Supersonic business jet aspirant Aerion has reopened the engine selection and airframe configuration for its 12-seat concept, effectively restarting the programme almost nine years after launch.

The process could result in Aerion dropping the supersonic variant of the Pratt & Whitney JT8D-219 as the propulsion system, and redefining the payload, size and range of the aircraft, says chief technology officer Richard Tracy.

Aerion still thinks it can meet its pre-2020 target for entry into service, but Tracy admits the timing will be tight.

The company is setting up meetings with engine suppliers General Electric, P&W and Rolls-Royce, revisiting certain concepts - such as a GE F110 derivative - or a clean-sheet supersonic powerplant it considered more than a decade ago, during the original engine selection process for the Aerion jet.

Aerion chose the low-bypass JT8D to power the twinjet because it was already certificated by the US Federal Aviation Administration, and could reach the maximum speed target of Mach 1.6 with few modifications. However, ICAO published a new standard for Stage 5 noise regulations earlier this year that would require Aerion to make more costly changes to the JT8D.

"Our awareness of the regulations and some of the other things are just making us realise we have to go back out and look," Tracy says.

Selecting a new engine, however, brings a new set of implications for the aircraft.

"This opens another Pandora's box - or maybe it's a treasure trove," Tracy says. The selection of the JT8D engine largely determined the Aerion aircraft's potential payload, size and range. "Now we can look at other options," he adds.

Aerion is considering making the aircraft larger and introducing new variants, he says. "Over the next few months we'll have taken a first run at that. Then we'll be talking, making a decision on what those changes are, what engine, what configuration and then we'll start really moving seriously into the development cycle."

Underpinning Aerion's long-running effort to build a supersonic business jet is its core competence in natural laminar flow (NLF) technology.

Tracy's PhD thesis and subsequent career were developed around this technology, which seeks to create a wing shape capable of reducing drag by maintaining a laminar, as opposed to turbulent, layer of air adjacent to the wing surface as far aft as possible. Drag reduction is critical for supersonic flight, as the thrust required increases dramatically to accelerate through the so-called transonic speed range - about M0.85-1.2.

Aerion has had some success, patenting a tapered bi-convex wing that was proven in 1999 on a NASA F-15 test aircraft.

Aerion president Brian Barents, speaking at the EBACE exhibition in Geneva, Switzerland, said Aerion is confident there will be a family of aircraft using its NLF technology. "Apart from business aviation we have had discussions about military and air transport applications," he said.

Barents is confident NLF will play a large role in next-generation business jets, and says the technology is already being tapped by other manufacturers on near-term applications for transonic platforms. He adds: "We're helping develop the next generation with Aerion technology.

"Up until now performance improvements have been driven by propulsion technology. We're harnessing the power of aerodynamics as well as propulsion."

Barents says finance for the supersonic business jet remains firm and the orderbook remains solid.

Source: Flight International