Definitions Thrust – The force which imparts a change in the velocity of a mass. This force is measured in pounds but has no element of time Power – Implies work rate or units of work per unit of time, and as such, it is a function of the speed at which the force is developed. Introduction The backside of the power curve, or being behind the power curve, can mean a couple of things. When talking about general aviation, one of the common interpretations is the aircraft’s speed