Jets on Duna

[Shark2199]

As the title says, are the jet engines supposed to work in Duna's atmosphere? Because if I remember correctly, last time they didn't...

Couldn't find thread like this, so I'm asking.

Edited January 5, 2014 by Shark2199

[Albert VDS]

There is no oxygen on Duna so air breathing engines won't work.

You can however use a Kethane jet engine, which is included in the Kethane mod.

[95tiger59]

yeah Albert is right they need oxygen so they only work on Kerbin and Laythe

[Shark2199]

Interesting, cause my air-breathing engines actually work on Duna. It might be a bug though.

PS. Oh wait, so intakes can store some oxygen...

Sorry, my fault. Nevermind.

Edited November 10, 2013 by Shark2199

[Geschosskopf]

The easy way to do jets on Duna is to make copies of the stock intake parts, name these copies "Any-Atmosphere Intakes", open their cfg files, and comment out the line that requires oxygen to make "IntakeAir".

There is also a Kethane-burning jet engine that works in any atmosphere whether oxygen or not. Instead of the usual "IntakeAir" resource, it needs "KintakeAir", which is provided ONLY by the integral intake mounted on the engine itself, so regular intakes won't help you. This engine also behaves entirely differently from regular jets in that the supply of KintakeAir really isn't a function of altitude, but mostly a function of your speed relative to your throttle setting. It likes to operate at high throttle but low speed. As long as this is happening, you have a full supply of KintakeAir. However, if you ever get going too fast for the throttle setting, the KintakeAir goes away all at once.

This makes the engine VERY challenging to use on Duna. It works great on Eve, where the thick air keeps you slow and requires lots of throttle to move at all. But on Duna, the thin air means you shoot up to a high speed very quickly and the engines flame out, but at least they all flame out at once so you don't go spinning. Then the thin air makes it take forever to slow down again even with a dozen airbrakes. Thus, when using this engine on Duna, design your plane for a flight profile of brief bursts of powered flight punctuating long intervals of gliding back to the surface where you can stop and your engines will fire up again. So all in all, I find it a lot less of a hassle to use the electric props from the Firespitter mod.

BTW, flying on Duna IMHO is THE challenge of all challenges for the aircraft designer. Not only does the atmosphere not burn but its so thin you can barely fly at all no matter what method you choose. And then you face the second challenge of getting your Duna plane off the ground at Kerbin, which is nearly as hard as making it fly well on Duna. All this is so difficult that I made a challenge thread out of it. Click the "Flying Duna Challenge" pic in my sig for details if you're interested. So far, many have shown interest but few have succeeded.