Let jet engines fly in methane/hydrogen atmospheres by burning oxidizer

[goduranus]

Jet engines should be useable in hydrogen or methane atmospheres, such as on Jool, by burning Oxidizer instead of Fuel.

In an oxygen-rich atmosphere, jet engines bring fuel to react with oxygen in the air, and use unburnt air as reaction mass.

Similarly, in a an atmosphere that's rich in "fuel"(Methane/Hydrogen atmospheres), jet engines can function by bringing it's own oxidizer to react with atmospheric hydrogen or methane, and similarly achieve higher ISPs than rockets.

This works in real life. Gameplay wise, it would enable a cool jet-powered plane doing Jool/Laythe mission, that uses Fuel for the Laythe leg of the mission, and Oxidizers for Jool.

Edited June 3, 2014 by goduranus
Clarify suggestion

[Deathsoul097]

At that point you just have a rocket engine though, as Jets have to expel the air. You would be better with a Jet/Ion/Electric Prop hybrid, and that's if you could escape Jool.

That said, using a LV-N to work as a reactor for a thermal TurboJet might be a more feasible idea.

[Kasuha]

You can use RAPIER engines for that purpose. Or Kethane jets.

[goduranus]

How would that be the same as a rocket?

It's using oxidizer from fuel tanks, reacting with hydrogen in Jool's atmosphere, and using unburnt hydrogen as reaction mass. It should be a vast improvement over rocket in terms of ISP.

[Red Iron Crown]

How would that be the same as a rocket?

It's using oxidizer from fuel tanks, reacting with hydrogen in Jool's atmosphere, and using unburnt hydrogen as reaction mass. It should be a vast improvement over rocket in terms of ISP.

That was my read on it, too, the OP means to burn oxidizer only when operating in an appropriate atmosphere, i.e. consume no liquid fuel.

While the idea is interesting, I wonder about its utility. Assuming that Eve, Duna and Jool are analogs of Venus, Mars and Jupiter respectively, only Jool's atmosphere would be usable for harvesting fuel. Is it worth implementing for the relatively rare usage of flying around in Jool's atmosphere?

Edited June 3, 2014 by Red Iron Crown

[Random Tank]

Is it worth implementing for the relatively rare usage of flying around in Jool's atmosphere?

It'd make Jool diving easier, to get the low atmosphere science... But not hugely useful really.

Edited June 3, 2014 by Random Tank
Damn s

[Kasuha]

This works in real life.

Do you have any reference where your idea works in real life? I strongly doubt jet engine designed for Earth atmosphere would work in atmosphere of kerosene fumes by injecting oxygen into the combustion chamber, particularly since atmosphere of kerosene fumes would have so vastly different physical properties that the engine would very probably fail to achieve required pressure and temperature for combustion to occur in the required way.

[LaytheAerospace]

This is about the least plausible engine, and least useful, engine I've seen suggested.

[Sirrobert]

How would that be the same as a rocket?

It's using oxidizer from fuel tanks, reacting with hydrogen in Jool's atmosphere, and using unburnt hydrogen as reaction mass. It should be a vast improvement over rocket in terms of ISP.

So basicly you want an engine that uses a COMPLETELY different fuel system than regular jet engines.

But for some reason, normal jet engines would just be able to switch between the 2 options?

yaaaa, no

[LaytheAerospace]

So basicly you want an engine that uses a COMPLETELY different fuel system than regular jet engines.

But for some reason, normal jet engines would just be able to switch between the 2 options?

Not just one different fuel, but two. Hydrogen OR methane. And it needs to be able to switch what it's taking from the fuel tanks from kerosene to liquid oxygen.

[goduranus]

I don't think it would be more challenging than getting the RAPIER to switch oxidizer on and off.

Kerbin> Fuel on, Oxidizer off

Space> Fuel on, Oxidizer on

Jool> Fuel off, Oxidizer on

[Sirrobert]

Yes it would.

The RAPIER always uses the same fuel mixture, the only thing that changes is where the oxygen comes from.

Your idea has to actually switch between different kinds of fuel AND has to account for fluctuations in the concentrations of said fuel in the air (which would, at the very best, cause wild fluctuations in the available thrust depending on pressure and makeup of the atmosphere)

There is a reason you destroy your car if you put in the wrong type of fuel.

There is also a reason why jet engines in KSP only work when there is actual oxygen in the air, rather than just 'there is atomsphere'

It may not be realistic, but it atleast has to be believable

[coolitic]

it doesn't work that way. Jet engines cannot consume oxidizer.

The exception is the rapier engine (switch modes) and it has the isp of most rocket engines when burning oxidizer.

[Red Iron Crown]

it doesn't work that way. Jet engines cannot consume oxidizer.

The exception is the rapier engine (switch modes) and it has the isp of most rocket engines when burning oxidizer.

OP is suggesting a third mode, where the engine would consume only oxidizer when drawing fuel to burn with it from an appropriate atmosphere. It's Isp would be higher than a rocket because it doesn't carry all its reaction mass with it.