The Terrans need a heavy fighter to be used before shields are invented. A Hercules prototype isn't right: Without big guns and shields, a Herc is cannon fodder with only 250 hitpoints. Here's a better solution:
GTF Heracles
Heavy Assault Fighter
Max Speed: 50 m/s
Max Speed with full engine power: 65 m/s
Max AB Speed: 135 m/s
Turn time: 4.0, 4.0, 5.0
Gun mounts: 6
Default Gun Banks: ML-16 Laser, HL-5 Laser (the HL-5 is a heavy laser)
Allowed Gun Banks: LL-45 Laser, ML-16 Laser, HL-5 Laser, Disruptor, Flail, PC-4 Plasma
Default Secondaries: MX-50, Phoenix IV
Allowed Secondaries, MX-50, Phoenix IV, EMP, D-Missile, Stiletto
Secondary Capacity: 80, 100
Hitpoints: 320
Countermeasures: 20
Power Output: 3.0 per second
Description: The Heracles is a formidable opponent, with 6 gun mounts, two huge missile banks, and loads of armor. Often used to shoot down bombers, gas miners, freighters, and similar foes, the Heracles is considered a heavy assault fighter. It is often favored by novice pilots for its sturdy hull.