[Public-List] Reinforcing the cockpit sole

[Stephen Gwyn]

Hi,

I've got two or three replies suggesting cutting out the top
skin, replacing the core and then putting the top skin back. I
have 3 problems with this:

1) Unless you make the join between the replaced top skin and the
edges as strong as the original, one piece construction, you will
have weakened the floor. To do this, you would need a 12:1 bevel
on both sides of the seam, with tape laid over the join.

2) Not being a professional fibreglasser, I'm pretty sure if I
did the bevel-and-tape thing, it wouldn't look very nice.

3) My core is fine. No audible voids, no signs of water
intrusion.

Although the current 3/16" FG + 1/2"balsa + 3/16" FG sole is
fairly stiff, it's not stiff enough. Allow me to help you
visualize it with the following thought experiment.

I want you imagine a 1/2" piece of good quality marine ply, say 2
feet by 4 feet, about the size of the cockpit floor. Picture it
in your mind's eye, supported all around the edges. Pretty stiff
looking right? Now imagine a 45lb iron weight dropping from a
height of 2 feet, THUD in the middle. You can see the board can
easily take that weight, but it flexes just a bit. It's that flex
I want to eliminate. Now imagine the same sheet sitting a row of
3 two-by-fours, spaced a foot apart. Same 45lb iron weight being
dropped, THUD. Not so much flexing. That's what I want to
achieve.

But, you say, what moron drops a 45lb weight into his cockpit on
a regular basis? It turns out my 4 year old son likes to jump
from the seats onto the floor. THUD.

SG

-- 
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Stephen Gwyn                       | Tel: 1-250-363-3136
Canadian Astronomy Data Centre     | Fax: 1-250-363-0045
Herzberg Institute of Astrophysics | Cell: 1-250-885-6969
5071 West Saanich Road             | E-mail: Stephen.Gwyn at nrc-cnrc.gc.ca
Victoria, BC, V9E 2E7, Canada      | http://astrowww.phys.uvic.ca/~gwyn/
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