posted on Dec, 12 2004 @ 05:49 AM
I believe that the F-19 designation was ,merely 'presumed' by the Aviation press in general once the existance of a secret stealthy single seat
twin jet aircraft became known, which was right back in 1981, well before the true appearance and designation was known. I still own the article from
Flight International which reported the existance of the aircraft with the headline "Secret 'F-19' Stealth Fighter Revealed In Budget". The F-19
designation was placed in inverted comma's because they made it up as the next number along in US Fighter designations, the F-18 had entered service
only two years earlier.
Why the F-117 bore this designation instead I do not know but the above is, I believe, the origin of the widespread use of F-19.
As for Interceptor duties, the F-102 and F-106 were merely replaced by the F-15, this was after all the first fighter to come along which could beat
the BAC Lightning, previously the worlds best Interceptor, in a climb, a major requirement for an Interceptor being the ability to climb very fast in
order to engage incoming bomber formations, not range as Tim said as range is more useful in standing patrols rather than Interceptions. The beauty of
the F-15 was that it combined the two in a single aircraft, as did the F-14 and, several years later, the Tornado F.3 which, in the UK, replaced the
Lightning Intercepr and the F-4 Phantom, which was clearly a better fighter overall than the Lightning but not such a good interceptor.
Finally, Tim, when you say you never hear about the F-21, you're right. You don't hear much of it but it did exist. F-21 was the designation applied
to a number of IAI Kfir C2's that the US bought in the 1980's.