Stopping LV(N) engines from overheating?

[Skorpychan]

So. Third attempt at a mission to Duna.

The first attempt, the LVN rocket overheated behind a jumbo Rockomax tank, and exploded. Crew were forced to abort back to kerbin.

Second, booster malfunction, everything detonated, got them back down.

Third attempt, running the LV(N) under two big grey rockomax tanks, at 80% thrust. Getting anywhere is taking FREAKING AGES, so I'm thinking any future attempts will have two.

However, with the overheat, it's an issue. They'd be attached to a fuel tank at the top, held onto the main one by struts and fuel lines. How would I stop a smaller one from overheating and cooking them?

Edited July 31, 2013 by Skorpychan

[arq]

The Jumbo x64 tanks have issues because they are so large. The physics engine doesn't treat them properly because the ends are so far from the CoM, and the heat dissapation doesn't work as well either. I also find they are more prone to Unplanned Rapid Disassembly than two x32's. I just use 2 x32's wherever I want an x64 and it tends to work much better (and usually the LVN's won't overheat in that configuration).

[ixolate industries]

For this ship can we have details and pics so we can help.

Your descriptions are a little vague pics really help

F1 for screenshots in case you didn't know already.

[Skorpychan]

The design I'm using is literally two X-32 tanks with an LV-N on the end, and it DOES overheat, albeit slowly.

I haven't worked out the twin-engine design yet. It's just something I was working on mentally during the 30-minute Duna insertion burn.

However, it'd probably consist of two small fuel tanks with the LV-Ns on, attached to cubic girder sections mounted on the lower of the X-32 fuel tanks.

[arq]

Many engines (Mainsail and LVN, at least) typically get *some* level of overheat at full throttle. However, for me they usually stabilize in the 40-80% overheat range. The overheat bar needs to get full (or very close to full) in order for an explosion to occur. With the x32 tanks I have never had a problem with engines, but I've been traveling so haven't played as much since 0.21.

So with the x32 configuration, is the LVN overheating to the point that it explodes, or just filling some of the overheat bar?

[Skorpychan]

It filled some of the overheat bar, then I got spooked and throttled it back down, after remembering what happened with the jumbo tank.

[annallia]

Put a pancake tank on the bottom (the smallest of the big tanks). Technically abusing the mechanics of the game but at the same time since it is a broken mechanic that is causing the overheat with the x64 tanks it evens out.

[Kilmeister]

Oh, so it's the tank size that's causing the overheat? I just thought it was a change in .21 First rocket I built with new patch had some mainsails that were overheating. I figured it was just a change, but I just realized its also the first time I've attached a mainsail to an orange tank instead of a grey one in a long time. I'm going to go slap a small one on the bottom of my booster stacks and see if that fixes the overheating so I don't have to feather the throttle during liftoff.

[painking]

Just letting you know that the LV-N is going to overheat, no matter what kind of fuel tank it's strapped to, at least in my experience. You can have it right on the edge of exploding at about 90% throttle. And if you're going to use LV-Ns then you need patience, they're slow as hell but very efficient.

[Skorpychan]

Just letting you know that the LV-N is going to overheat, no matter what kind of fuel tank it's strapped to, at least in my experience. You can have it right on the edge of exploding at about 90% throttle. And if you're going to use LV-Ns then you need patience, they're slow as hell but very efficient.

Patience is hard, but easier than trying to do transfers with a bigger, more powerful motor that drinks fuel like crazy.

[TinfoilChef]

Just letting you know that the LV-N is going to overheat, no matter what kind of fuel tank it's strapped to, at least in my experience. You can have it right on the edge of exploding at about 90% throttle. And if you're going to use LV-Ns then you need patience, they're slow as hell but very efficient.

I solve the LV-N overheat problem by using two or more of them and instead of attaching them to a large tank I mount them on FLT-400 fuel tanks. They overheat but it stops at about 60%. Doing this I've never had one explode from overheating and I get thrust times symmetry. Granted they're heavy and this increases launch mass but IMO it's a worthwhile tradeoff.

Edit: The FLT-400 + LV-N combo's are attached radially using 2x or more symmetry.

[Kilmeister]

I put the "pancake", as Annalia described it, on the bottom of my orange tank stacks and I was able to launch my rocket to orbit without having to feather the throttle except during the initial liftoff due to G-force now causing rapid deconstruction. I just had the strut the hell out of them since there was 700 some tons stacked on top of them. On the plus side it raised my payload to orbit from around 90t to 98t.

[Anton P. Nym]

I always put my LV-Ns on FL-800 outrigger mounts (or call 'em nacelles if you're in a Trek state of mind) to help with the overheating and to avoid the "shroud severs engine upon separation" problem. I still get a bit of overheat if I throttle up to 100% but it never gets beyond a third of the way through the overheat bar and I don't notice much of a performance hit.

-- Steve

[Camaron]

I just wanted to bring this back into attention.

A year and a half after this thread was made, my friend blew single LV-Ns which were mounted to Orange Jumbos. By some miracle I personally never mounted an LV-N to an orange Jumbo myself, so I had no idea this issue existed.

HOW is this still a thing??? This is a TERRIBLE bug to have, and then allow it to continue to exist all the way to 2015!!!

[sal_vager]

Not a bug, they run hot, and Jumbos are insulated (actually they are so big heat can't path though them)

Fit other parts to the Jumbos to act as heat sinks, or struts to the LV-N's

Also, closing for necro.