John Hazel wrote, re wing grids:
> exotic or maybe occult-
> http://www.rhone.ch/winggrid/induced_drag_reduction_with_the_.htm
I talked this over with a few of my profs here at Purdue. The decrease in
induced drag is real. It's the same thing birds do... sort of.
There are problems, of course. The most immediate is that each of those
little wings has its own little Reynolds number, and a lower Re is always
harder to deal with. Birds deal with it by having porous wing covering
(feathers) and by being naturally aeroelastic.
The mounting pod adds even more viscous drag.
The whole system puts weight outboard on the wing. This increases the
overall weight of the plane (causing more total induced drag) and also
increases the polar moments of inertia, making it less manueverable.
In the end, all you're really doing is making the airplane more expensive
to buy.
These are, BTW, all the same tradeoffs made for winglets, just taken to a
new extreme. The real reason to use winglets is not to increase the
efficiency, but to decrease the required span.
Daniel O. Miller
BRAIN: Pinky! Are you pondering what I'm pondering?
PINKY: I think so, Brain, but why would anybody want a depressed tongue?
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