Net Thrust of a Rocket Engine


A rocket engine, or simply “rocket”, is a jet engine that uses only stored propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton’s third law. Since they need no external material to form their jet, rocket engines can be used for spacecraft propulsion as well as terrestrial uses, such as missiles. Most rocket engines are internal combustion engines, although non-combusting forms also exist.

An approximate equation for calculating the net thrust of a rocket engine is shown.

Related formulas


Fnnet thrust of a rocket engine (N)
dmexhaust gas mass flow (kg)
dttime (s)
veactual jet velocity at nozzle exit plane (m/s)
Aeflow area at nozzle exit plane (or the plane where the jet leaves the nozzle if separated flow) (m2)
pestatic pressure at nozzle exit plane (N/m2)
pambambient (or atmospheric) pressure (N/m2)