Spoke to a friend of mine, he mentioned that the B777 has a more elliptical shape wing compared with the competition. Would this be beneficial for low speed/high speed or both in terms of design?
In theory an elliptical wing balances the upwash along the entire span of the wing. Induced drag directly relates to the amount of upwash created by the wing and upwash in turn is greatly affected by the wing tip vortex. ( Hence you can see why a winglet is beneficial to the reduction of induced drag. )
By balancing the upwash along the wing, the tip produces an equal amount of induced drag as the root....this is the most efficient state for the wing to operate under. A fully elliptical wing is not practicle however as it causes the entire wing to stall at the same time, making the aircraft extremely unstable and difficult to fly near the stall.
Take a look at the factors which effect Di and you will see why a more elliptical wing is beneficial in terms of performance.