Talk:Reaction engine

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Move to 'Liquid Fuel Engine'

calling them 'rocket' engines is ambiguous, it could mean either liquid or solid fuel engines. Thecoshman (talk) 10:12, 12 October 2012 (UTC)

Image broken

I broke the picture trying to make it clear the picture was from before 0.18. — Preceding unsigned comment added by GregroxMun (talkcontribs) 18:50, 2 July 2014‎ (UTC)

The reason was, that {{version}} does add a link on it's own and the caption was already a link. So there was then a link within a link.— xZise [talk] 12:08, 3 July 2014 (CDT)

Wikipedia says reaction includes jet engines...

Our terminology is wrong. So says the Wikipedia article on Reaction engines.

From the article (emphasis added):

A reaction engine is an engine or motor which provides propulsion (thrust) by expelling reaction mass, in accordance with Newton's third law of motion. This law of motion is most commonly paraphrased as: "For every action force there is an equal, but opposite, reaction force".
Examples include both jet engines and rocket engines, and more uncommon variations such as Hall effect thrusters, ion drives, mass drivers and nuclear pulse propulsion.

This article starts with “ engine that generates thrust solely through the use of onboard propellant.” Wikipedia's article on rocket engines starts with defining them as using “only stored propellant mass for forming its high speed propulsive jet”. The KSP engine types also match with Wikipedia's list of rocket engine types. Really, this article's contents should be in “Rocket engine”.

Currently, this article includes RCS thrusters. They do qualify as rocket engines for using only onboard propellant. But because KSP organizes them separately from “Engines” under Command and Control, I'd suggest keeping all RCS info in one place in the Reaction Control System article and just linking to it under a heading in this article.

Jet engines are reaction engines, but not rocket engines. Obviously, they should stay in their own article.

We could still have a Reaction engine article, but it would logically have to list rocket engines, jet engines, and I'd suggest listing RCS engines as a separate sub-category of rocket engines. --Brendan (talk) 20:42, 2 March 2015 (CST)

Why do you want to split it? All reaction engines work very similar and there is no difference between ion engines and rocket engines (excluding RCS thrusters). The only odd balls are RCS thrusters (as they are not throttable but apart from that work like the other engines) and jet engines (as they have a thrust curve which affects their thrust in a not obvious pattern, as the Isp and fuel flow don't change accordingly). I'm not sure why we need to split it just because they are in separate sections of the VAB part list, which also changed the last times. — xZise [talk] 07:55, 3 March 2015 (CST)
Not splitting so much as moving. The current article begins with a factually wrong statement "A reaction engine is an engine that generates thrust solely through the use of onboard propellant." This describes rocket engines (SRBs, liquid fuel, and ion, plus monoprop/RCS) and the contents should, logically, be moved to Rocket engine. Then, the Reaction engine page should be a list of all the reaction engines, i.e. the rocket engines (including RCS in a subheading) and jet engines, and link to their articles. Already, jet engines have their own article, for good reason as you've given. RCS has its own article, owing to being controlled differently, but I would still list them on the Rocket engine page.
So, no splitting. Just moving and listing to correct terms. --Brendan (talk) 01:45, 5 March 2015 (CST)
Ah I was under the impression that a rocket engine has a combustion which wouldn't apply to ion engines (or in theory nitrogen thrusters and the like). Regarding listing them would be fine (as they work physically the same as other rocket engines).
So move reaction engine to rocket engine and engine to reaction engine and remove rover wheels from that new engine article? — xZise [talk] 09:29, 5 March 2015 (CST)
Yes, I think that would be the cleanest way of making the improvements. --Brendan (talk) 14:18, 5 March 2015 (CST)
1/ And why not put a short sequence for the jets? <secondly: by many of the classification (and I agree with them, because by the "wide" definition even the old fashioned air-propeller is r.e. too) it is not reaction engine, just impulse-principled engine>
2/ The ion engine and nuclear motors are not rocket engines).NWM (talk) 17:16, 5 March 2015 (CST)
The reworked Reaction engine page would mention and link to Jet engines, as well as ion engines and nuclear engines. All provide propulsion (thrust) by expelling reaction mass aka working mass. However, since the ground can be classified as working mass, rover wheels can count as Reaction engines. Thus, moving Engine to Reaction engine has even better support as a place for even any propellers that might be added moving air as working mass. --Brendan (talk) 21:20, 7 March 2015 (CST)

