Turbo-jet engines exploding at 22,000 feet

[hanvyj]

Hi,

Are turbo-jet engines supposed to explode above 22,000 feet? I've built a little experimental jet powered kerbal ferry/lander:

I've tried two configurations but in both it works fine untill just over 20 thousand feet, (or meters?) where the engines just fall off! It doesn't say they explode, but "Structural linkage between turbojet engine and fuel tank failed", but that might be because the engine exploded...

This might either be a feature of jet engines, or I've done something wrong!

Also, if it is a feature - is there an easy way to shut off engines like in a 'stage' (turning on is easy, now I want the next stage to turn OFF the turbo-jets and move to the liquid rocket)

Thanks

Edited July 28, 2013 by hanvyj

[LoneRider]

I saw this behavior when the intake air (in the resources panel) reaches 0 - the engines need air to work, and in case the intake air reaches 0, SOME engines fell off my test plane, the others started to work again (since with less engines, the intake air was enough to cover the remaining engines). Did you have an eye on your ressources panel, especially the intake air?

[hanvyj]

I did not notice the air intake part of the resource panel! You are right.

So, second question: Can I assign a key to turn the damn things off? At the moment I have to cut all power, then frantically try select and turn them off and loose valuable rocketing time...

[heikkik]

Well, there's that magical thing called action groups in the VAB and SPH. At the top of the screen there are two tabs; one says parts the other one says action groups. Go to the AG tab and select the parts you want to have extra control over. Then assign them to a group. These groups are linked to the number keys.

[hanvyj]

Well, there's that magical thing called action groups in the VAB and SPH. At the top of the screen there are two tabs; one says parts the other one says action groups. Go to the AG tab and select the parts you want to have extra control over. Then assign them to a group. These groups are linked to the number keys.

Exactly what I need, thanks

[LoneRider]

With a little practice you can find a nice grouping - going up with all engines, use action groups to shut down a few, going on with the others... like starting with 8 engines, at some height cut down 4 of them, going on with 4 others, and after some while shut down another 2. Just always try to stay symmetrical so it stays controllable. And you can add more air intakes - there are some radial mounted you can attach. This will get you up even higher.

I also tried to optimize my rockets with turbijet engines, so *thumps up* The fuel efficiency is just amazing, and gets even better with higher speed (air intakes produce more air on higher speed).

[numerobis]

20km is about the altitude that a single intake will no longer provide enough air for a turbojet, a little lower if you're flying slowly. Then the engine flames out suddenly. Going from ~200 kN to nothing in an instant will cause things to flex, which could cause parts to bump each other -- especially if you have parts that intersect each other like those I beams and the engines and tanks.

The log rarely gives useful information as to what actually happened.