You talking about the Johnson swap of RS-71 to SR-71?
The truth is hard to determine in that case, but the fact is there were NEVER any other planes using SR
or RS, so the point is kind of moot.
You see, the F and A designations have always needed to be taken with a grain of salt.
The F-111, while originally INTENDED to be multirole (although not really within the same service--AG for USAF, AA for USN), totally failed in its carrier version. TAC got the F-111A/D/F and SAC got the extended range FB-111A (later F-111G). The F-111 had a gun but was a total joke in the AA arena.
The A-4 Skyhawk, designed as the world's smallest, lightest nuclear bomber, became known as a good dogfighter in its own right, armed with its pair of cannon and AIM-9s (or Pythons in Israel).
The F-100 was designed as the successor to the F-86, a successful AA fighter, but really sucked in that role (SFP1 proves that nicely!) and was instead pressed into the AG role in Vietnam, later becoming the Wild Weasel I prototype.
The F-104 was an interceptor that was used for decades as an attack plane by foreign air forces, even though the USAF canned it quickly.
The A-5 was designed as USN long-range nuclear bomber. It failed in the ground attack/nuclear strike role (a little problem with getting hit by its dropping ordnance) and was instead around for decades in the RA-5 recon variant.
The F-117A was numbered to follow the century series. Some of you may not no this, but legend has it the F-112 - F-116 and possibly higher are USAF designations used by ATC and such for captured Eastern Bloc aircraft--MiGs, Sukhois, ets. Their existence is secret as is their usage out there, but by calling the Nighthawk "F-117" you make it sound like another "boring" captured MiG--not the world's first operational stealth airplane!
The F-4 was designed as a USN interceptor, but as we all know was pressed into every other tactical fighter role there was: recon, attack, air superiority (not the same as interceptor!), and of course SEAD. It was so good the USAF swallowed their pride and bought them (as the laughable F-110 until McNamara slapped them down).
The F/A-18 was named as such because the USN wanted to emphasize the multi-role nature of the plane as it was replacing A-7s but could dogfight almost as well as the F-16. Slap 2 AIM-9s and 2 AIM-7s on a bomb truck, then once those bombs are gone you've got a better AA fighter than the F-16 (which in the original A version was incapable of carrying radar guided missiles, other than the ADF variant created for CONUS defense and never deployed). The USAF has since picked up on this with the silly F/A-22 designation.
The F-15E and F-16XL(E/F) were both designed to replace the F-111. Fighters being turned into bombers to replace a fighter turned bomber. The Beagle won, and for once it was probably wiser than making the F-16XL--something tells me we would've lost more F-16E/Fs than we did F-15Es in our Gulf fighting.
The USMC has the AV-8A/B/C. Ok, a vertical attack plane, tack a V in there. Then they add the F-16's radar and call it...the AV-8B +! It SHOULD be the F/AV-8B, shouldn't it?
Sweden does it right. Make letters for all the roles, then tack them on in the order of importance. The AA Viggen with a secondary attack role was the JA-37. The AG Viggen with a secondary AA role was the AJ-37. Simple! The fully multirole Gripen gets JAS-39, even though the S (recon in Swedish) isn't really there yet, but they'll get around to it once the recon Viggens are retired (can't remember what it's called). Oh, here:
The SF and SH 37 models are reconnaissance models with the SH optimized for maritime recon and with a secondary maritime strike role.The SK 37 is a two seat conversion training variant. Around 100 AJ, SH and SF 37s have been converted to a new multirole AJS standard.
Nice to see SOME militaries are logical about this.
I wonder what the A-11 was supposed to be. Was it the plane that competed against the A-12 and lost? Was it assigned to some TS program that never saw the light of day?