Thread: Discussion Gyrocopter Aerodynamics
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Old Dec 29, 2007, 08:41 AM
mnowell129 is offline
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Mickey from Orlando. Really.
Joined Nov 2004
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Quote:
Originally Posted by leadfeather
A long time ago it was stated that helicopters typically have higher disk loadings than do autogyros.

Can you explain why this is so?
The autorotative state is not the maximum lift state. When the rotor is powered you can operate it at higher lift, thus the disk loading can be higher. As the helicopter has collective pitch an autorotative landing can be at a higher disk loading since you can pull pitch at the end and cannot with fixed pitch.
Also when the rotor is powered it can be run at a higher rpm, this increases lift proportional to the RPM squared and lowers the coning and reduces all the side effects therein.

Quote:
Originally Posted by leadfeather
Does this change with size/scale?
probably not, none of the effects are scale related.
Quote:
Originally Posted by leadfeather
Would the ideal or typical disk loading on a PPR craft be somewhere in between?
I'm not certain. I'd guess so. It probably depends on whether or not you have collective pitch. I don't know how effective the PPR is on model scale since PPR is primarily used to increase the steady cruise efficiency and models don't spend to much time at steady cruise.
I had a partially powered rotor while testing my pre-rotator and it didn't make any noticable difference, although I didn't test very long.
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