Jet lander,

[FREEFALL1984]

Hey guys, I've recently designed a heavy (15 ton) unmanned lander to touch down on duna. the weight of the lander is suspended by 2 jet engines which are positioned in such a way that the vessel always floats upright, I then use the jets to make it hover and use RCS to maneuver unless I need high speeds and I'll tilt the vessel a little and throttle up like a jet-copter. Also the RCS are used to make me fly up and down since I need very little additional thrust beyond my jets (which I set at about 40% thrust depending on fuel remaining) in order to land I simply RCS downwards and then once I (gently) touch down, I kill the jets and wait for the thrust to stop while still RCSing down. I have an abundance of fuel and an abundance of mono-prop and the thing flies like a beauty on kerbin. The idea was to make an Vtol lander which could sample multiple biomes and transmit the data then find a good landing site to set up a duna base then wait at this location for my landing party in an in-game year or so.

But here's the problem. I tug the vessel to duna with my nuclear tug and aerobrake into a clean orbit disconnect the tug, then I reduce my peri until its about 6000m with RCS, but once I'm in the atmosphere I cannot for the life of me get my jets to fire up and my parachutes tear off resulting in my lander smashing into the ground at uber high speeds... I have a feeling that I accidentally fired them when I originally launched the vessel from kerbin but I can't check now because I'm at work, So here's my questions.

1 - If a flame-out has occurred, then what's the procedure for getting them going again if indeed there is a procedure.

2 - Whats the ceiling on a standard Jet with 6 radial intakes on duna?

Its also worth mentioning that on each engine I have 6 intakes, 3 pointing up for airflow when climbing and 3 pointing down, for use when falling.

I also have MJ, protractor and Scansat installed although they're not to blame for my poor designs lol

[SpaceGremlin]

Standard jets do not work on Duna. Duna's atmo contains no oxygen, which is required for jet engines to function. Kerbin and Laythe are the only bodies with oxygen in their atmosphere.

You could use Hooligan Labs balloons to achieve something similar to what you're trying. Or you could use a mod that includes nonstandard jets like KSP Interstellar thermal jets that work in any atmo.

[FREEFALL1984]

HAHA that would explain my misery, lol, So I'm guessing the ISP is still ATM on liquid fuel rockets and not VAC, might have to have a serious rethought of my lander design

[Red Iron Crown]

It's closer to Vac than Atmo for Isp calculations, Duna's atmosphere is really thin.

[FREEFALL1984]

So rocket landing it the best option, hmm I hoped to avoid that, its very fuel heavy.

[cantab]

IIRC you can land on Duna mostly with aerobraking and parachutes, and a little rocket thrust at the end.