Engine "cannot activate while stowed"

[GusTurbo]

While using the new fairings as interstages, I've discovered that engines cannot seem to fire from within the interstage on staging. They give an error that says "[Engine] cannot activate while stowed."

Here's a screenshot:

In this picture, there is a Skipper located within that conical fairing section.

Re-creation steps:

Build an upper stage, place a decoupler under the engine, then place a fairing base under the decoupler. Close the fairing on the upper stage, creating an interstage fairing. Try to decouple the upper stage and fire the engine. The engine will not activate, and it displays the error above.

This is obviously a problem, because it makes interstage fairings useless. An example of such an interstage is the one between the S-II and S-IVB stages on the Saturn V.

Edited April 28, 2015 by GusTurbo

[Master Tao]

Try adding a decoupler between the fairing base and your engine.

[GusTurbo]

Try adding a decoupler between the fairing base and your engine.

There is a decoupler between the fairing base and the engine. Note my re-creation steps.

[NoMrBond]

It seems like the same kind of shielding limitation that Scott Manley ran into in the live-stream, HarvesteR said at the time that a subsequent vessel change should trigger a state recheck (also it has already been fixed for post 1.0 patching)

So what if you stage the [interstage] fairings first, then decouple/activate separately in the subsequent stage rather than all together?

I mean the conditions are different, but the same shielding check logic may apply?

[GusTurbo]

It does work when staging the fairing first of course, but there are lots of real-life interstages that di not come apart. We should be able to replicate that in KSP.

[Giggleplex777]

Having the same problem here too:

[Superfluous J]

I can't see previous stagings, but in both pictures it looks like the fairings were not staged during separation. Does this occur if you stage the fairings at the same time as the decoupler and/or the engine?

[Giggleplex777]

I can't see previous stagings, but in both pictures it looks like the fairings were not staged during separation. Does this occur if you stage the fairings at the same time as the decoupler and/or the engine?

No, it works fine if you separate the fairings first. I wanted the fairing to stay in one piece like a lot of real life interstages.

[Alshain]

If you put a decouple below the skipper, the engine will create it's own fairing. Below that you can put a fairing base and close the interstage around the decoupler, but your problem is that you are closing the interstage around the engine itself.

Here are some pictures of how I did my Apollo mission, it worked just fine. In this case I utilized the docking port on the lander, I undock from it, turn around dock again and then stage away the decoupler over the poodle and decouple the lander for extraction.

Edited April 28, 2015 by Alshain

[Claw]

Yes, this is the same bug Scott ran into.

You can give this a try. I've included a fix for this problem that works on cargo bays, though I've not tested it in this scenario: http://forum.kerbalspaceprogram.com/threads/97285

My initial feeling is that it won't work for this, but I'll have to see if I can update it to work with your type of design.

Cheers,

~Claw

[GusTurbo]

It's really odd because rocket engine thrust should not have anything to do with airflow/occlusion. They work in a vacuum, after all.

- - - Updated - - -

If you put a decouple below the skipper, the engine will create it's own fairing. Below that you can put a fairing base and close the interstage around the decoupler, but your problem is that you are closing the interstage around the engine itself.

Here are some pictures of how I did my Apollo mission, it worked just fine. In this case I utilized the docking port on the lander, I undock from it, turn around dock again and then stage away the decoupler over the poodle and decouple the lander for extraction.

http://images.akamai.steamusercontent.com/ugc/39747379227510312/043039607CF0CC96C20D74CF180BA82E35896D58/

http://images.akamai.steamusercontent.com/ugc/39747379227510638/D3A4EAF02C372E99F63142C4DBFD962FCFCC03BE/

That doesn't achieve the look I want.

[Superfluous J]

No, it works fine if you separate the fairings first. I wanted the fairing to stay in one piece like a lot of real life interstages.

In real life do they ignite the engine while it's still inside the fairing? Or is the problem that your engine remains unlightable even after the fairing has slid away?

In any case, here is yet another (and a far better) example of something that should have been caught before release.

[Sean Mirrsen]

I have a different take on that problem. It, admittedly, is mostly relevant with Procedural Fairings, but mostly because those fairings provide the ability to do this sort of thing.

