Coax helicopters

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crytes

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how does a coaxial control yaw anyway? Seems like alot of extra complexity to do the same thing multi rotor and conventional choppers do and they are already a maintanence nightmare.
 

D Hillberg

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Coaxil yaw control is through collective pitch, one set of rotors gets more pitch & the others set get lower pitch, the change in drag yaws the helicopter. the QH 50 used drag (Blade Tip air brakes) It was the cure to yaw reversal in autorotation in coaxial set ups.

No helicopter is a maintenance nightmare, and all helicopters are a compramize in what the designers wanted. All helicopters have issues that come from the choises the builders made, Coaxils like tandems have all power going to the lifting rotors but suffer in yaw control. Single rotor machines got that pesky tail rotor
but it costs less to build. Compramize a helicopters middle name.
 

TFF

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The idea behind coaxial is it nulls out the torque; remove torque and it rotates. What the new push is to get rid of retreating blade stall so it can go faster than a normal helicopter.
 

Dana

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For a coax chopper with full collective pitch control, autorotation should be no more trouble than any other helicopter. It could even be better because you're not stealing some of the rotor's energy driving a tail rotor that contributes nothing to lift.

Dana

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BBerson

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For a coax chopper with full collective pitch control, autorotation should be no more trouble than any other helicopter. It could even be better because you're not stealing some of the rotor's energy driving a tail rotor that contributes nothing to lift.

Dana

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I would say no.
Autorotation rate is determined by disc loading, and downwash velocity, which are related. Coaxial usually has higher disc loading.
Yes, if disc loading is same the coaxial would be similar.
 
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