How X-planes may solve the sonic boom problem

On Mar 27, 2023

Rocket planes like the X-1 and X-15 were simply a hard act to follow. “You had this handful of pilots who are flying to the fringes of space and they were at the forefront of this new era,” says Teitel. “There was a sexiness about that which appealed to people as well. It wasn’t just the incredible technology. It was the future.”

Nevertheless, there have been many X-planes over the past 30 years – and records are still being set. Bahm worked on a good number of them.

The Lockheed Martin X-33 Venture Star was a demonstrator of the Nasa–Lockheed Martin project to build a successor to the Space Shuttle. It was cancelled in 2001 before any test flights could be carried out owing to the failure of the fuel tank during testing, although construction was 85% complete.

Bahm also worked on the X-43 scramjet-powered drone, whose sleek lines could have been designed by a Hollywood director. In March 2004, an X-43 set the record for the first time a scramjet-powered vehicle had flown under its own power. A scramjet is a type of airbreathing jet engine in which combustion takes place in the supersonic airflow through the engine. Eight months later an X-43 entered the record books when it achieved the speed of Mach 9.6 (or 7,000mph/km) and became the fastest airbreathing aircraft in history.

“That was a great, great, great project to work on,” says Bahm, who was deputy chief engineer on the record-breaking flight.

Now rather than going faster, the X-59 is aiming to be quieter, but it is only the start of the journey to quiet boom supersonic flight. “The X-59 is kind of fighter jet scale,” says Combs. “The next question is, can you build a bigger one that’s the size of a 737?”

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