REFLECTOR: Lay up c question

[Steve Goldman]

Andrew Ellzey wrote:
> 
> I made the rudder horn pocket on my wings also and I like the way it 
> turned out. I don't agree that the glass over the pocket doesn't add any 
> strength. If I ever build another pair of wings, I'll do it the same way 
> again.

I'd like an explanation as to how it adds strength to the 
winglet/attachement. Here's a simple thought experiment. Imagine layup 
D is simply a hinge and there is no layup C at all. Then obviously you 
can move the winglet towards the fuselage with no effort at all. Now 
imagine that all you have for layup C is the portion of glass over the 
bellhorn area. That piece of glass (except for maybe a very tiny 
amount just aft of the foam, i.e. the most forward piece of glass) has 
a bend in it so that the bellhorn can fit in the cave. So what happens 
now when you apply force to the winglet trying to move it toward the 
fuselage? It moves fairly easily (a short distance) until the glass is 
stretched out straight and is finally in tension. So at that point it 
does add strength. However in order for the winglet to be moved to 
that position all the glass of layup C "forward of the rudder 
bellcrank cutout" would have to tear. That's 15 or 16 inches of glass. 
If it has torn so that the aft section of glass can load you are 
already in serious trouble.

I think there is a reason why older manuals (and the video) describe 
the cave and the current manual says "Keep layups forward of the 
rudder bellcrank cutout". I did check with the factory and they said 
you don't need the cave. Building the cave doesn't hurt although it 
does seem to make accessing the connection of the cable to the 
bellhorn less convenient.

So I guess that means Andy says digital and I say analog and Matt has 
to make his own decision. :-)

-- 
Steve Goldman
'77 Tiger N28531
Velocity XL5-RG (T-2762 hrs) N758SG (reserved)
Pittsboro, NC (9NC8)
http://fatcatair.com