Air breathing engine that works in JOOL!

[enroger]

Jool atmosphere is mostly hydrogen right? What if we bring an scramjet engine to jool with oxidizer to make use of all those hydrogen? Should have pretty decent isp I think and help a lot with Jool ascent should anyone attempt it. Would also work in methane atmosphere too.

[Mecripp]

How you going to land on Jool ? It was a gas planet unless they changed it ?

[enroger]

How you going to land on Jool ? It was a gas planet unless they changed it ?

Not going to land on it (unless it is somehow possible?). Jeb just really want to fly on/in it for no good reason.

[*Aqua*]

I don't know of an jet engine which can fly on Jool but you can try electric propellers instead.

KAX, Freight Transport Technologies and the USI Exploration Pack each have one.

[Technical Ben]

Oxidiser is harder to transport for little gain (low density and bulky tanks).

Hydrogen alone is not much use until we build fusion powered devices.

[JoCRaM]

You need eight times the weight of oxygen as you do hydrogen, so it's "only" a weight saving of one part in nine to use atmospheric hydrogen.

Hydrogen has very low density, the compression drag on your scramjet would be high.

As you would be injecting oxidiser rather than fuel, in the "not yet burnt" regions there would be hot oxidiser. This is very corrosive and would likely lead to increased weight (and possibly inefficiency) in order to stop the engines destroying themselves.

[Seeker89]

Karbonite has engines that can...

http://forum.kerbalspaceprogram.com/threads/89401

http://imgur.com/a/Qfq9M#17

[Fengist]

As can Kethane engines and firespitter electrics.

[Nothalogh]

How you going to land on Jool ?

You're not, you're gonna Oberth like you've never imagined

[Requia]

Oxygen-hydrogen mass ratio is not 8:1. Excess hydrogen is used because H2 is substantially faster than H2O at the same temperature (both the mass of the molecule and the number of atoms alter the speed at a given temp, H2 beats everything we actually have the option of putting in a rocket) I believe the exact mix is variable, but for the shuttle it was ~6:1, though for a Jool scoop rocket I'd suggest a pure mix and inject the helium instead of filtering it out, (Helium is beats H2 as exhaust but isn't normally anything approaching realistic, either you need a massive tank or a multi gigawatt cooling system).

Secondly, its a jet, not a rocket. it can afford to move a huge amount of air at inefficient speeds to produce thrust because the air isn't ever going to run out. Earth/Kerbin based ones push 80% nitrogen out the back remember, its that more than the lack of oxidizer that gives jets a huge ISP.

The real trick to making a jet work at all at that kinda speed.

[Armchair Rocket Scientist]

Secondly, its a jet, not a rocket. it can afford to move a huge amount of air at inefficient speeds to produce thrust because the air isn't ever going to run out. Earth/Kerbin based ones push 80% nitrogen out the back remember, its that more than the lack of oxidizer that gives jets a huge ISP.

And that 80% figure is just the turbojets (do those actually run stoichiometric, or are they air-rich?) For turbofans, most of the reaction mass is air that never even goes through the turbine, especially for high-bypass turbofans.