# Helicopters and Angular Momentum

by azabak
Tags: angular, helicopters, momentum
 P: 32 How does an helicopter counteract the torque generated by its blades? And the tail blades, what are they for?
 Sci Advisor Thanks PF Gold P: 12,253 The main function of the tail blade (rotor?) is to counteract the torque applied to the main rotor. You can also use the tail rotor to control where the helicopter is pointing. If you lose drive to the tail rotor (/fan / nozzle) you are in real trouble.
HW Helper
P: 7,171
 Quote by azabak How does an helicopter counteract the torque generated by its blades? And the tail blades, what are they for?
The tail rotor is used to counter act the torque along the main rotor axis (yaw). This results in a net force to one side, so a true hover requires a helicopter to lean a bit towards the thrust side of the tail rotor.

The gyroscopic effect of the main rotor results in a pitch reaction to roll torque and vice versa. The pilot pitch and roll controls end up being advanced by 90° along the rotor axis to compensate for this.

 Sci Advisor Thanks PF Gold P: 12,253 Helicopters and Angular Momentum For the best description, ever, of all this, read the first couple of chapters in 'Chickenhawk' by an ex Vietnam Chopper pilot. He describes learning to fly a Bell Huey and leaves you, the reader, sweating and with palpitations as if you're actually in the pilot's seat. No fly-by-wire in those days.
 P: 32 Oh, I see. Thanks you guys!
Mentor
P: 3,928
 Quote by sophiecentaur For the best description, ever, of all this, read the first couple of chapters in 'Chickenhawk' by an ex Vietnam Chopper pilot. He describes learning to fly a Bell Huey and leaves you, the reader, sweating and with palpitations as if you're actually in the pilot's seat. No fly-by-wire in those days.
Although it's the last paragraph of the book that really sticks with you....

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