777-8 et 777-9

Paul a écrit:Faut pas se faire d'illusion, EK commandera un paquet de 777X. Pour les économies, 80% et même plus proviennent des moteurs, pour tout les appareils, à condition que celui-ci fasse le boulot mais GE a toujours bien fait côté consommation.

Admin a écrit:Injection d'eau
C'est quoi cette blague ?
C'est Tim Clark qui le dit ?
on l'injecte où l'eau dans le moteur ou en périphérie ?
Ca marche avec de la bière ?

Etonnant !

Beochien a écrit:Il doit y avoir un poil d'humour British, dans cette réflexion !

see the 777X as having a very expensive engine as they drive for higher thermal efficency, I do not see it selling in the volumes of the GE90 or GEnx, hearing Boeing has already asked for two thrust increases to cover weight and drag increases, and they are still 2 years away from a firm design.

@aspireaviation new 777X analysis is delayed until Thurs for Boeing Q3 results comment. It contains exclusive info~!

— Aspire Aviation (@aspireaviation) October 23, 2013

787-9′s HLFC reduces overall drag by 0.5%
“Software logic glitch” behind 787-9′s main landing gear door cycling on 1st flight
GE9X thrust increased to 105,000lbs, eyeing 108,000lbs
GE9X water injection increases mass airflow & decreases HPC temperature
GE9X water injection system carries weight & maintenance cost penalties
Boeing 777X to have Al fuselage
777X CFRP wing likely to be built in Charleston due to costs: sources
2nd A350 FAL & further A350-1000 stretch biggest threats to 777X
A350-1000 still requires significant design tweaks: sources
A350-800 yet to secure board approval to begin industrialisation process

In recent weeks, that figure was increased yet again to 105,000lbs with 108,000lbs of thrust being eyed by Boeing and General Electric, company sources at both companies confirmed. Boeing’s eventual goal, one of the sources claimed, is to match the 8,400nm range being offered by the considerably smaller 350-seat A350-1000 while providing superior payload-hauling capability.

A case in point is the 777-9X’s 4th-generation supercritical carbon fibre reinforced polymer (CFRP) wing, whose 71.1m (233.4ft) wingspan is 6.3m wider than the 777-300ER’s 64.8m. Despite the -9X’s 6.9% larger wing than the 777-300ER’s 436.8m² by adding 30m² (322.9ft²) to the wing area and a 12% better lift-to-drag ratio, thereby lowering the average wing loading per square metre by a similar amount, the GE9X’s thrust is only 8.9% lower than the GE90-115B’s 115,300lbs, or just 6.3% lower should the thrust rating be indeed raised to 108,000lbs.

Combined with the 777-9X being 10.3% more weight efficient in terms of maximum take-off weight (MTOW) per seat than the 368-seat 777-300ER, as well as 1.9% more weight efficient than the A350-1000, extending the -9X’s range to 8,400nm, a 7.35% increase over the -300ER’s 7,825nm, seems firmly achievable.

Similarly, Emirates has pushed General Electric (GE) to add a water-injection system to the GE9X for year-round operation under high-temperature, which will add complexity and increase maintenance cost for carriers not requiring the system in addition to weight penalty, Aspire Aviation‘s sources at Boeing said. The system will increase mass airflow and reduce the high pressure compressor’s (HPC) temperature.

This has wide-ranging implications on the 777X’s manufacturing process, with multiple Boeing sources now naming Charleston, South Carolina as the most likely site for building the largest wing Boeing has ever constructed primarily due to lower production cost. Following the loss of the JAL order, which was once thought to be a bargaining chip for the 777X wing’s work in Japan, the business case of having the 777X wing built in Charleston, South Carolina has strengthened, Aspire Aviation‘s sources at Boeing concurred. It would also utilise the 320 acres of land Boeing acquired for US$12.5 million in December last year with the option to purchase an additional 750 acres of land.

The drive of affordability also sees the Boeing 777X have a traditional aluminium fuselage, which the Japanese heavies will continue to supply its panels. The abandonment of the advanced lightweight 3rd-generation aluminium-lithium (Al-Li) material, which promises to trim 12% of weight and 6% of skin friction, is also directly attributable to cost-saving as Al-Li is “too expensive” and requires “major redesigns”, the same sources say.

On the plus side, the mission creep of the 777X means airlines will benefit from the aircraft’s improved payload/range performance that enables them to open up new routes, or tap into growth opportunities while balancing frequency and belly cargo. The 407-seat 777-9X will have a 20% lower fuel burn per seat and a 15% reduction in cash operating cost (COC).