Boeing chooses largest wingspan for 777X
As Chicago-based aircraft manufacturer Boeing heads into the future following a better-than-expected 2012 second-quarter net profit of US$967 million, or US$1.27 per share versus the Wall Street consensus of US$1.12 per share, it continues to map out its future widebody strategy that will see new members being added to its popular large twin-engine, long-haul 777 as well as the carbon composite 787 Dreamliner aircraft families.
Running ahead in these in-house evaluations is the 323-seat Boeing 787-10X, which will be 5.49m (18ft) longer than the 787-9 variant while burning 25% less fuel than an Airbus A330-300 on a 6,700nm-6,750nm (nautical miles) trip (“Airbus is right on A330 improvement strategy“, 10th Jul, 12). Another study into revamping the highly popular 777 jets which sold a record 200 examples to airlines last year, in the meantime, is understood to be less advanced and whose authority to offer (ATO) from Boeing’s board of directors will not come as early as the one for the 787-10X, which Boeing chief executive Jim McNerney put at “end of this year” or “beginning of next year” for the “perfect next step on the 87” during an earnings conference call with analysts.
Nevertheless Boeing is making some progress in the development of 777X, including opting for the largest-even wingspan for the 777X’s supercritical carbon fibre reinforced polymer (CFRP) wings.
Largest ever wing
According to Aspire Aviation‘s sources at the world’s second-largest airframer, Boeing has in recent weeks chosen the largest wingspan option for the 777-9X, a 407-seat successor to the 365-seat 777-300ER, at 71.1m (233.4ft).
While cautioning that the decision to put a largest-ever carbon fibre reinforced polymer (CFRP) wing on the 777X is “not final”, these sources say Boeing has declared the 71.1m (233.4ft) wingspan as the “baseline” in presentations and private discussions with potential airline customers, while adding 30m² (322.9ft²) to the 777-300ER’s wing area of 436.8m².
This will lead to the largest wing ever produced by Boeing, of which the 71.1m (233.4ft) wingspan is longer than the 747-8’s 68.5m (224.7ft) wingspan, the 777-300ER/-200LR’s 64.8m (212.7ft), the 777-200/-200ER/-300’s 60.9m (199.11ft) and the 787-8/-9/-10X’s 60.1m (197.3ft). In comparison, only the Airbus A380 superjumbo has a larger wing with a wingspan at 79.75m (261.1ft).
Boeing was previously studying 4 wingspan options for the 777-9X – 65m (213.3ft) with winglets, 68.6m (225ft) with winglets, 71.1m (233.4ft) with 787-styled raked wingtip, and a 233.4ft option featuring a folding wingtip before settling on the largest one.
In doing so, the 407-seat Boeing 777-9X will creep into the International Civil Aviation Organisation (ICAO) Code F category, which features airplanes with a wingspan between 65m (213.3ft) and 80m (262.5ft) whereas the ICAO Code E category to which today’s 777-300ER belongs includes planes with wingspans 52m (170.6ft) and 65m (213.3ft) and will require costly airport modifications such as runway and taxiway widening and larger aircraft stands similar to those seen before the A380 superjumbo’s entry into service (EIS) in October 2007.
Furthermore, building such a large carbon fibre reinforced polymer (CFRP) wing very likely leads to increased investment should Boeing opt to construct the largest composite wing ever built at its Everett facilities, although Mitsubishi Heavy Industries (MHI) does have a giant 700 metric tonnes autoclave that is 40m long and 8m wide at its Nagoya facility. People familiar with the situation said Boeing has yet to determine a site for constructing the CFRP wing.
Separately, Boeing is mulling to eliminate the overwing exit of the 777-300ER which will save 1,000lbs (453.6kg) in weight, the same sources say. This would stretch the separation between the 4 Type A doors on each side of the fuselage to a maximum of 60ft, thereby meeting the US Federal Aviation Administration’s (FAA) requirement to evacuate 407 passengers within 90 seconds with half of its doors blocked or being unavailable while saving weight.
‘Hot’ engine race
While the supercritical 787-styled composite wing which provides a considerably higher lift-to-drag (L/D) ratio is a cornerstone behind the 777-9X’s expected 21% lower fuel burn per seat than the 365-seat Boeing 777-300ER, another core pillar in this fuel efficiency drive would be the next-generation engine technology.
