Winglets, how do they work?

[bentandtwisted]

I know they provide a 3-4% saving in fuel burn and reduce induced drag, but why/how do they work?

Why don't the 777, 767 and 757 have them?

Do "Blended" winglets work better than normal winglets?

Thanks in advance.

[gas path]

A nice and simple description can be found HERE

[dolly737]

You could also look here or here

happy landings

[phnuff]

With the winglets reducing drag by reducing the vorticees, do they lead to a significant wake vortex reduction on landing/takeoff, or is the reduction too small compared to the turbulence caused by higher angles of attack ?

[Bre901]

You could also perform some searches on the PPRuNe Forums, lots of threads about winglets. See for instance :

http://www.pprune.org/forums/showthr...light=winglets
http://www.pprune.org/forums/showthr...light=winglets
http://www.pprune.org/forums/showthr...light=winglets

[hoss]

bentandtwisted,

haven't had a chance to check out all the above links,but try a search of 'supercritical wing' or 'reflex camber'.it may help answer your B777 etc question.

blended vs normal winglets, my guess would be blended wins.

safe flying, hoss