Swept-wing fighter aircraft center box fabrication

Late-1950s swept-wing fighters (wings move from sonic to supersonic configuration) required a large structural center box. Initially the motivating part for the 100,000-ton press; instead solved by electron beam welding.

The biggest forging presses are 50,000 tons. The Air Force had plans in the '50s to build a 100,000-ton forging press. They couldn't just build it anywhere — they found a granite mountain in Colorado for the base, and they were going to build this thing in the base of the mountain because they couldn't afford the foundation. It would have gone down like ten stories into the ground. They never built it, because electron beam welding came along, and it became more economical to design things to be electron-beam welded. Things like the center box for the first swept-wing fighters — at sonic speeds the wings would be like this, and at supersonic speeds they'd go back. That whole box — if you think of the wings as your arms, it was your chest part, and this was your shoulder, the shoulder joints of the aircraft — they learned to make that by electron beam welding in the late '50s. They never built the 100,000-ton press, but they had plans. It would have cost a fortune — in the 1980s these were going to be two billion dollars.