Have been curious about this for a while.
Whilst we're seeing a flurry of older aircraft being retro fitted with winglets (757 etc), as well as current designs both large & small getting winglets factored in, ( wing fences (A380).
With claimed fuel savings over a single long haul flight or accumulatively over a period of time between 2% -7%.
How do Winglets, & fences stack up compared to Raked wings, like on the 777-300er, 787 & so on?
- I've read that raked tips create even greater savings that winglets etc? - due to being simply a newer design philosophy in engineering evolution.
Are there any comparative studies between these methods of wingtip vortex /drag reduction (which is what they do?), that shows whether raked is a better method than winglets or fences or visa versa?