Bill,

I had same issue. It required a lot of stretching.

What I did was plan installing the seal so that all the stretch was taken along the sides of the cockpit, and then “over the top” at the back. I did this as I could imagine the seal trying to pull away from the concave sections – which would have been fun with wet silicone everywhere, and annoying if it later pulled away!

1. Before any silicone got close to the plane, I laid the seal roughly in position and fixed with masking tape across the front of the cockpit opening with no stretch in this section – making sure of course that the air line connection fits nicely in the right spot.  I then marked the mid point of the seal “at the back” - effectively the point that will line up top centre of the cockpit opening at the back, and taped into position.
2. I then marked a point on the seal both sides that was roughly equal to the length of the straight side sections, and marked the same distance back on the structure. This was to give me a reference for how much I was going to stretch the seal – with aim of getting it roughly the same both sides – not that it really matters that much I guess.
3. Next step was a bit of trial and error – but I then stretched both sides back to the “aft corners” (just below the latches).
4. Without any stretch, I taped the seal around the corners and up about 6”. At this point of course, the seal will not be sitting on the joggle up over to the top, and the masking tape you put in place at step 1 has probably given way at this point – but it doesn’t matter – in fact it makes it easier.
5. Once everything is secure both sides to points just above the latches, stretch the rest of the seal up and over the top, but aiming to get the top back centre marks you made in step 1 above to line up.
6. If at this point, the amount stretch seems OK, and is not substantially more and less than the tension you applied along the sides – you’re good to go!  If it doesn’t feel right, go back to Step 2......
7. I then made final marks every 10-12” or so all around the seal and the structure, so that I would know pretty much exactly where to lay the seal once I’d applied the silicone.
8. The rest is easy – apply silicone (not too much) as a lot squeeze out is bad = messy), and progressively place and tape in position as required to get it all to sit in place. Once taped roughly all the way around, where required I placed additional tape over the seal to make sure it was really pressed into the corner of the joggle.
9. When it was all set, removed all tape and marks.
10. I had then intended to go all the way around and squeeze some more silicone into the top gap.... But  after a year’s flying, still haven’t got onto it!!
    

Hope this helps!! Its a lot of words, but all up, prob only took a couple of hours – but two pairs of hands almost essential I think.

Regards,

John




John N G Smith
Tel / fax:    +61-8-9385-8891
Mobile:      +61-409-372-975
Email:         john@jjts.net.au

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From: Bill Bradburry <bbradburry@bellsouth.net>
Reply-To: Lancair Mailing List <lml@lancaironline.net>
Date: Tue, 13 Mar 2012 16:54:01 -0400
To: <lml@lancaironline.net>
Subject: [LML] Legacy Canopy seal installation

My plane is in the paint shop and I will be installing my canopy seal when it returns.  The seal is slightly smaller than the distance around the canopy which will require some stretching to make it fit.  Does anyone have any ideas as to how to accomplish this install with a minimum of difficulty?
 
Thanks,
 
Bill B