Blog: The Need for Supersonic Speed

Jun 25, 2018 - 8:00 PM

While I remain skeptical about the prospects for a large enough market to sustain the manufacture of a supersonic business jet (SSBJ), listening to Brian Barents extol the progress made by the Aerion team makes me wonder whether I’m wrong. Aerion is a company led by smart people who not only asked whether it’s possible to build an SSBJ, but then secured the funding and hired the talent to start working on the program.

Work done by Aerion so far puts it well ahead of any potential competitors and able to reap the benefits of being first to market. Aerion has hurdles to overcome, and there are other companies that have poured money into researching SSBJs, but Aerion has kept its eyes on the target and turned the financial spigots on to a much greater degree.

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Aerion AS2

Read the article that recently won “Best Business Aviation Submission” at the Aerospace Media Awards in Paris.

The result is that Aerion has a design—the AS2—and this is just a first-generation SSBJ, Barents pointed out at the JetNet Summit on June 20. As research progresses and the regulatory climate improves, Aerion already has plans for an even faster and more capable second-generation SSBJ.

It appears that, for the most part, major aircraft manufacturers are staying out of the SSBJ game. Gulfstream Aerospace has spent some money on research to lower sonic boom noise—dubbed Quiet Spike—but declines to indicate that it is doing anything other than that. Other SSBJ projects have come and gone apparently nowhere, such as the SAI Quiet Supersonic Transport.

Indeed, in 2004, the year that Aerion announced its intention to design and manufacture an SSBJ, then-Cessna president and CEO Jack Pelton said that Cessna would “sooner or later” build an SSBJ. This does not appear to be a prospect unless there’s something well under wraps in Textron Aviation’s secret Wichita laboratories.

HyperMach and Spike Aerospace claim they are actively developing SSBJs, and Boom promises to field a supersonic airliner, but it isn’t apparent that the billions of dollars needed to achieve certification and begin production are currently available. At $120 million each, how many Aerion AS2s would have to sell to make the product worth manufacturing?

Nevertheless, there is industry support. Flexjet in 2016 placed an order for 20 Aerion AS2s. In a survey conducted by JetNet last year, 29.1 percent of respondents strongly agree that an SSBJ will enter service in the next 10 years. And 40.1 percent somewhat agreed with that statement.

And thinking about SSBJs in general, there is an argument for their practicality. Looking at today’s most popular business jets, the ultra-long-range category is still doing well and also seeing the entry of new products. But is the opportunity to stay aloft for more than 15 hours without stopping that appealing? What if the same trip could be done in a third of the time, albeit in a smaller cabin? Isn’t that a significant and compelling advantage?

There is no doubt that there could be a decent-sized market for a super-fast aircraft. The ranks of ultra-high-net-worth individuals who might afford one are growing, and there is a never-abating thirst for the best of everything.

But there is a major roadblock in SSBJ development, and Barents hinted at how its removal could lead to future-generation faster fliers. The prohibitions against flying at greater than supersonic speeds over land are holding back development. Having to slow down over land, no matter how carefully designed to be as efficient as possible, is simply a waste of technology. A true SSBJ ought to be able to fly supersonic from shortly after takeoff to just before landing.

The regulatory climate is preventing the development of new technology for SSBJs, simply because of the fear of sonic booms. Certainly, these can be loud and disturbing, but not in every case. It might be possible at high altitudes to carve through the sound barrier without disturbing people on the ground. Why not permit an SSBJ, for example, to break through when above 50,000 or 60,000 feet?

According to NASA, “Altitude determines the distance shock waves travel before reaching the ground, and this has a significant effect on intensity. As the shock cone gets wider, and it moves outward and downward, its strength is reduced. Generally, the higher the aircraft, the greater the distance the shock wave must travel, reducing the intensity of the sonic boom.”

NASA also pointed out that “increasing speeds above Mach 1.3 results in only small changes in shock wave strength.” This points to the benefits of designing SSBJs that can fly much faster than the Mach 1.4 cruise speed target for the first-generation AS2.

Aerion certainly deserves credit for spending so much time, money, and engineering talent on one of the greatest challenges in business aviation. And perhaps manufacturers are paying attention. We notice that in May Gulfstream’s trademarks for the G1100 and G1200 went live on the U.S. Patent and Trademark Office’s website. And Dassault recently secured the trademark for the 10X. Could these be the speedy new monikers for a new generation of SSBJs?