Altri dettagli, anche se tanti dati sono ancora poco precisi:
http://www.aspireaviation.com/2012/02/09/boeing-develops-777x-to-challenge-airbus-a350/
As the development of the Airbus A350 XWB (Extra Wide Body) family aircraft gears up this year, with the first A350-900 example entering final assembly in March ahead of its first flight in the second quarter of 2013 (“Airbus faces a crucial year on A350 development“, 25th Jan, 12), the same holds true for the competitive response from its transatlantic arch-rival Boeing on the development of a revamped and upgraded version of the highly popular long-range 777 jets.
Boeing has been studying a major upgrade of the twin-aisle 777 aircraft, provisionally dubbed as the 777-8X and the 777-9X, that will succeed the 301-seat 777-200LR and the 365-seat 777-300ER, respectively and mount a significant challenge to the proposed 350-seat A350-1000, whose more powerful Rolls-Royce Trent XWB engines from 93,000 lbs to 97,000 lbs increases the range of the aircraft by 400 nautical miles (nm) to 8,400 nm or its payload by 4.5 tonnes over the same range, delayed the entry into service (EIS) of the largest A350 variant by two years from 2015 to 2017.
Under the Chicago-based airframer’s latest schedule on the 777X development in December, the concept development of the 777-8X and -9X has been successfully accomplished at the end of 2011, with a firm configuration of the aircraft due in the second quarter of 2012, followed by the securing of an authority-to-offer (ATO) from Boeing’s board of directors in the third-quarter, Aspire Aviation‘s multiple sources at Boeing revealed.
Once the offerability of the 777-8X and -9X is granted by its board of directors, Boeing could enter sales negotiations with the airplane’s potential customers around the world which will lead to a launch order that symbolises the official launch of the 777X programme.
Roll-out and flight tests of the aircraft, the same sources say, will take place at the end of the fourth-quarter in 2017 with an aggressive 9-month flight test programme that will be concluded by the end of the third-quarter in 2018. Entry into service (EIS) is expected to be in mid-2019.
The latest timeline on the 777X development matches the previously reported entry into service (EIS) date of 2019 and a programme launch of 2013 (“New Boeing 777X likely to be a highly efficient derivative“, 14th Sep, 11), and is the latest indication that the development of the revamped 777 is gearing up since Boeing issued a request for proposal (RFP) for a 100,000 lbs (445 kN) engine to the world’s three largest engine-makers General Electric (GE), Rolls-Royce and Pratt & Whitney (P&W) (“Boeing eyes 787 improvement along with production ramp-up“, 11th Jan, 12).
777X a major upgrade with significant technological advances
With the firm configuration of the 777X going to be reached in the second quarter of this year, the initial details emerged on the 777-8X and -9X resemble a highly efficient derivative that will incorporate significant technological advances featuring a 787-styled composite wing, a new engine and other improvements.
The bulk of the 15% reduction in block fuel burn per seat of the 777-9X over the existing 777-300ER aircraft will come from a new engine incorporating the latest generation engine technologies that are found on the Boeing 787 Dreamliner’s General Electric (GE) GEnx-1B and Rolls-Royce Trent 1000 engines.
While the request for proposal (RFP) for a 100,000 lbs (445 kN) engine powering the 777-8X and -9X was issued to General Electric (GE), Rolls-Royce (RR) and Pratt & Whitney (P&W), General Electric is likely to receive an extension of the exclusivity contract GE currently enjoys on the engines powering the popular 777-300ER and -200LR aircraft, despite the promising potentials in fuel burn savings offered by an upscaled Pratt & Whitney (P&W) geared turbofan (GTF) engine whose gearbox structure allows the engine fan to spin 3 times slower than the low pressure turbines (LPTs) which maximises the engine’s propulsive efficiency and eliminates 7 stage, or 20%, of an engine’s life-limited parts (LLPs), as well as Rolls-Royce’s potential offering incorporating elements from the Trent XWB engine which the Derby, England-based engine manufacturer touts as the “world’s most efficient civil turbofan”.
