Dave=0AI don't think you should shorten the added layups, that runs the ris
k of creating a sudden change of stiffness which would act as a stress rais
er. Not what you want in a spar. =0AWe need the wing to bend smoothly , mos
tly out towards the tip where high loading (gust etc) will result in bendin
g and =0Agust aleviation. With the original spar too much of the bending oc
curs in the spar tangs.=0AAll gliders have bendy wings and most of them giv
e a reasonably smooth ride in rough air. You don't get that with an excessi
vely stiff wing. You also get disruption of the laminar flow if the wing do
esn't flex. This was explained in Soaring mag 20 years ago (maybe 30!) by W
ill Schumann. He chopped 2 metres off the tips of an ASW17 Open class glide
r, (hot ship at the time) The wing then became too stiff and the performanc
e was way below what he had calculated.=0AGraham=0A=0A=0A=0A=0A____________
____________________=0A From: djaflyact <djaflyact@gmail.com>=0ATo: europa-
list@matronics.com =0ASent: Tuesday, 22 October 2013, 21:51=0ASubject: Euro
<djaflyact@gmail.com>=0A=0AThanks Nev. I have ground one spar tang today.
Had to quit due to roasting in the sun and just the mess of it. I'm wonderi
ng if anyone has done this mod on a flying airplane. The reason I ask is th
at the speed brake control tufnol block is right there where the fiberglass
is layed up against the root rib. To grind those payers off the root rib,
I would ahve to remove the controls for the speed brakes and also the ailer
ons. What I was hoping to do is leave the fiberglass on the spar out about
2 to 3 inches and then add the new layers as called for in the build manual
, but only run them up the root rib where possible. Otherwise, the new plie
s would essentially splice onto the existing pile on the root rib. Where I
can run them up the root rib, it would be thicker than called for in the ma
nual. There is also the issue of the glass that is holding on the wing root
fairing, which is why I'm asking about not taking off the layers that are
now on the root rib.=0A=0AI'm still getting lost in the terminology - roves
- tows, etc. Is there a source on the internet that defines what these ter
ms mean?=0A=0AI'm attaching a photo of it now, with the intensifier board o
n top for scale.=0A=0AOh - How far does the carbon fibre cloth go toward th
e rot rib? ALl the way to the 90 degree corner?=0A=0AOff to shower off the
dust - you are right - it goes everywhere. I am wearing a space suit and I
still get it on me.=0A=0A=0ADave=0A=0APS On one spar, There was a spot of s
omthing that looks almost like sap in a spot when I was grinding the shear
web layers - toward the wing root.- Like a pocket of sap or a pocket of s
omething that was not cured. This is about a 12 year old spar.=0A=0A=0A=0A
=0ARead this topic online here:=0A=0Ahttp://forums.matronics.com/viewtopic.
php?p=411138#411138=0A=0A=0A=0A=0AAttachments: =0A=0Ahttp://forums.matron
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