RJMAZ wrote:LDRA wrote:Rather than scale 787, just make a 787-8 V2 for MoM. Redesign structure for 200T MTOW, using lessons learned from 1st gen 787 structure, new 5000lb MoM engines, center wing box tank deletion, done!
7 across is rather inefficient use of space anyways
Smaller end of MoM space can be covered by NSA
This is why I think it will definitely be 8ab and slightly shorter. Any disadvantage to a stubbier fuselage is more than made up by the superior aisle efficiency of 8ab versus 7ab.
I always thought the 787-8 lightweight was a good option. It is worth noting that 200T MTOW on the 787-8 is still way too high for the NMA mission. It does reduce the MOM gap significantly though by providing a big efficiency boost to the 787-8 on shorter missions.
Boeing has different takeoff weights on their ACAP's and a standard 787-8 can fly 250 passengers nearly 5500nm with a 200T MTOW. Removing say 10,000kg of empty weight would increase range even further with that 200T MTOW. Removing that weight would actually be easy as the 787-8 has so many parts shared from the heavier 787-9/10. These parts are simply derated like the engines or overbuilt for the 787-8.
The centre fuel tank on the 787 is pretty large so unless the empty weight could come closer to 100T deleting the centre tank might not allow it to fly over 5000nm.
The more changed that get made to improve the 787-8 the closer you get to a cleansheet.
Yes, I've always seen the most prudent strategy as an NMA at "generous" 7ab also allowing a 8ab.
This allowing better volumetric efficiency as well as preventing a future AB 8ab "overunning" a "strict" 7ab BA bird - that is, avoiding the 767 vs A330 redux.
However an alternative strategy might go like this:
1) the NMA is indeed set at a "strict" 7ab, thus minimising cross-section/weight/drag/cost and maximising competitiveness with A321X/A322X in the specific MOM space; (**)
2) meanwhile in the event of AB subsequently launching a clean-sheet 8ab, then the 787 fuse is in turn given a whole new wing/wing box/gear/powerplant/empennage(?)
That is, in a direct competition, a good 8ab will defeat a good 7ab ... ("apples vs apples")
however in similar direct competition, a good 9ab will in turn defeat a good 8ab ... ("apples vs apples")
and BA already have the basis of the "good 9ab" ...
What think you?
(**) not to stress that the NMA offer-for-sale IMO marks the start of the big wheels turning which will eventually produce the NSA ... and the closer the NMA is to the NSA, the more-accurately the evolved NMA production-system will scale-down to the 6ab NSA
just sayin' ...