Wing Efficiencies

[cancidas]

i'm curious, is Boeing's 767-200 Wingletted wing more efficient than that off the 767-400?

imagine how cool this would have looked with raked wingtips:

[kc2aqg]

It is my understanding that Blended Winglets offer significantly better fuel savings/range increase over raked wingtips (even if they are not as cool looking, which I agree, raked tips are). My guess at the reason why this 767-200 design has blended winglets is because with all of that extra hardware mounted on the wings, the wingbox and spars will already require the modifications to handle the extra weight. Since those provisions would likely already be in place and be able to handle the weight of winglets, it would make sense to outfit the airframe with the more efficient fuel-saving design.

Purely my guess though, I could be wrong.

[moose135]

It's been a while since I've looked at it, but I believe you get about the same effect with either, and perhaps raked wingtips are even a little more efficient. But with ramp space at some operating locations at a premium, you save some room having winglets over raked wingtips.

[GrummanFan]

All wingtip designs have the same goal (decrease drag by increasing the effective wingspan). Which design works best for a certain aircraft depends on the wingtip device size, weight, structure required, etc. This isn't a rule by any means, but it seems to be the trend that winglets are more often retrofitted to older aircraft because they are easier to add on to an existing design. Raked wingtips are usually only considered when designing an all-new wing because it is easier to get the highest efficiency when you can modify the entire wing along with the wingtip.

[cancidas]

it just seems a little strange that boeing would go with a raked wingtip on the P-8 and wingets on the KC-767. i guess designing them that was just cheaper.