Fuel economy at 65 mph vs 60 mph

Stefonius wrote:

ACZL wrote:
You're pushing the same amount of air out of the way at 60 mph as you are at 70 mph.

Not true from a physics standpoint. When you double your speed, you encounter four times the wind resistance, and you need eight times the horsepower to maintain that speed.

Could have sworn it was speed squared and drag cubed. It =was= 40 years ago when I had physics... :-/

Lyle