In Gurps, how powerful do you need to fight a tank?

[Rupert]

Originally Posted by mlangsdorf

A flying super can get above a T-72 and go through the weak top armor, needing to penetrate DR 90 and do around 180 HP injury to bring it below 0 HP, at which point it will probably stop working in a few seconds given that it has HP 9. Based on the Ukraine war, T-72s may be Fragile: Flammable and Explosive, in which case a mere 90 points of burning or explosive damage past DR has a 80+% chance of setting it on fire, followed by an ammo explosive and turret high jump. A 6dx7 (2) bu attack, average 147 damage and halving effective DR, would be sufficient.

That's because of extra ammo being stored all over the place, and would apply to any tank that doesn't store all the ammo in something like the M1's rear turret bustle with its blast-proof doors and blow-out panels. A T-72 series tank with ammo only in the carosel won't be brewing up from anything that hasn't already fried the crew on the way past if it's a top or high side attack.

Also, most of the brew-ups you see aren't instant - they're after the interior has already caught fire, the crew has bailed, and then the ammo has cooked off. The problem here isn't that they're more flammable than other tanks, but that the fire suppression systems often aren't good enough, though in GURPS' terms that can be treated as all part of the initial 'does it catch fire' check. I'd go so far as to say that of the crew of a T-72 series dumped all the non-carosel ammo (so they're only carrying the 22 rounds that the carosel carries), it should lose the 'x' on its health.

Funnily enough 'x' is probably less of a problem for a vehicle than 'c' - Explosive only triggers on critical failuires vs major wounds and instant death fails. Flammable means catching fire on any major wound's HT being failed, with a -3 on the check for burning and explosive attacks or vital hits (cumulative). Vehicles in general are probably Combustible, but with the HP10+ automatic fire being a HT roll (because otherwise it's going to be an automatic thing when using heavy weapons, and combat experience with tanks and ships shows that this is not the case).