Exoplanetary jet engines

[Angeltxilon]

Exoplanetary jet engines? What want you mean brother?

Okay, the title can be confusing, but the idea is simple: I suggest add special jet engines to fly in "no kerbal like" planets.

Quote

Quote from the wiki:

A jet engine is an air-breathing engine which uses onboard liquid fuel and combusts it with the oxygen drawn from the atmosphere. Due to the lower air pressure at higher altitudes its thrust output varies accordingly.

Technically, any rocket engine is also a jet engine as it forms a high-speed jet of reaction mass. But for KSP players, the term is limited to engines dependent on intake air.

-snip-

• Cannot be used outside of an atmosphere that contains oxygen. In current version, it means they only function on Kerbin and Laythe.

The main problem of current jet engines is that only works in kerbin and laythe atmospheres.

This is not really a problem, because has logic, jet engines works burning fuel, so need a oxygen atmosphere.

However this do the planet exploration a little limited.

 

My idea is add special engines fly in not-oxygen atmospheres.

These are my ideas:

 

1. Propeller:

It would be a basic device, obtained in the first tech slot with relation with aircraft propulsion (ie, in the same slot that the "basic jet engine".

The propeller would have these disadvantages and advantages:

+ Propeller only needs electricity, and does not need fuel.

+ Propeller can work in any type of atmosphere (with notable density and pressure), because her propulsion is based by movement of such and not reaction.

+ Cheap.

- Propeller generates very little mounts of propulsion (low isp), unable to obtain supersonic velocities (in kerbal are 300 m/s), also can not support these velocities (explodes or simply does not work) and suffer very big increase of temperature at these speeds, so only works in subsonic and transonic slow speeds.

Also, propeller would require of special animation.

 

2. Dunian/Evenian jet engine:

It would be a special engine capable to work in any atmosphere that would make use of two things: intake air and "alkaline fuel".

What is alkaline fuel?

This jet engine that I suggest is based in real design for mars exploration aircraft. The real version make use of the atmosphere air (that can be of any type, except helium) and magnesium. The magnesium has a big relation with solid fuel, in fact my first idea was make use of solid fuel, but I think that by utility has more sense add a new different fuel.

Obviously "alkali fuel" does not fit much, it can be considered an aproximation of the final name, I am opened to suggestions to change the name.

This jet engine would be obtained in a advanced tech slot, like advanced landing, hypersonic fly or super-heavy rockery.

Disadvantages and advantages of the evenian/dunian jet engine:

+ Can work in any atmosphere.

+ Works as well as the "basic jet engine" (similar thrust) in Eve and Dune atmospheres.

+ Works as well as the cheap "turbofan engines" (similar thrust) in Kerbal and Laythe atmospheres.

+ Capable to obtain hypersonic speeds in cluster (in theory).

- Works with 1/2 the "basic jet engine" power in Jool atmosphere.

- Expensive as "RAPIER engine".

- Heavy as "RAPIER engine".

- Isp ever is minor to normal fuel-based jet engines, due to make use of alkaline fuel that is heavier.

The addition of this new jet engine also implies the addition of "alkali fuel tanks" that are a little heavier than fuel tanks.

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

Another alternative to "alkaline fuel" (if the idea of add a new material is not convincing), is the "solid fuel".

 

3. Nuclear jet engine:

We have nuclear thermal rocket engines, why not nuclear jet engines?

Nuclear jet engines would be heavy but would not make use of fuel, only intake air.

Disadvantages and advantages of the nuclear jet engine:

+ Does not make use of any type of fuel, works in any atmosphere.

+ Capable to obtain hypersonic speeds in cluster (in theory).

+ Unlimited flight possibility.

- Very heavy, like a "rocketmax engine".

- Power of thrust similar or superior to "basic jet engine", difficulty to obtain big velocities.

- Very expensive, like a nuclear thermal rocket engine or major.

As last curiosity, this type of engine was in development in the past: https://en.wikipedia.org/wiki/Nuclear-powered_aircraft

NEW: 4. Joolian jet engine:

A joolian would be similar to normal jet engine and dunian jet engine, but only can work in planets with hydrogen/fuel atmosphere.

Wait a moment the only hydrogen planet that we have is jool. I can not support this thing due to her specific single use.

Don't worry, be happy. Yes, we only have one fuel atmosphere planet, but is planned add two or three new gas giant in the future, in the update 1.1 or beyond.

Fount: http://wiki.kerbalspaceprogram.com/wiki/Planned_features#Celestial_bodies

 

How the joolian jet engine would work?

This engine would make use of the intake air in gas giant planets and liquid oxidizer.

 

Disadvantages and advantages of the joolian jet engine:

+ Can work in gas giant atmospheres.

+ Works as well as the medium price "turbofan engine" (similar thrust) in Jool atmosphere.

