Re still-air times: Suppose that you can launch to 600 feet (pretty good for still air with a 600 foot line). If your plane's loading is 9 oz/sq ft, at a CL of 0.9 it will fly 23 ft/sec. Therefore if the L/D at that speed is 23 the sink rate will be 1 ft/sec. That's 10:00 from 600 feet.
BUT -- there are a lot of moving parts in this "test." It's hard to get consistent flights with the same launch height and to keep the plane flying at minimum sink throughout the flight. And of course it doesn't take much air movement to change the results dramatically. If the air is rising at even 10 ft/min, you'll stay up 12 minutes instead of 10! This sort of air movement is easily possible even after dark. So it's mighty hard to be sure you're drawing the right conclusions about a plane's performance from "still-air" testing. __________________________________________________ Do You Yahoo!? Send your FREE holiday greetings online! http://greetings.yahoo.com RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED]
