Boeing 777x - question

[dukeboy749r]

So, into my inbox has popped this week's edition of Aviation Week & Space Technology. All good, so far.

However, as a non-plane designer, I am interested why this newest plane doesn't feature the recent (seemingly de rigueur) 'winglets'.

Is that the latest planes have such flexible wings that those miniature tails/fins/winglets, (please forgive technical nomenclature), are no longer needed?

Just curious.

Many thanks

[surveyor]

I'd guess its connected to the folding wingtips... Perhaps the additional loading would not help the design.

[phil squares]

Boeing has opted to use a raked wingtip rather than a winglet. There are advantages and disadvantages to both. But the result is the same in both cases, that is, additional wing area is created and less induced drag at the tip thus reduction in fuel burn. The raked wingtips tend to be better on long segments thus the 777/787 family has adopted this approach. The raked wingtip also is a lighter weight structure where the Airbus winglets are heavier than the winglet. Airbus has also adopted a more rigid wing which requires additional structure.

[5150]

dukeboy749r said:

So, into my inbox has popped this week's edition of Aviation Week & Space Technology. All good, so far.

However, as a non-plane designer, I am interested why this newest plane doesn't feature the recent (seemingly de rigueur) 'winglets'.

Is that the latest planes have such flexible wings that those miniature tails/fins/winglets, (please forgive technical nomenclature), are no longer needed?

Just curious.

Many thanks

I asked my Uncle back in the 90's (he was one of the Chief Engineers at BA) as to why the 777 didn't have winglets, like Boeing added to the 747-400. His answer was simply; 'it's a better designed wing'.

I guess with modern materials, plus improvements in design and construction techniques, we now see the wings we have today....winglets add weight and drag to aircraft, so if you can design a decent wing in the first place that beats the gains of adding winglets, then it's all money in the bank.

[Krikkit]

phil squares said:

Boeing has opted to use a raked wingtip rather than a winglet. There are advantages and disadvantages to both. But the result is the same in both cases, that is, additional wing area is created and less induced drag at the tip thus reduction in fuel burn. The raked wingtips tend to be better on long segments thus the 777/787 family has adopted this approach. The raked wingtip also is a lighter weight structure where the Airbus winglets are heavier than the winglet. Airbus has also adopted a more rigid wing which requires additional structure.

The raked tip produces less bending force on the wing, meaning the wing can be lighter - they've really pushed the overall weight down with the 777x, despite having huge wings, so adding a blended or fenced wingtip would probably have pushed the structure too far over the weight they were aiming for.

[dukeboy749r]

Thanks, all. Very much appreciated.