SR-71 Blackbird with just one engine in full afterburner
The SR-71 Blackbird was built to penetrate deep into hostile airspace while avoiding interception through its exceptional speed and extreme operating altitude.
The aircraft’s development began in secret during the late 1950s with the A-12 reconnaissance aircraft. The A-12 made its first flight in April 1962 and remained classified until 1976. On February 29, 1964—more than six months after the aircraft’s maiden flight—President Lyndon Johnson publicly revealed the YF-12A interceptor variant. The SR-71 itself first flew on December 22, 1964.
Because the Blackbird could operate safely at altitudes exceeding 16 miles, or 25,908 meters (85,000 feet), and reach speeds of up to Mach 3.3, its crew had to wear pressure suits similar to those used by astronauts.
The striking photograph in this post shows an SR-71 flying with one engine operating at full afterburner.
Why would it do that?
SR-71 pilot Stormy Boudreaux explains:
“This is a photograph of a practice single-engine go-around. The left engine is at idle, while the right engine is operating at full afterburner. The pilot has applied full left rudder and is beginning a right bank, all to keep the aircraft flying straight. He has also retracted the landing gear. One particularly unique feature of the SR-71 was that either the left or right hydraulic system could retract the landing gear.”
Two methods to retract the gear
If an engine failed during takeoff, and the pilot elected to continue the departure, or if a go-around became necessary, the thrust from only one of the SR-71’s widely spaced engines would produce a powerful yawing moment. To counter it, the aircraft had to be banked toward the operating engine while the full opposite rudder was applied, and the landing gear had to be retracted.
The reason was that, with the aircraft experiencing severe yaw, the extended nose gear acted like a canard or fin exposed to the airflow, increasing the yaw even further.
The aircraft could quickly become uncontrollable if the landing gear, particularly the nose gear, could not be retracted. Under certain low-speed conditions, recovery would not have been possible without retracting the nose gear. For this reason, the SR-71 was designed with two hydraulic methods for retracting the landing gear, one using the system on each side of the aircraft.
Most aircraft have a normal and an emergency method for lowering the landing gear, but only a single system for retracting it. Because retracting the nose gear was so critical during low-speed, single-engine operations, Lockheed designed the SR-71 so that the gear could still be raised if either engine failed.
The aircraft did, however, have only one hydraulic system for lowering the landing gear. If that system failed, a manual mechanism could unlock the gear and allow it to free-fall as a backup.
An interesting story
The incident became even more remarkable when the engine intended to power the practice single-engine approach and go-around failed during the exercise, turning the simulated emergency into a genuine single-engine go-around.
Boudreaux concluded that the Blackbird pilot quickly advanced the previously idling engine to full afterburner to obtain the thrust needed after the other engine failed. The situation depended on the idling engine transitioning smoothly and reliably from idle to full afterburner, making the event an exceptionally tense and remarkable example of emergency airmanship.
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The book Ohio to Supersonic: Flying the SR-71 Blackbird to the secret world of the Skunk Works by Colonel Richard “E.” Butch Sheffield and Linda Marie Sheffield is available for purchase here.
Photos by HAEAHDDANCER7
