Boeing gets closer to the Sonic Cruiser

Computer simulation of the Boeing Sonic Cruiser in an airport environment; extensive use has been made of computational fluid dynamics to refine the design.

This year's Farnborough Air Show was, overall, very much about strategic business and technology consolidation rather than immediate innovation, although behind the public statements and the aircraft and systems on display, there was a deep dialog about advanced design—and the continuing need to achieve systems, functions, and information technology integration.

Boeing's bold Sonic Cruiser, which is projected to cruise at up to Mach 0.98 with fuel consumption per passenger "comparable to today's best-performing wide-body twinjets," is very much part of this agenda. Plans for the Sonic Cruiser are moving forward cautiously, but the design—expected to make extensive use of composites—continues to mature.

"We have looked at more than 25 wing planforms, 50 nacelle shapes, and 60 fuselage designs in the past 16 months," said Walt Gillette, Vice President and Program Manager for the Sonic Cruiser, at Farnborough. This attention to detail could not have been done, he added, without the use of advances in computational fluid dynamics (CFD) modeling to evaluate aerodynamic flows.

Boeing's Sonic Cruiser's design continues to evolve, with more than 25 wing planforms having been considered.

A second round of wind tunnel tests show "that the CFD coding is predicting performance to within 1%," said Gillette. Progress being made on the fundamentals needed to create the Sonic Cruiser involves the technology, processes, and basic configuration exploration needed to refine the "very best shape" for the aircraft.

Based on the present status of work, some 60% of the Sonic Cruiser will be manufactured using composites; a fuselage test section has been built. "Competition is a wonderful thing," said Gillette. "As soon as we started talking about this being a mostly composite airplane, we began to get very interesting proposals from the aluminum manufacturers regarding new alloys with better properties and economics."

Boeing is considering those options, but at Farnborough it announced that additional specialist composites companies based in Europe were joining the development team. GKN Aerospace is to help develop "advanced technology solutions" according to Jeff Luckey, Director of Supplier Management for the Sonic Cruiser program. He said GKN would bring its expertise in resin transfer molding and propulsion structures to the program. Fischer Advanced Composite Components, based in Austria, is now linked to Sonic Cruiser. It is a supplier to four established Boeing programs. And Stork Fokker Aerostructures, based in the Netherlands, is also becoming involved with Sonic Cruiser. It is a specialist in designing, developing, manufacturing, and supporting structural airframe components and is also involved with other Boeing programs, both civil and military.

Boeing is placing great emphasis on the Sonic Cruiser concept's environmental performance. Click to enlarge

Boeing reports that it is keeping an open mind on materials, but work is pushing ahead on manufacturing technology applications and efficiencies, including lean manufacturing. "Boeing has reduced production time by half on one of its lines through the introduction of the moving line," said Gillette. "The improvements are continuing."

Boeing anticipates that the use of advanced technology will give the Sonic Cruiser a significant edge over "conventional" airliners, combining markedly higher performance together with lower noise levels, benefiting from research and development work being applied across the company's product range. It should also benefit from cost-reduction targets and work on emissions. The Sonic Cruiser will be a "more electric" airplane, using electricity to drive systems traditionally driven by engine bleed air. "Faster flight is what passengers want," said Gillette. "But faster must not come at the expense of environmental performance. We understand that."

- Stuart Birch

Boeing's smart alliances

Boeing is working with Cranfield University on blended wing body concepts.

Boeing is working on blended wing body (BWB) research with Cranfield University (and its wholly owned commercial subsidiary, Cranfield Aerospace) in the UK. As the Farnborough Show opened, Cranfield confirmed that it is to design and build a sub-scale (6.4-m wing span) demonstrator of a BWB aircraft. Boeing has been studying BWB applications for commercial and military use.

Also, Boeing has said that it is working in the UK with Sheffield University's Advanced Manufacturing Research Center to develop technologies for materials cutting, materials joining, metal working, castings, and preformed materials. Boeing said at Farnborough that it planned to work with Cambridge University on information technology research.

- Stuart Birch

NRC studies flow

The National Research Council (NRC) of Canada's Institute for Aerospace Research has designed and built a pilot-scale facility to study low Reynolds No. flows for micro aerial vehicles that operate at high altitudes. The NRC claims this is a "world first" development.

Developments in nanotechnology that make it possible to build tiny airborne vehicles has generated particular interest in low Reynolds No. flows, "but the applicable aerodynamics hasn't caught up." According to Ernest Hanff, a Principal Research Officer at NRC, "It's very difficult to test (micro aerial) vehicles in conventional facilities like a wind tunnel or water tunnel. Because the models have to be so small to preserve the correct Reynolds No., it's almost impossible to study the flow around them or measure the aerodynamic loads acting on them."

Hanff created a 1 x 1 m cross-section pilot facility to demonstrate the concept of moving a model through a mixture of glycerine and water contained in a tank with no free surface. Modern flow diagnostic techniques are being adapted to the new test environment, says the NRC.

- Stuart Birch