Seriously Supersonic

posted on 9th October 2018
Seriously Supersonic

It’s important, I believe, to approach every interview with an open mind. The interviewee holds the key to the real story and the interviewer’s job is really to listen. But when the opportunity was offered to meet and chat with then Aerion CEO Brian Barents at July’s Farnborough International Airshow, I was fairly certain I knew the story.
Judging by the size of its NBAA-BACE booth, Aerion is a major player, yet the supersonic business jet it has been promising for so many years seems only to be inching closer. Add to that the recent addition of Lockheed Martin to the mix and I was firmly sceptical. Lockheed Martin (LM) knows how to build seriously supersonic aircraft, but did Aerion? I thought not.
Breaking all my own rules, I sat down with Brian expecting to discover that the company’s AS2 was little more than wishful thinking. I reckoned there’d be a run of half a dozen or so jets, before the programme disappeared into a deep pit of wasted dollars.

LM magic
I spoke with Brian alongside a huge model, in a slightly ramshackle room. The model depicted the AS2 in its latest form, after the application of a little LM magic. Coincidentally, LM’s wand has left the concept with a passing resemblance to a Lockheed of legend, the F-104 Starfighter, and Brian agreed there was a similarity in planform. In fact, the AS2 has a military fast jet feel to it and Brian explained: “Fast airplanes have certain characteristics in common and clearly the AS2 has them!”
On the Aerion board since 2003, and executive chairman and CEO from October 2017, Barents stood down to remain only on the board of Aerion directors this past August, handing the reigns to former Northrop Grumman Aerospace Systems president Tom Vice. Brian’s knowledge of and passion for the project are without measure, but I felt that bringing LM on board as recently as December 2017 may have been a response to the sudden realisation that building a supersonic jet was beyond Aerion’s means, even with Airbus already signed up as a long-term partner.
“Lockheed Martin hadn’t actively participated prior to our December 2017 announcement that they and General Electric were collaborating with us, but we’d been having active discussions for quite some time,” Brian recalled. “They’d been assessing the programme and all our activities over the previous 15 years. Early on in our programme we identified a number of critical phases where we’d need to collaborate with other companies. We’re aerodynamicists, we’re not airplane or engine builders, but we designed an airplane that we felt addressed market needs at a price the market was willing to pay. We always knew it would take a credible, established OEM to build it and support it. And an engine that would comply with the very demanding requirements for noise and emissions. All those elements, in addition to financing the programme, were essential to our success.”

Sweet spot
Back in 2003, Aerion judged the business and VIP aircraft market ready for a supersonic jet. But that was a decade and a half ago. Is the market still willing to accept such dramatic change? “Even more so. The economic globalisation and need to travel intercontinentally lends itself to a fast airplane.
“And among the large segments we’ll address is high net-worth individuals. The number of billionaires has almost tripled in the last decade and I believe it’s forecast to double in the next decade. These are people that value their time. They can afford this type of airplane and they’ll represent a good portion of our buyers.”
And yet, the latest competitor models already have maximum operating Mach numbers around 0.92, while Aerion expects the AS2 to long-range cruise at 0.95. Is that tiny Mach increment between Aerion and existing high-performance jets really worth the additional investment? “The difference is that when we go .95, that’s our sweet spot, for maximum range. When a competitor aircraft goes .92, it’s typically sacrificing around 30% of its range to do so – their long-range cruise is more like 0.85. Historically, we’ve seen competitors argue over 1/100th of a Mach to be able to say which has the faster airplane, but when you mention ‘supersonic’, they say speed isn’t all that important; you have to decide one way or the other!
“Our airplane really has two sweet spots. On a mission profile where you can use the supersonic speed, it’s there. On a mission profile where you may be prohibited or restricted on how fast you can go, you aren’t paying a range penalty for going transonic.”

