Believe it or not, it’s partly built from hand-me-downs — a landing gear from an Air Force F-16, a control stick from an F-117 stealth fighter, and a cockpit canopy from a NASA T-38 trainer.
Yet it could be the most futuristic aircraft of its type.
NASA’s newest supersonic X-plane, the X-59 QueSST, which is expected to fly in 2021, will provide data that will allow engineers to scale down sonic booms, so that they sound more like muted thumps, Mark Strauss of Air & Space magazine reported.
The US banned supersonic travel over land in 1973, allegedly over noise concerns from sonic booms, but some suspect it was designed to deliberately halt the commercial progress of the Concorde.
The X-59 was cleared for final assembly in late 2019, and, in May, the program reported its latest milestone when GE Aviation announced that the first engine for the X-59 had been shipped, Air & Space reported.
While legendary test pilot Chuck Yeager’s X-1 used a four-chamber rocket engine to accelerate beyond Mach 1, the X-59 will use the F414-100 turbofan — providing 22,000 pounds of thrust — which is adapted from the engine that powers the Navy’s F/A-18 Super Hornet.
“A single-engine aircraft is attractive because it has a smaller footprint on the airplane,” says Ray Castner, the NASA propulsion lead for the X-59. “It takes up less space. Sonic boom is all about volume and shaping.”
Another significant aspect of the engine design is its placement on top of the airplane, so that the delta wings block shock waves from the nacelle from reaching the ground, Air & Space reported.
Meanwhile, significant progress has also been made on the X-59’s frame at Lockheed Martin’s secretive Skunk Works.
“All the major structure of the fuselage is complete,” says Jay Brandon, the X-59 chief engineer at NASA.“It’s in the process of getting its skins put on.”
According to NASA, the secret to “quiet” supersonic travel was first theorized in the 1960s.
It all has to do with the unique shape of the aircraft hull. In a conventional aircraft, shockwaves coalesce as they expand away from the nose and tail, resulting in two distinct and thunderous sonic booms.
In newly designed supersonic aircraft, the shockwaves are sent away from the aircraft, in a way that prevents them from coming together in two loud booms. The result is much weaker shockwaves, and, perhaps a quick series of soft thumps heard on the ground, if it all.
In 2003, a NASA F5E Tiger jet fighter with a modified nose demonstrated the boom-reducing theory successfully.
“The big innovation on this airplane is the (elongated) shape,” says Brandon. “So, it’s basically a cost and schedule mitigation to try to use things that have already been there. It’s not inventing things we don’t need to invent.”
Aside from the sonic boom issue, commercial supersonic travel faces other hurdles, such as the economic viability of the business model, as well as emissions challenges. From an ecological viewpoint, some analysts think it’s going to be a hard sell.