Aerion, the U.S. company seeking to attract risk-sharing partners for a proposed supersonic business jet, has announced a number of design changes that it said are necessary to achieve weight and performance targets.

The Mach 1.8 airplane’s forward fuselage has been reshaped to provide a slightly raised cockpit, larger cabin and reduced drag. Cabin height and width have grown slightly, as has the width of the cabin floor. The tail has been stretched substantially, a design change that Aerion said will improve takeoff performance, cut overall weight and reduce cruise drag. The change adds 13 feet to the airplane’s length, now measuring 148 feet.

Aerion also announced that Pratt & Whitney has completed a reliability study of the JT8D-219 engines that would power the airplane. Aerion designers have refined the engine inlets and nozzles to improve performance and cut noise. The airplane is expected to meet Stage 4/Chapter 4 noise requirements without difficulty, the company said.

Aerion this year has significantly stepped up its Paris Air Show presence compared with two years ago. Company executives are here holding discussions with would-be OEM partners and launch customers about the project in the hope of moving the airplane from the initial engineering phases that have been completed so far into advanced design.

“Many of the possible first-tier suppliers are here at Paris and we are holding dialogues with those potential partners,” said Aerion vice chairman Brian Barents, adding that the company chose the Paris venue over the EBACE business aviation show in Geneva last month because all the players it hopes to speak with are here this week.

Whether the sleek design ever takes to the skies as a flying prototype is uncertain at this time, but it appears the timeline the company announced when it was formed in 2004 will slip significantly. Barents indicated last year that Aerion planned to secure a major risk-sharing manufacturing partner in 2007, but so far none of the major OEMs have signed on to the project.

Led by billionaire investor Robert Bass, Aerion can certainly afford to wait for suitable partners to come onboard–and there are signs the company will do just that. Noted aerodynamicist and Aerion chief technology officer Dr. Richard Tracy said the design for the Aerion jet has been frozen until a supplier team can be created. An OEM partner would have the freedom to change specifications of the design, he said, as well as brand the aircraft under its own name.