Talk:Electric-pump-fed engine

Title

The title is incorrectly using an en-dash, rather than a hyphen. Please could an admin move it? The Rambling Man (talk) 06:30, 23 January 2018 (UTC)

The title was correctly using an en dash when The Rambling Man incorrectly moved it. It now needs to be moved back. See thread below, per instructions at Wikipedia:Requested moves. — ¾-10 01:34, 24 January 2018 (UTC)

Nope, but I wish you luck in your endeavours! The Rambling Man (talk) 07:42, 24 January 2018 (UTC)

AC DC

The article quite incorrectly implies that electric pump fed rocket engines will generally use an inverter. This is provably false as the only extant operational design uses a DC motor. The article also states that electric motors generally need alternating current. This is also not true. Hopefully someone with more free time than I have at the moment will fix this. It's become more important since the New Zealand launch. Georgekwatson (talk) 00:27, 24 January 2018 (UTC)

would be nice to say why this design is an improvement, or more efficient, or whatever

Yes for me too, please: Why should an heavy and inefficient battery with low specific energy plus an expensive, slow and not specially efficient electric motor be an improvement over a fast and versatile gas turbine burning an high specific energy propellant? 194.174.76.21 (talk) 10:25, 25 January 2018 (UTC) Marco Pagliero Berlin

I've removed the inverter stuff.

As to why a heavy battery would be an improvement: I think it would be good to have this added. I strongly suspect that the answer is that in weight / power terms, it isn't. But in terms of simplicity of engine and pump design it is a big win William M. Connolley (talk) 11:34, 25 January 2018 (UTC)

You may be right, but as you say, it should be added and sourced. I could not find any explanation on RocketLabUsa. 194.174.76.21 (talk) 14:40, 26 January 2018 (UTC) Marco Pagliero Berlin

There is a paper that discusses the advantages here. To summarize, compared to a pressure-fed rocket engine, an electric pump-fed engine exhibits higher exhaust velocity aka specific impulse, due to a higher combustion chamber pressure. A pressure-fed engine is common for relatively small vehicles due to its simplicity, such as the Falcon 1 upper stage, the Apollo service module and LEM, and so on. Another propulsion type frequently seen in small stages is a solid motor, such as the Star 48 kick stage. Specific impulse for solid motors is also relatively poor, and they are additionally unable to perform multiple burns. Compared to advanced turbo-pumped cycles, which may have extremely good specific impulse, an electric pump-fed engine exhibits lower development and manufacturing costs due lack of high temperature turbomachinery and easier controllability. Rocket Lab recently posted an update giving a specific impulse of 343s for the upper stage engine, which is rather good for a LOX/RP-1 engine. For a comparison of another LOX/RP-1 upper stage engine with similar thrust it's useful to look at Kestrel (rocket engine) used on Falcon 1, with a specific impulse of 317s. To summarize the summary, it's not the highest performance cycle known, but electric pump-fed has a niche where the other choices are either much lower performing or much more expensive and difficult. ArbitraryConstant (talk) 08:03, 3 February 2018 (UTC)

Requested move 24 January 2018

The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review. No further edits should be made to this section.

The result of the move request was: page moved to Electric-pump-fed engine. (non-admin closure) Steel1943 (talk) 19:05, 1 February 2018 (UTC)

---

Electric pump-fed engine → Electric pump–fed engine – My edit corrected a venial mishyphenation (https://en.wikipedia.org/w/index.php?title=Electric_pump-fed_engine&diff=prev&oldid=821874204); The Rambling Man's edit un-fixed it to restore the venial error (https://en.wikipedia.org/w/index.php?title=Electric_pump-fed_engine&diff=next&oldid=821921671). The principle that hyphens do not bridge across open compounds is covered at Wikipedia:Manual of Style § Instead of a hyphen, when applying a prefix to a compound that includes a space. In this instance, there is no rewording/recasting of the term to be done, because the established name (of the type of engine) is the established name. But what does need to be done is professional punctuation rather than the amateur type. Who can move the page? In professionally edited work, "an engine that is fed by an electric pump" is an "electric pump–fed engine" or an "electric-pump-fed engine" but not an "electric pump-fed engine". As opposed to work not professionally edited, in which the latter would no doubt be found. — ¾-10 01:34, 24 January 2018 (UTC)

I have saved a quote from another 'net exchange, that is appropriate I think for all such discussions, especially in such tenor:

There's no winners here, just the sad trolling the bad trolling the mad. I call Cripple Fight on this.

