Sept. 20, 2022, © Leeham News: Blake Scholl, the founder and CEO of Boom, the start-up company, continued to paint an optimistic picture about the Overture Supersonic Transport.
He told the US Chamber of Commerce Aerospace Summit last week that the Overture, a Mach 1.7 88-passenger aircraft concept, will revolutionize international air travel.
But Boom has big challenges ahead—not the least of which is that there is no engine manufacturer so far that has stepped up to provide an engine. The Big Three—GE Aviation, Pratt & Whitney, and Rolls-Royce—have either outright rejected participation or other priorities exist.
With Rolls and GE saying they aren’t interested, and P&W’s priorities focused elsewhere, where will Scholl find an engine for the Overture? Flight Global reported that GE’s partner in CFM International, Safran, also says it won’t provide an engine.
Scholl is undeterred. In a quick interview following his presentation, he said Boom would have an engine partner by the end of the year. With RR, GE, Safran, and P&W uninterested, Scholl nevertheless said he will have an announcement by year-end. “I’ll tell you when I can tell you. I feel really good about this.”
This summer’s report from the UN’s International Civil Aviation Organization on reducing the environmental impacts of aviation throws doubt on the viability of super-sonic commercial jets. The report’s inclusion of analysis from ICCT said supersonic transports don’t fit in with the industry’s need to drive carbon emissions down, and it specifically rejects the idea of using sustainable aviation fuels (SAFs) to power jets flying faster than sound.
“In a nutshell … supersonics are a poor use of scarce SAF supplies,” the ICAO/ICCT report said.
The problem is that supersonic engines burn seven to nine times more fuel per passenger-seat-kilometer than similarly sized sub-sonic jets, the report said.
And with SAF costing two to five times what standard aviation fuel does, “the combination of SAFs higher cost and SSTs greater fuel intensity could increase fuel costs to 25 times that of subsonic aircraft burning Jet A, threatening the already questionable finances of supersonics,” ICAO reported.
SAFs also would do nothing to lower the impact of commercial aviation on global warming, the report continued. “More surprisingly, even if SAFs were widely available, their use in supersonic flight could actually backfire after accounting for the full atmospheric impacts of SSTs.”
Because SSTs fly at high altitudes – Boom says 60,000 feet — the emissions from their engines hang in the air longer.
Furthermore, because of the specific characteristics of SAFs, burning that particular fuel at those altitudes “could actually exacerbate the medium-term climate impacts,” the ICAO report warned. Citing data from NASA and the Massachusetts Institute of Technology, the agency said supersonics burning SAFs high in the atmosphere would have 120 to 230 times the climate impact of a subsonic jet burning kerosene at lower altitudes.
“Assuming that SAFs can address the climate impacts of supersonics is premature,” the report concludes. “Moreover, economic modeling concludes that the high cost of SAFs will make them cost prohibitive for supersonics for the foreseeable future.”
Scholl was dismissive. “This is the first airplane capable of net zero carbon. It flies at a higher altitude, which is advantageous in a whole bunch of different ways. We care deeply about making this not just good for passengers and not just good for airlines, but also good for the planet. We take the science really seriously. Whenever we have opportunities to make the airplane more friendly for the planet, we do. That’s part of why it’s a Mach 1.7 airplane vs 2.2 where we started. A lot of that is about minimizing noise footprints around airport communities, making it as quiet as the latest generation airplanes.
“We think this is going to be a net good for humanity in a really big way.”
Scholl recently repeatedly claims there is a market for “thousands” of Overtures. The 2013 Boyd study estimated the demand from 2022 to 2032 of 1,318 airplanes. In the interview, Scholl declined to reveal what “thousands” means.
“To take people who are flying subsonic business class supersonic on routes where there is a big speed up for passengers and enough demand and the appropriate fares to make the airplane profitable, there are hundreds of airplanes in commercial use without assuming any kind of demand stimulation. People fly more when flights are faster,” he said.
“As we’ve partnered with Northrop Grumman and deepened our ties with the Department of Defense, we also see this as a very significant platform to provide a capability for Defense. It’s like we found the other half of the market there,” he said. Taking Boyd’s estimate at face value, Scholl’s response suggests demand for 2,600 Overtures.
The original Overture concept envisioned a Mach 2.2 airplane. This was later revised to Mach 1.7. In the 2013 Boyd study, the higher speed was described as a “critical factor, as the market advantages of slower supersonic speeds—for example, the 1.5 Mach now planned for some proposed business jets—are not sufficient to offer significant time-reductions on long haul flights.” Mach 1.5 is 1,150 mph; Mach 1.7 is 1,304 mph and Mach 2.2 is 1,687 mph. Scholl said the lower speed is more environmentally friendly (see below).
“We’ve looked at that in a lot of detail and we feel great about 1.7 Mach,” Scholl said. “That’s part of why United and American are placing orders. The airlines are voting with their dollars.”
However, a technical perspective concluded that Mach 2.2 is beyond the capabilities of the engines that have been examined. Even engines capable of Mach 1.7 have a huge drawback: they’d have to be overhauled after only 4,000 hours.
While Scholl touts nearly 130 orders from Japan Air Lines, United, and American airlines, these are conditional orders. If Boom was a publicly traded company, all would be classified as not firm under ASC 606 accounting rules.
“Most importantly, we have to deliver the airplane that has been promised,” Scholl said. “We would not have the customer relationship we have if the airplane we were building was not one that the airlines wanted.”
Boom has so far raised a fraction of what is needed to bring the Overture to market. AIN Online reported that Bloomberg’s aerospace analyst estimates Boom needs $10bn. “Boom claims to have drawn $600m of its estimated requirement of between $6bn and $8bn…,” AIN wrote.
Scholl declined to make any additional comment during the interview.
Entry into service originally was targeted in 2023. Now it is targeted for 2029.
Bryan Corliss contributed to this report.