Mainsail overheating?

[Agost]

Hi all, today I was trying to add some parts to my station...

However my rocket engines strangely started overheating very quickly, especially the mainsail I put under a 2.5 KW rocketry tank. I thought it was because of other engines, but it kept overheating even when I jettisoned the others.

The Vesta 2.5m did something similar... What could be the issue? KW rocketry tanks? I used the painted ones.

Thanks

[Vaporo]

I don't think anyone can really help too much without a picture of the craft in question.

[UmbralRaptor]

There's a longstanding heat transfer bug, especially with tall tanks. The Mainsail's heat production was reduced a few versions back to compensate, though.

That said, if the engine isn't exploding, the overheat bar doesn't matter.

[Agost]

There's a longstanding heat transfer bug, especially with tall tanks. The Mainsail's heat production was reduced a few versions back to compensate, though.

That said, if the engine isn't exploding, the overheat bar doesn't matter.

Yes, it eventually explodes... I'll try with shorter tanks on the bottom. But not today, it's too late

[Kesa]

Engines overheat on their own.

The first think I can think of : deadly reentry. It greatly lower the heat limit of every parts (divide by 2 most of the temperature tolerance).

Here are my advice :

(1) As long as the mainsail does not explode, don't bother overheating. If it does :

(2) keep other engines away from it (if they are not just beside it, it sould be fine)

(3) attached parts acts as heat sinker (aka radiator). If you have any mods that add radiators, they probably are intended to be on your craft, between the tank and the engine. if not, you can try attach radial thing to the engine/tank. Also I don't know much about how ksp manages heat, maybe some structural parts are better sinkers than tanks (and I don't know at all about KW tanks, you sould maybe check stock tanks)

(4) throttle down to a safe point, and throttle up when your rocket goes higher and the engines less overheats. (you might add srb to compensate the losss of twr at launch)

edit : ninja'd

[Agost]

Engines overheat on their own.

The first think I can think of : deadly reentry. It greatly lower the heat limit of every parts (divide by 2 most of the temperature tolerance).

Here are my advice :

(1) As long as the mainsail does not explode, don't bother overheating. If it does :

(2) keep other engines away from it (if they are not just beside it, it sould be fine)

(3) attached parts acts as heat sinker (aka radiator). If you have any mods that add radiators, they probably are intended to be on your craft, between the tank and the engine. if not, you can try attach radial thing to the engine/tank. Also I don't know much about how ksp manages heat, maybe some structural parts are better sinkers than tanks (and I don't know at all about KW tanks, you sould maybe check stock tanks)

(4) throttle down to a safe point, and throttle up when your rocket goes higher and the engines less overheats. (you might add srb to compensate the losss of twr at launch)

edit : ninja'd

1) it does

2-4) it actually didn't explode until I jettisoned the SRBs and went full throttle... and I was at ~ 25 km

3) never happened with other tanks... But since the Vesta 2.5m from KW overheated too, I think it's because the long tank bug.

It actually start burning at 1750° C, so DRE isn't affecting its maximum temp. With DRE I've even made a LV 909 re-enter atmosphere without burning.

Thank you all, tomorrow I'll try a better design and I'll post some screenshots.

Edited December 14, 2014 by Agost

[Kesa]

Picking it from the wiki, the max temp for the mainsail is 3600, so DRE does affect its max temp (making it 1800, and starting to burn a bit before) http://wiki.kerbalspaceprogram.com/wiki/Parts#Liquid_Fuel_Engines

Edited December 15, 2014 by Kesa
360->3600

[zekes]

eaiest solution is attach struts to it - they dissipate heat.

[The_Rocketeer]

eaiest solution is attach struts to it - they dissipate heat.

I'd have thought a little throttle control would be 'easier'.

Clustering engines too tightly can also be a problem - they seem to 'share' their heat.

[MarvinKitFox]

Badly implemented feature, not a true bug.

Engines generate heat.

Adjacent components bleed off this heat.

KSP does *NOT* consider the nature, size or mass of the adjacent component for its heatsink capacity,

but it *does* consider the linear distance the component is from the heat source.

i.e.

1 Mainsail under 1 orange tank == boom (1 component)

1 mainsail under 2 half-orange tanks = very hot, but not boom. (2 components, 1 touching 1 rather far)

1 mainsail under 4 quater tanks = cucumber. (4 components. 1 touching, 1 close, 1 further, 1 far)

1 mainsail under 1 orange tank, with 4 * smallest radial batteries == cool!!! Yes, a teeny battery mounted on the orange near the engine absorbs as much heat as the whole orange tank!

[rkman]

Almost every part is able to cool almost every engine to the point where heat is virtually irrelevant in the game, in spite of it being coded for.

The exceptions being the Rapier (looks like heat is working as intended there) and the Mainsail (not working as intended).

I don't recall it being mentioned in talks about beta, but the heat thing has to be taken somewhere eventually. Maybe there will be reentry heat after all.

Are real rockets designed so that fuel tanks cool the engines?

[Agost]

Almost every part is able to cool almost every engine to the point where heat is virtually irrelevant in the game, in spite of it being coded for.

The exceptions being the Rapier (looks like heat is working as intended there) and the Mainsail (not working as intended).

I don't recall it being mentioned in talks about beta, but the heat thing has to be taken somewhere eventually. Maybe there will be reentry heat after all.

Are real rockets designed so that fuel tanks cool the engines?

Real rocket engines are either ablative ( the internal part of the bell has an ablative coating ) or cooled by cryogenic fuel or oxidizer, depending on the design