If a helicopter's tail rotor shears off while flying then the helicopter's fuselage will start rotating in the direction opposite to the main rotor's rotation direction. During autorotation, if I switch off the engines of the helicopter, then will it affect the rate of rotation of helicopter?

  • $\begingroup$ The actual procedure for a tail-rotor failure in a helicopter is to maintain as much forward speed as possible. If you have no forward speed (ie hovering), you need to lower the collective as quickly as possible to remove the torque from the main rotor. After this you follow normal auto-rotation procedures and hope you don't build up too high a turn rate before hitting the ground. Tail rotor failure is survivable under certain circumstances. $\endgroup$ – Ron Beyer Jun 20 '19 at 2:53

with the engine disconnected from the main rotor, no torque is being applied to the rotor by the engine so there is no torque reaction trying to rotate the fuselage backwards. In this case, the only torque being applied to the fuselage is the frictional drag in the main rotor bearing, which will be small. If a tail rotor failure occurred and the fuselage began rotating because of this before the engine failure, then the fuselage will remain in rotation after the engine failure and will slowly lose rotational speed as the main rotor bearing friction acts on it.

  • $\begingroup$ Of course yaw stability will stop the rotation if sufficient forward speed can be maintained... $\endgroup$ – Cpt Reynolds Jun 19 '19 at 21:31
  • $\begingroup$ I assumed he'd be autorotating straight down... $\endgroup$ – niels nielsen Jun 19 '19 at 22:56
  • $\begingroup$ Not recommended $\endgroup$ – Koyovis Jun 19 '19 at 23:25

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