Study on performance enhancement of electrically controlled rotor using 2/rev flap control

Abstract

Electrically controlled rotor (ECR) system has been demonstrated in the primary control of helicopter. Without the restraint of the swashplate, ECR is also an efficient means to enhance the rotor performance by applying higher harmonic flap input. In order to investigate the potential of 2/rev flap input to enhance ECR performance, corresponding aerodynamic model of the ECR rotor and flight dynamic model of the ECR helicopter are established, in which the variation of ECR aerodynamic characteristic due to the deflection of trailing edge flap is emphasized. The analytical study is accomplished by simulating the ECR helicopter in trimmed flight for various combinations of takeoff weight, flight speed, and amplitude and phase angle of the 2/rev flap input. By studying the variation of the profile drag distribution over the rotor disc in detail, the physical essence through which 2/rev flap input affects the ECR power is explored. Subsequently, the parametric study of the blade pre-index angle affecting power reduction is conducted. Finally, the effectiveness of ECR approach for power reduction is compared with that of the conventional individual blade control approach. The simulation results show the potential of the ECR system for power reduction.

Keywords

Electrically controlled rotor helicopter active control swashplateless performance enhancement

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