[Jeff Chambers]

See I would have said RWHP. The equations of motion don't know anything about the internal losses, just what it takes to accelerate a given mass over a fixed distance...that would mean the power required at the ground. Its assuming a linear or constant rate of acceleration too, which is far from reality. Its such a simple calcuation, that it doesn't take in to account other variables such as aerodynamic drag, rolling friction, etc. I'll have to dig out my old physics and mechanics books and see if I can verify the numbers.