Another one

[Ton van Bochove]

Cargolux Selects 777-8 Freighter as Preferred Replacement for 747-400 Fleet

[Jeroen Hoppenbrouwers]

Engineering game.

Suppose we re-engine a 747-8 (because it is the most modern incarnation of the family) with 2 big fat blowers like off the 777X or whatever.

Would we get the required economy boost by dropping two engines while still retaining the VOLUME that the 747 still offers over a 777? And would the resulting sales offset the development costs?

Forget about systems -- the hydraulics, pneumatics etc are all divided by two, that is a nightmare. Just hull and blowers.

Alternative game.

Take a 777 and redesign it with a nose door and the associated elevated flight deck and upper deck. What now?


Hoppie

[Hardy Heinlin]

I guess the average wing tip location will be a bit higher above the CG as the outer wing area will be lighter. This might increase the lateral stability above the authorized values.

If the engine pod width is greater, the gear struts need to be longer ...

If the average fuselage height is greater, modify all avionics that refer to certain radio altimeter data ...

If the engine pod width is greater, the thrust vector sits lower below the wing, especially if there's no engine in the outer wing area anymore. That might increase the pitch-up effect when the thrust is increasing.

Alternatively, to place the new engines higher, you also need to place them more forward, and then you might get that ugly 737-MAX problem (autotrim software etc.) ...

...

[martin]

Suppose we re-engine a 747-8 (because it is the most modern incarnation of the family) with 2 big fat blowers like off the 777X or whatever.

Sounds suspiciously like a "747 MAX", no?
 

[Jeroen Hoppenbrouwers]

It's more like a 747 ZERO