Engines not getting hot since 1.0.5

[Jimbodiah]

I used to need some hefty cooling for running atomic engines like the NERV and lightbulb, but lately I don't need any kind of cooling at all and they still do not go over 400-500K much. Am I just so cool, or is something up? :cool:

[Venusgate]

Heating was rebalanced, and integrated into the twopart skin/core heating. LONG burns with NERVAs will generate enough heat to need radiators. The more NERVAs you use, the more radiator you'll need.

[More Boosters]

Well, with two small active radiators and a single NERVA, I did a 15 minute burn without overheating. When it ended the engine was at 2200 K I believe (KER), over the maximum allowed 2500. It was glowing red hot.

[Mastikator]

I've found that radiators are necessary for drills & ISRU now more so than engines.

[ForScience6686]

I've dealt with the Panthers over heating when running fire long durations in wet mode.  May also be drag related but nothing else was over heating.

[Geschosskopf]

I find all this humorous.  Nobody (other than me, it seems) has ever mentioned that since 1.0.0, Mainsails haven't overheated AT ALL.  Used to be, you couldn't run them at full power during launch, and even if they didn't explode themselves, they'd for sure still pop any orange tank stacked directly above them so you had to stick a pancake tank in between :).

[Snark]

1 hour ago, Geschosskopf said:

I find all this humorous.  Nobody (other than me, it seems) has ever mentioned that since 1.0.0, Mainsails haven't overheated AT ALL.  Used to be, you couldn't run them at full power during launch, and even if they didn't explode themselves, they'd for sure still pop any orange tank stacked directly above them so you had to stick a pancake tank in between :).

Really?  I've used Mainsails all over the place since I started KSP with 0.23.5, and never had a single problem with them overheating, ever, under any conditions.  I didn't even know they could overheat.

@Jimbodiah:  One thing to bear in mind is that radiators got a lot more effective in 1.0.5 (especially the static panels, though even the folding ones got a boost).  They can now actively pump heat out of something that's not as hot as themselves. This means you can have your radiators get blazingly hot even though your engine is still warming up, which in turn means the radiators can get a head start on radiating that heat away.

It's also worth noting that radiators need electricity now while they're operating-- something to be aware of.  You can turn the folding ones off when you don't need them, by retracting them (which makes them stop cooling and stop using electricity).  However, the static panels have no way to turn them off-- they're on all the time and sucking electricity all the time, regardless of whether you actually have anything that needs cooling at the moment.

Fortunately there's a little mod that *cough* I wrote to address the latter problem. 

Edited December 8, 2015 by Snark

[Jimbodiah]

Ah, okay... didn't know they changed anything. But I can run the Nerv without a heatsink at all. In 1.0.4 I could run it 1-2 minutes tops and it would blow up.

[NathanKell]

@Geschosskopf that was a bug. Heat only transferred when parts' origins where within sqrt(20) meters of each other. The orange tank's origin was just far enough away from the Mainsail's origin to prevent any heat transfer. That was chucked out with the rest of the old heat system in the 1.0 upgrade.

[RokRoland]

I've a craft where the first stage consists of a Twin Boar plus 4 additional orange tanks worth of fuel and 6 kickbacks. Even with 2 radiators and one deployable little radiator one the Twin Boar heats up enough to explode unless I throttle back.

I never seem to read about anyone else using that engine, but I have good use for it in my career mode. The biggest downside is it seems to be very overheat-prone.

[Geschosskopf]

23 hours ago, NathanKell said:

@Geschosskopf that was a bug. Heat only transferred when parts' origins where within sqrt(20) meters of each other. The orange tank's origin was just far enough away from the Mainsail's origin to prevent any heat transfer. That was chucked out with the rest of the old heat system in the 1.0 upgrade.

@Snark See, I told ya.  I do drink when I play KSP but that was such a constant in the old days that I remembered it anyway  

But to return to the actual topc of nuclear engines overheating, THIS SHOULD NOT BE A THING as any cursory reading of the actual research papers and test results should make clear.  The whole point is to take the heat and throw it out the back, and the real nuclear engines were designed to do that most efficiently.  Hydrogen, after all, is one of the best heat-sinks in the universe.  So quit whining that nuclear overheats ain't happening.  They shouldn't ever be happening.  It's wrong that they do.  Period.  End of story.

[panzer1b]

From my experience it all depends on how i build a craft.  Ive had good results with nukes and 0 radiators for anything but extremely low TWR (which i dont even build), and burns that are roughly 10-15min long, any more and you will likely need to throttle down near the end of that burn.  Sofar the best solution ive found (for SSTO craft) is to place a nuke behind a rapier and attach that to the rest of your ship.  Ive NEVER managed to overheat that thing at all, and its only risky if the part you attach the rapier to is a cockpit, anything with over 1200K internal temp will never fry itself even if you burn for 30minutes straight.  Ofc, adding even a single small radiator makes it impossible to overheat anything with this arrangement (since the rapier has a very high heat tolerance, and the nuke itself also, meaning that the only risk is by conduction through the rapier, which is a minor problem from my experience is the part behind the rapier is say a fuel tank or other 2000K part.

Aside from that, issues ive found are with the boar when ran at extremely long burn times (only had this on one ship before which used it as a interplanetary burn engine), and for the common use as supplementary boosters, they will not burn long enough to actually fry even at 100% the whole way.  Then ofc there are jets that will overheat, especially the subsonics if you go supersonic with em, and the panther when you try to go very very fast with it, but it takes a long time and throttling down even a tiny bit will make it impossible to fry.  This is expected behavior as turbofans start having issues with very high velocity (there is a reason the sr-71 doesnt use a high bypass turbofan), so the overheat when you really push its maximum rated speed is expected.  All in all, if you have a turbofan engine, dont expect it to be good at high speed, throttle down some so the engine doesnt fry or turn it off when you start to exceed its intended max operating speed.