The biggest wars are over minutiae. Shenme (talk) 04:09, 24 January 2018 (UTC)

Well is it an (electric pump)-fed engine or an electric (pump-fed engine)? – Nixinova ⟨T|C⟩ 05:05, 24 January 2018 (UTC)

• Move to electric-pump-fed engine per MOS:HYPHEN. It's very definitely an "(electric pump)-fed engine" not an "electric (pump-fed) engine"; it is not an electric engine of any kind, but a rocket-fuel engine, fed by an electric pump. An alternative, already mentioned in the article, is electric-feed engine, which is more WP:CONCISE but probably not the WP:COMMONNAME, which seems to be one variant or another of "electric[-]pump[-]fed engine", with officialese usually dropping hyphens because that's just what officialese does (and WP is not written in officialese, but following its own style guide; if anyone thinks COMMONNAME is a hyphenation style policy they are mistaken). An en dash (–) is not correct anywhere in this name, per MOS:DASH; it is used when juxaposing and indicating a relationship between essentially equal things, as in the Sapir–Whorf hypothesis and the Mexican–American war.  — SMcCandlish ☏ ¢ 😼  07:35, 24 January 2018 (UTC)
• Keep as is or move to electric-pump-fed engine. We'll use our MOS for this. The Rambling Man (talk) 07:42, 24 January 2018 (UTC)
• I find electric-pump-fed engine to be clearest, other constructions sound like they are referring to an electric rocket engine. I don't think the MOS on applying prefixes applies. — Carl (Seaplant (talk) 08:12, 24 January 2018 (UTC))
• This constitutes the fourth support for move to "electric-pump-fed engine", if not willing to use the en dash. The MOS section does indeed apply to this, and Chicago Manual of Style 16th edition at section 6.80 shows exactly how (the examples there include "the post–World War II years" and "country music–influenced lyrics"). The principle behind the rule is not "only with a prefix, because it is a prefix"—the principle is that hyphens don't bridge across open compounds; they only link the words they're connected to (in professionally edited text as opposed to text by Randy from Boise, whose punctuation choices or omissions are not a reliable source). I will be moving this page to electric-pump-fed engine soon unless multiple orthographically valid objections appear below. — ¾-10 11:49, 24 January 2018 (UTC)

  No, you won't move anything now, as you are clearly involved. This move request should be processed by someone who can indpendently assess the proposal and the community consensus, along with taking Wikipedia's manual of style into account. So please desist from making further threats of sudden closure. The Rambling Man (talk) 12:00, 24 January 2018 (UTC)

  Right; correct consensus instinct, but one does not close an RM one started, nor move an article while RM is open; a third party needs to do it.  — SMcCandlish ☏ ¢ 😼  19:59, 25 January 2018 (UTC)

  And that's a misreading of CMoS. There is no open compound here, because it is not an (electric) (pump-fed) (engine), nor an (electric-pump) (fed-engine), nor an (electric-pump) (fed) (engine), nor an (electric) (pump) (fed-engine). It is an (electric-pump-fed) (engine), more specifically an (electric-pump-fed) [rocket] (engine), a.k.a. an (electric-feed) (engine) for short.  — SMcCandlish ☏ ¢ 😼  19:59, 25 January 2018 (UTC)

I disagree with SMcCandlish; it is an ((electric-pump)-fed) engine. Zaslav (talk) 20:21, 25 January 2018 (UTC)

That's not disagreeing, thats being more specific, and agreeing with that I said in the earlier round, using different formatting: 'It's an "(electric pump)-fed engine" not an "electric (pump-fed) engine".' Could be laid out other ways, e.g. ((electric (pump (fed))) (engine)), etc. The point being, there is no open compound here. People who are not following typical hyphenation style are manufacturing the appearance of one when they write things like "electric pump-fed engine", which would be a type of electric engine; or "electric-pump fed engine", which doesn't appear to mean anything parseable, since "fed engine" isn't a thing. People do stuff like this mostly because some prescriptivist teacher in 7th grade mistaught them to use only one hyphen per construction no matter what, and there was at least one style guide from the 1980s or so that actually pushed such a "rule".  — SMcCandlish ☏ ¢ 😼  20:36, 25 January 2018 (UTC)

Indeed, perhaps now Three-quarter-ten should stop claiming to have the "answers" when those "answers" are not correct. It's all very well pointing to sections of non-Wikipedia guidelines, but that's not how it works here. The Rambling Man (talk) 20:41, 25 January 2018 (UTC)

