> Drag is already very low on modern jetliners. It's so low that they have to add a bit of drag in the right place to prevent stalling (the small fins on top o

> Drag is already very low on modern jetliners. It's so low that they have to add a bit of drag in the right place to prevent stalling (the small fins on top of wings). > No fuel in the wing? Then fuel weight is not distributed and the wing must be stronger.. thus heavier. It's also less secure in cases of emergencies, as far as I know. I forgot why but I think there where also some really good reasons (beside closeness to fuel) why turbines are now mostly below the wings. Aslo wouldn't building 3 wings more expensive even if they are smaller? And then I have very little experience with aero dynamics, but my intuition tells me that there are some tricky parts around the (forget name: movable parts at the back of wings) and additional failure cases as you now (likely??) have to have 3 sets off them on each side.