The secret behind one of the fastest jets in the world, the SR-71 Blackbird, was the design of its air inlets, specialised blog portal The Aviationist reported on Saturday. According to the portal, the aircraft managed to reach a maximum speed of Mach 3.2 due to its Pratt and Whitney J-58 turbojet engines and the air inlets, which provided more than 32,000 pounds of thrust at sea level.
"The engine made extensive use of high-temperature nickel superalloys, especially Inconel and Waspaloy, to withstand temperatures ranging from 800° F (about 430° C) in the inlet to 3200° F (1760° C) in the afterburner duct", the article said.
Among other technological features, the jet also had a characteristic movable conical spike used to change the inlet's geometry. It also had forward bypass doors used to relieve the pressure, and grills on the outside of the nacelle, which were connected to the hollow body of the spike.
The SR-71 used a special fuel designed for this specific aircraft, allowing it to withstand the extreme conditions of flying at Mach 3 speeds.
The details of the J-58's design are no longer a secret, but no one has been able to replicate the technology of the engine and inlets.
Despite being retired two decades ago, the Blackbird still holds the world record for the fastest air-breathing manned aircraft, attained in 1976.