What's the deal with LV-N engines?

[Streetwind]

I've had these researched for ages, and never got around to using them, since my existing designs did everything I needed. Now I'm using them for the first time in a rocket, and promptly I'm having issues. For example, everytime I activate the stage they are in, they simply explode. Is that some sort of in-joke on the "atomic" part, or are they actually usable and I'm just doing it wrong?

Edited January 19, 2014 by Streetwind

[Taki117]

A pic would help, but what it sounds like is that you have decouplers on them and the shrouds are causing things to explode, or they are overheating.

[Streetwind]

Yes, there are decouplers on them. I want to eject the empty stage below them, so I need decouplers.

But why would the shrouds cause damage? Shrouds always disappear for me the moment I decouple the thing below them that causes the shrouds to exist in the first place...

[Vanamonde]

The LV-N has two half-cylinder cover panels which fly off to the sides when the engine is activated. You need to arrange the engines so that those panels don't hit anything, either by rotating the engines when you place them, or making sure nothing else is at the same level.

[Taki117]

It has to do with the way they are attached, most other shrouds just come straight off, if you look the shrouds for the LV-N is actually split, so if you have more than one of them (i.e a cluster) they the shrouds will collide with each other (Or the Engines) and cause explosions.

[SRV Ron]

The shrouds of the LV-N are different. They break into two separate parts that fly sideways. Therefore, if you cluster them in a stage, you will have a catastrophic failure every time you stage them.

[sal_vager]

If you are using the tri, bi or quad coupler to mount more than one LV-N, you will need to rotate the engines with (shift+) A or D so the fairings don't hit them

[Dave Kerbin]

This is the shroud on the LV-N which fires off with some force (they don't just gently drift off).

The LV-N is fragile, and if those shrouds bounce off something and come back at the LV-N it will likely be destroyed. The same goes if you have a cluster of LV-Ns, you'll need to make sure the shrouds don't hit one of their neighbors.

[Streetwind]

...Welp. Yes, I am using a tricoupler. >_<

In that configuration, if parts are thrown out symmetrically to the sides, the shrouds won't hit the engines if properly rotated but they'll always hit each other. Will that also cause issues / should I be avoiding multicouplers altogether with these engines?

https://dl.dropboxusercontent.com/u/44754370/screenshot7.png

[Markus Reese]

Yup to the above. One main thing with the LV-N is to never have the decouple and activation in the same stage. Also, I always have them throttled off before activating for a more stable de-coupling.

[sal_vager]

If the fairings hit each other they will bounce away and not cause your engines harm

Rotate them so the seam between fairings points directly outwards.

[Streetwind]

Alright, thanks for the explanation! I'll give it a try. That's quite annoying, suddenly having one engine out of the entire pack of them behave completely different...

[Streetwind]

Okay, tried it out. This time the engines survived the two-step staging process, and yes, I did see the shrouds fly away with some force.

I still got a violent explosion upon decoupling (even before the shrouds got involved, they only split off once you activate the engines). Two of the three decouplers spontaneously ended their existance. Not sure why, but it seems these engines just don't want to play nice. I just hope the explosions remain confined to the decouplers and don't take out the engines again in future flights.

[sal_vager]

I'm guessing you have another tricoupler below those engines, two of the decouplers won't be attached so when you fire them they fly off with a lot of force, and impact the tricoupler.

[Streetwind]

Ahhh, I see. So it's a result of the fact that parts cannot properly attach to multiple points at once.

[Captain Sierra]

Ahhh, I see. So it's a result of the fact that parts cannot properly attach to multiple points at once.

That is correct, and is a limitation of the Unity part tree. I've always been curious what would need to be done to make a workaround. I mean, unity can't load curved terrain textures natively, so Squad made PQS as a workaround for Unity's ineptitude.