On Tue, 04 Feb 2014 07:28:31 -0800, J. Nieuwenhuize wrote:

After some back and forth discussion, it seems pylon-mounted wings could
have a lot of potential for sailplanes.
WRT aerodynamics, they make a laminar upper wing and much more extensive
laminar flow on the fuselage possible.
Structurally, notably yaw forces might be problematic (ground-loop), but
nothing impossibly difficult. With the possibility of a mid-wing one can
remove the heavy spar stubs and control connections and also reduce
complexity a lot, notably for drag brakes and flaps.

A few designs from the past come to mind. SH had a pylon-wing on an
experimental Cirrus and it reportedly flew well. The Streifeneder
Albatross and the Akaflieg München Mü31 are heading in that direction,
but are only halfway to the advantages of a full pylon wing.

So why don't we see pylon-mounted wings on modern sailplanes? I can see
why not in production ships from the established factories; any radical
change demands a steep and risky learning curve. But for new factories
and/or experimental ships, at first glance there seems a lot of
potential.

Any major issues with pylon wings that we've overlooked?

One. You need a fair pylon height to avoid interference drag in the gap
between the top of the fuselage and the wing's lower surface. I'd say
interference drag is relatively high on the Sunseeker shown he
http://www.solar-flight.com/

However I'm not an aerodynamics expert and have no idea what the optimum
height sound be except that its unlikely to be less than 10-15% of the
wing chord, think of the Wien for this pylon height, and that its one
problem the Ku-4 Austria didn't suffer from.


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martin@ | Martin Gregorie
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