Zitat

Original von Claas
Servus,

ich denke, wir sind alle daran interessiert, was Drela zu Peters Profil sagt, laß uns nicht an Unwissenheit sterben...

VG Claas

damit niemand stirbt...............
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David,

The PW1211 looks pretty good.
Despite the slightly negative viscous Cm, I calculate
that the neutral point is at 20-22% chord, because of
the positive dCm/da. See attached plot. The dots
are the neutral point location, defined as
(x/c)_np = 0.25 - (dCm/da)/(dCl/da)
The rearward movement of (x/c)_np below Cl=0.2 is
a little scary, but this may be reduced by the slight
turbulation action of the hinge at high speed.
A slightly thinner airfoil may be better here,
maybe 6.2-6.4% or so.

The mylar/vacuum-bag construction used by American DLGs
is the lightest I'm aware of. The SG2 is about the same
weight as the light version of the FW3, but the SG2
is much more damage resistant and could be made lighter.
For lower weight I would use a lighter foam like the pink
Foamular 250, and lighter wing spars. The CF rod spars
on the new Taboo GT are especially light and effective.
Reaching 200g for a plank is quite possible I think.

I still don't see how you will damp out the large yaw rate
from the discus launch.


- Mark
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gruß

d@vid