The M18 Hellcat is an American tank destroyer. It is lightly armored but extremely fast and armed with a powerful 76mm cannon. The Hellcat’s speed is used to flank the enemy hitting heavier tanks in the side or rear.
― Heroes & Generals
The Hellcat is the fastest armoured vehicle in the game. It can easily reach a blistering speed in seconds after starting to move, but has weak amour.
This tank is fast enough to outrun tank turret rotation at very close distances, so you'd want to close in and wonder in enemy lines. Look into destroying gun breech after having flanked and approached enemy tanks by shooting into the back of the turret, next targets are tracks starting from the one that prevents the enemy from turning into the same direction that you intend to circle in, engine/transmission, and turret ring if possible.
Given the absence of armor it's best to stand sideways to opposing tanks when dueling over long distances, as you're nimble enough (in both reverse and forward) to dodge enemy rounds if you can time the reload cycles of enemy.
This tank is very fragile and it will rarely bounce a shot, do not count on your armour when engaging enemy armour. AT rifles will pierce you, and readily destroy you. Russians have a semi-auto variant of AT rifle.
The Hellcat has a mounted 12.7 M2 Browning MG, However it is EXTREMELY vulnerable to infantry fire.
Despite its negative characteristics, the Hellcat is arguably the best Tank Destroyer in the game.
The Hellcat has the fastest reverse acceleration and speed of any tank in the game.