The GE9X engine will have a 10% lower engine specific fuel consumption (SFC) than the GE90-115B1 engine and will incorporate the twin annular pre-mixing swirler II (TAPS II) instead of the dual annular combustor (DAC), composite variable-bleed valve ducts at the exit of the booster stage. The GE9X will have the same fan diameter of 325 cm (128 inches) as the GE90-115B1 engine and delivers a thrust of 99,500 lbs (443 kN), compared to the GE90-115B’s 115,300 lbs (512 kN) of thrust.
“I’m spending over US$50 million on technology development on it in 2012. We’ll be ready,” GE Aviation chief executive David Joyce told Bloomberg, adding the new engine powering the 777-9X will be 6%-8% more fuel efficient than the GE90-115B1 engine.
The GE90-115B1 engine burns 0.25 pounds of fuel per pound of thrust delivered per hour (lb/lbt/hr) whereas the GEnx-2B engine on the 747-8 burns 0.274 lb/lbt/hr. It is noteworthy, however, that a direct comparison between the GEnx-2B and GE90-115B1′s fuel burn figures is skewed as the engine fan efficiency improves as the fan size increases. As the GE90-115B1 has a fan diameter of 135 inches, including the engine nacelle, whereas the GEnx-2B engine has a diameter of only 105 inches and the -1B engine has a diameter of only 111 inches, Aspire Aviation‘s sources say a 10% reduction in engine specific fuel consumption (SFC) of the GE-9X versus the GE90-115B1 engine is achievable.
Meanwhile, the 777X will feature a 787-styled composite supercritical wing that is going to have a considerably better lift-to-drag (L/D) ratio and is significantly lighter than the wings of the 777-300ER, with a wingspan of as large as 71.1 metres (233.4 feet).
Aspire Aviation‘s sources at the Chicago-based airframer confirmed that Boeing is studying 4 wingspan options – 65 m (213.3 ft) with winglets, 68.6 m (225 ft) with winglets, 71.1 m (233.4 ft) with raked wingtip, as well as a 233.4 ft option featuring a folding wingtip.
The larger wing of the 777X will make it an International Civil Aviation Organisation (ICAO) Code F aircraft instead of the Code E category that the 777-300ER and -200LR are in today as well as a US Federal Aviation Administration (FAA) Airplane Design Group (ADG) Group VI aircraft whereas the 777-300ER and -200LR are Group V aircraft. The ICAO Code E and FAA ADG Group V categories include airplanes whose wingspan is between 52 m (170.6 ft) to 65 m (213.3 ft) whereas the Code F and ADG Group VI categories include airplanes with a 65 m (213.3 ft) to 80 m (262.5 ft) wingspan.
Moreover, the same sources say Alcoa’s 3rd-generation lightweight aluminium lithium (Al-Li) is a “viable option” for the 777X, which will feature a 10% weight saving and a 6% reduction in skin friction drag, while cautioning the decision in the choice of the material for the 777X’s fuselage will not be made anytime soon.
Indeed, a 777X featuring an advanced aluminium-lithium fuselage with a composite wing makes sense in significantly trimming weight, thereby further improving the fuel burn performance of the aircraft. In addition, advanced aluminium-lithium (Al-Li) is a well understood technology that requires little to no modification in the production process and will not complicate the US Federal Aviation Administration (FAA) certification for the 777X. Put it simply, advanced aluminium-lithium technology is what Aspire Aviation‘s sources characterise as a “low-hanging fruit” that could be incorporated into the design and the production of the 777X very easily, while providing a considerable weight saving.
Coupled with either slightly stretching the 777-300ER’s 73.9 m fuselage to accommodate several additional rows of passengers, or “internal stretching” without actually lengthening the 777-9X’s fuselage by removing internal frames in some sections to provide more room to accommodate 10 seats in a single row, the 777-9X will have an improved payload/range capability carrying 380-390 passengers, despite having a lower maximum take-off weight (MTOW) of 342 tonnes (753,000 lbs) than the 777-300ER’s MTOW of 351.5 tonnes (775,000 lbs).
A350 under pressure amid 777X & continuously improving 777-300ER
Having been delayed by up to 6 months when Airbus’ parent European Aeronautics, Defence & Space Co. (EADS) announced its 2011 third-quarter financial results, the A350 is already struggling with shortage of parts at tier-2 suppliers, which Aspire Aviation‘s sources at the European plane-maker say was an “ongoing problem” and the programme margin built in the latest delay is “being chipped away”.