Powerplant decision
While the AS2’s configuration may have something of the fighter jet about it, its powerplant does not. Based on the core of CFM International’s best-selling CFM56, the jet’s three-engined powerplant will satisfy international noise and emissions regulations. There’ll be no afterburning, or reheat, a common feature of military engines, where fuel is injected into the hot exhaust efflux, generating a dramatic increase in power at the expense of a massive spike in fuel consumption; afterburning enabled Concorde to take-off and reach supersonic speed, but was also responsible for its smoky, noisy departures.
Brian stresses that the AS2 powerplant is not derived from military technology and yet the chosen core was derived from that developed for the supersonic General Electric F101 engine still powering the US Air Force’s B-1B Lancer bomber fleet. It’s a relationship not lost on Brian, since his 34-year military career included a period in command of a B-1B wing.
Unlike the Lancer, or Concorde, Brian says: “We have to comply with the most stringent noise restrictions and they’re going to be even more demanding after 2020, when Chapter 5 comes into compliance. We’re ready to do that now, but the reason it’s taken so long for us to get the airplane where we are today has primarily been propulsion. We studied engines for a long time, looking at cores that met our performance requirements and satisfied the environmental and noise regulations. They had to be exportable too. Some military engine cores may have the potential for modification to meet our needs, but their technology isn’t always exportable to every country.
“It took us a long time to reach the correct conclusion, and even when we’d chosen to select from the General Electric product line, it still took us five years to identify an engine that would support our performance requirements, was practical for what we wanted to do and was supportable. We’ve chosen an engine core with over one billion hours of service and that’s supported around the world – that’s clearly important when you’re buying a US$120 million aircraft.”

Full-scale engineering mockup for cockpit and cabin design at Design Q in Redditch, England

With a very mature global support network ready to apply itself to the AS2’s modified GE core, Aerion is satisfied that its customers’ engines will be easily taken care of. But what about the airframe? In military aerospace, exotic materials are part and parcel of achieving high-speed. Will the AS2 require specialist techniques, even new technologies, to support its airframe maintenance?
“It’s supportable around the world and we’ll have an MRO network set up, including established organisations. That’s why we’ve stayed in this ‘space’. We chose 1.4 Mach, so we don’t need exotic materials like titanium. We’ve taken a very pragmatic approach to everything. The airplane will be composite. The systems will be similar to those you’d find in an airliner or large business jet, there’s nothing unique about them. The powerplant is proven. There’s nothing out of the ordinary. The only thing remarkable is that it goes fast!”
But supersonic aircraft typically have complicated engine air intake geometry, often featuring systems providing variable area to control mass flow. Has Aerion avoided that issue too? “If we were going Mach 1.8 or above we’d need a much more elaborate intake design. It’d add a lot of complexity; some day we may be there, but today we feel we have a first-mover advantage and we wanted to eliminate all that risk.
“And that’s even true of certification. We’ve developed our business plan assuming we’d have to fly subsonic over the US, where supersonic flight is prohibited by law. Some day that may change, but we wanted to do things we could manage. We can’t guarantee that we can persuade congress or the regulators to change the rules. If they do, we’ll benefit, but we didn’t want that as a constraint in our development.” The crux of the Aerion offering is therefore that as soon as the aircraft enters service it will cruise faster and more efficiently over the US than any existing jet; should the regulations change, it’ll immediately be ready for supersonic cruise too.
“And don’t forget that if we wanted to, we could fly at 0.99. There’s nothing to stop us. It wouldn’t be as efficient, it would be like one of the current heavy business jets flying at 0.92, but we could do it. In fact, and although it’ll require a degree of acceptance, we could already exploit boomless flight outside the ICAO. Travelling at around 1.2 Mach, the aircraft’s sonic boom doesn’t reach the ground, that’s a proven fact. It means we can fly supersonically over land.
“But in the US, it’s prohibited by law. It’s not a noise restriction, it’s a supersonic restriction. It was primarily an anti-competitive measure from when the French and the British were flying Concorde and the US airlines weren’t. Once we’re flying and we demonstrate to the FAA and the regulators that we can manage the boom, that it won’t hit the ground, we may see that change. But still, we tell our customers, ‘Don’t buy the aircraft expecting to go supersonic over the US anytime soon’.”

