On Dec 10, 10:44*am, sisu1a wrote:
Why would aircraft designers want to keep weight towards the wing
tips?

I think increased outboard mass increases the calculated flutter
speed.

-Paul

N7LW has it right. It has to do with bending moments developed in the
spar. At any given flight condition the wing supports a given amount
of lift that can be expressed in lbs/ft of span (or N/m if you
prefer). The fuselage doesn't produce any lift and has to be
supported by the lift produced on these long cantilever beams on each
side. Weight toward the middle of the aircraft increases the wing
bending. If the weight can be moved toward the outer portions of the
wing the bending loads are decreased. The paper airplane is a good
way to visualize this.

Craig