specific impulse

American  

noun

Rocketry.

1. a measure, usually in seconds, of the efficiency with which a rocket engine utilizes its propellants, equal to the number of pounds of thrust produced per pound of propellant burned per second.

2. the specific impulse that a given combination of propellants would produce in an ideal rocket engine providing complete combustion, no friction losses, and no lateral expansion of the exhaust.

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specific impulse British  

noun

1. the ratio of the thrust produced by a rocket engine to the rate of fuel consumption: it has units of time and is the length of time that unit weight of propellant would last if used to produce one unit of thrust continuously

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Etymology

Origin of specific impulse

First recorded in 1945–50

Example Sentences

Present combinations, e.g., liquid oxygen and kerosene, have a specific impulse of about 245 Ibs.

From Time Magazine Archive

When the two components come together, they burn with extremely high specific impulse, the measure of rocket power.

From Time Magazine Archive

The specific impulse of the traditional kerosene-oxygen combination is only 249.

From Time Magazine Archive

Its reaction has a specific impulse of 373.

From Time Magazine Archive

But we were missing an important number—the specific impulse of zincoshine.

From "October Sky" by Homer Hickam