I didn't quite know which category to post this under, but here goes.

A fellow RC buddy I sometimes fly with told me that to compute the engine "load factor" of a particular prop you use the formula "Diameter to the 4th power times Pitch".

For example, for an 11 x 6 prop it would be 11 x 11 x 11 x 11 x 6 or 87846. For a 12 x 4 prop it would be 12 x 12 x12 x12 x 4 or 82944.

Does this really work for determining which prop to substitute for a "standard" prop such as a 10 x 7 for a .46 size engine. If so, what would be the acceptable load range for say an OS .46FX, or Thunder Tiger Pro .40, etc.? Or is this just hogwash?