Making a Canopy

On Tuesday, January 21, 2014 2:21:41 PM UTC-6, Guy B wrote:
I have a glider, a canopy frame, and a new plastic canopy, and now my problem is making them all come together into a functioning unit. I've searched this site, and found a bit of info, but still really need some detailed instruction on fastening the plastic to the frame.

I know the frame has to be fitted to the glider first, and the plastic cut, fitted, and glued to the frame, while in place on the glider. I understand that screws aren't necessary, and may in fact cause trouble.

I think I need a fine tooth circular saw, and grinder, some way of clamping, a specific adhesive and info on how to use it. I can't do any of this, but will be working with an experienced aircraft engineer, who is willing to give it a try.



Any help from this community would be appreciated. Or pointers to some place or person who can assist.



Thanks,

Guy

Kestrel 19 CF-FGR

First off, I would seek professional assistance. This is a major undertaking, even for someone who has experience.

Here are some suggestions that hopefully will help steer you in the right direction.

1. You can start by protecting the canopy from scratches and scuffing by using Spraylat. This is a water based compound that can be painted or sprayed on the canopy that leaves a thin rubber coating. You can peel back the coating on your mating surfaces for bonding and peel off the rest upon completion of the project.

2. Turn the heat up and only work on the project when the canopy and environment are above 70 degrees, 80 works even better.

3. When you trim the canopy only use high speed cut off wheels or a drum sander. Using any type of a saw will cause chipping and stress fractures.

4. Fit the canopy frame to the glider for a good fit to start with. When you bond the canopy to the frame, do so when the frame and canopy are in place on the sailplane. If you bond it to the frame off of the sailplane you will end up with a twist and poor fit. I used 3M Panel Bond that is a two part adhesive. When it hardens it will still be somewhat pliable which is what you want for the environmental thermal expansion/contraction.

5. Don't drill any holes thru the canopy as this may introduce stress cracks at a future date. I used bicycle inner tubes stretched over the structure for bonding with localized wood blocks between the tubes and canopy around the frame for a tight fit.

6. My last suggestion is to cut the canopy 1/8" short around the perimeter and fill in the gap with micro. This suggestion if for impact resistance. The micro will take the hit instead of the Plexiglas. If the Plexiglas takes the hit it may propagate a stress crack.

Chris