Worse yet, Aspire Aviation‘s multiple sources at Airbus say the carbon fibre reinforced polymer (CFRP) in Section 19, the tail section that is behind the rear pressure bulkhead, have misalignment issues with Section 18 that are traced to a defective mould at an Airbus facility in Spain. The Section 19 is more than 5.5 metres (18 feet) long with a surface area of 53 m² (570.5 ft²) and has a diameter larger than 4 m (13.1 ft) at its widest portion, is built by the Advanced Composites Centre in Illescas, Spain.
While these issues, along with the overweight issue of the A350 XWB, of which the -900 is the least overweight variant with a 3-4 tonnes overweight (6,614 – 8,818 lbs) overweight whereas the -1000 is around 5 tonnes (11,023 lbs) overweight and -800 is the most overweight variant, are going to be progressively solved, any new A350 delay will further boost the appeal of the offering of its arch-rival, the 777-300ER, and give strategic advantages and more leverage to Boeing in terms of the 777X development.
For instance, Boeing is studying performance improvement packages (PIPs) that will further reduce the block fuel burn of the 777-300ER by 4% and up to 5%, in order to bridge the gap in fuel efficiency and lower operating costs between the existing 777-300ER and the proposed mid-2019 entry into service (EIS) target of the 777-9X.
The 777-300ER enhanced by performance improvement packages (PIPs), dubbed as the 777-300ER+, is likely to incorporate a recontoured belly fairing, a different wingtip, as well as weight reduction and an improved GE90-115B1 engine, Aspire Aviation‘s sources at the Chicago-based airframer said.
The enhanced 777-300ER+, coupled with the 777-9X’s entry into service (EIS) in just two years after the A350-1000′s service entry, are going to pose a significant challenge to the largest A350 variant and could potentially undermine its business case.
Most importantly, the 777-9X will have a maximum take-off weight (MTOW) of 342 tonnes (753,000 lbs) and carry 380-390 passengers over an improved range which Aspire Aviation‘s sources say will be around 8,000 nm with 407 passengers, or modestly more with 380-390 passengers, the A350-1000 will have a considerably lower maximum take-off weight (MTOW) of 308 tonnes (679,000 lbs) with 350 passengers.
Industry sources have indicated that the dissatisfaction of A350-1000 customers such as Middle Eastern carrier Emirates Airline and Etihad Airways is centred on the aircraft’s insufficient passenger capacity, whose gap will be widen from the extra 15 passengers that the 365-seat 777-300ER carries to the extra 30-40 passengers being carried by the 380-390 seats 777-9X over the 350-seat A350-1000.
Furthermore, should the 777-9X’s fuselage be lengthened beyond the -300ER’s 73.9 m (242 ft) fuselage length, the revenue cargo volume of the 777-300ER will further increase from its current figure of 5,200 ft³, thereby enabling the 777-9X to carry not only more passengers, but also more cargoes than the A350-1000.
Meanwhile, built on the 777-300ER’s broad customer base with 601 examples being ordered from over 30 airline customers around the world as of the end of January 2012, the 777-8X and 777-9X should have a warm market reception with plenty of 777-300ER operators such as Dubai-based Emirates Airline, Cathay Pacific, International Airlines Group’s (IAG) British Airways, Japan Airlines (JAL), All Nippon Airways (ANA), Singapore Airlines, etc, looking for a significant fuel burn saving and cash operating cost (COC) reduction with more capabilities than its competitor in two years’ time after the A350-1000′s entry into service (EIS) in 2017.
In conclusion, now that Boeing has opted to develop a re-engined 737 MAX, coupled with a steadily declining research and development (R&D) cost and the generation of strong cash flow, this has essentially freed up financial resources to develop a major 777 upgrade to strengthen its market leadership in the 350-400 seat segment. Along with the 320-seat 787-10X being mulled that is expected to be 20% more fuel efficient than an A330-300 with a 6,800 nautical miles (nm) range, whose launch and entry into service (EIS) dates are expected to be in 2014 and 2017, respectively, Boeing is now forming its competitive response and aligning its product line in the 300-400 seat segment of which the A350 XWB family is envisioned to compete against both the 777 and 787 at the same time. It is indeed interesting times ahead with major developments taking place at the widebody aircraft programmes across the Atlantic this year.
