It also wasn’t stealth, or an attack aircraft.

> The second operational aircraft[38] designed around a stealth aircraft shape and materials, after the Lockheed A-12,[38] the SR-71 had several features designed to reduce its radar signature. The SR-71 had a radar cross-section (RCS) around 110 sq ft (10 m2).[39] Drawing on early studies in radar stealth technology, which indicated that a shape with flattened, tapering sides would reflect most energy away from a radar beam's place of origin, engineers added chines and canted the vertical control surfaces inward. Special radar-absorbing materials were incorporated into sawtooth-shaped sections of the aircraft's skin. Cesium-based fuel additives were used to somewhat reduce exhaust plumes visibility to radar, although exhaust streams remained quite apparent. Kelly Johnson later conceded that Soviet radar technology advanced faster than the stealth technology employed against it.[40]

https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird

To be clear, a 10m^2 radar cross section is enormous compared to the F-117 (0.001 m^2) The F-117 was in a completely different league than the SR-71, but the SR-71 was in fact designed to be stealthy.

A-12 did stay classified for a while.

There were actually two A-12s. The Lockheed A12 was introduced in 1967 and retired in 1968. The McDonnell Douglass A12 was never built and finally cancelled in 1991.

https://en.wikipedia.org/wiki/Lockheed_A-12

https://en.wikipedia.org/wiki/McDonnell_Douglas_A-12_Avenger...

The SR71 succeeded the Lockheed A12. It was hard to keep secret.

https://en.wikipedia.org/wiki/Lockheed_SR-71_Blackbird

https://nationalinterest.org/blog/the-buzz/keeping-the-sr-71...

> There were actually two A-12s. The Lockheed A12

I bet this was made on purpose. USA has learned some tricks from Soviets with their "fake patterns"

F-117 wasn't a fighter, and A-12 was not a CAS aircraft. Pretty much like Kirov was not really an "auxiliary craft," and Tu-22 M-1-2-3 were all nearly completely different aircraft

Tanks are so named because during WWI, the British decided to conceal their true purpose by calling them 'water carriers.' 'W.C.' was deemed an inappropriate initialism though, so the name was changed to 'tank' as in "a tank of water."

The F117 is also the USAF designation for an aircraft engine (Pratt & Whitney PW2000), used on the C-17.

Someone suggested to me a few years ago that might be the reason why the F-117 was designated that way.