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An engine producing 'dry' thrust is said to be at 'military power', a useful distinction from reheat / afterburner.

It's always seemed an odd phrase to me. There's nothing particularly military about it, and why would afterburner not be military? 'Military' has always been used as a word that always relates to soldiering in some form or another - it is a curious choice to define the operation of a jet engine.

It must, of course, be a twentieth-century phrase. Can any light be thrown on its origin?

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The etiology of military power is from War Emergency Power (WEP) which in the WWII era was a higher than normal rating power (i.e. >100% rated power) setting on an aircraft engine. Such power settings were approved for short durations (typically 5 minutes or less) such as takeoff and battle maneuvers.

The term was quickly shortened to military power.

Sometimes military power is assumed to be simply full throttle, but that may not be accurate, particularly in blown engines, where turbochargers or superchargers may be set to permit higher than normal air delivery to the combustion chamber.

Finally, military power was used for more extended periods of times, when conditions dictated, but at a reduction in reliability and service life. Sometimes in war, service life is not a pilot's greatest concern.

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  • $\begingroup$ Thanks, I think the confusion is because (notwithstanding your answer) "full military power" - a fairly common phrase - is really an oxymoron. It can give the impression that "military power" is "normal power", when it's really not. Makes its etiology much clearer. $\endgroup$
    – Party Ark
    Oct 20 '17 at 11:45
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    $\begingroup$ Interesting you used the word etiology, @PartyArk. One contributor suggested a different word, etymology, which is the study of words. The definition of etiology which I rely on is: the investigation or attribution of the cause or reason for something, often expressed in terms of historical or mythical explanation. Some people think etiology is disease oriented, but the term is frequently used in other engineering or scientific contexts. The military power explanation I gave is essentially what was shared with me by Dick, who was the FE on the B-17 "Fuddy Duddy" in WW II. $\endgroup$
    – mongo
    Oct 20 '17 at 17:53
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"Military power" is less about the distinction between dry and wet thrust, but more about the distinction between civilian "maximum power" and "military maximum powerÄ which usually puts more strain on the engine than desired in a civilian context.

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