Is hovering helicopter torque ever exactly = 0 ?

[Loren Booda]

Can a helicoptor, considering its primary and secondary rotors, ever generate exactly zero torque, i. e., while hovering? The secondary compensates for the primary's torque, but what compensates for the secondary's torque? Is there such a thing as or a need for a tertiary rotor?

 

[brewnog]

The helicopter will always provide torque to overcome the air resistance (which is needed anyway for the helicopter to work). If the tail rotor compensates for the turning effect of the primary rotor, nothing needs to compensate for that of the tail rotor because the "turning effects" of each rotor (and here I mean orientation of the aircraft, not of the rotor itself) cancel each other out in order for the helicopter to point forwards.

 

[drag]

Loren, is that a philosophical question ?

 

[Averagesupernova]

Actually I don't think that the 'turning effects' cancel each other so to speak.

Obviously, the tail rotor is used to push against the tail to counteract the torque on the machine caused by the main rotor. But what I suspect Loren wants to know why the torque caused by the tail rotor doesn't cause the whole machine to turn end over end in the opposite direction that the tail rotor is going. One reason is that the pitch is constantly changing on the main rotor blades. It is set up in such a way that in order to move in different lateral directions the main rotor is pitched to torque the body of the machine, but not torqued in the vertical axis, the other two. This so called torque causes the machine to 'slide' in the appropriate direction as well as counter the small amount of torque caused by the tail rotor. If this is not what you were getting at Loren, just ignore my ramblings...

P.S. I would also suspect gyroscopic effects come into play keeping the machine stable. Not only that, but consider that a helicopter is being 'hung' by it's top center. Gravity is probably enough to keep it from turning end over end from the torque caused by the tail rotor.

 

[Loren Booda]

An above-average explanation, Asn. The pitch has it!

Have any of you ever flown a helicoptor? I think I would get airsick.

Anyone hear of a third rotor or similar device?

 

[chroot]

I've been thinking about getting a helicopter license after I finish my single-engine land aircraft license.

- Warren

 

[Loren Booda]

I've been thinking about getting a helicopter license after I finish my single-engine land aircraft license.

They're two very different beasts, from what I hear.

 

[chroot]

Totally different. The only things common to both licenses are the FAA regulations concerning e.g. speed limits at altitudes and flight path separation distances and so on.

- Warren

 

[Loren Booda]

I passed the FAA ground school test in 1974 when I was 15, but never pursued my pilot's license due to vestibular hypersensitivity. I remember studying weather, instruments and regulations.