All of the world’s three-biggest engine-makers – General Electric (GE), Rolls-Royce (RR) and Pratt & Whitney (P&W) are competing for the 100,000lbs engine prize after a request for information (RFI) in late 2011 which Aspire Aviation firstly revealed (“Boeing eyes 787 improvement along with production ramp-up“, 11th Jan, 12).
Given its exclusivity contract with Boeing on today’s long-haul 777-300ER and ultra long-haul 777-200LR, the Evendale, Ohio-based engine-maker GE Aviation is very likely, if not almost certain, to secure a place on the 777X programme.
General Electric (GE) is developing an improved version of its GEnx engine, dubbed GE9X, that will slash engine specific fuel consumption (SFC) by “very close to 10%” lower than the GE90-115B engine on the 777-300ER platform, which will have a 99,500lbs thrust for the GE9X powering the 407-seat 777-9X and a 88,000lbs thrust for the smaller 353-seat 777-8X sibling.
The 325cm (128in) fan size GE9X will have a 10:1 bypass ratio, 60:1 overall pressure ratio (OPR) and 27:1 high pressure compressor ratio, versus the corresponding 42:1 and 23:1 on the GE90-115B engine (“Boeing develops 777X to challenge Airbus A350“, 9th Feb, 12) and will feature a third-generation twin-annular premixing swirler (TAPS III).
“We feel really confident that the calling card for GE in this next generation 777 is going to be the technologies we’re developing for the GE9X. My incumbency as well as my commitment to the GEnx has given me a suite of technologies that are going to be very very competitive when Boeing has to make a decision on the 777,” GE Aviation president and chief executive David Joyce said at a Farnborough Airshow briefing.
Meanwhile, as the request for information (RFI) did not stipulate whether the engine on the 777X will be dual-sourced or be another exclusivity contract at all, according to Aspire Aviation‘s understanding, the remaining potential spot on the 777X programme has sparked intensified competition between Rolls-Royce (RR) and Pratt & Whitney (P&W), which even prompted a RR-PW joint venture speculation.
While such an engine joint venture is unlikely at this stage, as Derby, UK-based Rolls-Royce looks set to defend its significant role in the widebody market, both engine makers have presented proposals that clearly outline a highly fuel efficient and advanced commercial aviation engine, albeit with decidedly and fundamentally different engine architecture.
For Rolls-Royce, its larger 337cm (132.5in) RB3025 engine will improve upon and incorporate latest technologies adopted by its Trent XWB engine which the UK engine-maker touts as “world’s most efficient civil turbofan” and is already exceeding its original specific fuel consumption (SFC) target, according to Aspire Aviation‘s sources at Airbus, it will reduce engine SFC by “more than 10%” against the GE90-115B engine, while providing 99,500lbs of thrust for the 777-9X.
The RB3025 will have a bypass ratio of 12:1 and an overall pressure ratio (OPR) of 60:1, according to a flightglobal report.
“We’re the only engine-maker that has an optimised engine on the three latest engine programmes, the Airbus A380, A350, and Boeing’s 787. Pratt & Whitney and General Electric don’t,” Rolls-Royce vice president (VP) for strategic marketing Robert Nuttall told Reuters.
“The smooth entry into service of the Trent 1000 engine on the 787 shows that we can be trusted and I think that showed to Boeing they can rely on us. We have tremendous incumbency on the widebody market – half of the widebody order book that is out there is powered by Rolls-Royce,” Nuttall reiterated.
Rolls-Royce has been pitching its 76,000lbs Trent 1000-TEN (Thrust Effciency New Technology) at Farnborough Airshow powering the 787-9 and -10X, which promises to slash its engine specific fuel consumption (SFC) by a further 3% from Trent 1000 Package B engine, of which the Package A engine missed its original engine SFC target by 4.3% and the Package B engine will exceed the SFC target by 2% and the Package C engine upgrade will bring its fuel burn performance to “within 1% of specifications”.
