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Colonel_Panic

Mod to add non-oxygen atmospheric jet engines?

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Quite simply, it should be possible to run a jet engine in atmospheres not containing oxygen, as long as you provided your own oxygen source (oxidizer tanks), and it would have the benefit over rocket engines that it would still be far more fuel efficient for providing thrust. This would allow construction of spaceplanes made specifically for atmospheres on bodies such as Duna and Eve. Perhaps even including special methane-breathing engines that require ONLY oxidizer to run in atmospheres containing the combustible substance (Eve?)

Before anyone suggests it, I am not looking to run Kethane mod. I want something simple that adds only 2-4 engine prototypes and maybe special air intakes for this specific purpose and doesn't need exotic resources to work. My VAB has enough useless parts already.

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Jet engines efficiency lies in the fact you don't have to carry oxydizer. If you have to carry it, you can throw away compressor and turbine because there's no intake air to pressurize, and you end up with a rocket engine.

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I think what you are describing is a rocket engine. Using oxidizer instead of atmospheric oxygen is one of the primary differences between the two. If you're looking for a rocket that's more efficient in atmosphere, I suggest an aerospike engine or RAPIER.

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I think you misunderstand the concept here. It would not be as efficient as an air breathing engine in an oxygenated atmosphere, but the energy of combusion can be much more efficiently harvested to produce thrust by turning a turbine. Think of it as a turbojet with direct oxygen injection, or an internal combustion engine with a prop and NOS. The idea is you're using a tank of oxygen to allow combustion, and it's still more efficient to do it this way than just dump propellent out the back, so long as you have an atmosphere to swim through.

This is the reason speedboats and submarines use propellers and not rockets, despite being unable to breathe water.

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I think you misunderstand the concept here. It would not be as efficient as an air breathing engine in an oxygenated atmosphere, but the energy of combusion can be much more efficiently harvested to produce thrust by turning a turbine. Think of it as a turbojet with direct oxygen injection, or an internal combustion engine with a prop and NOS. The idea is you're using a tank of oxygen to allow combustion, and it's still more efficient to do it this way than just dump propellent out the back, so long as you have an atmosphere to swim through.

This is the reason speedboats and submarines use propellers and not rockets, despite being unable to breathe water.

You mean like this? http://en.wikipedia.org/wiki/Air-augmented_rocket

Basically, you want to suck air in the intake with a compressor and possibly a bypass fan, inject both fuel and oxidizer, burn them, run the exhaust through a turbine and then out a nozzle to produce thrust, right?

I also definitely support having jet engines that operate in a reducing atmosphere and carry onboard oxygen.

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You mean like this? http://en.wikipedia.org/wiki/Air-augmented_rocket

Basically, you want to suck air in the intake with a compressor and possibly a bypass fan, inject both fuel and oxidizer, burn them, run the exhaust through a turbine and then out a nozzle to produce thrust, right?

I also definitely support having jet engines that operate in a reducing atmosphere and carry onboard oxygen.

Yes, exactly, well, more or less.... a ramjet based design would be useful for high speed and transatmospheric flight, SSTOs, etc..., but even a turbojet based design makes sense when you're thinking outside the box of terrestrial atmosphere. Kerbalnauts may want for example to operate an aircraft on Eve for short distance, low-speed flights, and the cost of fueling it would make efficiency gains easily outweigh those of raw speed or thrust.

Sir, that's called a hybrid rocket, less efficient than a jet engine and less performance than a rocket.

But, may I interest you in a Nuclear Thermal Ramjet

I don't need anything especially exotic. Anything is more efficient than a jet engine that produces no thrust due to lack of breathable oxygen.

That said, thinking outside the box here, it makes sense in a non-terrestrial environment to pursue alternative propulsion engines capable of utilizing compounds present in alien atmospheres. Just because an atmosphere lacks oxygen doesn't mean it lacks the potential for harnessing the power of exothermic chemical reactions when introduced to other compounds carried as fuel.

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He's not after a rocket, turbines move reaction mass no matter what atmosphere they're in. He's just after one that provides all it's own propellant rather than pulling some out of the atmosphere; you'd need a lot of oxidizer but it'd still be more efficient in a reasonable atmosphere than a straight-up rocket as it's not relying on the propellant for all the reaction mass.

Turbines for methane atmospheres which just provided oxidizer would be another thing.

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He's not after a rocket, turbines move reaction mass no matter what atmosphere they're in. He's just after one that provides all it's own propellant rather than pulling some out of the atmosphere; you'd need a lot of oxidizer but it'd still be more efficient in a reasonable atmosphere than a straight-up rocket as it's not relying on the propellant for all the reaction mass.

Turbines for methane atmospheres which just provided oxidizer would be another thing.

^what he said.

