Originally Posted by astrohog

Suppose a full size Cub flies at 60 miles per hour or one mile per minute. You would want a quarter scale Cub to fly one quarter scale mile in one quarter scale minute. Since in quarter scale distance is divided by four and time is divided by two our model will fly at one half the speed of the full size Cub or 30 miles per hour. Like scale time, scale speed varies as the square root of the scale factor. To fly at scale speed our models need to fly slower than the real airplane by an amount equal to the square root of the scale factor.
In your bearcat scenario, the 1/4 scale model would need to fly at 250 mph.
Hope this helps!

Regards,

Astro