Though a gearbox in the Rolls-Royce Trent 1000 made by its supplier Hamilton Sundstrand has suffered from corrosion issue owing to a new manufacturing process, prompting Japan’s All Nippon Airways (ANA) to ground 5 of its 11 787s in its fleet. Four examples have been fixed while Boeing chief financial officer (CFO) Greg Smith said the “gearbox [issue] you saw was a very small number of airplanes. We’ve swapped four of the five out. We expect to be complete early next week”.
For Pratt & Whitney (P&W), the world’s third-largest engine-maker has presented 3 different proposals to Boeing, including one with a geared concept. Aspire Aviation‘s source at P&W said the 100,000lbs geared turbofan (GTF) will have a geared ratio of 3:1, same as the much smaller PW1425G PurePower engine, and will reduce SFC by 13%.
While both General Electric (GE) and Rolls-Royce are boosting the overall pressure ratio (OPR) of the engine, which is likely to lead to an increase in the engine operating temperature, thus necessitating the use of ceramic matrix composite (CMC) which is expensive and may not be available by 2019, Pratt & Whitney (P&W) relies on a gearbox that consists of only 7 moving parts that allows the engine fan to spin at a speed 3 times lower than the low-pressure turbine (LPT), thereby maximising propulsive efficiency and fuel efficiency.
As in the case of the narrowbody engine battle between the CFM International Leap engine and the Pratt & Whitney (P&W) PurePower engine, Aspire Aviation thinks offering both engine architectures on the 777X not only will improve its appeal to airlines and lessors, but also provide a hedge against any engine architecture outperforming the other one.
3rd-generation aluminium-lithium fuselage
As Boeing is studying a potential aluminium-lithium (Al-Li) fuselage for the 777X, this has rekindled a debate between the choice of materials between traditional aluminium alloys and the advanced 3rd-generation aluminium-lithium (Al-Li) alloy.
Sceptics point to the fact that cost of material for Al-Li is higher than the cost of traditional aluminium and that the fabrication process of Al-Li is more “demanding” and “more difficult”, as well as noting the brittleness of the Al-Li material.
Indeed, Boeing has in the 1990s evaluated 1st-generation aluminium-lithium (Al-Li) and has decided not to adopt the material after discovering drilling in the 1st-generation Al-Li would result in tiny cracks, while they do not propagate, they might result in public relations issue and airline customers might be reluctant to receive new airplanes with “acceptable cracks”.
According to an Airbus A380 materials and structure briefing back in 2003, Airbus’ “1st generation” Al-Li had been developed back in the 1980s with around 2.5% of lithium added to the aluminium alloy, which resulted in a 8%-10% less density but the research was suspended owing to prohibitive production costs and crack deviations. Airbus then developed the “Airbus 2nd generation” aluminium-lithium (Al-Li) during 1994-2000, but abandoned the effort owing to fatigue crack growth in 3.5% salt (sodium chloride, NaCl) solution.
In the 2000s, Airbus adopted the “Airbus 3rd generation” Al-Li technology, which was in fact Alcoa’s 2nd-generation Al-Li for the A380 floor cross beams, along with carbon fibre reinforced polymer (CFRP) floor beams.
Time flies and the aerospace industry’s understanding on the fatigue and strength properties of aluminium-lithium (Al-Li) deepens significantly. Fast forward to 2010 and Alcoa Aerospace, the aerospace unit of the world’s largest aluminium producer, has developed the 3rd-generation Al-Li technology with doubled, if not more than doubled, the corrosion resistance of the Al-Li material.
For example, the traditional aluminium alloy AL7150-T775’s stress corrosion is 25 KSI while the stress corrosion of Alcoa’s 3rd-generation aluminium-lithium (Al-Li 2099-T86) has doubled to 50 KSI. The 3rd-generation Al-Li 2099-T86 is also 5 times as stress corrosion resistant as Al2024 traditional aluminium alloy.
Alcoa now claims the 3rd-generation Al-Li has “doubled inspection intervals consistent with 12-year heavy check cycle” while providing 20% weight saving. Now Alcoa also claims its 3rd-generation Al-Li has achieved parity in terms of weight saving with the carbon fibre reinforced polymer (CFRP), according to an April 2012 presentation by Alcoa Aerospace.
