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Old Jan 17, 2011, 11:22 AM
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The 'Wack, BC, Canada
Joined Oct 2002
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By all means play with such a setup if you wish but my feelings from reading about the blown flaps systems suggest that it won't be enough at all. The big guys that did this used a bypass off the high pressure area of the engine compressor area. That's both serious volumes and serious pressure. The idea is that it's not just a bleed of air but a high velocity sheet that blasts over the upper side of the flaps. Just leaking air from below will not have anywhere near that sort of energy. Especially with a light model where the pressure difference is only fractions of an oz per sq inch. Think about it... at a wing loading of around 4 to 6 oz per sq foot, which is needed to fly at around 10 kph or a medium running speed. The pressure difference per sq inch is 6/144 or just .042 oz per sq inch. Or putting this into pounds per sq inch or PSI it's .042/16=.0026 psi That isn't going to move air with any sort of energy at all. So to do this in a way that won't reduce your lift by merely leaking air from below you'll need a pump system that can provide the sort of energy needed to actually pull the air down.
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