Remove the terrible "can't activate engine while stowed" mechanic

[Whirligig Girl]

There is absolutely no reason why I shouldn't be able to activate an engine while it is still inside a fairing. None at all. It helps no one in any way. Rocket engines already apply a force when they are thrusting into something, starting an engine should push on the fairing and prevent any net force from being applied to the vessel.

At first, it sounds like a good idea. Problem is, a lot of people like to build their own jet engines or bearings powered by rockets or jets that could be made nice and neat if packed into a fairing. Unfortunately for them, such a thing is impossible due to this mechanic.

The absolute worst result of it is when you are in a time sensitive mission with an engine cluster. Your staging puts the engines in the same stage as the fairing. The fairing deploys but the engines do not activate. You can't just stop and turn each engine on individually, you'd completely flip out! You revert the flight, and try again, this time putting the rockets on a separate stage from the fairing. Fly up, ready to stage. [Spacebar]. Wait. Where's the thrust? "Can't activate engine while stowed."

At this point there are three possible reactions. Sane, Insane Happy, and Insane Angry. Sane: "Darn it, I'll have to rebuild this part of the rocket." Insane Happy: "That's such a great idea. I need to go give the developers a big old high five, hug, and take them out to a fancy dinner!" Insane Angry: [Redacted] [Redacted] the [Redacted] [Redacted] game! [Redacted] all!" 

You then try to calm down from whichever reaction you chose, as you try to toggle the engines on. "Can't activated engines whi--" At this point your previous response is repeated except an order of magnitude larger. This may involve a decidedly frustrated sigh, temporarily converting your room into a dance party, or breaking one or more limbs. At this point you close the game out of frustration, excitement, or total and complete burning rage, and write a post on the forum either complaining to, congratulating and thanking, or murdering whoever it was who wrote that bit of rocket-blocking code.

 

EDIT: After having calmed down, I want to just say that some of what I've said is unfairly bent due to me still not having been calmed down enough.

 

Edited December 14, 2015 by GregroxMun

[sal_vager]

Hi @GregroxMun, can you show me any instances in 1.0.5 where engines or any other occluded part remain stowed when the fairing is staged?  As this is meant to be fixed.

Also, I totally understand the sentiment against cramping gameplay options, but this was by design and to help change the minds of the ones who designed this we need to present use cases, that can't be achieved by some other method.

I do have to argue this point however ...

23 minutes ago, GregroxMun said:

There is absolutely no reason why I shouldn't be able to activate an engine while it is still inside a fairing. None at all.

I'll point you to the interlock, though I'm sure there are other examples of methods to prevent activating machinery in an unsafe state, while some other parts are prevented from functioning for other reasons, such as wings not providing lift as there is no air flow inside a fairing.

[Temstar]

I too find myself wanting to use fairing to "bundle up" multiple 1.25m SRBs into a large first stage and become disappointed that you can't do this.

Perhaps instead of fiddling with fairing, a better solution is to have a procedural fuselage part. Works the same way as fairing does now, except lighter, cheaper, cannot be jettisoned and does not prevent actions of parts stored inside, except for extending solar panels and radiators.

[Whirligig Girl]

30 minutes ago, sal_vager said:

I'll point you to the interlock, though I'm sure there are other examples of methods to prevent activating machinery in an unsafe state, while some other parts are prevented from functioning for other reasons, such as wings not providing lift as there is no air flow inside a fairing.

Good point.

[cfds]

6 hours ago, sal_vager said:

Hi @GregroxMun, can you show me any instances in 1.0.5 where engines or any other occluded part remain stowed when the fairing is staged?  As this is meant to be fixed.

Also, I totally understand the sentiment against cramping gameplay options, but this was by design and to help change the minds of the ones who designed this we need to present use cases, that can't be achieved by some other method.

I do have to argue this point however ...

I'll point you to the interlock, though I'm sure there are other examples of methods to prevent activating machinery in an unsafe state, while some other parts are prevented from functioning for other reasons, such as wings not providing lift as there is no air flow inside a fairing.

