Aerion Paving Path To Bring AS2 To Market

Hoping to bring a civil supersonic business jet to market around 2026, Aerion Supersonic is laying the groundwork. In late April, it announced it would break ground later this year at Melbourne, Florida's Melbourne International Airport (MLB) for a $300 million factory to build its Mach 1.4, 12-place AS2 trijet. This news came as Aerion described what it believes is the final design for the airplane, whose new look incorporates a delta-shaped wing, revamped empennage, and an elongated nacelle shape that employs new materials and technologies.

While the company is expected to announce full specifications of the changed design soon, it has already revealed that the airplane's length, which has been shortened to 144 feet, 11 inches, as well as its wingspan (79 feet) and height (29 feet). Aerion executive vice president and chief sustainability officer Gene Holloway likened the configuration to that of the more traditional “Coke bottle” shape associated with supersonic aircraft, with a narrow "waist” that flares out in the back.

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“The airplane looks remarkably very different from what most people have become accustomed to seeing [with the AS2],” said Holloway, referring to the move away from the more straight-line wing that incorporated supersonic natural laminar flow shapes refined over years of research and the previous T-tail empennage.

As the company looked to optimize the speedy aircraft, engineers narrowed their choices to enable Aerion's vision of cruise performance and level of luxury while addressing environmental challenges, Holloway said.

While keeping many of the enabling technologies proprietary, he specified that the aircraft employs advanced materials and composite structures that previously had not been fully explored on commercial aircraft. “We're at a point in time where we can begin to leverage a lot of the advanced development work that's [been done] over the last few decades to begin to bring some of those capabilities to bear on developing lighter-weight structures overall.”

Holloway also pointed to advances in avionics systems and ground communications to better manage flights, including prognostic health management. The company has stepped up its selection of suppliers, with GE Aviation providing the Affinity medium-bypass twin-shaft, twin-fan turbofan, and Fadec-controlled engines and Honeywell supplying Primus Epic avionics. Several other well-established companies have been tapped to provide aerostructures, wiring, nacelles, landing gear, and the aircraft doors, among other components. These include Spirit AeroSystems, Safran, GKN, Aernnova, and Potez Aeronautique. Boeing remains an integral partner with engineering and other support.

The use of traditional suppliers reflects another consideration in incorporating design changes: “There's a timely need to enter the market,” Holloway said, pointing to the target of the middle of the decade. “The world's ready for that. The market's ready for that.”

Along with that is ensuring the producibility of the ultimate design; it must be efficient but also “buildable,” he said. “There are clearly things that you can conceive, build models, and aerodynamically look really good. And then as you get further downstream, you start looking at how [you've] got to go build that.” The design has to work with the materials and manufacturing technologies available.

This is important as the company maps out its production facility in Florida. Aerion will maintain a small team there as it leads up to groundbreaking. It hopes to begin production in 2023 and kick off flight tests in 2024.

“We're all looking anxiously towards the opening of the offices down there,” Holloway said. The massive project, building from a “greenfield position,” provides advantages, he added, particularly as Aerion designs the factory from a sustainability standpoint. “We're committed to being good environmental stewards as we go do this,” he said. “We strongly emphasize that creating a sustainable product—a green, environmentally responsible product—is as important as creating the product to begin with.”

This is a balancing act, requiring a holistic approach to how the company builds a jet and how it is operating, he said, adding that this requires “a lot of counterbalancing” and a total-life-cycle approach. And now for Aerion, this approach is “not just in terms of the aircraft itself and its design and operations, but also in terms of the manufacture of the aircraft.”

This means designing a facility with the lowest possible environmental footprint. “We’re going to great lengths as we work with our architects to incorporate a lot of the different technologies that are emerging and maturing to a point where they become viable commercially,” he said. This ranges from how the facility is powered [and] how the walls are designed and what windows are used to the protections implemented for air quality and even rainwater collection and storage.

Aerion, which is planning a jet that will meet Stage 5 noise requirements and run 100 percent on biofuel, has promoted its approach to sustainability as it faces skepticism from the environmental community and strict environmental requirements that prohibit supersonic flight over land. While deeply involved in international research and deliberations on what may be acceptable in the future, Aerion has taken a practical approach to its design requirements for the AS2, believing that it must be efficient at subsonic, lower supersonic, and higher supersonic speeds.

“We have three design points,” Holloway said, looking at a Mach 0.95 subsonic cruise where the aircraft can reach a range greater than 5,000 nautical miles and a Mach 1.4 supersonic cruise targeting about 4,200 nautical miles. “But then we have a Mach 1.2 design point.” That “boomless cruise” mid-range is aimed at the possibility of one day flying low supersonic speeds over land. Aerion is hoping to prove that, at these lower speeds, there is a “Mach cutoff,” a point where the sonic boom would no longer reach land. Instead, it would dissipate in lower strati of air, depending on a number of conditions. This is where advanced weather technologies can play a role, he said, explaining that the idea is to “just kind of skim the sonic boom off of a layer of the atmosphere.”

These concepts will have to be proved over time, but Holloway said he was encouraged that the FAA notice of proposed rulemaking released last summer to facilitate flight testing is a good first step toward that goal.

As for its supersonic natural laminar flow research, which is one of the hallmarks of Aerion’s engineering expertise, he sees this being incorporated into future projects, both commercial and military. He said other projects are in the works at a “high level” of activity.