Boeing made the apparently radical decision two years ago to use composites for most of the primary structure of its new 787 jetliner, resulting in a need for around 35 tons of the material per airplane. Japan’s Toray Industries, whose Torayca pre-preg is used already by Boeing for the 777’s tail and floor beams, was selected a year ago to supply the raw material, which combines carbon fibers with toughened epoxy resin.

Toray expects the deal with Boeing to be worth approximately $3 billion over the 18 years covered by the agreement. The company is building a new factory in the U.S. to supply the pre-preg. In April it announced that because of better-than-expected 787 orders and increased 777 production, it would raise production in Japan to supply the pre-preg to Boeing’s Japanese partners, who will build around 35 percent of the new airplane’s structure.

Mitsubishi Heavy Industries is building the wing box. Kawasaki Heavy Industries will supply a section of the forward fuselage, the main landing gear wheel well and the main wing fixed trailing edge. Fuji Heavy Industries is responsible for the center wing box and its integration with Kawasaki’s wheel well. The wings will include titanium graphite composites as well as the Torayca carbon fiber reinforced plastic.

In the 18 months leading up to Boeing’s choice of composite construction, a team of more than a dozen aerospace companies had weighed the choice between advanced composites and new aluminum alloys.

Mike Bair, senior vice president of the 787 program, at the time said that generally accepted assumptions that composites would weigh significantly less but cost significantly more than aluminum proved untrue. “The aluminum companies did a great job of offering new alloys that were about as light as the composite materials, and the composite companies made a lot of progress on cost,” said Bair.

The composite fuselage offers some important advantages. Its lack of susceptibility to metal fatigue has allowed Boeing to plan a higher internal pressure, providing a cabin altitude of 6,000 feet rather than the normal 8,000 feet, and the larger windows featured in cabin presentations. Immunity to corrosion should help with maintenance. Bair also cited better durability and increased potential for future developments.