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Hi Rob,
I seem to recall that Charlie K. gathered data on a
IV both with and without winglets. Charlie, was the number 7 knots? That
is, 7 knots faster WITHOUT the winglets.
Several knowledgeable folks have responded that
winglets are mostly an advantage at very high altitudes, and this is true.
I would add that my conversations several years ago with some Boeing engineers
indicated that the exact shape and placement of winglets was ultra critical.
Probably not something that any of us could design and install in our shop
and have any hope of improving performance. Extensive wind tunnel testing would
be required to get it right. My wind tunnel (powered by hot air) is out of
service. To be successful, the winglets would need to reduce drag by more than
the increase in drag that they would necessarily cause by
increasing wetted area and weight. Imperfectly done, they
have the likely outcome of slowing you down. Keep it simple, leave 'em
off.
Rob, do you fly out of YPPH or YPJT?
Bill Harrelson
N5ZQ 320 1,650 hrs
N6ZQ IV under construction
I am
building a L360 in Australia, and will soon have to make the decision about
what wing tips to use. The kit comes with the standard tips. However, I have
seen some Lancairs with winglets, and am wondering whether they are worth the
investment in time and money. Has anyone out there in LML land done any
research into the benefits of winglets? I am interested particularly in before
and after comparisons, both in terms of speed and general
handling.
Any
info would be greatly appreciated.
Rob
Stevens
Perth,
Western Australia.
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