Originally Posted by
Twin Wasp
The winglets also add weight. Japan airlines has 747-400s without the winglets because on their short legs they wouldn't pay off and they'd take a payload hit. I've heard the wing on the -400 is so twisted when the plane is heavy they actually make drag the first couple hours but as the weight drops they pay off.
Exactly... it was my understanding that not all aircraft even benefit from the winglets they were designed with. Just depends I guess.