When a fairing, or cargobay as well I suppose, is open-ended, and an engine is inside of it, pointing out the open end, it should be able to activate. However, it counts as stowed, and thus does not.

I mostly question the limitation itself. The engine should be able to fire regardless of where it is inside the rocket. Its thrust may be occluded by fairings or cargobay walls if it is positioned in such a way, but it should be able to activate.

Edited April 28, 2015 by Sean Mirrsen

[Claw]

Things are supposed to be disabled while inside. But once detached, it shoud no longer be disabled. That's the bug, and it goes well beyond just disabled engines.

Thanks for the great detective work though.

Cheers,

-Claw

[GusTurbo]

Things are supposed to be disabled while inside. But once detached, it shoud no longer be disabled. That's the bug, and it goes well beyond just disabled engines.

Thanks for the great detective work though.

Cheers,

-Claw

Thanks Claw. I will endeavor to model future bug reports on this one.

I wish I'd applied to join the experimentals team way back when I had a chance.

[Sean Mirrsen]

Things are supposed to be disabled while inside. But once detached, it shoud no longer be disabled. That's the bug, and it goes well beyond just disabled engines.

Thanks for the great detective work though.

Cheers,

-Claw

No, see, the problem is exactly that. Engines should not be disabled while inside. Unable to produce thrust if occluded, yes. It worked that way with the old cargobays. But not unable to work at all, because it leads to cases such as mine. The "bay" is nominally closed, since the fairing is complete. But the fairing has a big open hole on the other side. There is no opening or closing involved, the engine is designed to never leave this "bay", and since it's firing through an open space, it is expected to work.

The bug is the "feature", in this case. Not that engines are not activated when they leave the bay, but that they are disabled in the first place.

[Redhotita1]

Even with the fix it doesn't work

I reported it yesteday but due to the bug spam nobody noticed

http://forum.kerbalspaceprogram.com/threads/116805-Engines-won-t-start-with-interstages

[GusTurbo]

Even with the fix it doesn't work

I reported it yesteday but due to the bug spam nobody noticed

http://forum.kerbalspaceprogram.com/threads/116805-Engines-won-t-start-with-interstages

Ah sorry, I didn't think to search before posting this thread. Maybe the threads can be merged?

[Giggleplex777]

In real life do they ignite the engine while it's still inside the fairing? Or is the problem that your engine remains unlightable even after the fairing has slid away?

In any case, here is yet another (and a far better) example of something that should have been caught before release.

I demonstrated that they don't fire even when they are out side of the fairing by first pushing the stage out with ullage motors before trying to ignite the engine.

No, see, the problem is exactly that. Engines should not be disabled while inside. Unable to produce thrust if occluded, yes. It worked that way with the old cargobays. But not unable to work at all, because it leads to cases such as mine. The "bay" is nominally closed, since the fairing is complete. But the fairing has a big open hole on the other side. There is no opening or closing involved, the engine is designed to never leave this "bay", and since it's firing through an open space, it is expected to work.

The bug is the "feature", in this case. Not that engines are not activated when they leave the bay, but that they are disabled in the first place.

I agree. What was the point of disabling things inside the fairings anyways? They should reverse this decision ASAP.

Edited April 28, 2015 by Giggleplex777

[John FX]

I also want to be able to fire my engines inside fairings, as I am sure we were told we would be able to.

[GusTurbo]

I demonstrated that they don't fire even when they are out side of the fairing by first pushing the stage out with ullage motors before trying to ignite the engine.

I agree. What was the point of disabling things inside the fairings anyways? They should reverse this decision ASAP.

Maybe we just need to convince them that it's really "Kerbal" to start an engine in an enclosed space.

[Master Tao]

There is a decoupler between the fairing base and the engine. Note my re-creation steps.

Whoops. Sorry about that. I could have sworn I'd tried this already.

[ShadowZone]

I have to chime in into this discussion:

Engines need to be able to fire inside a cargo bay or fairing, especially if already decoupled. There should not be any restraing on activating an engine inside a vessel. Maybe it's an elaborated self destruct mechanism. Who knows? Just let us build something like that

[Claw]

It is a bug. The same one that affects radial chutes near service bays.

Cheers,

-Claw

[andrestirabo]

I'm having the same problem too. I hope squad will fix this soon...