Using the C_DA calculated from the air drag at a single tunnel speed, we determined drag for a speed range from zero to 225 mph, indicating the engine power needed to overcome air drag. Rolling resistance also must be considered. The sum of the air and rolling drag forces multiplied by the speed gives us the power figure needed to pull that speed. Repeating the multiplication across our 225 mph speed range demonstrates how the Hayabusa's superior aerodynamics require less power than the ZX-12R to achieve a given speed.  View Related Article