Cambered leading edges

In article <1992May28.151503.18650@e2big.mko.dec.com> sasaki@tle.enet.dec.com writes:

>Actually, I've got some looseness in the Katana. It's there to allow
>the kite to bow along the spreader to allow the kite to change shape.
>This makes things like skate/helicopters easier.

>The first dozen or so Katana's had a double layer of fabric along the
>trailing edge. This was done as an attempt to keep the edge from
>stretching. The new Katana's don't have this double layer and seem to
>fly just as well as the old ones.

But does it stretch?

>The Katana has an extra whisker to help with vibration in this area
>and the difference in performance with and without the whisker is
>quite noticeable.

I remember seeing that whisker on Darryl's Katana--was that before or after
you saw a Scorpion?  ;-)

>The Big Brother is single layer in this area, but the grain of the
>fabric panel in this area is parrallel to the trailing edge. I suspect
>that the Pro has a double layer in this area because the grain of the
>fabric (without the extra layer) is not parallel to the trailing edge.
>The extra layer helps with the stretch.

Sort of.  Actually, out toward the very tip, there are _two_ layers on 
the Big Brother.  There's the trailing edge, which starts by the stand-off
and goes all the way to the wingtip.  Then there's another big triangular
panel at the wing tip.  I believe these overlap, creating two layers on
the trailing edge for the last several inches before the wing tip.  In fact,
I think the large triangle's edge falls roughly where your second set of 
whiskers does.

The Pro actually has 3 layers out by the wing tip.  Dean has changed the
design several times (I've seen at least 3 different ones).  The original
Pros, delivered at Jacksonville, have two layers--the main sail, and the
narrow piece on the front along the trailing edge, from the standoff to
the wingtip (looks very similar to the panel on the Big Brother).  Dave and
Sherrie Arnold fly some of these original Pros, and they're still flying
incredibly well and incredibly silently--and because they're framed with
Easton, they've seen higher winds than many other Pros.  The second generation,
of which Darryl's is a part, have a 3rd panel, much like the Big Brother's
triangular panel.  Dean put this one on the back of the sail.  I believe
that this was roughly when Dean started using Carrington, so perhaps he
felt he needed another layer due to stretching.  The latest version has
3 layers out by the wingtips, but he's cut down the traingle on the back by
quite a bit.  A variant of this has the main part of the sail ending early,
so extra colors show through on the front.  

>It's obviously a sign of a fertile imagination with not enough work to
>do. ;-)

People to be jealous of, eh?  <grin>


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