Author Topic: Rocket Engine Testing Q&A  (Read 999 times)

Offline nicp

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Rocket Engine Testing Q&A
« on: 08/21/2018 05:43 PM »
I've been trying to find some reference to how rocket engines are tested for high altitude or vacuum performance.

By all appearances, MVac is tested without the extended bell, which I suppose is valid. But what if you have a 'vacuum native' engine such as the original Saturn J-2, or the first RL-10's where you can't just omit the bell extension?

Now somewhere I've read there's some trick with steam, to simulate high-altitude conditions but I'm sure I've never seen an explanation of that.

I hope it's ok to have started a new thread and hope I'm not duplicating stuff.

Where's my Guinness?

Offline Jim

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Offline zhangmdev

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Re: Rocket Engine Testing Q&A
« Reply #2 on: 08/21/2018 11:43 PM »

Offline SBerger

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Re: Rocket Engine Testing Q&A
« Reply #3 on: 08/22/2018 11:21 PM »
The Wikipedia article provides the basic method for getting the test chamber pressure down before engine start.  One technique that has been/is used to keep the pressure down once the engine is running is to use the engine exhaust to drive the ejector (instead of steam).