GURPS BattleTech, working out heatsinks and the effects of heat buildup

[Fred Brackin]

Originally Posted by cosmicfish

One thing this thread has made clear is that Vehicles 3e (4e?) should include thermal management. It isn't just Battletech, every modern vehicle has and needs a cooling system - es.

This would amount to "Design a cooling system that's big enough to meet your needs and install it." and that's what the rules assume is being done and abstracts the whole process.

[Varyon]

Originally Posted by Fred Brackin

This would amount to "Design a cooling system that's big enough to meet your needs and install it." and that's what the rules assume is being done and abstracts the whole process.

Personally, I think some sort of heat management mechanic (and associated design options) would be a welcome addition, but it could add to GURPS' (unearned) negative reputation as an overly-complex system, so I'm generally fine with it being largely abstracted. Spaceships does have a nod to it in the "Main Radiators" option, but that's pretty simple - if you have any systems that call for a Main Radiator, you have to have the Main Radiators open and functional while those systems are in use, and if you close them (or they are damaged/destroyed), you get a set amount of time (regardless of how many such systems you have) before those systems shut down, with the option to extend this by using up coolant stored in fuel tanks.

[AOTA]

Not sure if this has been posted or not. I used this article in Roleplayer to run my GURPS Battletech game years ago.

http://www.sjgames.com/gurps/Rolepla...onversion.html

[Rupert]

Originally Posted by cosmicfish

One thing this thread has made clear is that Vehicles 3e (4e?) should include thermal management. It isn't just Battletech, every modern vehicle has and needs a cooling system - easiest way to take out a car is put a bullet through the radiator, and modern spacecraft have massive heat issues.

Aside from spaceships, very few vehicles have a thermal system that isn't simply part of the powerplant, and it's not managed in any way that's separate from managing the engine itself. They certainly do not have a 'pool' into which heat from weapons that has to be managed.

[Anthony]

Originally Posted by Rupert

Aside from spaceships, very few vehicles have a thermal system that isn't simply part of the powerplant, and it's not managed in any way that's separate from managing the engine itself. They certainly do not have a 'pool' into which heat from weapons that has to be managed.

And, again with the exception of spaceships, real world vehicles with heat problems beyond what they can cover with air cooling generally use expendable coolant, which means you don't get the Battletech "performance declines as heat builds up", you just have "You're fine until you run out of coolant, at which point your engine melts".

[Rupert]

Originally Posted by Anthony

And, again with the exception of spaceships, real world vehicles with heat problems beyond what they can cover with air cooling generally use expendable coolant, which means you don't get the Battletech "performance declines as heat builds up", you just have "You're fine until you run out of coolant, at which point your engine melts".

Or you have automatic weapons that are fine until they overheat and then you have to stop using them until they cool (or you've changed the barrel). However, they don't affect the rest of the vehicle, and if they're set up for sustained fire with water-cooling, they usually have good enough cooling that heat simply isn't an issue.

[johndallman]

Originally Posted by Anthony

And, again with the exception of spaceships, real world vehicles with heat problems beyond what they can cover with air cooling generally use expendable coolant, which means you don't get the Battletech "performance declines as heat builds up", you just have "You're fine until you run out of coolant, at which point your engine melts".

Well, large vehicles tend to be waterborne. That has two advantages, in reducing power demands because of low friction, and in providing a practically unlimited supply of liquid coolant. The coolant is corrosive, but that "just" means you need heat exchangers.

[Fred Brackin]

Originally Posted by Anthony

And, again with the exception of spaceships, real world vehicles with heat problems beyond what they can cover with air cooling generally use expendable coolant, which means you don't get the Battletech "performance declines as heat builds up", you just have "You're fine until you run out of coolant, at which point your engine melts".

Or you can have the SR-71 and the Concorde that used their fuel as a coolant to keep their skin temperatues down before they burned it as fuel. You ahve to land or refuel before you run out of coolant.

Then there's chemical rockets. They use first use their "fuel" as coolant for their engines and then use it as an energy source and finally use it as reaction mass.

It's nuclear and antimatter thermal rocket engnes that use fuel as coolant and reaction mass only that can melt when they run out.

[Ulzgoroth]

Originally Posted by Rupert

Or you have automatic weapons that are fine until they overheat and then you have to stop using them until they cool (or you've changed the barrel). However, they don't affect the rest of the vehicle, and if they're set up for sustained fire with water-cooling, they usually have good enough cooling that heat simply isn't an issue.

Like a battlemech, you can continue to use a machine gun or cannon (or for that matter insufficiently cooled internal combustion engine) while it is overheated. It's just damaging and potentially ineffective.

[Rupert]

Originally Posted by Ulzgoroth

Like a battlemech, you can continue to use a machine gun or cannon (or for that matter insufficiently cooled internal combustion engine) while it is overheated. It's just damaging and potentially ineffective.

There's a very narrow band between "Cool enough it's fine" and "It's broken and probably blew up", not at all like BT's heat track. Also, only that one weapon (or engine) has the issue, again quite unlike BT.

As far as I can tell, BT's mech are some crazy piece of steampunk technology where someone, for some reason, ran the steam lines through the crew compartment and if you run the thing at 100% too long it literally cooks the crew.