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<DIV><FONT face=Arial size=2>ED,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I can send you some photo's of how I do it when I
get home tonight.</FONT></DIV>
<DIV><FONT face=Arial size=2>The spars, whether they are c.f or glass, do
provide a definite increase in strength. It is important to have the
upper and lower spars directly in line with each other top and
bottom. I also tie the aileron box together with a square of
thin c.f. between the forward and aft spar top and bottom with negligible weight
gain. This has little effect on raising the balsa and
what it does can be sanded smooth. I use urethane glue and lay
up the c.f. strips with the sheeting and cores at one time. The urethane
works great and your wing will be plenty strong. There are several
methods of sheeting and I am sure they all have their good points.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Wayne G.</FONT></DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Ed_Alt@hotmail.com href="mailto:Ed_Alt@hotmail.com">Ed Alt</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Tuesday, December 21, 2004 6:39
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> fiberglass mesh in foam
wings</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>I'm getting ready to sheet a pair of Temptation
wings and have questions about using the fiberglass screen mesh reinforcement
strips they call for. First, how necessary is it to even use any?
I can see where it obviously adds strength and stiffness in those
sections directly under the mesh, but at the same time, it will also create a
raised-up section of sheeting directly adjacent to the mesh strip. It
seems possible that there would be no bonding of sheeting to foam for about
1/4" to 1/2" wide all along those seems, at least not if a thin layer of epoxy
is used. It also seems that at the point where the sheeting does begin
to bond with the foam again, it would be subject to shearing forces that might
tend to pop the foam beads out over time due to bending loads on the
panel. Maybe not? I have no experience with this method, so it's all
speculation. It seems that a fairly heavy application of epoxy would be
needed to bond foam to mesh, mesh to sheeting. Is it possible that the
same or better strength result could be accomplished with a slightly heavier
wood selection and still be as light or lighter than adding mesh and extra
glue?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Asuming the mesh is really necessary: The
2nd question is about the adhesive to use if the mesh is used. I
normally use either Pro Bond or Elmers polyurethane glue, which does a
terrific job of bonding several bead layers deep into the core. I think
it probably stiffens the structure alot as a result. However, it's not
clear to me if this would be a good adhesive with the mesh applied. In
theory, it would do a good job of filling that gap I'm worried about along the
mesh edges. Has anyone tried this and are you happy with the
results?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The last question is about how far to run the aft
reinforcement strip. Do you really need to run it all the way to the
tip? At some point, you really get diminishing returns as you get
further out in the panel. Sorry for so many questions!</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ed</FONT></DIV></BLOCKQUOTE></BODY></HTML>