Gidday,
Does it matter if the additional ply of hinge reinforcement cloth is added
between the full length plies or added ontop of the final full length ply?
If there is to be a difference in the amount of layers of additional cloth
between preconstructed and post-constructed, I can only assume there may be
an ideal way to lay this additional ply in. I figure it would be best to go:
full length....hinge reinforcement......hinge reinforcement.......hinge
reinforcement (recessed inwards)........full length.
This would encapsulate the additional ply, which is different to the
post-constructed method which would be:
full length................ hinge reinforcement............hinge
reinforcement.............full length ...........hinge reinforcement.
Am I right in this hypothesis, that the additional strength can only be
gained in the preconstructed method if the additional ply is sandwiched
between the 2 full length plies? I understand that 2 plies is the maximum
thickness to maintain a max. of 25:1 ratio of ply distortion to maintain
strength, so the additional ply needs to be larger creating a small step up
off the first full length ply and another larger step (2 plies) before the
last full length ply goes over the top. This is achieved by maintaining a
min of 12mm (1/2") between each step.
I do this layup tomorrow so any help would be appreciated.
Reg
Tony Renshaw
Yes the text of the Tech Note reads:
"The occasional Europa has been noticed to suffer from cracks in the paint
local to control surface hinges, indicating excessive flexing of the flange.
We are not aware of any damage to the flange itsel being found do far. If
your Europa shows similar sysmptoms,, the addition of two plies of 'bid'
will stiffen the flange sufficiently. Check the integrity of the flange
prior to this repair, and please let us know of any flanges themselves found
to be cracked. If in doubt, you will need to remove the paint to inspect the
glass fibre surface.
On aircraft not yet built, add one ply of hinge reinforcement to both flying
surface and control surface flange."
By implication one additional layer when building is equivelant to adding
two layes to an already built flying/control surface.
Reg
Tony Renshaw
Builder No.236
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