It states CFRP has a 45% density advantage versus the 3rd-generation Al-Li, but 25% of that advantage is lost owing to the lay-up process and another 10% is lost owing to the addition of copper mesh and fasteners and their corresponding weight and the last 10% was lost owing to addition of other materials for strength such as “shimming” – a task that was originally designed to be eliminated by the adoption of the 787’s CFRP one-piece contoured barrel (OPCB).
Make no mistake, while carbon fibre reinforced polymer (CFRP) retains several advantages over the 3rd-generation Al-Li, including higher humidity despite 3rd-generation Al-Li’s increased corrosion resistance, higher tensile strength and cracks do not propagate, it does have some issue such as delamination when handled improperly, which will further be improved by 2nd and 3rd-generation carbon composite technology.
For example, Australia’s Quickstep which manufactures F-35 Joint Strike Fighter’s CFRP parts, says its out-of-autoclave (OoA) technology reduces the time required in the curing process by 43%, along with a higher delamination resistance and a higher fibre-matrix adhesion which are achieved through “lower initial resin viscosity”. And the carbon nanotube reinforced polymer (CNRP), which is used on the non-bearing structure of the wings of F-35 from low-rate initial production (LRIP) 4 onwards, a 50% single-walled nanotube (SWNT) CNRP is 17% stronger than the CFRP, yet 30% lighter, according to a study conducted by MITRE.
All in all, 3rd-generation aluminium lithium (Al-Li) fuselage such as those adopted by Bombardier’s CSeries is the only realistically technology available today that reduces weight by 12% and a 6% reduction in skin friction that suits the 777X’s needs and timescale with an entry into service (EIS) provisionally in mid-2019.
Admittedly, while it is true that 3rd-generation aluminium lithium (Al-Li) is more expensive than traditional Al alloy, it is a cost-benefit trade-off as in every single matter. Aspire Aviation believes the adoption of Al-Li will enable the 777X to maximise its fuel efficiency and reduce weight with a relatively low-risk technology that is available today without significant investment on giant autoclaves and any burden or spillover effects onto the once-beleageured 787 global supply chain.
Boeing, though, has yet to make a decision between aluminium (Al) alloys and 3rd-generation aluminium-lithium (Al-Li), Aspire Aviation‘s sources at Boeing confirmed.
Boeing stands to benefit the most should there be any further significant A350 delay, following a 1-month delay in the arrival of the A350-900’s wing set in the Toulouse, France finally assembly line (FAL) by October instead of September. Airbus switched to manually drilling instead of automatic drilling by robots as programming it took longer than expected.
“We don’t want to rush to final assembly with incomplete wings. This will not happen with me as Airbus CEO. I have no intention of repeating past mistakes,” Airbus chief executive Fabrice Bregier said.
“We would prefer to delay by a couple of weeks, instead of rushing and then discovering problems later. This is the biggest lesson we have learned,” Bregier commented.
Airbus has so far managed the execution of the A350 programme well, despite a 6-month delay in the A350-900’s entry into service (EIS) and then a fresh 3-month delay in entry into service (EIS) to second-half 2014 announced during the release of its parent European Aeronautics, Space and Defence Co. (EADS) 2012 first-half results today, which resulted in a €124 million charge.
Importantly, Airbus won a significant endorsement for the A350-1000 from Hong Kong-based Cathay Pacific, with Cathay switching 16 of its 38 A350-900s previously on order to the larger -1000 variant, in addition to ordering 10 additional A350-1000s in a deal worth US$4.2 billion, with US$1 billion being the conversion to the -1000 variant.
Subject to confirmation by its board of directors, Cathay Pacific will have a fleet of 22 A350-900s and 26 A350-1000s, including two leased -900 examples.
“[Cathay’s A350-1000 order] confirms that when we do things right, we listen to the customers even if we’ve had to postpone a little bit the entry into service of this aircraft,” Airbus chief executive Fabrice Bregier said, adding “We didn’t change it [the -1000 for Cathay]. We don’t intend to change it. They could stay at the lower gross weight. We can make that less-capable version. Cathay looked at it – and said ‘no'”.
“As an all-new design, it will outperform existing aircraft in its size category on every count – as well as any future derivatives of those aircraft,” Bregier asserted.
