eng.rocket-exhaust-velocity Calculator
Calculates rocket exhaust velocity (Isp × g) and thrust from chamber pressure, nozzle geometry, and propellant combination. Specific impulse (Isp) is the rocket's fuel efficiency metric — liquid hydrogen/oxygen (450 s) significantly outperforms solid propellants (250–280 s).
Inputs
- Chamber Pressure Mpa
- Force per unit area (Pa). Atmospheric pressure at sea level: 101,325 Pa. Check whether gauge or absolute pressure is required.
- Exit Pressure Kpa
- Force per unit area (Pa). Atmospheric pressure at sea level: 101,325 Pa. Check whether gauge or absolute pressure is required.
- Chamber Temp K
- Thermal state of the substance. Check whether the formula needs Celsius, Fahrenheit, or Kelvin (K = °C + 273.15).
- Gamma
- Energy to raise 1 kg of material by 1°C (J/kg·K). Water: 4,186 J/kg·K. Metals are typically 100–900 J/kg·K.
- Molecular Mass G Mol
- Total mass (kg). Distinct from weight — weight = mass × gravity. Mass is constant; weight varies with location.
Results
- exhaust velocity ve (m/s)
- Reference formula or conversion factor shown for context.
- specific impulse Isp (s)
- ISP (specific impulse) — rocket engine efficiency in seconds. Higher ISP means more thrust per kilogram of propellant consumed.
- Isp = ve/g₀
- ISP (specific impulse) — rocket engine efficiency in seconds. Higher ISP means more thrust per kilogram of propellant consumed.
- pressure ratio Pe/Pc
- The proportional relationship between two quantities.
- typical Isp ranges
- The difference between the maximum and minimum values.
- Tsiolkovsky: Δv = ve·ln(m₀/mf)
- Sample size or count used in the calculation.
impulse specific exhaust chamber engineering