I thought the YF-12 was the proposed fighter derivitive of what ended up as the SR-71. The thing I remember about that plane was that, first, it was faster than bullets, literally, so they couldn't arm it with guns. Therefore they came up with a missle specifically for it's use. Though they dropped the fighter variant, they kept the missle for other planes and dubbed it the Phoenix.
A couple of folks who should know have told me that's wrong. A couple who should know have told me that's the way it was. It still gets the point across about the planes speed.
I saw the SR-71 in person in what I understand to be one of the first times it was shown to the public. We were visiting a friend at Travis AFB who was waiting for a MAC flight to his home in Hawaii. He was retired due to injuries in Vietnam and could fly free, but he was waiting for weeks because it was in the middle of the PATCO strike, so anyone who could fly MAC was and a retired Marine grunt was WAY down the list. They had an airshow up a Travis so we used the excuse to go spend time with him ("meet me under the wing of the B-52" were his instructions). That would have been in 1981.
They had the SR71 on display but kept the public about 30 feet away, behind ropes, with armed guards around it. The pilot (I think a Colonel) was at the rope line talking to the public. When asked how fast the plane could fly he told a story "he had heard, but couldn't vouch for." There is an internationally accepted speed record for aircraft set from a fixed point in international waters off of England to a fixed point off of New York. A Russian Mig was flying that route to set the record and prove the superiority of Soviet airplanes. About halfway across the Atlantic an SR-71 sidled up along side the Mig, the American pilot waved at his Russian counterpart, smiled and waved, then hit the afterburners. The SR-71 left the Mig far behind. The Russian turned around and went home at that point.
I bet the story is apocryphal, but I love it.
SR-71
The plane "grew" 11 inches in length when at operational altitudes...heat expansion
It leaked like a sieve: no fuel bladders...it only got tight when it got hot.
A one degree climb angle resulted in 3000f/m increase in altitude.
It regularly flew over the Kamchatcha Peninsula and Sakhalin
Island and would be chased by a series of Russian fighters doing ballistic climbs trying to get close enough to fire on it.
The offical top speed was just over 2,400 mph, ceiling at 80k.
Unoffical speed closer to 3k mph
Unoffical altitude closer to 120k feet
Most of the above from my brother who helped design the bird.