Boeing's Plastic Dream Machine
Inside Boeing Co.'s (BA ) cavernous development center in Seattle, the future of its commercial jet business is taking shape. That future is plastic -- and lots of it. At center stage in the tightly guarded building are three huge fuselage sections, dubbed barrels, made entirely of composites known as carbon fiber-reinforced plastic. Engineers swarm over the structures, looking for imperfections that could weaken the wafer-thin yet granite-tough material. Over in one corner, mechanics are sculpting the world's biggest composite aircraft wing.
Nothing on this scale has ever been attempted with composites, which are used in everything from golf-club shafts and tennis rackets to giant underground storage tanks. But even the latter can't measure up to what Boeing is creating -- namely, the entire airframe of its upcoming 787 Dreamliner jet.
Boeing knows this is a gutsy, bet-the-company move. But after falling behind archrival Airbus in sales over the last four years, executives felt they had to come up with game-changing technology that would captivate financially strapped airlines.
So far the strategy looks like a winner. Boeing is heading into the Paris Air Show in June with 266 orders and commitments for the Dreamliner from 21 customers. That makes the 787 one of the fastest-selling commercial jets in history. And the plane is already playing a key role in a remarkable reversal of fortune between Boeing and Airbus.
The reason the 787 is selling so well is simple: Customers get tremendous bang for their bucks. For $120 million -- about what they paid for the comparable Boeing 767-300 back in the 1980s -- airlines get an all-new aircraft that flies faster than the competition and costs substantially less to operate. That's compelling at a time when fuel prices are high and airlines are just emerging from the worst industry recession ever. Combined with more fuel-efficient engines, composite materials are "changing the paradigm of the industry, which was based on aluminum," says James C. Seferis, a materials professor at the University of Washington who has consulted for Boeing.
One big plus: Jets made of composites require far fewer parts, so there's less to bolt together. And since these plastics weigh less than aluminum, the planes should burn less fuel. Boeing says the Dreamliner will also improve passenger comfort. Why? The superior strength of the composite fuselage will allow the passenger cabin to withstand higher pressurization -- equal to the air pressure at an altitude of 6,000 feet instead of the usual 8,000 feet. So it's easier to control cabin temperature, humidity, and ventilation.
As sales take off, Boeing must deliver on its promises. The big question is, can it mass-produce the composite fuselage and wing at a high rate and at targeted costs? In the six months since trial production began, there have been some sour notes, including a machining problem on the first barrel that put the program about a month behind schedule.
Boeing officials say they have made up for the lost time and insist that things are under control. "Can we build the 787 at production volumes?" says Michael B. Bair, vice-president of the 787 program. "That has always been the challenge, but we're confident."
Traditionally, making large composite structures has been a slow, manual process, and the quality of finished parts depended on the craftsmanship of experienced workers. Much of that must be automated for the 787. That initially left some of Boeing's global manufacturing partners and suppliers worrying about how to maintain quality, meet weight targets, and stay within original budget estimates of $6 billion to $8 billion. David Polland, Boeing's composites guru and lead engineer for the 787, concedes the design is still overweight but says that's typical for new aircraft at this stage of development. Meanwhile, he adds, the 787 team is making solid progress in developing efficient manufacturing methods.
Making carbon-fiber parts might be described as a massive wallpapering operation -- with the paper really being wide tape, loosely woven from superstrong carbon fibers, then soaked in a honey-thick mixture of polymers. The gooey tapes are plastered on the inside of molds or wrapped around shells called mandrels, and then baked. The heat triggers a chemical reaction that turns the polymers into a hard, incredibly sturdy structure.
The first bake-off of plastic barrels came last Thanksgiving, when the Dreamliner team produced the world's first one-piece fuselage section. It was 22 feet long and 19 feet in diameter and could be attached to other sections with almost no rivets. Now, Dreamliner engineers are discovering that their composites are even tougher than they initially imagined. So Boeing is able to guarantee customers that maintenance costs will be 30% lower than for aluminum planes.
The biggest savings will come on inspections. Because composite materials are more durable than aluminum, government regulators may call for fewer inspections. After just six years in service, a normal plane undergoes a meticulous and costly check for corrosion. The composite 787, in contrast, may remain in service for 12 years before its first structural test. By staying out of the shed, the Dreamliner can make up to 113 additional flights. "The corrosion and fatigue benefits are going to be astounding," says Bair. "It's probably a bigger story than the fuel [savings]," he adds, referring to the 20% drop in fuel costs the 787 can deliver compared with other planes.
While composites are used extensively in military and some small business jets, their incorporation into large commercial planes has been slower. Boeing's 777 is only 11% plastics, mostly in the tail section. But composites will make up 100% of the 787's skin and 50% of all the materials in the plane. "We have always wanted to design in composites," said Alan R. Mulally, Boeing's CEO for commercial airplanes and champion of the 787, at a May 17 investors' meeting. But only recently, he added, have material costs become competitive with aluminum.
Before Mulally could get his wish, another issue had to be solved. Execs fretted about ramp crashes -- service vehicles bumping into parked planes. Since carbon-based composites are normally very rigid, a hard hit from, say, a food-service truck could crack the plane's skin, not merely dent it. Even cracks too small to see could then spread under the stresses of high-speed flight and the dramatic changes in outside air pressure and temperature as a jet climbs to around 30,000 feet.
To prevent that, Toray Industries Inc., the Japanese supplier of Boeing's carbon-fiber tape, impregnates the fibers with a proprietary mixture: The epoxy that provides strength and hardness is surrounded by a polymer with a different density. This combination makes the surface less prone to impact damage -- and if damage does occur, it prevents cracks from spreading. Because of this breakthrough, "I will be sleeping soundly whenever I take off on a composite airplane," says Washington University professor Seferis.
On the manufacturing side, the benefits of plastic fuselage sections are undeniable. One metal barrel requires some 1,500 sheets of aluminum held together by nearly 50,000 rivets. With plastics, the number of fasteners drops by 80%. "The magic in cost reduction is fewer and simpler parts," Bair says.
The main challenge, on the other hand, is the sheer size of the 19-foot-diameter fuselage sections. These require multiple layers of carbon-fiber tape to assure structural integrity. But each added layer of tape increases the likelihood of variations or flaws, says Michael W. Hyer, an engineering professor and composites expert at Virginia Polytechnic Institute & State University.
Last November, as the first barrel was baking in the autoclave oven, waiting engineers were clearly nervous. Sure enough, on close inspection, there were flaws -- bubbles on the skin. This so-called porosity could weaken the material and eventually cause cracks by allowing water to seep under the surface, then freeze up and expand at high altitudes. But nobody expected perfection on the first attempt, says Boeing's Polland. When barrel No. 3 was pulled from the oven, it had fewer defects.
And the wings? Bair says the program is moving ahead smoothly. He expects to lock up the Dreamliner's complete configuration later this year -- a key milestone that means engineers can begin working on final designs of parts and production tools.
Once the Dreamliner's barrels, wings, and other parts are ready, Boeing hopes to assemble each 787 in just three days, down from 11 days for the 737. "It takes time to choreograph the dance that happens in final assembly," says Bair. If three days proves to be a tad ambitious, he adds, "we'd be happy to get to four." Welcome to a bold new era for commercial aviation.
By Stanley Holmes