Its not only Boeing that is looking at folding wingtips. Airbus is at it too, but their solution folds down rather than up.Airbus’ patent application can be seen here. As the image suggests, it looks like this idea is focused on a twin engine aircraft.
Airbus points out that larger aircraft need longer wings but this runs into the airport gate box size limitation. Which is of course the same thinking Boeing has. But then they point out that the the upwards folding wing “requires heavy actuators and/or locking systems”. They also point out that during flight the forces of flight are “urging the wing to the folding position”. Hence their interest in downward folding tips.
These are interesting points Airbus makes. Of course Boeing could point out that the upward folding wing offers considerably less opportunity for “ramp rash”. It is, unfortunately, true that vehicle drivers around aircraft are often clumsy and hit aircraft.
Either way, now that both big OEMs are moving towards folding wingtips, the path ahead is clearer about this concept. We know why Boeing is doing this. But why would Airbus be doing this? Might this idea be signalling a growth model A350?