11. This variability maintains a comparable exhaust velocity and back pressure throughout the engine s rev range. 12. Chemical rockets operate as heat engines, and Carnot's theorem limits the exhaust velocity . 13. The effective exhaust velocity in units of m / s is also in reasonably common usage. 14. With higher fusions gains comes higher exhaust velocity , higher specific impulse and lower electrical power requirements. 15. In general, the exhaust velocity should be close to the ship velocity for optimum energy efficiency. 16. These engines, with their lower exhaust velocities , produce less jet noise and use less fuel. 17. He also advocated the use of liquid hydrogen and oxygen for propellant, calculating their maximum exhaust velocity . 18. PPTs have much higher exhaust velocities than chemical propulsion engines, but have a much smaller fuel flow rate. 19. For low exhaust velocity with respect to the mission delta-v, enormous amounts of reaction mass is needed. 20. The sound intensity from the shock waves generated depends on the size of the rocket and on the exhaust velocity .