Sizeable machine
In its current configuration, AS2 is 170ft long; a Gulfstream G650 is just a shade under 100ft and an ACJ320 a little over 120ft, so the AS2 is a sizeable machine. “We’re looking at an adaptation where it might get shorter. In an earlier iteration the aircraft had all three engines at the rear and we needed the length for balance, but we’ve moved the two side engines under the wings, for a number of reasons.
“One was for improved balance and another was that the fuselage now blocks some of the engine noise. We also moved them to satisfy rotor-burst criteria. There was nothing wrong with the initial design, but this evolved version is better and may enable us to shorten the airplane by as much as 10ft.”
But isn’t that still a large aeroplane to fit into available hangar spaces? “It’s a consideration, but we’re serving a narrow-niche market, maybe around 30 airplanes per year. We’re not looking at a huge global fleet. In future, as the fleet grows, there’ll be economies of scale and we’ll make an investment to ensure it is supported.”
Developing a supersonic aircraft is undoubtedly an expensive business and with Aerion predicting a maximum market of 36 AS2s per annum, are its investors looking at a very long wait before they see money in the bank? “Not as long as you think…
We believe the price is competitive, while the business plan is very attractive to investors.”
Brian was persuasive, but I struggled to understand how a price could be competitive when there was no competitor. Isn’t Aerion actually in a market place where customers either have an AS2 or they don’t? “We have what we call first-mover advantage, where we control the cost. The price is competitive, but it doesn’t necessarily reflect what it costs us to bring it to market. Look at the empty weight, at around 62,000lb, and compare it with a current heavy jet, which is typically around 60,000lb. Do a parametric analysis, including cost per pound and, other than the engines, the cost to build AS2 is comparable to a current heavy jet.”
And why wouldn’t it be, because other than the powerplant, there’s nothing really new or exotic in the aircraft? “We’ll have to recoup our development costs over a smaller number of airplanes,” Brian reminds me, “but even then, it’s a very attractive investment.”
The partnership with LM may also open Aerion up to military and government markets; the AS2 might appeal as a head-of-state transport. Brian also sees the jet continuing to tempt the fractionals. “It’s not an airplane you’d use every day – if you’re flying 300 miles, you won’t take an AS2, unless you want to show it off – but if you have a mission that requires speed over distance, it’s what you need. And, of course, our first customer was Flexjet, with an order for 20 airplanes.”

In an earlier iteration the aircraft had all three engines at the rear and we needed the length for balance, but we’ve moved the two side engines under the wings, for a number of reasons

Still determined to find a reason not to like the AS2, in a last-ditch attempt at derailment, I put it to Brian that anonymity is much valued among business and VIP aircraft users. The option to arrive at a small airfield in a white jet without anyone noticing can be very attractive. Arriving anonymously in an AS2 is not an option…
With its balanced field length of 7,500ft, Brian recognises the AS2 won’t be using small airports, “But that’s at full gross weight for a 5,000nm mission and it’s about what you’d expect for an airplane of this size. If you have a mission of 2,000nm or less, you’ll use around 5,000ft or less.
“And in this market, customers will not care that the world knows they have arrived. The Wall Street Journal quoted me as saying that high net worth individuals will buy the AS2 because they can. The reality is that they will be important to this market, because they’ll talk to their friends and they’ll want one too.
“We’ve been at this a long time. I boast a little bit, but in my 52-year career I’ve been privileged to introduce 13 brand-new airplanes that have all been successful and are all still flying. I’m not sure there’s anyone else left who can say that. At Aerion we put together a team of similar experience, including Brian Moss, former CEO at Gulfstream, who’s on the board as a senior advisor. He brought seven airplanes to market, so that’s 20 between us, and I was involved in other programmes as a board member as well.
“The Aerion team is knowledgeable and credible and we’re in our comfort zone. We’ve said we’ll fly in 2023 and I’m certain we will. We’ll certify in late 2025, after a two-year flight test programme, and start deliveries in early ’26. Everything about this airplane is conventional. We may meet unforeseen challenges as we work with the certification authorities, but not with the technology.”