I do not see why we have to provide specific use cases to overturn a design idea that
- adds nothing to the gameplay (or has anyone ever been in a situation where he thought "Woo, luckily my antenna did not deploy in this very moment!")
- causes problems, at least with interstage fairings
 

[AlamoVampire]

Want a valid reason to not have this mechanic? Soyuz. It hot stages, as in stage 1 is nearly spent, then the next stage ignites WHILE STILL STOWED IN THE FIRST STAGE. If firing a rocket motor off while its inside a non detached segment is good enough for ROSCOSMOS and American astronauts being lifted by it, then it SHOULD be good enough here. 

[steve_v]

8 hours ago, sal_vager said:

Also, I totally understand the sentiment against cramping gameplay options, but this was by design and to help change the minds of the ones who designed this we need to present use cases, that can't be achieved by some other method.

How about we try this the other way around, as valid use-cases (Soyuz etc.) have now been presented.
Have you any use-cases where this mechanic is actually helpful?
If I stage an engine before I meant to, that's my screwup - whether it was inside a fairing at that point is completely irrelevant.
What does this add to gameplay, besides aggravation when engines unexpectedly refuse to operate?

The 'wings' example is irrelevant, wings not working inside a fairing is obvious and emergent... from the fact there is no airflow. Engines do not have the same limitation, hell, they'll work quite happily underwater - why not inside a fairing, or a closed cargo bay for that matter?

I can't actually think of any part I'd want disabled when inside a fairing - RL radio antennas work just fine inside a non-metallic shroud for example.

On the interlock argument, is this not precisely what the "lock staging" function is for - preventing unintended engine firing or stage separation?

As far as I can tell, this is just a half-arsed fix for the half-arsed nature of fairings and the lack of same-craft collisions. Antennas or rocket exhaust coming through a fairing wall looks silly - hey, I know, lets just disable them.
Or, one could fix the issue properly, and have things collide with the fairings / cargo bay doors as they should.

Same goes for wings, model aerodynamics based on actual shape (ala FAR) and the problem of wings providing lift inside a fairing and needing to be disabled goes away by itself.

Edited December 14, 2015 by steve_v

[jwbrase]

8 hours ago, sal_vager said:

 

I'll point you to the interlock, though I'm sure there are other examples of methods to prevent activating machinery in an unsafe state, while some other parts are prevented from functioning for other reasons, such as wings not providing lift as there is no air flow inside a fairing.

While I don't care much either way, I can see two arguments for not having interlocks built into the game:
 

1. It is the rocket scientist's job to provide interlocks, not the universe's (so to speak).
2. Reading through the part flavor text in game, "interlock" does not seem like a word that would be in the Kerbal vocabulary, except maybe as a very recent coinage by Albert Kernstein.

Number 2 just got me thinking: Range safety charges would be an interesting part idea (of course, the Kerbal way to use them would be as range unsafety charges).
 

15 minutes ago, steve_v said:

I can't actually think of any part I'd want disabled when inside a fairing - RL radio antennas work just fine inside a non-metallic shroud for example.

A telescoping antenna might not work especially well if prevented from extending to its full length by the shroud.
 

[steve_v]

Just now, jwbrase said:

A telescoping antenna might not work especially well if prevented from extending to its full length by the shroud.

In which case it should either generate an error and retract again, or simply break. - i.e. collide with the shroud.

[sal_vager]

@AlamoVampire, don't scream at me, if you want this changed give me stuff I can put on the tracker to convince the powers that be that this should be changed, and "SOYUZ RANT" isn't suitable.

[Stoney3K]

20 minutes ago, sal_vager said:

@AlamoVampire, don't scream at me, if you want this changed give me stuff I can put on the tracker, "SOYUZ RANT" isn't good enough.

How about there not being a single use case that would benefit from the "Cannot activate while stowed!" dynamic? The laws of physics don't prevent engines from firing inside a fairing.

If users want to blow up their spacecraft by firing their rockets while they're still stowed, it's their party. At least give us the ability to disable the protection mechanism when we want to, because right now, it's also triggering on a lot of false positives which hamper proper craft operation, while serving no practical purpose.

