# Pulsejets and ramjets

**URL:** <https://boards.straightdope.com/t/pulsejets-and-ramjets/409367>\
**Category:** Factual Questions\
**Created:** [June 25, 2007, 6:23pm UTC](https://boards.straightdope.com/t/pulsejets-and-ramjets/409367 "2007-06-25T18:23:26Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Enola\_Straight](https://avatars.discourse-cdn.com/v4/letter/e/dec6dc/32.png) [@Enola\_Straight](https://boards.straightdope.com/u/Enola_Straight)\
**Post date:** [June 25, 2007, 6:23pm UTC](https://boards.straightdope.com/t/pulsejets-and-ramjets/409367/1 "2007-06-25T18:23:26Z")

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Both are simple, minimally-mechanical thrust engines with little or no moving parts.

Is it possible to have the same motor work as a pulsejet at low speeds and transform to ramjet at high speeds?

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**Author:** ![Tranquilis](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tranquilis/32/3639_2.png) [@Tranquilis](https://boards.straightdope.com/u/Tranquilis)\
**Post date:** [June 25, 2007, 6:27pm UTC](https://boards.straightdope.com/t/pulsejets-and-ramjets/409367/2 "2007-06-25T18:27:58Z")

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Sure. Well, kinda. Well… No - You’d need to provide shutters for the ramjet inlet, and arrange to have a variable internal configuration, probably by moving plates, and a host of other adaptations. But why bother? A pulsejet is _supremely_ unlikely to be an efficient or reasonable means for getting a ramjet up to speed. IIRC, pulsejets cease to operate well below minimum ramjet speed, so there’d be no _purpose_ to such a hybrid.

Not mention that most hybrids are compromises that do nothing particularly well.