Well, there is certainly a can o wahtever.
The wing design must be balanced. There is an optimum wingspan for the ac config...
but that is optimum...
while the optimum wingspan for fuel efficiency at flight is X (that also depends on optimum) The wingspan must be able to work with all of the settings, and access, for it all to work.
With the 737, the wingspan optimum wingspan for each wing, ends up to be about 6 feet longer that the ac has. This is a function of better design software than 20 years ago, but also as a balance.
If the wingspan on the 737 were extended to the new optimum, the ac would no longer be a CAT C aircraft. Hence, it was found, that if you turn the wingtip up, you had an 'equivalent' wingspan, the software showed reduced drag, and therefore...better fuel efficiency.
But this was all based on the average model, of the wing section in flight.
So, what you really needed was more of a variable section, that would better perform though more phases of flight.
While the Airbus T and the end of the wing was really good, the software models didnt really understand how to properly calculate the results, hence a square peg in a round hole.
The recent 737 MAX winglet, appears to optimize more flight conditions, but in reality, still appear to use the same CFD models, which get you so far, but are still 40 year old technology.
In reality, we are seeing a transition.
From trying, at all cost, to keep within certain CAT wingspan requirements, to optimum wingspan design.
Last edited by FlightPathOBN; 1st Jun 2012 at 00:41.