Why is there on F-103 in the USAF Century series fighters?
I assume you mean “no” instead of “on”…[:)] There was an XF-103, which reached the mock-up stage before it was cancelled. Anigrand did a resin 1/72 kit of it. It was a Republic design for a Mach 5 80,000 foot interceptor.
That was indeed a strange bird…
