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Off Topics > Hovering planks?
 
 
bjames
Heliman
Location: Singapore

I have heard that planks can be hovered, and have even seen one recently.

Now a heli has tail rotor to prevent the body from spinning, while a plank does not have it.

Any idea why planks does not spin up during its hover?

(*obviously I'm still in the hovering stage and hence asking this *)
07-16-2003 Over year old.
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rover
Senior Heliman
Location: Brandon,FL

They do spin, due to the ambient torque of the motor. Torque roll as it is called. The planes can be somewhat controlled when hanging on the prop. The ailerons help a little.
Dustin

Rover
Mechanical Engineer
07-16-2003 Over year old.
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MJA
Key Veteran
Location: Cumbria-UK

It's because it is being corrected for with some right aileron.If it isn't corrected it turns into a hovering torque roll.The amount of torque roll that needs correcting varies depending if the plane is ascending or descending , also varies to a larger degree with the pitch and diameter of the propellor being used.
The torque roll is quite slow and nowhere near as fast as a heli with no tailrotor


Martin
07-16-2003 Over year old.
 
 
bjames
Heliman
Location: Singapore

Thanks,

That makes sense, but ... do the ailerons work when the plane is not moving ? Or does the air flow produced from the propeler somehow allow the aileron to work though the plan is not moving?

The one I watched is from video, from a camera mounted in a heli, so I can't really see whether the plane is moving or not moving or moving slowly.

cheers,
07-16-2003 Over year old.
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MJA
Key Veteran
Location: Cumbria-UK

Generally the planes you'll see doing good prop hanging and 3D with authority ,have massive control surfaces plus a lot of movement, like 40 to 60 degrees of deflection.With ailerons that size the airflow from the propwash is enough to give plenty of control even when the plane has no groundspeed or is hanging vertically on the propellor,enough to roll with or against the torque and still have enough aileron to counteract & roll right against the torque.Rolling against the torque depends on the powerplant,even big surfaces may struggle with a big petrol motor swinging a large diameter course pitched prop but in the other direction it would be quite fast

It's possible to hang on the propellor with std types of planes so long as they have generous power (or are very light) but if it goes too far out of shape in yaw or pitch there isn't enough authority/control power to stop it falling out in pitch (hammerheading) or falling over sideways (running out of rudder)


Martin
07-16-2003 Over year old.
 
 
bjames
Heliman
Location: Singapore

Very clear explanation. I got it now.

Thanks !!
07-16-2003 Over year old.
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Off Topics > Hovering planks?
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