Fast Enough for 2029 FAA Certification?

After losing engine partner Rolls-Royce in September 2022, Boom Technology (trade name Boom Supersonic), the Denver-based American company about the perilously speculative business of bringing to market a supersonic civilian airliner, announced in December 2022 that it will partner with three aviation companies to develop and build engines for its proposed Overture Super Sonic Transport (SST).

Boom Supersonic executives disclosed their engine-building plans during a ceremony at North Carolina’s Piedmont Triad International Airport (GSO)—ostensibly the future site of the company’s aircraft manufacturing operation. Boom has pledged to create 1,760 jobs in the Guilford County/Greensboro area and invest $500-million in the project through the end of the decade.

Boom founder and CEO Blake Scholl informed an audience gathered on the GSO terminal’s upper concourse that his company would team with a consortium of three lesser-known aerospace concerns to design, produce, and maintain a jet-engine capable of powering an economically-viable, environmentally responsible SST.

"Developing a supersonic engine specifically for Overture offers by far the best value proposition for our customers," Scholl remarked.

Florida Turbine Technologies, a division of defense contractor Kratos Defense, will design the engine; GE Additive will provide technology consulting on additive manufacturing (3D printing); and Arizona-based StandardAero will maintain the engines once certified specimens take to operating afield. The powerplant resultant of the collaboration is to be called—naturally—Symphony.

In addition to its ambitions to see Overture deliver a Mach 1.7 top-speed and a range of 4,249-nautical-miles, Boom intends to run its inchoate SST’s quartet of Symphony engines on Sustainable Aviation Fuel (SAF).

"We are optimizing Symphony for sustainable commercial supersonic flight by designing it to run on one-hundred-percent SAF from day one," a company representative asserted.

Speaking to the subject of Boom’s objective to attain net-zero CO2 emissions by 2025, Scholl set forth: "SAF is truly the best and really only way to rapidly decarbonize aviation.”

Scholl announced, also, that Boom has chosen Jupiter, Florida, as the site for the assembly plant in which the first forty Symphony engines will be built. A second site is to be selected to facilitate the manufacture of the thousands of Symphony engines Boom contends future demand for its aircraft will occasion.

A 2020 engagement agreement between Boom and Rolls-Royce established, albeit informally, the latter’s interest in developing engines capable of motivating Overture to Boom’s fantastical speed and range aspirations.

That Rolls-Royce apparently reconciled itself with the fact that the engine after which Boom pines is patently beyond the purview of extant aero-propulsion technologies is evinced by a September 2022 statement in which the storied British marque asserted: “We’ve completed our contract with Boom and delivered various engineering studies for their Overture supersonic program. After careful consideration, Rolls-Royce has determined that the commercial aviation supersonic market is not currently a priority for us and, therefore, will not pursue further work on the program at this time.”

Rolls-Royce’s reticence was echoed by Pratt and Whitney, GE, Honeywell, and Safron—all of which stated outright that they’d no interest in developing engines for supersonic civil aircraft. Only Pratt and Whitney expounded upon its rationale, stating supersonic travel is "tangential" to its business.

Asked whether the engine makers left Boom or Boom left the engine makers, Mr. Scholl responded: “It became clear that this was far and away the best path for us to go. We could have taken a subsonic engine and adapted it. We could have taken a subsonic business model and adapted it. That works, but it’s not nearly as good for our customers and our passengers because it brings the baggage of designs that were never optimized for supersonic flight and significantly increased operating costs.”

Notwithstanding developmental setbacks, pervasive doubt about the viability of commercial supersonic flight, and the fact his company is now three-and-a-half years into its planned ten-year developmental period and has neither an airframe nor an engine to show for it, Scholl asserts he remains confident Boom’s 2029 target for Overture’s FAA certification remains realistic.

FMI: www.boomsupersonic.com