Reply-To: <RHHELMS-VIENNA@worldnet.att.net>
From: "richard helms" <RHHELMS-VIENNA@worldnet.att.net>
To: <lancair.list@olsusa.com>
Subject: Re: LNC2 Foward Hinged Canopy Carbon Reinforcement
Date: Tue, 6 Apr 1999 21:23:21 -0400
Message-Id: <19990407012311.ICZY23110@helms>
Mime-Version: 1.0

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Thanks Scott.
    It had not occurred to me that the bending might be between the two
forward canopy/header tank attach brackets.  I thought it was taking place
somewhere between the gas strut attachment on the canopy side and the
forward attach bracket.  I already have a 1/4 inch piece of foam (per the
plans) across the front area and extending to about six inches above the
front corners but will see if I can bend that area by hand.  Actually, I
don't have a header tank and am just getting to the panel cover so there is
no interference to worry about, yet.
  Thanks for the invite but I'm passing on Sun and Fun to build. 

Guy, I don't want any pinching of the canopy to the longerons.  I applied
carbon per the plans (with one exception noted below) before and after
applying the 1/4 inch form stiffener.  Latter duplicated the stiffener I
had to cut out to lay down the first layers of carbon:  Total plies are 8
to each front corner, two 5 inches wide the total width of canopy, 4 - 32
inches long on center under the hinges and 6 - 20 inches on center under
the hinges.  Half are under and half over the 1/4 foam.  I just went and
remeasured to see if my carbon extended the 14 inches back from the leading
edge of the canopy (with the first 3/4 inches free) per the plans and I
don't quite go back 13 inches.  That puts the gas attach bracket (not shown
on the plans) just outside the carbon fiber layers.  I would not think that
I would be getting that much bend between the gas strut attachment on the
canopy and the 8 ply carbon but maybe that is where my bending is taking
place.  I think the reason I ended up an inch short is because I was trying
to keep away from the plexiglass attachment area while still getting it all
the way to the forward hinge.  The instructions clearly say add that
attachment after applying the carbon.  

  Mike Reinath, chapter 17 page 33 shows 80 feet of 5 inch wide
unidirectional carbon is needed.  I won't tell you how much I had left over
but it was not much and okay maybe it is 16 inches, just enough to extend 8
plies another inch on each side.  (I just checked and I have much more than
16 inches left over.  It did occur to me that I may have forgotten several
plies but no I did not <g>.  Of course I am capable of forgetting them and
that is why I cut them all in advance and double checked.  Frankly, there
is no way you can do all those carbon layups with Jeffco through the 1/4
inch foam (and them stop for it to set up with the curve) without
precutting all the carbon and hustling thorough the application.)  Note
that the 80 feet is from the chapter in volume two. The chapter which comes
with the hardware bag, chapter 17-A supplement does not show any quantity,
and it does not have what I think is a much easier means of doing the gas
strut/longeron attachment bracket.  That is shown on page 17-46 in the
book.  Cheers

After all this, I 'm inclined to remove the gas strut attachments on the
canopy and where the attachments were, add about 8 ply 4 inches wide
another three inches or so back on each side and run them about half way to
the canopy leading edge. 

Hollis Helms
904 Carole Ct, SE
Vienna, VA 22180
703   255-0631

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