REFLECTOR:Fiberglass Panel Backing

[Wayne Lanza]

Hi Guys,
  I have built about 30 Velocity panels over the past four years. As far 
as the holes
getting enlarged with time and vibration, well let's just say that's 
pure B.S. I have also
worked on some older panels and will say that I have seen some cracking 
due to flex.
Most of the panels that exhibited the cracks were not braced at the top 
center and none
had any type of stiffener added. The flex issue is even more prevalent 
in the older non-
molded panels. To address the flex issues simply add a fiberglass lip 
across the top
edge of your panel about 1" wide, 3-4 plys of bid will suffice. In 
addition, if your panel
is going to be heavily loaded, you can add 1/4" x 1/2" aluminum bar 
stock across the
panel in the major cut out areas. Glue the bar on edge to the back of 
the panel and
secure with 4-40 or 6-32 flathead screws. Counter sink the screws so 
that you can fill
over them and paint... Adding the bars is common when there are more 
than 3 large
instrument holes (wide) across or when there is an EFIS involved. 
Adding carbon to the
back of the panel (2 plys max) will help to stiffen but adds weight. 
Understandably, an XL
will require more consideration in this area that will a Standard.
  The big name panel shops like to bond metal to the panels because they 
don't like to work
with fiberglass. It takes a lot of effort to get a nice smooth finish & 
clean edges around cut
outs and holes. They would rather charge you double and crank out the 
job... In some
cases a metal sub panel is a practical alternative of you intend to do 
a major upgrade as
funds permit. This is a great idea, I have done this using either 
0.062" or 0.090" aluminum.
The sub panel is fitted over a large cut out in the panel, machined & 
painted to match.
  Another important place to add an aluminum bar is all the way across 
the bottom of the
panel. Glue this down to the bottom molded lip and again secure with 
screws. It's purpose
in life is to reinforce the bottom of the panel so that some 'heavy' 
doesn't break the panel
in half when trying to pull their seat forward... This will really 
cause a "crack"!.

Hope this helps & Fly Safe,
Wayne Lanza
(Velocity Contractor)
Composite Design, Inc.
_______________________________________________________________________


On Tuesday, December 2, 2003, at 10:35 AM, Bob Jackson wrote:

> I heard from one of the avionics vendors that there are problems with 
> using
> fiberglass instrument panels like we use in the Velocity because some 
> of the
> bigger, heavier instruments widen out the fiberglass holes over time 
> with
> airframe vibration, hard landings, etc.
>
> Have people flying had this problem?  Are you using metal insert 
> panels,
> metal backing plates, carbon fiber backing, or other similar methods to
> prevent the problem?
>
> Thanks,
> Bob Jackson