From: Spike Jones (spike66@attglobal.net)
Date: Thu Dec 13 2001 - 17:36:33 MST
Mike Lorrey wrote:
> ...a 30 shp engine should do the trick. Spike messed up on scaling
> those 5 hp radio controlled helicopters, I think, since aerodynamic
> efficiency doesn't scale linearly...
That's right. The longer rotor is more efficient for lift/power
requirement. Of course it then requires more power to
cancel the greater torque and of course gets heavier and less
convenient to use.
What I think would be worthwhile is to research as
many VTOLs as we can find online, find their maximum
shaft power rating and their lift at that rating (craft
weight plus max payload.) Then we can create a graph
with rotor diameter on the horizontal axis, the ratio
of power to weight on the vertical. That relationship
should be nearly linear, if I recall the equation from
my helicopters textbook correctly. spike
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