Nukes [Heat up and push out at high speed and pressure] Fuel Only

[Brotoro]

I wouldn't bother making Nuclear engines use fuel only 'for realism' when our fuel is too unrealistically dense to be hydrogen.

[NERVAfan]

I wouldn't bother making Nuclear engines use fuel only 'for realism' when our fuel is too unrealistically dense to be hydrogen.

I can see that, but I think having 1 kind of LiquidFuel represent UDMH/kerosene/hydrogen fits the level of abstraction KSP mostly uses, while the oxidizer thing is just an unnecessary inaccuracy. So I'd still like them to burn just LF.

And technically you can use other things (ammonia/methane) in nuclear engines... but you wouldn't get KSP's 800 seconds specific impulse.

EDIT: And actually the specific impulse of the LV-T30/45, LV-909, Skipper, Poodle are closer to methane performance than kerosene or hydrogen.

Edited December 27, 2014 by NERVAfan

[sal_vager]

This is the kind of thing that's not massively important to gameplay, why can't a nuclear rocket engine also roast a few oxygen atoms for good measure? The only real life reason would be to prevent oxidation of the engine components.

This has also been brought up before several times, the devs do know of it but there's better things to do right now, such as the planned aero changes and resource mining

Technically, you can run an NTR on anything, even water.

[NERVAfan]

This is the kind of thing that's not massively important to gameplay, why can't a nuclear rocket engine also roast a few oxygen atoms for good measure? The only real life reason would be to prevent oxidation of the engine components.

Also, oxygen has higher molar mass so hurts your specific impulse.

This has also been brought up before several times, the devs do know of it but there's better things to do right now, such as the planned aero changes and resource mining

Oh, definitely, but it would be nice to see in the final version.

[zxczxczbfg]

It might be worth pointing out that, according to the sadly-postponed resource chart, LF isn't kerosene or hydrogen, it's Propellium

[Torquemadus]

Technically, you can run an NTR on anything, even water.

It's worth pointing out that the ISP of a rocket engine depends on it's exhaust velocity, which depends on the molecular weight and temperature of the exhaust gas. Ideally, you want the gas coming out of the exhaust to be molecules of a very light gas such as hydrogen, heated to the highest possible temperature without melting the engine. Remember that the goal is to give the rocket as much kinetic energy as possible for a given mass of fuel.

Nuclear and solar thermal rockets can use hydrogen because they don't have to react it with anything else to get the energy needed to heat the propellant. The absolute best performance available from chemical rockets is achieved by reacting the hydrogen with oxygen to produce water.

An alternative way to fuel a thermal rocket is to use water. This will produce the same ISP as a chemical rocket, but has the advantage that you can refuel anywhere you can find water. If you want to refuel with hydrogen instead, you'll need to electrolyse some water to get the hydrogen out, which requires a lot of electrical power.

The performance of the LV-N in KSP suggests that it uses hydrogen, since it has a much higher ISP than the chemical rocket engines.

[Whirligig Girl]

This is the kind of thing that's not massively important to gameplay, why can't a nuclear rocket engine also roast a few oxygen atoms for good measure? The only real life reason would be to prevent oxidation of the engine components.

This has also been brought up before several times, the devs do know of it but there's better things to do right now, such as the planned aero changes and resource mining

Technically, you can run an NTR on anything, even water.

But it would be so easy to implement in stock! Literally just remove Oxidizer requirement from the engine and you're good! The only reason I don't do it already is because that would make it inconsistent with other people's games and that matters to me for no good reason.

[Renegrade]

But it would be so easy to implement in stock! Literally just remove Oxidizer requirement from the engine and you're good! The only reason I don't do it already is because that would make it inconsistent with other people's games and that matters to me for no good reason.

I like it - change two lines in one file, and you're simulating the heavier tankage that LH2 requires for a REAL NERVA, and maybe encouraging people to move on from the neophyte stage of spamming nukes at EVERY problem that appears...all without crufting stock up with a thousand different types of tanks and fuels.

[Scoundrel]

Heh, I was wondering when someone would suggest this. NovaSilisko made the LV-N, and with him gone, likely Squad forgot to change it from LFO to LF once tweakables were added. I too would like to see LV-Ns changed to LF only.

[Renegrade]

I like this idea so much, it's going into my Horrible Nerf:

// LV-N Atomic Rocket Motor :: Squad/Parts/Engine/liquidEngineLV-N/liquidEngineLV-N.cfg
@PART[nuclearEngine]
{
	// @mass = 2.25
	@MODULE[ModuleEngines]
	{
		// @maxThrust = 60

		// Make the LiquidFuel ratio 1:1, and remove Oxidizer.
		@PROPELLANT[LiquidFuel]
		{
			@name = LiquidFuel
			@ratio = 1.0
		}
		!PROPELLANT[Oxidizer] {}
	}
}

I hereby place the above code block into the public domain. (Translation: Please feel free to use it)

By the way, that reduces effective tankage from 9:1 (for 1.25/2.5m parts) to the following:

1.25m/2.5m tanks: 4.6:1

mk1 jet fuel tank: 5:1

mk2 jet fuel tanks: 7:1 (short and long at least)

mk3 jet fuel tanks: 9.3333:1 (9 and 1/3 to be exact)......OP!! NERFPLOX

Maybe this wasn't such a good idea with those mk3 tanks floating around...what the heck, Squad??