This fight was nasty. That Long Tom's biggest accomplishment wasn't actually hitting the Thunderhawk (which was the only damage the Hawk suffered all day), but that shot also splashed into the Pilum Fire Support Vehicle and got a motive hit, reducing it to a 2/3 and leading to its demise.
Ultimately, the biggest thing the Thunderhawk did was using some direct fire with its Arrow IV to nail the Purifiers, thanks to Artillery targetting the hexes and Robyn having been kind enough to keep them bunched together for easy squishing.