REFLECTOR: Lay up c question

[Matt Bucko]

Thanks for the replies from everyone. Good thoughts to ponder.
Matt
  -----Original Message-----
  From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On
Behalf Of gattenby at tulsaconnect.com
  Sent: Tuesday, June 17, 2008 11:47 AM
  To: Velocity Aircraft Owners and Builders list
  Subject: Re: REFLECTOR: Lay up c question


  I join the group that thinks that the "cave" doesn't add to the strength
that much...
  I made the cave to keep water out of the lower winglet.
  I've seen more than one lower winglet filled with water.
  Rather than dilling a hole in the bottom of the winglet, (to let the water
drain out)
  I glassed all sides of the bellcrank space.

  Noel

  On Mon, 16 Jun 2008 21:56:58 -0700 (PDT)
   Andrew Ellzey <ajlz72756 at yahoo.com> wrote:
  > Everyone has to decide which direction that they prefer
  >on this issue. Neither method is wrong. Since I chose the
  >cave method, it the one I am most familiar with. The
  >reason that everyone keeps asking what they should do is
  >that the manual is unclear on this issue. One of the
  >main reasons that I like about the cave method is
  >that you have a completely sealed compartment for the
  >rudder horn to operate in. See the attached photo's of
  >my almost completed winglet and rudder. Even if you don't
  >do the cave method, you will still wind up with a cave
  >when you add your bottom to your winglets. Your cave
  >wouldn't have a bottom other than the bottom of the
  >winglet. I also added the two closeout bulkheads that are
  >bonded into place with velocipoxy and milled fiber. Since
  >the vertical bulkhead is bonded to my cave opening (C
  >layups) and the lower winglet, it should add strength in
  >compression of the C layups. The exposed foam that is
  >seen in my photo will be
  > covered with one ply bid when I get around to it. I also
  >left more length on my rudders than the manual called
  >for, my personal choice.
  >
  > Andy Ellzey
  >
  >
  >
  > - Original Message ----
  >From: Steve Goldman <steve at fatcatair.com>
  > To: Velocity Aircraft Owners and Builders list
  ><reflector at tvbf.org>
  > Sent: Monday, June 16, 2008 8:52:41 PM
  > Subject: Re: REFLECTOR: Lay up c question
  >
  > 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
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