The en dash style is NOT orthographically incorrect. I now understand and accept that WP will not use that style, but that has nothing to do with it being misguided orthographically. What I pointed to in CMOS is not orthographically incorrect. The CMOS example of "country music–influenced lyrics" (that's an EN DASH there, NOT A HYPHEN) is one of several correct styles in English, along with "country-music-influenced lyrics" (those are two hyphens). But *"country music-influenced lyrics" (one hyphen) is not correct. The style with the en dash is the style of the American Medical Association, so don't anyone tell me that it's wrong, or that I'm misguided about it, just because they were ignorant of that fact. And "country music" there is in fact an open compound, whether anyone here fails to understand that or not. Just as "country music–influenced lyrics" (EN DASH) or "country-music-influenced lyrics" (two hyphens) are lyrics that are influenced by country music, an "electric pump–fed engine" (EN DASH) or an "electric-pump-fed engine" (two hyphens) is an engine that is fed by an electric pump. Now, it is a valid point that WP's MOS isn't identical to CMOS, and WP:MOS is what will apply here. That's fine, I accept that, and I now understand that WP:MOS won't use that piece of CMOS style (if only because the people arbiting WP:MOS don't even properly understand that style, as seen here). But if anyone is misapprehending that the en dash style is "incorrect" in the sense of orthographically wrong, as opposed to just "not the style that WP prefers", they are just displaying their own ignorance. Regarding the WP bureaucratic rules about who is allowed to move, I am now duly informed. — ¾-10 02:41, 26 January 2018 (UTC)

Nice combination of wall of text, shouting and personal attacks. Duly noted. The Rambling Man (talk) 06:28, 26 January 2018 (UTC)

Imagine whatever you need to imagine to make yourself feel great. The selected caps were for emphasis to ensure clarity/prevent misreading. The facts are facts regardless of who understands them; that's not an attack, it's just a fact. The paragraph is not a wall of text to anyone willing and able to read it. Wrong times three. Not attacking you, just noting facts. — ¾-10 12:17, 26 January 2018 (UTC)

No, we call it SHOUTING. The wall of text is obvious. Suggesting that people are "displaying their own ignorance" is clearly a personal attack. I suggest you quit before this becomes a real problem that could prevent you from editing further. The Rambling Man (talk) 12:34, 26 January 2018 (UTC)

... threatens the person who's supposedly against "threats"? How rich. Good thing I'm done with this now. — ¾-10 03:12, 27 January 2018 (UTC)

Good. If you have a moment, please re-read WP:NPA. The Rambling Man (talk) 09:16, 27 January 2018 (UTC)

• Move. To a non-expert "electric pump-fed engine" looks like an electric engine, which would be exciting and is what attracted my attention. I oppose "electric pump-fed" for that reason. Bear in mind that not all WP readers are expert on rocket engines.

How about "electric-pump engine"? The "fed" is redundant, as what else does a pump do? I would favor "electrically pumped engine" for best grammar, but I know that won't (pardon the expression) fly. I also know that there may be established usage. Zaslav (talk) 20:47, 24 January 2018 (UTC)

• Move. Makes sense to me. A very minor error but if it floats your boat then lets do it. Lord David, Duke of Glencoe (talk) 21:25, 24 January 2018 (UTC)

I cannot catch the logic of "an electric engine fed by a pump" 194.174.76.21 (talk) 09:56, 25 January 2018 (UTC) Marco Pagliero Berlin

To Marco Pagliero Berlin: That is why I think it should be changed to something that makes sense. Zaslav (talk) 20:23, 25 January 2018 (UTC)

Thanks, so I'd say Move too, Electric-pump-fed engine sounds OK to me 194.174.76.21 (talk) 14:18, 26 January 2018 (UTC) Marco Pagliero Berlin

• Agree that "electric pump-fed engine" is wrong. Electric-pump-fed engine looks to be best. It is an engine, fed by an electric pump. Not an electric engine, fed by a pump William M. Connolley (talk) 22:30, 25 January 2018 (UTC)
• Move. Suggested title more accurately describes the function of the engine. WolreChris (talk) 14:43, 26 January 2018 (UTC)
• Electric-pump-fed engine since the en dash version is not one of the uses suggest by MOS:DASH, and is less clear. Dicklyon (talk) 05:14, 27 January 2018 (UTC)
• Move to electric-pump-fed engine. The current title is confusing in this context (even though it may follow the MOS). Using two hyphens is significantly clearer. (For the record, the MOS is referring to compounds, which I'm not sure applies here)♫CheChe♫ talk 15:52, 27 January 2018 (UTC)
• Suggestion How about Electric feedpump engine? No hyphens needed, no ambiguity. I would support the three-hyphen solution (Electric-pump-fed engine) if this isn't acceptable. Tevildo (talk) 22:32, 28 January 2018 (UTC)

---

The above discussion is preserved as an archive of a requested move. Please do not modify it. Subsequent comments should be made in a new section on this talk page or in a move review. No further edits should be made to this section.

The wired.

> The pumps are powered by an electric motor, with electricity from a battery bank.

Strictly speaking that statement in the article is not not true. Some french rockets used wire spools for stabilization during early phase of flight, see: https://en.wikipedia.org/wiki/V%C3%A9ronique_(rocket). It is theoretically feasible to supply electric-pump rockets with juice via metallic wires during the first crucial few hundred meters of flight, so as to limit the weight of lithium batteries they need to be carry onboard and the environmental pollution their jettison could cause. 94.21.229.49 (talk) 20:27, 11 December 2023 (UTC)