+ Capable to obtain hypersonic speeds in cluster (in theory).

- Only can work in gas giant atmospheres.

- Expensive as "RAPIER engine".

- Heavy as "RAPIER engine".

- Isp ever is minor to normal fuel-based jet engines, due to make use of oxidizer that is heavier.

The addition of this new jet engine also implies the addition of separed oxidizer tanks.

 

Thanks for read.

 

 

Edited April 4, 2016 by Angeltxilon
Information addition.Corrections.

[Wjolcz]

I agree. Electric propellers is something I've been wanting for a while. Not sure about the alkaline and nuclear jet engines, BUT we have the NTR and SABRE engines, which were never really used, so why the hell not?

[Rath]

I want electric props, and a fuel burning one in In the first node.  Give us a straight wing, fixed landing gear and a simple flap too.

nuclear Jets would be cool, but they must have a TWR under 1

[jwbrase]

I would not make them explode on high velocities per-se, but I would give them a low temperature limit. I would also make them incredibly draggy with the engine activated near or above Mach 1, and moderately draggy with the engine deactivated above Mach 1 (prop stopped and feathered) or with the engine activated and in idle throttle below Mach 1 (this corresponds to real properties of propeller-driven aircraft). I would give them good thrust and ISP (or power usage per unit thrust for electrically-powered) at low speed, degrading to fairly poor performance around Mach 0.5 or 0.6, and atrocious performance above that (though maybe with a high tech "Tu-95" style propeller that pushes the limit up by 0.1 or 0.2 Mach).

 

Also, one thing that annoys me with mod propellers that I've seen is that, IIRC, they don't seem to model prop torque, it would be nice to see that in stock props.

 

 

As far as extra-kerbal jets, I wouldn't have the ability for non-nuclear ones to work on Duna (where I think there's actually the potential for the NERV to be a good enough, though probably not great, aircraft engine). I'd have an atmospheric resource, in the manner of oxygen, on Eve and Jool called "Explodium vapor", representing vapor from the explodium seas (or at least similar chemicals) on Eve and representing hydrogen on Jool, and I'd have special jets that burned oxidizer with atmospheric explodium vapor. On the other hand, it's mentioned on the wiki that the density of the explodium seas is close to that of hydrogen peroxide, in which case it is chemically implausible for Eve's atmosphere to lack oxygen, as peroxide decomposes spontaneously to water and oxygen. In this case Eve could use the same jets as Kerbin or Laythe.

 

As an aside, something just struck me: As far as plausibility as real planets, Eve and Laythe are somewhat backward. The most plausible explanation for Eve's explodium seas (except for their density, which does tend to indicate peroxide, which is unlikely for other reasons) is some type of hydrocarbons, but for astrophysical reasons hydrocarbon seas (as seen on Titan) are not likely to occur in places with the warm temperatures found interior to the orbit of Ceres/Dres. On the other hand, Laythe, having liquid water on the surface, is much too warm for its position orbiting Jool, and would be much more plausible as a "Dinosaur Venus" planet as seen in sci-fi from the first half of the 20th century.

 

I'm a bit ambivalent about nuclear jets. On the one hand they're a logical next step in any setting where nuclear thermal rockets are available. On the other, they seem a bit overpowered for KSP as a game.
 

[KerikBalm]

Forget your alkaline fuel, what you want is an air augmented rocket/ramrocket/turboramrocket

https://en.wikipedia.org/wiki/Air-augmented_rocket

I've brought this up before:

In that first link, I even made a variant of the Turbo-Racmjet that functions somewhat like a ramrocket should... it gets 1200 Isp at sea level, 1600 Isp at 5 atms (ie, at Eve sea level, its Isp is half that of the Rapier on Kerbin), with Isp declining as it gets in thinner air, until its just a rocket with pretty poor Isp (295) and a bad TWR (6:1)

 

"Works as well as the "basic jet engine" (similar isp-power)"

No... it can have a similar TWR, but the Isp should be significantly lower, but still significantly higher than a normal rocket. By basic jet engine... do you perhaps mean the Juno?

" Works as well as the "turbofan engines" (similar isp-power)"

You must mean the wheesely... which used to be called the basic jet engine... or do you mean the whiplash, which used to be called the turbofan? you should really specify specific engine names here.

"Capable to obtain hypersonic speeds (in theory)."

-Not if its getting the Isp of the wheesely/goliath!

 

Nuclear thermal jet engines... I'm ok with that, they should be really heavy, Prokjet's atomic age pack seems to be a good balance.

As for propellors... there's firespitter... but I don't bother with firespitter, I jsut go with "ducted electric fans" Its easy to make a simple mod to add them.

