Ok, I'm going to try one more time, and then I give up.
The question really is where in the fuselage can you put that much fuel...because it would be a lot.
Yes, I am aware exactly how much it is, and I stated the exact numbers in my previous answer to you. You continue to vaguely say it is "a lot", whereas I say it is 24,750 litres. Take note of the difference!
I also specified exactly where it should go.
Strangely, Airbus have already performed the same exercise with their ACTs (Additional Center Tanks)
And, to be fair, you took my hint and eventually came up with that solution too (with reservations).
The final obvious option would be to do what they now do with auxiliary fuel tanks and just block a section of the hold space for fuel from the cabin floor to the bottom of the aircraft. That seems problematic because of the volume of fuel, the potential CG impacts, and the massive loss of cargo and bag storage space.
Er… "massive loss of cargo space"? Would you like to quantify that? Like what I did?
I believe Finnair operate their A321s with one or two ACTs in place of ULDs, enabling a full load of passengers (& baggage) between Helsinki and the Canary Islands. The downside is that the return flight is unable to carry as much extra cargo, such as fresh flowers or ready-to-eat avocado pears (mmmmm). The link will show you that each ACT directly replaces one ULD.
Qatar A319LR have provision for up to six ACTs, adding 18,000 liters capacity to the existing 8,250 liter fixed center tank.
Unless my math is wrong, this equates to having the wing tanks empty, and is exactly the solution we need for Boeing's proposal. I haven't heard anybody suggest Qatar's aircraft are unable to perform their role, although it is certainly a fact that their cargo capacity is reduced.
As regards potential CG problems - you'll have to take that up with Airbus in case they overlooked that small detail.https://www.scribd.com/doc/30183955/All ... 320-Family
All the above is based on existing adaptations to existing airframes. Imagine what we could achieve if we opened our minds to a totally new airframe, designed from the outset to carry all it's fuel within the fuselage! (Yes, I suggested that too... but I cannot claim all the credit; I believe Boeing also have that in mind)
Finding storage space for fuel is a small problem to be traded off versus the gains from a radically different wing. It is not a "killer"
So, I still say the design may be perfectly feasible, but I'm not sure whether operationally it would be practical for an airline.
If governments legislate to make less fuel efficient designs unwelcome, if airports cost their landing fees to penalise higher pollution from less fuel efficient designs, and if the price of oil goes up, then the airlines will not have a choice, it will become the ONLY practical solution. It will not be cost uncompetitive, because every
airline will be obliged to fly something similar, one model designed by A, another designed by B, and probably a third offering from China, if they ever get their act together.
Nothing to see here; move along please.