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Old Feb 04, 2013, 10:25 AM
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Lift is cheap - Drag sucks
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Socorro, NM
Joined Jul 2004
3,717 Posts
Kevin,

Thanks for the equation and explanation.

I have built plank sheet gliders - 1/16th flatplate, with 12" span 2" chord - dihedral and a rudder. They glide very well unless you throw them hard or add camber to the chord, which fits your discussion.

So, if I had added a small amount of camber and a tall rudder the models might have still had a flat glide. That leads to a design similar to the one you posted a while back - a tall fin with a split rudder. Two servos could provide control of both drag and yaw.

Assuming such a scheme would work - what are the economics? A drag rudder would have to provide the same force as a reflex section to balance Cm. So, where's the benefit? Perhaps the rudder has an advantage because of it's longer moment?

Tom
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