Winglets?

[ackattacker]

the 777 doesn't have winglets because the wing is designed more or less perfect. Metal needed to renforce the energy forces created and the weight on the wing exceeds the usefullness of having a winglet on the 777. the 747-440 winglets actually are for marketing. the extra weight to renforce the wing actually counter acts the usefullness of having them. at that time boeing was struggling to compete with airbus... a big wintip fan. although the 73 and 75 series seem to be a different case. the addition of a windlets has increased range and efficentcy such that the mod. is worth the money or atleast that is what the bean counters are telling us...

Also some 777's have raked wingtips which has a beneficial effect similar to winglets.

 

[Huck]

They told me down at alabama polytechnic that they produce roughly the same effect as if you iron them flat - i.e. increased aspect ratio.

Also make a dam fine place to vent fuel tanks....