Velocity of Exhaust Gases At The Nozzle For a Solid Propellant Rocket Engine Using Specific Impulse Calculator

The velocity of the exhaust gases at the nozzle exit for a solid propellant rocket engine is determined by the rocket equation, which is based on the conservation of momentum and mass. Solid propellant engines use preloaded, self-contained propellant that cannot be shut down once ignited.

The formula for calculating the nozzle exhaust air velocity using the rocket equation is:

Where:

• V_exit is the change in velocity of the rocket (in meters per second, m/s).
• I_sp​ is the specific impulse of the rocket engine (in seconds, s).
• g₀ ​ is the acceleration due to gravity at the Earth’s surface (approximately 9.81 m/s²).
• m₀​ is the initial mass of the rocket (including propellant, air and structure, in kilograms, kg).
• m_f ​ is the final mass of the rocket (after propellant burnout, in kilograms, kg).