FLUG REVUE September 2005: Boeing 787 progresses

September 2005

HALF TIME FOR THE BOEING 787

By Sebastian Steinke

Mike Bair, Boeing Vice President and 787 programme manager, believes things are looking good. “We are in the middle of the 'Firm Configuration' phase.” By the end of September Bair wants to have the basic design phase of his brand new aircraft finished. In its day, the first pictures of the 7E7, with its a dolphin-like tailfin and flowing forms, had suggested an aircraft designed more to produce a spectacular marketing effect in public. The design of the 787 is now well advanced and bears a close resemblance to the wind tunnel model we presented in FLUG REVUE 8/2004. Compared with the 7E7, the nose of the 787 is blunter and the cockpit windows are a different shape. The engine cowlings have been treated with noise-reducing sawtooth extensions on the reverse side so that the bypass flow mingles with the ambient air more quietly. The 787's noise footprint will apparently be half that of the 767. Bleed air will be used only for de-icing the air intakes on the two engines.

Boeing 787

Bair: “What is efficient about this is that we are not taking away any force. We save around 40 percent of the energy, as the bleed air is too hot and has too much pressure and would have to be cooled and pressure-reduced with significant loss prior to use.” Otherwise the jet uses electrical energy. Bair: “Up to now the electronics have not been sufficiently advanced to control the enormous power requirements. That has now changed.”

The passenger cabin windows have been taken over from the 7E7, and are one-third bigger than today's windows. Another design feature is that even in the centre seats it will always be possible to view the horizon line out of the corner of one's eye, thus enhancing subjective well-being. The low interior noise will also contribute to this, along with higher humidity, greater cabin pressure and cabin air that is filtered of both solid and– for the first time– gaseous impurities.

The vertical fin is unusually small and now has little in common with the striking, but sadly aerodynamically useless fin shape of the 7E7. The 787 uses active controls which for the first time achieve a turbulence reducing effect about all three axes and are intended to ensure that the flight is very calm. The tips of the two very thin wings with high aspect ratio are bent upwards at the ends, achieving an effect that is a cross between the blended winglets of the 787-800 and the raked wingtips of the 767-400. Only the short-haul version, the 787-3, which has a shorter wingspan, uses traditional, large winglets.

Bair amplifies on the programme status. “In Japan we have already selected our three structure partners who are now beginning to build their 787 production facilities. The tests are going as expected, and in Wichita we have already built a first nose section 41 and four test fuselage segments. These are the biggest pressurised CFRP components ever.” In Everett near Seattle, the first wing box has been built. This will be needed for certification of the production processes and tools. The time allowed for subsequent serial final assembly of the components delivered to Seattle from Asia is only three days.

Through extensive use of computers in the design of the 787, Bair's team is able to handle the development a whole year more quickly than on earlier programmes. Bair: “We are using the latest software package from Dassault Systèmes.” This is Version 5 (Release 15) of the Catia, Enovia and Delmia design programs. “On the 777 we were still using Version 4 as we needed an aircraft model that was true to the original. On the 787, we are able to create a standard data record for every aircraft on the computer which will accompany it over its entire lifetime. All changes and modifications will later be noted here. A year before we begin building it, and two years before the first 787 flies, we know that our design works.” At the same time the new software enables the production partners from around the world, who are linked up on the same network, to access a central database, so that everyone is always at the latest stage of development.

Many features which were once options have been incorporated into the 787 as standard. Thus, customers have to decide on their individual cabin configuration only four months before production commences instead of eight to twelve months. The novel features in the cabin include a power supply to the seats, running through the seat rails. Whereas the 777 cabin interior takes between 3,000 an 5,000 man hours to furnish, the aim is that on the 7E7 the same activities should take only one-tenth of that time.

Half of the 787 by weight is constructed out of new materials, notably out of carbon fibre (CFRP.). As Mike Bair explains, “We have been working on this technology since the early 1980s. Back then we built five test horizontal tail units for the 777 out of carbon fibre. Then it was a lot more expensive than aluminium, but we were determined to gain experience in this area. Today CFRP is cheaper.”

Bair considers that requirements in military aircraft construction, where CFRP has been used for some time, are not readily transferable to his civil programme. “On a military programme all the components are designed for extreme loadings of 9g and are produced only in relatively small unit numbers. By contrast, our production is heavily automated. We could not produce like a military programme.”

