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The specific impulse of a rocket can be defined in terms of thrust per unit mass flow of propellant. This is an equally valid (and in some ways somewhat simpler) way of defining the effectiveness of a rocket propellant. For a rocket, the specific impulse defined in this way is simply the effective exhaust velocity relative to the rocket, v e ...
Engine Origin Designer Vehicle Status Use Propellant Power cycle Specific impulse (s) [a] Thrust (N) [a] Chamber pressure (bar) Mass (kg) Thrust: weight ratio [b] Oxidiser: fuel ratio
The most important metric for the efficiency of a rocket engine is impulse per unit of propellant, this is called specific impulse (usually written ). This is either measured as a speed (the effective exhaust velocity in metres/second or ft/s) or as a time (seconds). For example, if an engine producing 100 pounds of thrust runs for 320 seconds ...
In the 1960s, Rocketdyne test-fired an engine using a mixture of liquid lithium, gaseous hydrogen, and liquid fluorine to produce a specific impulse of 542 seconds, likely the highest measured such value for a chemical rocket motor. [2] Despite the high specific impulse, the technical difficulties of the combination and the hazardous nature of ...
The F-1 engine is the most powerful single-nozzle liquid-fueled rocket engine ever flown. The M-1 rocket engine was designed to have more thrust, but it was only tested at the component level. The later developed RD-170 is much more stable, technologically more advanced , more efficient and produces more thrust, but uses four nozzles fed by a ...
The engine produces a specific impulse (I sp) of 452 seconds (4.43 kN-sec/kg) in vacuum, or 366 seconds (3.59 kN-sec/kg) at sea level, has a mass of approximately 3.5 tonnes (7,700 pounds), and is capable of throttling between 67% and 109% of its rated power level in one-percent increments. Components of the RS-25 operate at temperatures ...
In particular, since the oxygen is heavier than the carbon or hydrogen, essentially all combustion rocket engines run fuel-rich to reduce the exhast molecular mass, increasing exhaust velocity and thus specific impulse (and as a side benefit, temperature and cooling are reduced too). This effect favors ligher elements like pure hydrogen.
Specific impulse (usually abbreviated I sp) is a measure of how effectively a rocket uses propellant or jet engine uses fuel. By definition, it is the total impulse (or change in momentum) delivered per unit of propellant consumed [4] and is dimensionally equivalent to the generated thrust divided by the propellant mass flow rate or weight flow rate. [5]