I really don't know what Eve's atmosphere is supposed to be composed of, but if it contained, say, a high amount of methane, it would be worthwhile to have special methane-breathing engines that used oxidizer as fuel for the sole purpose of EVE spaceplanes.

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This is an awesome idea, it'll make leaving Eve something feasible with sub-par potatoes like my own.

Although I did once see a thing somewhere suggesting magnesium as a fuel and burning it with the high concentrations of CO2 in the atmospheres of Venus in Mars, however I'm no scientist (unless you consider going up 5 meters and turning around science, then I'm an expert) so I can't say whether that'd actually work, but this would make the engines more versatile instead of them only working on Eve.

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Nothing beats Nuclear Thermal, for non oxygen atmospheres.

Though perhaps the radiation is getting to me...

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Not exactly what you are looking for, but KSP interstellar had nuclear thermal jets.

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You'll want a Jet Engine with an oxidizer input in addition to liquidfuel, and an air intake with the CheckForOxygen option turned off. I could do that if you tell me which Jet Engine and Air Intake you want to use as the basis for your 'Turbofan-Rocket'.

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And my first mod is done.

I think this is quite exactly what you wanted, and gave my best to balance it by realism and gameplay so that you still have your challenge.

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I do not know of non-oxygen jets.

But for non-oxygen atmospheres, you could use electric props, eg from KAX or USI Exploration.

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No mention of Karbonite? I haven't checked if the karbonite fuelled jets need oxygen though, but the propfan doesn't.

Theres some ducted fans in FTT as well.

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I'm working on a mod called "It's Just Air". It allows jet engines to use oxidizer. I literally JUST finished the coding for the first test but if everything goes well, we'll be flying around on Eve in no time. I'm also adding intakes and fuel tanks for oxidizer that can also be used on rockets. My favorite use would probably be putting a small intake on top of a rocket and using very low thrust to lighten the load dramatically

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Although there is much discussion I have had difficulty finding work on this subject I have found the following:

Scientists have been researching atmosphere breathing engines in non oxygen atmosphere since before 1958.

the following link is a PDF file titled Atmosphere Breathing Engines In Astronautics by S.W. Greenwood and D.S. Carton

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwi05vvkk_POAhUL54MKHQwICCIQFggkMAE&url=http%3A%2F%2Frepository.tudelft.nl%2Fassets%2Fuuid%3A9b471a04-c479-4ab6-8939-24e910fce6f7%2FCoA_Note_No._88.pdf&usg=AFQjCNFU5u1pXHDjAUQpcd3keEr3381vRA&sig2=tmF9_1VT_p4QlvbsEjVATQ

Another link i found titled WSPC Develops Martian Jet Engine

http://www.wickmanspacecraft.com/marsjet.html

I think atmosphere breathing engines in non oxygen atmosphere is quite feasible especially considering some atmospheres like Jupiter, and Saturn have atmospheres that are combustible (hydrogen).  Instead of fuel all you need is an oxidizer.  I look forward to any mods on this.  I found Fireheart318 It's Just Air mod on Curse but there is no download link.  Picture looks like a J-X4 Whiplash engine that has been modified.

I miss the Kethane mod and would like to see something replace it.

Although it's not working completely as I like I have been messing around with the J-90 Goliath's .cfg file with much success as part of an Eve return mission.  I just changedcheckForOxygen to False, added an oxidizer, and deleted IntakeAir.  It works.  Although I would like to assume Eve's atmosphere is combustible considering it has Explodium Sea's and only an oxidizer is required I looked up Saturn's moon Titan which has lakes of methane and found that it's atmosphere is 98.4% nitrogen and only 1.4% methane, and 0.1-.02% hydrogen.  Comparing this to Earths 20.95% oxygen atmosphere and I have a hard time justifying using Eve's atmosphere as a fuel source.

In conclusion even if you have to provide both a fuel and an oxidizer, turbine engines are far more efficient then rocket engines.  Real scientists are working on the subject of atmosphere breathing engines in non oxygen atmosphere and I don't see any reason why it shouldn't be part of Kerbal Space Program.

 

 

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You can do it all in module manager - you just need an intake which mixes inert atmosphere ( usual resource name is IntakeAtm ) & O2 using the stock converter module. The fuel burn for turbines is horrible assuming ~20% oxygen content, however closed cycle piston engines are quite reasonable & useful things & have been around since WW2 ( in diesel form ).

Prop planes on Eve are reasonably viable, not something I've tried recently though.

Spoiler

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Edited by Van Disaster

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What you are really doing would be multiplying your jet engine's fuel consumption by the oxidizer/fuel ratio, then adding 1. If your jet needs 2 units of oxygen for every unit of fuel, you end up being one-third as efficient as a pure jet engine. This assumes you can practically burn the fuel-oxidizer mix using a jet-engine design, but that is beyond the scope here. 

I personally would like to see more electric fan/turbine engines. Places like Titan, Venus and Eve would then be optimal for planes. 

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