Bair goes on to compare the reduction in the amount of work required that comes from using carbon fibre instead of aluminium. “If you imagine a section of the fuselage with stringers, shells and doorframes, an aluminium construction would entail up to 15,000 individual parts. Using CFRP, we can build it as a single unit. With an aluminium component, 85 percent of the production costs relate to wages, whereas with CFRP it is only 10 percent.” Moreover, he adds, with aluminium components only 3% of the quantity of raw material used is actually utilised, whereas with CFRP it is 95%.

Carbon fibre is becoming steadily cheaper as the high level of demand has had the effect of increasing supply. The carbon fibre mats are wound like plaster casts around the fuselage segment, which is suspended in a holder unit so that it can be rotated, until it has the desired strength.

“First you wind it round, then you insert the stringers, then you wind it some more, then finally everything goes into the oven and is baked for eight hours like a turkey. Window and door openings can then be added afterwards, rather like cutting out biscuits,” Bair enthuses, rather like a chef. Only the frame assemblies are mechanically inserted at the end.

A lot of airlines initially had reservations about the fact that it is very difficult, compared with aluminium, to spot and repair structural damage in the CFRP skin of an 787 caused by vehicles on the ramp, known as “ramp rash”. Mike Bair dismisses these fears by saying, “Ramp rash was actually a concern of the customers, but CFRP is a lot stronger than aluminium.” Bair sent the airlines suitcases with fuselage pieces made out of aluminium and CFRP and a hammer. Whereas the aluminium dented, the CFRP apparently proved resilient and returned to its original shape. “If you cannot see any damage from a distance of 2 metres, it will last the life of the aircraft.” For other cases, Boeing envisages two types of “patchcraft”: the first variant dries within an hour and lasts until the next shop visit, the second variant on the other hand needs between six and 12 hours to dry but lasts an entire aircraft lifetime. Moreover, where structural damage is suspected, it is possible to check CFRP with ultrasound sensors applied to the outer skin. CFRP is also UV-resistant and the special primer can accommodate paint of any colour.

The durability of the CFRP fuselage should also lengthen the intervals between maintenance events. Compared with the 767, the 787 does not need a line check after 500 to 700 flying hours but only after 1,000. The base check is due only after 36 months, compared with 18, and the major heavy check is needed only after 12 years instead of after six.

Not all the parts on the 787 are made out of CFRP. Titanium is used for the landing gear and the attachment of wings and empennage to the fuselage. Mike Bair: “Titanium is also corrosion-free and gets on well with CFRP, whereas aluminium and CFRP tolerate each other poorly.

The 787-8 is expected to have its maiden flight in mid-2007 and to enter service a year later. The short-haul version, the 787-3 for 296 passengers, should follow in mid-2010 and the stretched long-haul version, the 259-seat 787-9 at the end of 2010. Mike Bair: “The 787-9 has room for a few more rows of seats. We want to conquer more than half the market with the 787.”

Compared with its rival, the A350, the Boeing manager believes that the 787 has the upper hand. “We are eight percent cheaper in costs per seat than the A350-800 and nine percent cheaper than the A350-900. We are also 20 to 30 tonnes lighter and offer more cabin space. We have wider seats and wider aisles.” Alternatively, Boeing plans to offer customers with very high capacity requirements nine-seat rows.

Mike Bair is not worried that the 787 will be competing with the Boeing 777. “The future of the 777 lies in the -LR, the -300ER and the Freighter version. They will replace a lot of 747's. The 787 offers the possibilities of the 777, with the dimensions of the 767. Our wing is bigger and more effective than the A350's. We can grow bigger than they can.”

In 2008 and 2009 Boeing plans to produce 95 787's altogether. Only later will production be ramped up still further. According to Alan Mulally, President and CEO of Boeing Commercial Airplanes, Boeing currently has 21 contractual partners for the 787, who intend to buy 266 aircraft. Another 27 customers are negotiating about a further 427 aircraft. The first three years of production are already sold out. Mulally sees the 787 as the pulse generator for the rest of the company. “One day we will take 787 technology to replace the 737. Then we will be even more competitive.”

In response to a question from FLUG REVUE regarding the strategic effects of relocating 787 production to Japanese partners, Mulally replies, “We have always had partners and we have been working with Japan for 46 years. They are also our customers. 70 percent of a Boeing has always come from outside the company. If anyone can do things better, then they should do so. We are concentrating on system integration on a large scale.”

From page 22 of FLUG REVUE 9/2005

Last updated 18 August 2005

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