Talk:Rocket engine
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"Exhaust speeds as high as 10 times the speed of sound at sea level are not uncommon." Who ever said this is wrong. Exit mach numbers in chemical rockets tend to be 2.8 - 4.0, not 10.
- That was me, Mr. Anonymous. The speed of sound at sea level is ~340m/s. The exhaust velocity of the SSMEs are about 4500m/s. You do the maths. Hydrocarbon engines can be 330 seconds or more.WolfKeeper 10:52, 29 May 2006 (UTC)
- You may have confused the speed multiplier given by a De Laval nozzle relative to the sonic velocity at the throat. They give speed increases of about that range. However the sonic speed in the hot gasses that are typically put through such nozzles is much higher than the sonic speed of air at STP, so the final speed is far higher.WolfKeeper 10:52, 29 May 2006 (UTC)
- For example, if you put a hot gas through a De Laval nozzle where the speed of sound in the hot gas is 1000km/s, and the nozzle coefficient is 3, then the final velocity is 3 km/s.WolfKeeper 10:52, 29 May 2006 (UTC)
- Reverted.WolfKeeper 10:52, 29 May 2006 (UTC)
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[edit] Vernier engine?
What's a "Vernier engine"? I found it mentioned in at least one NASA document but there's no Wikipedia entry with that title.
- It's just a small engine used to supplement the bigger engine that allows you to change the overall thrust or the direction of the thrust slightly. For example you can use a Vernier engine for roll control.WolfKeeper 23:09, 14 August 2006 (UTC)
[edit] Mass Drivers
Woflkeeper, you have a strange defintion of a rocket. Mass drivers belong in the same category as electric propulsion, including ion propulsion and plasma. You should remove those also. —The preceding unsigned comment was added by Cfrjlr (talk • contribs) 18:55, 11 February 2007 (UTC).
- Mass drivers are reaction drives, they do not emit an exhaust jet. They lack a nozzle or a throat; as do Ion drives and most plasma drives. They are not normally considered to be rockets. The only exception currently in the article is VASIMR which has a magnetic throat and nozzle. I'm planning to largely remove but reference out to ion drives. There has to be some scope to the article otherwise it would end losing focus.WolfKeeper 19:16, 11 February 2007 (UTC)
[edit] Reorganize
OK. I will help reorganize this page, the whole space tech part of wikip is a mess and needs a lot of work, I wish I had more time. —The preceding unsigned comment was added by Cfrjlr (talk • contribs) 19:20, 11 February 2007 (UTC).
[edit] Reorg complete
OK I have completed the re-org. I hope you agree it makes the page easier to read, and improves the logical flow.Charles 20:02, 11 February 2007 (UTC)
[edit] Rocket engines → Spacecraft propulsion
Please see this request for discussion about the rocket engines redirect. Sdsds 21:18, 1 March 2007 (UTC)
