Large scale model rockets, or high-power rockets, typically use motors with more than 160 Newton-seconds of total impulse. They can reach altitudes of several thousand feet, depending on their design and motor size.

A rocket exceeds the definition of a Model Rocket under NFPA 1122 and becomes a High Power Rocket under NFPA 1127 if it: Uses a motor with more than 160 Newton-seconds of total impulse (an “H” motor or larger) or multiple motors that all together exceed 320 Newton-seconds; or