"goneill" wrote in message ...
I have purchased an ASW20L and want some feedback on winglets
M & H quote 5% improve in l/d with their set .
Does anyone have an opinion on how accurate this claim is.
Is there other manufacturers that make them ,net sites please
and opinions if you have them.
gary

Good winglets certainly can improve handling. They have their largest
effect
at high lift coefficients such as when tightening in a turn. As a
result they can have a remarkable abilty to improve climb.
With respect to max L/D, the best a winglet could do is reduce induced
drag by the equivilent to the span increase that would result if they
were flat. It is true that localized flow around the inside of the
winglet can improve the flow ate the tip a bit, the improvement is
relatively small.
So, if you want to estimate(call it guessing) the max improvement,
calculate the improvement from equivilent span increase and factor it.
Knowning geometry such as cant angle is useful. Likely the improvement
is between 40 and 60% of the theoretical span addition, plus whatever
gains result from localized flow improvement.
Measured improvement at L/D max on my 20C with winglet not unlike M&H
winglet was just under 1 point.
All this said, M&H has, in my opinion, the best aftermarket winglet
available for the '20.
UH