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This is a repeat of a note back in 19 Jan 2004 and in the archives:
If your forward hinge canopy flexes just a tad when operating, particularly
across the front, you may find you didn't add enough layers of carbon fiber.
I had problems understanding completely the blueprint and layout schedule
for my forward hinge canopy (and still might not be clear) so I talked to
support (Justin ... thanks for his patience) at Lancair several times about
it. Come to find out the layup schedule on the blueprint and in the
supplement for the forward hinge is wrong. You start the layups with 4
layers (8 total) wrapped around the underside forward area. This starts 14"
from the leading edge of the canopy frame and back 3/4" from the leading
edge. That was correct. Next, according to the blue print, apply "10 total"
plies carbon fiber full width along the front, 3/4" back from the front edge
... this is a 49" layup. This infers that since there will be 8 layups of
the wrapped fiber, there are only 2 layers for the full width (10 ply total
carbon f.) This is wrong. The correct callout is 10 plies carbon fiber full
width. Look at page 17-54 of the FB kit plans and in step 24, 1 ply of UDG
is called out. That should be 5 ... and the other 5 comes after the foam
stiffener is added.
So if you built the front of the canopy frame with a total of 18 plies ...
you're off by 8 plies that run full length across the front.
Of course when looking at the blue print you find it difficult interpreting
the application of the first 8 ply layup, you might interpret this
differently.
jim
-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Larry
Henney
Sent: Monday, February 23, 2009 7:01 AM
To: lml@lancaironline.net
Subject: [LML] FW: forward hinge canopy bid thickness LN360
Doug,
I went with the 18 Bid per the plans on 3 aircraft.
If you are referring to the leading edge contact at the header tank
thickness..?.... All 3 that I built required trimming the carbon back the
width of the header tank overlap (or about 3/4").
No problems on mine 850 hrs to date. No cracking.
Am I missing your question. Why would resultant calculated thickness have
anything to do with plans requirement of bids?
Larry Henney
-----Original Message-----
From: Doug Baleshta [mailto:dbaleshta@tru.ca]
Sent: Friday, February 20, 2009 12:51 PM
To: lml@lancaironline.net
Subject: forward hinge canopy bid thickness LN360
Hi folks, the forward hinge canopy calls for up to 18 bid of unidirectional
carbon fiber. I measured the thickness and according to the plans it should
be around .140". The only unidirectional fiber I've found measures in at
.023, or about 7 bid. Has anyone else come across this and what did you do?
Did any of you use bi-directional CF with any problems?
Thanks
Doug
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