods. Finally, the stability and maneuverability ofthe NOTAR is analyzed by difference method under the small perturbation assumption.