Wingtip Vortex: Heavy, Clean, Slow - Why?

"steve.t" wrote in message
oups.com...
Is this why there are fences on wings? [I am assuming that the over
sized chord shaped flat metal blade on a wing is a fence]. That is to
keep the air flow straighter than it would otherwise flow?

And speaking of winglets, would a winglet provide sufficient efficiency
increase for piston singles to make it worth the cost of the
modification (field approval or STC)?

Later,
Steve.T
PP ASEL/Instrument


Without getting into a bunch of searching for proof, what I recall reading
is that winglets can be thought of as more wing, to keep the vortices from
coming off the wing tip. Vortices still come off the winglet. Some of the
energy is reclaimed by making the vortices from the winglet flow over the
airfoil, adding lift. Angle and size are important, as being slightly wrong
can soon destroy any gains.

They are most efficient at speeds above what piston singles can attain.
Fences and other trick wing tips (drooped, angled) are better at low speeds.
You are better off adding more wingspan to increase the aspect ratio, at our
size.

Airliners can't simply add more wing length, and still fit in the gates and
hangars, and keep the spars strong enough, so they put on the winglets.

I'm sure that some of this is not quite right, but I think the general
concepts are correct.
--
Jim in NC