I had read that they were having trouble with the weight outside of the completion. The thing is supposed to have BOW of 34,300lbs but I can specifically remember an article about flying the second production model where it said its BOW was 37,800lbs. I'm sure they've improved since then but to what degree? What you're talking about with the galley is also interesting.

Hmm. Seems like it would have trouble flying Paris to LA westbound (the flight that it was supposedly designed for). Plus, with the enlarged galley you're talking about, now you have to seat a crewmember in the passenger cabin for flights where you need 3 pilots and a stewardess? And then without the crew rest you can't fly more than 10 hours under part 135, right?

Also, is your 10k fuel example apples to apples? The G550 only holds 10k more fuel than the 7X, so that would mean that it burned all its fuel on this 5000-5500nm trip... doubtful unless it was flying faster than the 7X.

I'm sure that the 7X is a great performer, but it seems like it could have benefited from better planning and some more development time. My understanding is that it was originally conceived to be able to do 5,700nm at M.80 and 5,300nm at M.85, but that those goals were changed to be able to connect more city pairs (Paris to LA is always mentioned), and they already had their wing so to do that they increased the fuel tanks and slapped on undersized winglets (by that I mean that they were limited by what the wing could stand and not by what would have maximized performance). I remember reading a reputable flying magazine that related an interesting bit of information from Dassault: the 7X winglets only increase the plane's range by 2%. That seems terrible when I see bolt on aftermarket winglet kits for some jets (including other Dassaults) improve performance much more than that.