Originally Posted by
hamster
I find it improbable that any aircraft, even human-powered and tiny, can maintain the average airspeed of 18.9 mph for 4 hours without stalling and crashing.
It's all about the airfoil. Here's a link to the NASA flight test results for Daedalus:
http://ntrs.nasa.gov/archive/nasa/ca...1989001519.pdf