Boom Supersonic announced the final design selection for its planned Overture supersonic jet. Now sporting four engines mounted on gull wings, as well as a contoured fuselage, company executives announced the revised configuration at the Farnborough International Airshow outside London this week.
Aviation has not seen a giant leap in decades. Overture is revolutionary in its design, and it will fundamentally change how we think about distance.– Boom Founder and CEO Blake Scholl
Boom says the chosen design was the best of 51 full iterations, processed via 26 million core hours of software simulations. The company also conducted five wind tunnel tests to select and finalize the new specification.
Power plant predicaments
The company did not, however, solve the most pressing vendor challenge. Overture still does not have an engine.
Similar to past events, Boom CEO Blake Scholl said the design is progressing and that the company is “looking at multiple different options.” That comes two years after the company announced a research partnership with Rolls-Royce.
And four years after Scholl suggested the engine would be a relatively easy design shift from existing products, “It is not a new technology engine, it is a new design engine. You’ve got knobs on an engine like bypass ratio and pressure ratio and they’re set in certain places for the 787 and you want to set them in different places for this airplane.”
That the company is still without an engine, while asserting a finalized design, is somewhat concerning. Engine specifications are critical to the aircraft’s success. Mandating a design from the top down rather than cooperating with the supplier to see what can be delivered is a risky approach. And even if it is just “moving the knobs” to an existing engine core design rather than inventing something that’s never been certified before, the testing and certification processes are not trivial.
The company also says that the four engine design will reduce noise and airline operating costs. This claim is particularly interesting given the shift across the rest of the commercial aviation market to the very efficient super twin engines. The twin-engine designs are more efficient and quieter than their predecessors. Why that will be different for Boom’s quad engine approach is unclear.
Questionable market demand
Scholl also continues to push the company line of more than 600 viable routes across the globe. Many of these include significant overland sections, where supersonic flight is not viable.
A Boom representative previously stated, “Overture is designed to fly at supersonic speeds only over water, and our business case does not require any changes to existing regulations, in the US and elsewhere, on overland supersonic flight.” This position is not well supported by the theoretical route maps shared nor the discussions of how many city pairs could be served.
The company has also adjusted the time savings pitch in some of the key markets. Tokyo to San Francisco is now cited at 4.5 hours in the promotional materials, down from 5.5 hours in 2018. This comes despite the aircraft’s top speed dropping from M2.2 to M1.7 over the same time. And it would still likely need a pit stop in Anchorage – including customs clearance for passengers – to make the trip work.
Still, Boom insists Overture will be “the most profitable new addition to global commercial airline fleets” because of its speed. The ability to operate twice as many flights in a day compared to traditional subsonic aircraft drives that claim. It also ignores that many of the most valuable markets where supersonic could succeed would not work with doubled frequencies.
Boom did secure a partnership with Northrop Grumman to help develop a military model of Overture. And it received a $60 million federal grant earlier this year to help boost research. But Boom is still short several billion of it will require to properly develop, certify, and deliver production planes.
Boom also announced it will outfit its Iron Bird facility, where Boom will construct its first full-scale testing model of Overture, in Centennial, Colorado. The 70,000-square foot facility will house the systems integration labs (SIL), which include the iron bird test model and fully functional flight deck simulators. That comes in advance of the company’s plans to open a factory in Greensboro, NC for production builds in 2024.
The company also continues to hold to its latest development timeline, including first Overture rollout in 2025, first flight in 2026, and passenger flights by 2029. Those dates are all very optimistic, especially for a 100% clean sheet aircraft from a new company.
The A350 and A380 went from first flight to commercial service in 18-24 months, with another 12 months for assembly of the first frame to become the test aircraft. The 787 also took about two years to go from first flight to commercial service, along with a longer buildout timeline. The A220 (then known as CSeries) took almost three years to make the jump from flight to commercial service.
All of those came from companies with long histories in aircraft manufacturing and certification. Boom will be doing it all for the first time.
Fuel burn and emissions challenges
Flying supersonic will consume more fuel per passenger mile than today’s subsonic flight. The combination of increased fuel consumption and higher cost per gallon for SAF could lead to fuel costs 25 times higher per seat-mile than subsonic flight, should an airline choose to power Overture with 100% SAF. Assuming any airline can source enough SAF by 2030 to operate a fleet of supersonic jets.
Even at the most optimistic end of projected production growth, the industry will barely have enough SAF to meet subsonic emissions targets in 2030. Adding aircraft that burn significantly more fuel per seat won’t help.
And the overall industry optimism on SAF production levels will require significant advances to be realized. Boom expected to at least partially fuel its XB-1 demo program with SAFs from partner Prometheus Fuels. That is no longer the plan, however, with the desired fuels presumably unavailable. Even as new production pathways emerge, the cost of developing and supplying SAFs in volume is driving some to consider less environmentally beneficial production methods. Converting food crops to fuel or razing forests to create farmlands for source materials will not deliver the big picture benefits desired.
Finally, even burning 100% SAFs, the emissions impact from a supersonic jet might not be as climate-friendly as the marketing pitch would have you believe. A recent MIT/ICCT report suggests that, because of the way the SAFs burn and the higher altitude at which Overture would fly, “a small fleet of supersonic aircraft, providing between 0.1% and 0.6% of the total number of seat-km of the projected subsonic fleet, could cause ozone depletion equivalent to up to 8% of the total impact of CFC emissions” at their peak.
Ultimately, the mid-term radiative forcing of commercial aviation could increase by two-thirds, despite covering less than 1% of all traffic in ASKs and flying with SAFs. If, however, we assume SAFs remain cost-prohibitive and relatively unavailable for supersonic flight the radiative forcing is not as bad, but CO2 emissions go back up.
There is no true good environmental news about operations that require that much more fuel per seat-mile flown, regardless of how the fuel is produced.
More on Boom's development
- An investment Boom from Japan Airlines
- Engine selection “core” to Boom Supersonic’s success
- Boom’s supersonic timing slips
- PaxEx Update: FTE Asia edition
- Behind the scenes with Boom Supersonic
- Supersonic sound standards set; Boom schedule slips
- Boom Supersonic picks an engine manufacturer (for further discussions)
- Virgin Galactic makes a move in supersonic travel
- United Airlines plans supersonic Boom with new order
- Boom fires up the engines on XB-1 supersonic demonstrator
- Boom building at Greensboro, new environmental concerns revealed
- Boom Overture adds engines in design revamp
More news from the 2022 Farnborough International Airshow
- Delta confirms 737 MAX 10 order
- Boom Overture adds engines in design revamp
- Porter Air boosts Embraer E2 commitment in advance of service launch
- Dash 8 adds IFE/C with Starlink option
A favor to ask while you're here...
Did you enjoy the content? Or learn something useful? Or generally just think this is the type of story you'd like to see more of? Consider supporting the site through a donation (any amount helps). It helps keep me independent and avoiding the credit card schlock.