Initially, I used the old "basic jet" model and the old "engine nacelle" model to make my ducted electric fans:

 

Then I decided the goliath looked better, so I madea .cfg file to rescale it to 1.25m, and changed it into an electric fan (the original goliath is still there), as it uses the same textures as before, it doesn't do much of anything to the memory use of KSP.

All you need to do is have an air intake set to "check for oxygen = false" ... this would allow that intake to supply any jet with intake air though... so I added a new resource: IntakeAtmosphere ... and made the intake supply that instead of "IntakeAir" ... so it won't supply IntakeAir to allow normal jets to run.

Next, I changed the resource use of the modded goliath to use IntakeAtmosphere instead of IntakeAir... and set "Ignore for Isp" to false (as intake atmosphere is the only resource it uses with mass), and changed the liquid fuel resource to electric charge... and of course changed the ratios. Then I changed the mass and thrust and velocity curves, and set part rescale to 0.5 to turn the 2.5m part into a 1.25m part... and I changed the name and description.

(I've since changed the name to E-125 "Rotor" Electric Fan)

(ox-stat-XLs from the asteroid day mod, to keep partcount down)

This version I made weaker than my previous version, which was a bit OP'd

I'm thinking of further changing it so that it doesn't produce any trails

[Angeltxilon]

An air-increased rocket or turborocket has the same problem of jet engine and ramjet in not-oxygen atmospheres.

I want mean that a turborocket would work equal to a RAPIER engine or normal chemical rocket in a not-oxygen atmosphere, since turborocket must obtain air with oxygen to burn such with the liquid oxygen.

In summary, air-increased rocket is not a good way to obtain exoplanetary aircrafts.

Edited April 3, 2016 by Angeltxilon

[KerikBalm]

"An air-increased rocket or turborocket has the same problem of jet engine and ramjet in not-oxygen atmospheres."

No they do not.

 

[Angeltxilon]

Okay, so, we suppose that the atmosphere air combustion also would work in not-oxygen atmospheres (thing that I doubt).

What would be the basis of this afirmation?

What are the chemical reactions of combustion/reduction that occur in, for example, N2 - CO2 atmosphere (type martian/dunian, venusian/evenian)?

 

At least an scientific article about the possibility of use turbo-rockets in Mars (for example) or other planet could be useful.

 

Edit: I read more about turborocket engine, it could work in martian atmosphere but only if make use of solid fuel (fuels like magnesium, aluminium compounds, etc; that can react with CO2, hydrogen and others) and not liquid fuel and oxidizer.

Again this is the same concept that the Evenian/Dunian jet engine that I suggest.

Edited April 3, 2016 by Angeltxilon
Aclaration

[KerikBalm]

*sigh* apparently you won't read the link, so I have to copy and paste/type it again.

"air combustion also would work in not-oxygen atmospheres"

NO! not combustion with air... combustion with carried fuel and oxidizer. An air augmented/Ramrocket could use fuel and oxidizer... on earth they run fuel rich because earth's atmosphere has oxygen... but that's not the main priciple here... its not the main way that jets are more efficient than rockets, or how propellors work.

in atmospheres this produces more thrust by using the hot fuel/oxidizer-mixture to heat and expand the collected reaction mass. But out of the atmosphere it's basicly a normal rocket engine in a "tube".

The main thing is using the atmosphere as reaction/working mass. An atmosphere of Inert gass like Argon/Krypton/Xenon would work equally well.

 

Suppose I have enough energy in 1 kg of fuel to expell that 1kg of mass to 4,200 m/s every second...

That means I also have enough energy to expell 4kg of mass at 2,100 m/s every second, which will provide twice as much thrust. If I mix my 1kg of fuel with 3kg of inert atmosphere, I can do that.

I also have enough energy to expell 16 kg of mass at 1,050 m/s every second, which will provide 4x the thrust of the initial rocket.

I simply need to find 15 kg of mass ot act as reaction mass, thats where the atmosphere comes in.

There is combustion, by the rocket using internally carried oxidizer, which produces a hot exhaust, when it mixes with the cooler atmosphere, that cooler atmosphere warms up and expands, which can produce thrust

Normal rockets the fuel and propellant/reaction mass are the same thing. Actually, fuel is what supplies the energy, and propellant is the reaction mass that you dump the enrgy into. In a standard chemical fuel rocket, there is no need to draw that distinction.

In a nuclear thermal jet, the uranium is the fuel, and the intake air is the propellant.

Its the same way here, except we're not using nuclear reactions to supply the heat, just fuel and oxidizer.

 

[Angeltxilon]

Okay, now I see the point of ramrockets.

Edited April 3, 2016 by Angeltxilon

[Angeltxilon]

About the exoplanetary jet engine, I thought a new jet engine: Joolian jet engine.

Basically is the same than a Dunian or normal jet engine, but make use of ozidizer instead fuel or alkali.

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Okay updating the thread.