Talk:Liquid-propellant rocket/Archive 1

Does liquid oxidizer imply cryogenics
Should the article somehow indicate that using a liquid oxidizer (e.g. LOX) almost certainly requires cryogenics? Given the absense of a usable oxidizer that is liquid at room temperature and reasonable pressure, the conclusion is obvious. But is there a reliable source to cite for this? (Sdsds - Talk) 04:21, 23 May 2007 (UTC)


 * Ummmm.... 98% Hydrogen peroxide works just fine as a rocket oxidiser and is room temperature. The Isp is a few tens of seconds lower, but it has flow on orbital and suborbital missions. Also nitrogen tetroxide has seen extensive use as well.WolfKeeper 05:27, 23 May 2007 (UTC)


 * Oops, what was I thinking?!? Thanks for the correction! (Sdsds - Talk) 07:08, 23 May 2007 (UTC)

This is a huge issue, particular in the Soviet Union. H2O2 has been tried, but isn't really a great oxdizer. More popular has been nitric acid or nitrogen tetroxide. Non-cryogenic propellants were popular for military use, where rockets could be kept fueled in stand-by mode. The Russian Proton rocket used N2O4, but they are planning to switch it to the more efficient and less toxic LOX/Kerosene combination like Soyuz uses. The Chinese still use N2O4, and there have been some dreadful toxic accidents. DonPMitchell (talk) 04:42, 9 October 2008 (UTC)


 * It's not actually that bad, it has better ISP density than LOX. Bruce Dunn ran a whole bunch of different numbers, and it looks like some peroxide/fuel mixes outperform lox/kero in a launch scenario. And HTP is used on every Soyuz launch to run the turbopumps of course, so there's extensive history of use, as well as Black Arrow.- (User) Wolfkeeper (Talk) 00:05, 27 December 2008 (UTC)


 * There are other liquid oxidizers that are not cryogenic: Nitrogen tetroxide, Hydrogen Peroxide, Nitric Acid, Nitrous Oxide N2O. Why is there abnsense? Also, hydrogen peroxide is already mentioned to have somehow lesser ISP, but it has greater density which means less weight for the axidizer tank. And N2O, although liquid at room temp but at relatively high pressure. Nitrous oxide boiling temp at std pressure is far higher than that of LOX, is it considered cryo or not, at this temperature. Dian Nikolow (talk) 17:58, 5 June 2021 (UTC)

The diagram
That NASA diagram has a little problem in that the propellants should really be drawn out of the bottom of the tanks unless they are both gaseous. I dunno quite how to fix it myself, so leave it for someone more savy... Bill Wwheaton (talk) 14:56, 16 March 2008 (UTC)
 * There were two redundant schematic images in the lead. I have removed the latter, which lacked the propellant pumps it mentioned, and was in any case less realistic than its rival. The problem with the other, in that the propellants are shown as drawn from the 'top of the tanks remains, however.  This obviously would not really work. Wwheaton (talk) 16:32, 26 December 2008 (UTC)

Move
Maybe we should move it to liquid-fuel rocket instead of liquid rocket. —Preceding unsigned comment added by Stinkypie (talk • contribs) 05:46, 27 September 2008 (UTC)
 * I arrived independently at the same conclusion and moved the page. Oleg Alexandrov (talk) 17:34, 26 December 2008 (UTC)
 * Um... shouldn't it be at liquid propellant rocket?- (User) Wolfkeeper (Talk) 23:50, 26 December 2008 (UTC)
 * Perhaps should really be at liquid rocket engine, although issues like slosh are liquid rocket specific, so I'm not 100% sure.- (User) Wolfkeeper (Talk) 23:54, 26 December 2008 (UTC)

Suggest merging engine issues into rocket engine
Given that we have a fairly comprehensive article on rocket engines that discusses liquid-fueled engines, I suggest that the sections in this article on injectors, combustion instability, cooling, and ignition be merged into that article, and this one concentrate on overall vehicle and system issues. Wwheaton (talk) 17:00, 26 December 2008 (UTC)


 * I don't think it's a good idea. This article is on liquid *rocket*s rather than liquid rocket engines.- (User) Wolfkeeper (Talk) 00:08, 27 December 2008 (UTC)


 * ?? I'm confused, (User) Wolfkeeper (Talk); your statement is exactly what I intended to say, I think. So do we agree, or disagree?  I suppose that the engine-specific details should be in the rocket engine article rather than be repeated here.  Mainly because I want to avoid the need to maintain near-duplicate material, and not have to be constantly trying to keep it up to standard in two places with inevitably different occasional editors dipping in and out.  Wwheaton (talk) 07:20, 27 December 2008 (UTC)


 * No, I mean I think that injectors, combustion instability, cooling, turbopumps etc. are specific to liquid rockets/engines and hence are probably better covered here rather than in the general article rocket or rocket engines. Both articles are too general to cover these topics well, although need to mention them. Also things like slosh, and antivortex baffles, and tank pressurisation issues need to be here, in reasonable detail, possibly with links out to more specialised articles.- (User) Wolfkeeper (Talk) 10:47, 27 December 2008 (UTC)


 * If the article gets too big here then we could create an article liquid rocket engine.- (User) Wolfkeeper (Talk) 10:49, 27 December 2008 (UTC)


 * Hybrids do suffer from some of these issues, but probably are better of linking to coverage here.- (User) Wolfkeeper (Talk) 10:47, 27 December 2008 (UTC)

Paulet's Claim Likely A Fraud
In George Sutton's seminal work "History of Liquid Propellant Rocket Engines", he spends a page discussing Paulet's claim in detail. Paulet claimed to operate a 90 kgf engine, using gasoline and nitrogen pentoxide. He reported operating it in a pulsing node, like a combustion engine, using a spark ignition system to create 300 explosions per minute. Sutton concludes that it is very unlikely he could have achieved this result on his own or ignited a large engine at this frequency. Other historians have pointed out that and engine of this power, operating in pulsating mode in Paris, would have attracted widespread attention due to the tremendous noise it would have produced. How could there have been no witnesses or reports? At best, it was unprofessional for him to claim such an important invention with no proof. At worse, itappears to be fraudulent. DonPMitchell (talk) 07:22, 17 November 2010 (UTC)

Good point. Just for fairness, I will point ot that there are many things... even momentous things... that happen without leaving a solid, verifiable trace. Although I do find Paulet's claim to be unlikely, I will concede that it is possible. Gingermint (talk) 03:54, 25 January 2011 (UTC)