>.. a lighter plane will sink slower... Well, a lighter plane will fly slower. Sink speed is the product of flight speed * L/D, so unless the L/D goes up as fast as the the forward speed, a lighter plane will indeed sink slower.
But the L/D does go up some with wing loading because of Reynolds number effects. And then there is the matter of L/D lost due to control inputs, which I think is where a lot of this controversy comes from. In air that isn't perfectly smooth, a light plane may require lots of corrections to maintain straight and level flight, or a nice smooth thermal circle. Each control input reduces efficiency and increases effective sink. A more heavily loaded, faster-flying plane may hold its attitude with less pilot intervention. We see some of this even in the realm of HLGs. Taking everything into account, it's not clear that the lighter plane has any material advantage in sinking speed in air other than early morning or at dusk. Besides, if there's lift of even 100 ft/min, most any plane will climb. If it can reach the lift. A slower-flying plane will make smaller circles for a given sink rate; a typical 8-oz/sq ft plane will fly in roughly 42 foot circles for a sink rate of 2 ft/sec, while the same plane at 10-oz/sq ft would need 57 feet of diameter. So if the thermal is really little, and you can place yourself really precisely, this can be an advantage. Again, if the wind is blowing, this is moot. But what the heck, anybody can fly whatever they like -- that's why they make ice cream in different flavors. __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
