Hear is a prime example a 1:3,4 scale Gypsy Moth. Now the full size had a cruise speed of 85 mph, stall as low as 25 mph with engine on and landing speed 42 mph. That would mean by simplistic conversion you might expect this model to fly at 25 stall at 7 and land at 12 clearly not realistic if one likes to keep their models in one piece. Besides flown as shown in the video though not scale speed still looks very convincing.