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Old 05-28-2005 | 04:41 AM
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David Gladwin's Avatar
David Gladwin
 
Joined: Feb 2002
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From: CookhamBerkshire, UNITED KINGDOM
Default RE: Kingcat vs Hustler.




I have seen BV and others do some impressive pattern flights with the KC......only thing it lacks is a real clean entry and exit to upright (+G) spins and flicks due to the wing planform......same deal with the BobCat and Bandit using a similar wing planform, but outside (-G) spins and flicks are clean.....


Tom

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Actually, Tom, the difference between upright and inverted spinning is not a function of wing planform it is wing SECTION AND INCIDENCE. The Bobcat wing and presumably the Kingcat since you align the two, has a thick symetrical root section tapering to a semi-symetrical tip which is washed out. At the stall the root stalls first, as it should, and makes the spin entry uncertain and the spin itself, oscillatory. Inverted, we now have a wing which has an adversely semi-symetrical section (flatter on top) and washed IN. Thus at the stall the tip stalls first, making the spin entry cleaner and the spin more stable.

That section change is what causes the wing rocking on the Bobcat as it gets near the stall, an excellent visual indication of the approach to the stall in a model as we have no tactile warnings of the stall or an ASI to refer to!

Thats exactly how my Bobcats behave and I have done great number of spins with them , both upright and inverted.

I suspect that if these models had symetrical section wings they would stall and spin in similar fashion uright and inverted but we would lose the benign handling at the approach to the upright stall.

Regards, David Gladwin.