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This article is poorly written and needs to be revised and possibly intergrated into the Water rocket article. —Preceding unsigned comment added by 71.71.73.98 (talk • contribs)

I have made substantial changes to it, and added two references/citations. If you believe it should be incorporated into Water rocket, add a Merge tag. --Jatkins ^{(talk - contribs)} 17:12, 6 October 2007 (UTC)[reply]

I agree here. This article is in desperate need of...Wikification, I think they call it. Indeed; I found this article by an internal link through Water rocket; and I also voice the opinion of merging the two articles. Danny Sepley 17:34, 4 November 2007 (UTC) —Preceding unsigned comment added by Danny sepley (talk • contribs)

It's not a water rocket though. Water rockets emit... water. Hot water rockets emit steam.WolfKeeper 18:30, 4 November 2007 (UTC)[reply]

I agree. The term "hot water rocket" makes them sound amateur; whilst very uncommon, they are entirely different rockets - indeed, as you noted, they emit water vapor, not liquid water. --Jatkins ^{(talk - contribs)} 18:33, 5 November 2007 (UTC)[reply]

Where the article says mass fraction, perhaps it should say mass ratio instead? A high propellant mass fraction is a bad thing; a high mass ratio a good thing. -- 80.168.225.30 (talk) 13:52, 18 June 2009 (UTC)[reply]

Careful here, it depends what you're optimising for. If you're optimising for absolute performance, everything else being equal, a high mass fraction is highly desirable; you want to stuff as much propellant in as possible.- (User) Wolfkeeper (Talk) 14:01, 18 June 2009 (UTC)[reply]

The article suggests that 'a modern hydrogen engines' (sic) can produce an Isp of 465 seconds. I assume the author is referring to liquid hydrogen/ liquid oxygen engines so 465s is too high. In reality it's more like 405s in vacuum, and slightly less than 400s in atmosphere. 465s Isp is reserved for engines using rather more exotic (and toxic) propellants. — Preceding unsigned comment added by 147.197.164.73 (talk) 15:27, 17 December 2013 (UTC)[reply]