If you do an all CFRP fuselage and redo everything else from wingbox over MLG to wings and engines, why would you not optimize the fuselage for the lower MTOW? You will need a new production line anyway and in the end it is just laying the carbon fibre matts less thick and at a different angle. The better question is if you can produce the large barrels of the 787 at a price that is suitable for the MoM, or if you are not better off looking at metals or a A350 style fuselage.
Exactly. The MOMs opportunity marked window has to include LCCs on medium range mission – e.g. Asia – WITHOUT hauling much cargo anyway. Cargo hauling is less and less important and fares are going down all the time. The 787 fuse is a big cargo hauler with it’s LD3 capability.
It is vertical oval for overhead crew rests – all a waste for the mission profile of a MOM. Yes, you could use some cargo space for toilets or catering, but that brings weight in it’s own (stairways) and didn’t help the A340 much.
The structure is to heavy build, including center wing box, a 787-based MOM would get very short, which has many negative implications in it’s own.
To start from a heavier base and ripe that base off weight is much, much more difficult than the other way around. One of the reasons is tha every single part of the millions defining a 787 are more-or-less designed for a big long haul twin. You have to screen through every single item and look if it could be downgraded.
At the end you may even have a MORE comlicated design than to start from scratch. Abaove a certain point on design changes on in the ballpark of the 77X it just doesen't make any sense to commit to a certain base.
It’s not gone be based on a 787-fuse – believe it or not, I’ll guess we’ll see soon enough.