[xEvilReeperx]

@GregroxMun

11 hours ago, GregroxMun said:

There is absolutely no reason why I shouldn't be able to activate an engine while it is still inside a fairing. None at all. It helps no one in any way. Rocket engines already apply a force when they are thrusting into something, starting an engine should push on the fairing and prevent any net force from being applied to the vessel.

Here is a MM patch that simply removes this limitation:

@PART[*]:HAS[@MODULE[ModuleEngines]]
{
	@MODULE[ModuleEngines]
	{
		%shieldedCanActivate = true
	}
}
@PART[*]:HAS[@MODULE[ModuleEnginesFX]]
{
	@MODULE[ModuleEngines]
	{
		%shieldedCanActivate = true
	}
}

Ten seconds of testing indicates it seems to work like it should. I don't know if thrusting against a fairing base results in zero thrust as my test craft's lower half promptly disintegrated attempting it so that's good enough in my book

[sal_vager]

@Stoney3K, maybe you think I'm a dev?

I'm not the one to convince, and while the devs do look here when they have time we have the best chance of them seeing what we want on the KSP tracker.

I could only find one other report on the tracker that dealt with fairing issues, no one has left feedback asking for your idea.

As for the laws of physics, I'll refer you this post and the notion that safeties exist to prevent unsafe activation, it's not about physics so physics is not a suitable argument.

[Stoney3K]

23 minutes ago, sal_vager said:

@Stoney3K, maybe you think I'm a dev?

As for the laws of physics, I'll refer you this post and the notion that safeties exist to prevent unsafe activation, it's not about physics so physics is not a suitable argument.

I can understand the safety concern, however, as it is implemented now, there is no way to (purposely) defeat it in scenarios where it may be necessary.

IMO, it is up to the "engineer" building the rocket to decide whether or not to use any interlocks in their design, not KSP's. A warning in the Engineer's report would be sufficient, just as there is a warning about badly staged parachutes right now (which will happily stage even if they are rendered totally useless by doing so).

[Bill Zarr]

I'd rather have things not activate by default while stowed.  Having things not activate by default prevents having to disable and use action groups excessively. ie Antenna - the game defaults to the best antenna, which if it is on a stowed satellite may not be the one you want to use. Having the antenna of a stowed satellite deploy through fairings or cargo bays  (or get damaged as was suggested) is completely idiotic. Another example of something not to activate while stowed is landing legs. I've no wish for landing legs to toggle while stowed. Returning a lander via spaceplane for a specific example. Last time I tried this the legs did deploy and I ended up having to use action groups rather than the default toggles. Engines? No I certainly don't want engines to operate while stowed in a cargo bay. Do I want engines to activate while in a fairing?  In general - No. There may be instances where one may want to activate them while stowed but there are many instances where you specifically do not want them to be activated while stowed.

In general the default behaviour of things not activating while stowed is more useful to me, and I would suspect that is true of most players. Arguing for the 1% of cases when activation would be useful against the 99% of the time when you don't want this behaviour doesn't really cut it.

A simple (in terms of UI) solution would be to have a toggle on the fairing/cargo bay/service bay that allowed activation of the things inside it (for good or ill).

[Stoney3K]

The issue isn't really about activating stuff inside a fairing or bay that is *actually* stowed, which in most cases you wouldn't want.

However, there are a lot of situations like described above, where the fairing is decoupled and left behind without deploying it, which would happen on situations like interstage fairings. The parts inside the fairing are incorrectly still marked as "stowed" and will therefore not activate.

Also, there are situations where you want a fairing or bay just as a means of aesthetics and not as a functional part. In those cases, there should be an option to disable the occlusion check.

[Scarecrow]

1 hour ago, Bill Zarr said:

In general the default behaviour of things not activating while stowed is more useful to me, and I would suspect that is true of most players. Arguing for the 1% of cases when activation would be useful against the 99% of the time when you don't want this behaviour doesn't really cut it.

 

I disagree that what you say is true of most players, and I certainly don't agree that this feature is useful in 99% of cases.

Action group keys can be used for activating specific items, with stowed items being omitted from the key so that they don't deploy whilst stowed.  Activating a stowed engine can be prevented by correct staging.  There's no need for the game to default to such a setting to protect us from our own mistakes.  After all, how many times when you started playing did your parachutes deploy as you hit the stage button for your engines at take off because they were staged together?  

