SR-71: A Mach 3.5 Spy Plane? While modern fifth-generation fighters like the F-22 Raptor and F-35 Joint Strike Fighter are often synonymous with the world’s greatest, fastest, and more sophisticated platforms, they actually fall behind a jet that was introduced more than four decades ago.
The SR-71, dubbed the “Blackbird,” is unquestionably the fastest airframe across the board.
When the powerful platform first entered service with the United States Air Force in the late 1970s, no other aircraft – or missile for that matter – could catch it in flight.
Although one aircraft in the Blackbird’s history was actually able to achieve a missile lock and visual contact with the speedy American spy plane, the SR-71 notably dodged more than 4,000 missiles during its tenure in combat.
The SR-71 could technically reach speeds of Mach 3.5, however, operating at this speed would also result in serious damage to the fighter.
What happened when the Blackbird surpassed Mach 3.3, as explained by a former SR-71 pilot:
Former SR-71 pilot Bredette BC Thomas described the Blackbird’s speed capabilities in an Aviation Geek Club piece.
According to Thomas, the formidable airframe could surpass Mach 3.3., the speed limit listed by the Flight Manual, since it was not power-limited:
“However, doing so would exceed the compressor inlet temperature limit, as well as other limits both heat related and structural. I am certain that no pilot ever put both throttles in maximum afterburner and let the aircraft accelerate to see how fast it would go. That would be a violation of military orders, the flight manual restrictions, and common sense. I, and most probably all other pilots, never purposely violated any published limits while flying the SR-71.
“The SR-71 could attain Mach 3.5, but the aircraft would be in an untested and prohibited area outside of its flight envelope, and serious damage to the aircraft might occur. The SR-71 was point-designed to cruise continuously at Mach 3.2, which is quite an achievement, but it was not intended to have a lot of margin above that speed.”
The SR-71 Blackbird- Specs & capabilities:
The fact that flying at speeds greater than Mach 3.3 would inflict damage to the airframe does not take away from the fighter’s unparalleled capabilities. The F-22 Raptor, the world’s first fifth-generation fighter platform that is often considered to be among the best airframes on the planet, can attain speeds of Mach 2.25 (around 1,500 mph). While this number doesn’t compare to the SR-71’s capabilities, the Raptor is recognized as an incredibly fast fighter that has concerned American adversaries since its introduction to service.
In order to achieve its awe-inspiring stats, the Blackbird sports a variety of unique features. The SR-71’s engine intakes included advanced mechanisms that slowed the air below the speed of sound before it entered the engines.
Additionally, the Blackbird was constructed of titanium, a metal able to withstand the high temperatures associated with flying at such fast speeds. For these reasons, the SR-71 played a critical role in the Vietnam War. However, due to the airframe’s high cost, the Blackbird was relegated to museum duty by the late 1990s.
Maya Carlin, a Senior Editor for 19FortyFive, is an analyst with the Center for Security Policy and a former Anna Sobol Levy Fellow at IDC Herzliya in Israel. She has by-lines in many publications, including The National Interest, Jerusalem Post, and Times of Israel. You can follow her on Twitter: @MayaCarlin.