Thrust curve

A thrust curve, sometimes known as a "performance curve" or "thrust profile" is a graph of the thrust of an engine or motor, (usually a rocket) with respect to time.
Most engines do not produce linear thrust (thrust which increases at a constant rate with time). Instead, they produce a curve of some type, where thrust will slowly rise to a peak, and then fall, or "tail off". Rocket engines, particularly solid-fuel rocket engines, produce very consistent thrust curves, making this a useful metric for judging their performance.