It’s been around a year and a half since Boom unveiled its prototype supersonic demonstrator, the XB-1. Also known as the ‘Baby Boom’, this aircraft is designed to provide proof of concept for the technologies and materials planned for use on the full-size mass supersonic transport of the future, the Overture.

In test at the firm’s home at Colorado’s Centennial Regional Airport, the XB-1 has been put through its paces over the last 18 months. Things were relatively quiet for the first year, with testing focused on systems and other non-motion-related checks. But in December last year, the first reports began to come in that the engines were running.

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Ground testing on the XB-1 continues. Photo: Boom Supersonic

Since then, Boom has undertaken multiple test runs for the three engine jet. The single-seater aircraft has also been undertaking taxi tests in Colorado, often a clear sign that the first flight is rapidly approaching. I caught up with Blake Scholl, founder and CEO of Boom Supersonic, to find out where the project is at right now. He told me,

“We are in, basically, the final stages of ground testing now. The airplane is operational, all the engines are up and running. We’ve retracted the landing gear, run the environmental control systems. We're through about 80% of our pre-flight testing and it’s going great.”

Originally, Boom had hoped to get the XB-1 in the air in 2021; however, the delay is not significant, and given the many unique challenges presented to the team, is hardly anything to be concerned about. The company says that the EIS date for the full sized Overture has not shifted at all.

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Photo: Boom Supersonic

Flight testing later this year

The next stage in the process will be getting the XB-1 off the ground. This won’t happen at the Colorado base, however. The developers plan to take the XB-1 out to the Mojave Air and Space Port in California for its flight testing, something that could happen as soon as the end of the summer.

For Scholl, this is the culmination of around seven years of hard work, and is an incredibly exciting time for him and his team. He told me,

“It’s a really exciting time. The test pilots have begun all their training for the first flight, both in the simulator as well as doing recurrency training in fighter trainer aircraft. They're boosting back up their supersonic skills. So it is a super exciting time with XB-1, and we expect to be in the air later this year.”

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The simulator has been designed and built by Boom. Photo: Boom Supersonic

Boom has developed its own in-house simulator, which it has said is 100% representative of the flight controls and handling of the aircraft. Even before the XB-1 rolled out, test pilots had spent many hours flying the simulator to prepare for the eventual flight tests.

In both the simulator and the XB-1, Boom has put the pilot’s comfort first. The stick and throttle embrace ergonomic design principles to ensure they are in the ideal position, and all other critical equipment is within arm’s reach. Displays are designed around the pilot’s line of vision, giving them unrivaled visibility of the instruments.

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The ergonomically designed cockpit gives better visibility of instruments and the outside. Photo: Boom Supersonic

With Concorde, one of the major issues was its lack of exterior visibility, something that was ultimately mitigated with its droop nose. Heavy and expensive, this was not ideal for Boom, so they have solved the problem with the installation of a forward vision system. This employs a screen in the center of the instrument panel to feed visuals of the exterior to the pilot, giving them a clear view of the surrounds regardless of the nose attitude of the plane.

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Pilots are preparing for flight testing later this year. Photo: Boom Supersonic

What is the XB-1?

Revealed in October 2020, the Baby Boom, as it’s called, is the miniaturized demonstrator for the eventual Overture. It is 68 feet long and has a 17-foot wingspan. It is powered by three 4,300 lb/f engines and will only have a range of around 1,000 NM. Although it’s a one-seater test plane, it’s an important technology demonstrator for the larger Overture to learn from, as Scholl explained,

“The XB-1 is the demonstrator airplane; it’s the 1/3 scale prototype for Overture. So it’s a smaller airplane, but with the same technology such as carbon fiber composites, Software Defined aerodynamics, etc. that’s going to be on Overture.”

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Unlike the Overture, the XB-1 still uses afterburners to reach supersonic speeds. Photo: Boom Supersonic

While the XB-1 embodies a lot of what will make the Overture great, one place it doesn’t tie up is in the powerplants themselves. Its three engines are off-the-shelf GE engines - J85s – which power aircraft like the Cessna A-37, the Northrop F-5 and the Canadair CT-114. These are, clearly, not the engines that will power the Overture.

The Overture is being designed to fly on 100% sustainable aviation fuel (SAF). Boom is in conversation with Rolls-Royce about the engine spec, and Scholl notes that they are now at an exciting point in the process where they have a combination that works. While he was unable to share further detail right now, he noted that more announcements will likely follow later this year.

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Boom is working on technical specifications for powerplants for the Overture in partnership with Rolls-Royce. Photo: Boom Supersonic

Boom has not only had to face down the naysayers who believe supersonic passenger flight was a flash in the pan and shouldn’t be revisited. It has also had to battle through some of the most difficult times in aviation’s history. The disruption of the COVID crisis continues to play havoc on supply chains, and the looming troubles in Eastern Europe continue to threaten project timelines and costs.

For Blake Scholl, the fact that none of this has seen the timeline slip from the 2029 EIS projection is a point to be proud of. To see the XB-1 in the air later this year will be a milestone for the company, and most certainly an emotional moment for Scholl.