APU, but not the guy from The Simpsons

Just how much power does the APU provide? I actually hardly ever use it, because on airfields I just have ground power hooked up and don't have to worry about it. But how much power does the APU actually provide? A few times I really wanted it to at least power hydraulics in case the JPTC got shot out (seams to be the equivalent to the P-51D's prop-governor, one stray bullet and *BANG* governor dead) and I can't count how many near misses I've had from missiles and nearly every time the JPTC is dead, and soon after the engine and all controles, but I've never managed to control anything with the APU turned on.

So what should work through APU power in flight in an engine-out situation?

The APU only provides electrical power. The hydraulics are run with pumps run off the engine, so loss of engine power means loss of hydraulics. Loss off JPTL is weird. Depending on actual damage, you should be able to switch to the Manual Fuel System to continue flight, but i've not had that succeed too well. But loss off both hydraulics or loss of engine is almost always an eject situation.

The APU only provides electrical power. The hydraulics are run with pumps run off the engine, so loss of engine power means loss of hydraulics.

As the Brits say, oh bother!

Loss off JPTL is weird. Depending on actual damage, you should be able to switch to the Manual Fuel System to continue flight, but i've not had that succeed too well. But loss off both hydraulics or loss of engine is almost always an eject situation.

Hmmm... JPTL is the Jet Pipe Temperature Limiter... I'm not sure how that exactly controls fuel flow, but I guess it's worth giving it a try.

Thanks for the replay, Marsvinet :thumbup:

Hmmm... JPTL is the Jet Pipe Temperature Limiter... I'm not sure how that exactly controls fuel flow, but I guess it's worth giving it a try.

 

Thanks for the replay, Marsvinet :thumbup:

The JPTL works by limiting fuel fed to the engine to keep temperature within limits. So switching to manual fuel should bypass the JPTL (I think, have to check the manual-that-shall-not-be-named again). Problem is that JPTL warning can mean a lot of possible failures. I can be from a DECU failure and that is "fixed" by switching to secondary DECU. But the guaranteed way to "fix" is to turn off JPTL and switch to MFS. Then you have to manually keep the engine within limits, but you also won't be limited by a faulty system. If that is modelled in DCS, of course.

Thanks Marsvinet. I may must have to try it out without waiting for damage. I guess just flipping the switch would be good enough to see how well it works.