Some players, myself included, who like to use the fairings to give a smooth appearance to our rockets, are handicapped by the current way fairings work.  If you have no wish to actually deploy a fairing, but just need to jettison it with the rest of the stage it is attached to, the current game mechanics don't allow us to do this.  Once the fairing has been jettisoned without being deployed, the engine that was stowed inside it can't be activated.  Unfortunately there is no easy work-around for the 'cannot activate engine whilst stowed' problem, so yes it should be looked at.

I know this is basically repeating what Stoney3K has said above. but it irks me that a so called 'safety measure' which isn't really required, is preventing me from building my rockets the way I want to.

Edited December 14, 2015 by Scarecrow

[pokeman]

No idea what the best solution for this bug is but I know that removing the stowed restraint from engines is a good start. Seems everyone who objects to removing the "feature" doesn't want solar panels and antennas to deploy, which makes perfect sense, so keep those how they are but there's no reason an engine shouldn't be able to fire in a confined space. Why do we even need the engines to do this? Restricting design choices and potential accidental explosions seems like a very un-kerbal "feature" to me.

[sal_vager]

Well, as far as solutions go I have asked on the tracker that the removal of the part you close your faring around is used as the trigger for an occlusion check, if it's not reachable in the vessel tree, consider the fairing open and unocclude any parts inside it, unfortunately it's not currently tracked in the save or craft file which part this is.

That's what's missing here, there's no event to tell KSP the fairing is open until it is either staged or you are reloading the scene (F5/F9).

You still won't be able to activate parts that are stowed, but you would be able to stage a decoupler without staging the fairing, enabling Apollo style separation which is the only use case I've come up with so far.

[NathanKell]

Without "taking sides" or anything, here is a use case in the other direction: place a Mainsail in a Mk3 bay. The raycast for checking if the exhaust hits anything is, IIRC, shorter than the bay length, so it will not think it hits anything, therefore giving you free shielded thrust you can run for an infinite (fuel willing) amount of time despite the cargo bay being closed.

 

Note that Russian LVs do not have solid interstages, they have meshwork ones so the exhaust can escape.

[cfds]

36 minutes ago, NathanKell said:

Without "taking sides" or anything, here is a use case in the other direction: place a Mainsail in a Mk3 bay. The raycast for checking if the exhaust hits anything is, IIRC, shorter than the bay length, so it will not think it hits anything, therefore giving you free shielded thrust you can run for an infinite (fuel willing) amount of time despite the cargo bay being closed.

 

I give you that this situation should not work. But it should not work any if you open the cargo bay, and there the game does not prevent activating the engine.

By the way, does the engine deactivate when the cargo bay gets closed again?

[AlamoVampire]

@sal_vager I am sorry Sal. I agree you are not the one to convince but dismissing a valid point as a rant is wrong twice over. It is valid. We use NASA approved parts from the ARM mission and NASA style drop then ignite staging, but that does not mean Soyuz/Russian hot staging is instantly invalid. Many mods model Soyuz parts. Novapunch for example. Dismissing a real world example out of hand is wrong. If anything Sal its proof positive that the mechanic in question needs to be fixed. If thats not enough then the mods that use Russian designs certainly does.

[NathanKell]

Again, I don't disagree the mechanic can be annoying, but...does this look like a fairing to you? Do please at least give examples of engines that ignite inside an insterstage fairing, not inside an open mesh.¹

 

¹There are a handful of cases, mind. Just...not the common ones being cited.

[AlamoVampire]

@NathanKell Wouldnt KSP still call that stowed mesh or not? If so, id say its still a valid point.

 

edit: also the op's complaint is about a stowed engine being unable to fire, which to me IMHO that further validates the Soyuz comparison, as the engine to be fired is stowed. Mesh or fairing matters not I think, as stowed is stowed.

side thought, look at any Boeing 737 aircraft and its main gear (not the nose gear) in its flight config, you see the wheels, yet they are stowed. Just a though there.

Edited December 15, 2015 by AlamoVampire

[sal_vager]

Stock Soyuz connector ring.

The KSP fairing is not the correct part for this use case.