Talk:Hypergolic propellant

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Surely that should be Aniline-Nitric acid, not Hydrazine-aniline? PML.

"... the trend in ICBMs has been to move toward solid fuel boosters."

Oh man, this sounds almost sarcastic to me. There are trends in ICBMs, really? What's hot this year, haha.

Not funny. -- .~.

Article talks about "hyperbolic" engine. That's probably incorrect, but someone who actually knows should make the edit.

[edit] 4th Paragraph

The fourth paragraph opens with the sentence: "They are less likely to explode when starting." But the previous sentence refers to both Solid Fuels and Hypergolic Fuels - so which is less likely to explode? I assume Solid Fueled rockets because the article implies they're more stable, but I'm not a rocket scientist.

The article for hard start seems to focus on hypergolic fuels, so I would assume that they are more likely to explode than solid fuels. Solid propellants should not explode if the nozzle opening is sufficiently large to prevent a buildup of pressure inside the engine. I suppose a hypergolic engine could explode if the components were mixed too quickly, in the wrong proportions, etc. I am not going to make any changes until we can get a source. --71.227.190.111 00:45, 16 July 2006 (UTC)

I think you misread the article. Hard start is particularly an issue with non hypergolic liquid fuels, as in addition to the fuel and oxidiser entering the chamber, ignition and associated timing is required. Ignition failure or delay is the normal cause of a hard start. Hypergolic fuels self ignite on mixing, so the ignition step is not required/not as critical.The specific inclusion of hypergolic fueled systems in the hard start article is, I believe, because although a hard start is less likely with a hypergolic fuelled rocket motor, it is by no means impossible. So my understanding is that in order of risk of startup is liquid fuel non hypergolic - hypergolic - solid fuel.

Solid fuel rockets are essentially uncontrollable and fixed thrust, so lack flexibility. Liquid fuelled rockets can provide variable thrust, can to get higher specific impulse, and in some cases handling is easier than for hypergolic fuels. On the pad ignition is easier to control. Thus a common set up is solid booster/liquid fuelled first stage, with hypergolic upper stage(s) where ignition is required in flight. The Shuttle main engines are liquid fuelled, but the orbital manoeuvring system is hypergolic.

(Fair use image removed by bot) Serious hard start --Shoka 23:03, 24 October 2007 (UTC)

[edit] Linking to disambiguation pages

Perhaps the disambiguation page was created after this, but I'm so tired of articles linking to disambiguation pages, when it clearly should be linked to an article. Anyway, I linked MMH properly, and not to a disambiguation page.

[edit] HTP / kerosene

Why isn't this a "true" hypergolic? In an article on rocketry, the crucial factor making hypergolic propellants of interest is their simple and reliable ignition, without the need for separate igniters and the risk of hard starts. Although the British HTP / kerosene engines did use a prior catalytic decomposition, they had all the engineering benefits of being hypergolic engines (just look at their reliablilty record, compared to their contemporaries). In a purely chemical context, the question of whether cold HTP + kerosene is hypergolic is indeed arguable, their place in rocketry seems secure. Andy Dingley (talk) 13:13, 28 April 2008 (UTC)