ORIGINAL: cappaj1
Is there any formula to determine if a plane is considered light or heavy? For example, I was told the following plane was on the 'heavy side' :
Wing span 72 inches.
Wing Area 960 sq. in.
Fuselage Length 62'' (Rudder to front of cowling)
Fuselage length 65'' ( Rudder to front of spinner)
Weight 9 to 10 lbs
I personally like to use "Wing Loading" as a measure of how a plane can be expected to handle. Its not the only one, but it works for me. For the numbers you provided, at the low end of the weight scale (9 lbs) it works out to 21.6 ounces per square foot. As a rule of thumb:
Gliders - 7 oz/sq ft or less
Trainers - 16-18 oz/sq ft.
Sport aerobats - 18-22 oz/sq ft.
War birds - over 22 oz/sq ft.
In general for planes that are loaded at 18 oz/sq. ft people tend to describe them as "floaters". They will take off easily, and if balanced correctly, will sink slowly in a neutral trim condition. In case its not obvious, the higher the wing loading, the faster the plane must fly (generally) to keep it in the air. Higher wing loaded planes do better in the wind, as they don't get thrown around as much, but will also stall easier, and have to have more speed on landing.
Brad