www.sr-71.org 404 Not Found (linkrot)The SR-71 flight manual is available online, mostly declassified. “[Maximum] liftoff speed corresponds to 234 knots groundspeed (rated tire speed minus 5 knots).” But normal takeoff speed is only 207 mph. Or rather, you start pulling up the nose at 207, and five seconds later you are airborne. By then, you’re going 241 mph. For comparison, a 747-400 takes off at about 170 mph and a 737-300 at 190. (Aircraft Statistics, Air New Zealand) The SR-71 has about a 44% thrust to fully loaded weight ratio; a 747 29%, and an F-15 74%. The magic, apparently, is not in the raw power so much as in the not melting like butter when cruising at Mach 3.3.
And the tires really do explode:
SR-71A (61-7950 / 2001) The prototype SR-71 was lost on 10 January 1967 at Edwards during an anti-skid braking system evaluation. The main undercarriage tires blew out and the resulting fire in the magnesium wheels spread to the rest of the aircraft as it ran off the end of the runway. Lockheed test pilot Art Peterson survived.
SR-71A (61-7954 / 2005) This aircraft crashed on 11 April 1969 under conditions similar to 61-7950. New aluminum wheels and stronger tires with a beefed up compound were retrofitted to all SR-71s because of the crash. Lt. Col. William "Bill" Skliar and his RSO Maj. Noel Warner managed to escape uninjured.