Simulation of uncontrollable (“spontaneous”) rotation on a helicopter flight simulator

Abstract

This paper presents the simulation predictions of the helicopter uncontrollable ("spontaneous") rotation obtained on the VPS-5 helicopter flight simulator. A special feature of the research was the use of the coefficients which take into account the tail rotor (TR) operation under uncontrollable rotation in the flight simulator mathematical model. During the simulation, the operator - pilot forced the helicopter into rotation about the vertical axis to the predetermined value of the rotation velocity (100 deg/sec, 120 deg/sec). After reaching the preset value of the rotation velocity, the operator-pilot recovered the helicopter from uncontrollable rotation by sharply kicking the right pedal to the hard stop. For these two regimes the yaw control power was shown and the comparison of the yaw control power with the minimum flying quality requirements was performed. The results of this study show that to prevent this helicopter from falling into uncontrolled rotation, it is necessary either to ensure the helicopter rotation rate limiting to the value at which the condition of generating the specified control power is met when fully kicking the right pedal or to increase the control power at a higher helicopter rotation rate.