While the 350-seat A350-1000 will be in the market niche that the Boeing 777-300ER created in 2004, Boeing will have moved on with its 407-seat 777-9X, which coupled with any potential further A350 delays, will undermine its business case.
The 76.48m (250ft 11in) long 777-9X will accommodate 407 passengers and carry significantly more revenue cargo flying a range of around 8,000nm (nautical miles), albeit shorter than the A350-1000’s 8,400nm range. It will feature a maximum take-off weight (MTOW) of 344 tonnes (759,000lbs) and has a 21% lower fuel burn per seat and 16% lower cash operating cost (COC) per seat than the 365-seat 777-300ER.
The 353-seat 777-8X will be 69.55m long and feature a MTOW of 315t and will succeed the 777-200ER.
“We are not particularly impressed with what [Airbus has] done. I think they reacted to what they thought was the market requirement. It would have helped if they’d spoken to us first. They produced a new specification for the aircraft which, in my view, fell short of where it should be,” Emirates president Tim Clark told flightglobal.
“I think we were very instrumental in getting [the 777-300ER] designed and built in the way that we’d asked them to do it. And the [GE90-115B] engines are absolutely superb. Two years ago they had it in a position that we were very interested in it. We asked them to do a few more things, they’ve been working on that,” Clark elaborated.
“Faffing around and waiting to see what [Airbus] does to the -1000 or the -900 makes no sense at all. If you’ve a good product and people are interested in it, you go for it – don’t worry about what the competition is doing,” Clark commented.
As the 777-9X stands today, it is poised to be a true one-for-one replacement for the 747-400 along with the 365-seat 777-300ER while offering natural growth opportunities without compromising flight frequency and revenue cargo volume (“Revamped 777X may limit sales prospect of Boeing jumbo“, 3rd Jul, 12).
“If they’re going to develop something that’s going to be a step change, we want visibility around that. The 777 is a fantastic aircraft and my biggest regret is that I didn’t order even more earlier. But it’s difficult to commit to an aircraft knowing that something’s going to overtake it,” International Airlines Group (IAG) chief executive Willie Walsh told Bloomberg.
And should there be any further A350 delays spilling over to the A350-1000’s mid-2017 entry into service (EIS), its time advantage ahead of the 777-9X’s proposed EIS in mid-2019 will evaporate and give Boeing further leverage in not only the 777X’s design, but also selling additional 777-300ER to provide interim lift and further expand its strong customer base for a transition to a bigger, more fuel efficient -9X variant.
Given Airbus has just announced a 3-month delay in the A350-900’s entry into service (EIS) to second-half of 2014, Airbus must now work to minimise any spillover effect onto the work of A350-1000 and A350-800, of which Aspire Aviation thinks a 6-month delay, instead of 3, would build in additional margins for error.
“Airbus is making progress on the A350 XWB programme. The assembly of the static test aircraft is ongoing and the fully-equipped front fuselage section of the first flying aircraft has been delivered to the final assembly line. Entry into service has moved into H2 2014 mainly due to the time taken for the implementation of the automated drilling process for the wings,” Airbus parent European Aeronautic, Defence and Space Co. said in a statement.
“We’re looking at everything at this moment. We’re very comfortable with the process. We’re comfortable where we are. When we get it figured out, then that’s when we’ll go forward,” Boeing Commercial Airplanes president and chief executive Ray Conner said of the 777X development.
With the A350 still facing risks of yet another delay following the latest 3-month delay and Boeing’s strong balance sheet and cash flow, particularly after the decision to re-engine the 737NG (next-generation) instead of pressing ahead with a clean-sheet new small airplane (NSA), Boeing now has the leverage on its side on the 777 programme and stands to gain more on the 777X development.
Update1 on 27th July, 2012 1500 GMT+8 – Addition of details on A350 3-month delay announced today.
Categories: Airbus, Airbus Group, Boeing, British Airways, Cathay Pacific, Emirates Airline, General Electric, Pratt & Whitney, Rolls-Royce Tags: 777-300ER, 777X, A350 XWB, A350-1000, A350-900, A380, Airbus, Boeing, British Airways, Cathay Pacific, Emirates Airline, General Electric, GEnx, Pratt & Whitney, PurePower, Rolls-Royce, Trent 1000, Trent 1000-TEN, Trent XWB
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