Reaction Engines which are Rocket Engines or not

We group parts into categories so users of this wiki can get their questions answered. Depending on your meaning of "expelling" working mass, aka (equal-and-opposite-)reaction mass, even rover wheels could count as reaction engines. At worst, wheels can be mentioned and linked.

Players of KSP care what engines can be used in space. No wheels or air-breathing jet engines. So, what should be included while sticking to the science that inspires KSP?

Starting with this from Wikipedia's article on rocket engines:

A rocket engine, or simply "rocket", is a jet engine that uses only stored rocket propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law. Since they need no external material to form their jet, rocket engines can be used for spacecraft propulsion as well as terrestrial uses, such as missiles. Most rocket engines are internal combustion engines, although non-combusting forms also exist.
  • Provides thrust by expelling working mass
  • Is a w:Jet engine
    • Forms a fast moving w:Jet stream of fluidic material into a surrounding medium
  • Uses no external material to form its jet

This describes just about everything in the Engines parts tab in KSP. There are some objections raised, though, about ion engines and, recently, nuclear engines.

The PB-ION Electric Propulsion System is based on the real-world Hall effect thruster. w:Hall effect thruster describes a process where propellant is positively ionized and attracted to electrons trapped in magnetic fields (Hall currents). The expelled reaction mass could be considered a beam rather than a jet, maybe. To the player, this is totally a non-issue. They work in space. Though the virtual necessity of collecting light on solar panels has parallels to collecting intake air, the expelled mass is all onboard xenon. Bottom line, they belong with the rockets with, at most, a disclaimer.

The LV-N Atomic Rocket Motor is based on the real-life w:NERVA, or "Nuclear Engine for Rocket Vehicle Application" and is a type of w:Thermal rocket. The energy to expel its working mass doesn't come from chemical reactions as with the other liquid fuel+oxidizer rockets, but it is a kind of rocket. In KSP, the LV-N uses standard rocket fuel including oxidizer. It works in space. It belongs with the other rockets.

As for SRBs and monopropellant engines, we've already agreed they are rockets. So Rocket engine should include:

  • Liquid fuel engines (including Vernor Engine)
  • Solid fuel engines (SRBs)
  • Nuclear rocket engines (just LV-N for now)
  • Ion thrusters (just PB-ION for now)
  • Monopropellant engines (O-10 and RCS thrusters)

If there are reasoned arguments why this list of rocket engines should be amended, make them below.

By this mutilated "definition" a kid standing on the well oiled skate-board after drunk 5 pack of beer, and propels the skateboard forward by pissing backwards is a rocket engine! In the original definition the energy derives from the propellant. NWM (talk) 07:13, 8 March 2015 (CDT)
What the?! Ever heard of … tone and decency? Just because you don't agree doesn't mean you can be rude. (And I don't care if you are invested in this wiki… in that case you should be even more considerate). And well that is Newton's third law for you… We usually don't think of it but it's a very important part. And your “kid” woul also work in space. Apollo astronauts couldn't get rid of the waste water whenever they wanted (I can't believe I made that reference).
Now to be honest I don't think it's important to split the parts into the real life counterparts but if at all only depending on game mechanics. The LV-N is not a thermal rocket… it's simply a normal rocket engine like any other LFE. It doesn't make sense and I don't have a problem with a short sentence/line/paragraph noting that. But there is nothing other to say about the engine how it works which isn't already covered by LFEs.
And I'm against something like a “monopropellant engine”, because RCS thrusters and O-10 work differently and only share the fuel type (and the features of that fuel type). If you look in the part definition all engines except RCS thrusters are defined almost identically but just with different fuel ratios. — xZise [talk] 10:15, 9 March 2015 (CDT)