In 1969, everything was finally going the way of USAF planners who hadn’t had their own design of an air superiority fighter since the 50s. The F-4 Phantom was a navy design. The F-111…don’t even get me started…Whiz kids. Anyway, nothing was going to be allowed to jeopardize the F-15 Eagle. The F-15 was going to be a relatively conventional low risk design, like its predecessor, the F-4. It needed to go faster, have bigger engines, more range, bigger fuel tanks, bigger radar, bigger missile payload, and lots of room for the best radar and avionics.