Buff upgrade

[henra]

Originally Posted by ORAC

That would mean a total pylon/ wing redesign along with hydraulics, electrics etc along with flight testing for engine out performance etc.
They opted for swap 8 for 8 to minimise the changes required.

https://theaviationist.com/2022/09/2...nacelles-test/

https://www.airandspaceforces.com/ar...-for-the-b-52/

While USAF once considered four large-fan commercial engines instead, it stuck with eight to avoid substantial redesign of the wing, cockpit, and other components, and to minimize risk and delay.

At the end of the day it is always cost vs. benefit. The advantage of 4 bigger modern engine compared to 8 modern Business Jet engines won't be terribly big. And for this little extra advantage you have to redesign A LOT of systems and validate structure and aeroelasticity of the wing and in the worst case make structural changes to the wing structure. And have less redundancy plus potential directional control problems in case of engine failure of the outer engines. And all this for <5% less fuel burn (0.657 vs 0.627 lb/lb/h cruise sfc RR725 vs CFM56-7).