Making a Canopy

On Tuesday, January 21, 2014 3:21:41 PM UTC-5, 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



PLEASE PLEASE PLEASE get help from a professional, or send it to a professional. this is a detail oriented process and they can go horribly wrong. a canopy is too expensive to risk it. you have to think about fitting it properly, not having glue overflow, not accidentally gluing the frame to the glider, painting it so that it doesn't look awful et. cetera... the list of potential problems goes on an on.

On Wednesday, January 22, 2014 1:14:01 PM UTC-5, Andrew Brayer wrote:
On Tuesday, January 21, 2014 3:21:41 PM UTC-5, 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 PLEASE PLEASE PLEASE get help from a professional, or send it to a professional. this is a detail oriented process and they can go horribly wrong. a canopy is too expensive to risk it. you have to think about fitting it properly, not having glue overflow, not accidentally gluing the frame to the glider, painting it so that it doesn't look awful et. cetera... the list of potential problems goes on an on.

My friend JJ used to call stuff like this "do it yourself brain surgery".
UH

Please make a video; we are all looking forward to
seeing the demolition on YouTube...

On Wednesday, January 22, 2014 1:00:27 PM UTC-8, Dave Nadler wrote:
Please make a video; we are all looking forward to

seeing the demolition on YouTube...

Just be glad you're not doing a Libelle or something where you can't lay the canopy blank over the cockpit to mark something close to the net shape. The biggest problem with canopy work is the high cost of failure. The advice to work with warm materials, use an abrasive cut-off wheel and have the frame locked down on the fuselage when mounting the plastic is critical. Beyond that it's just a myriad of details.

Hope all goes well,
Craig

gluing the canopy.
About 35 years ago, I was using ( and still do)silcone RTV for a wide
variety of jobs needing a gap filling glue.
I repaired an extensively damaged Kestrel, with a smashed canopy.
I dislike screws for holding plexi. After doing test samples,
the canopy was glued with clear silicone RTV (type I)
using a commercial primer on both surfaces .
this method avoids localised stress and was OK for ten years.
I recently saw this gl;ider for sale with a canopy which
looked like the blue tinted canopy I installed.
PS yes, cut the plexi using a cutoff flexi disc. I melts and
aneals the cut surface.
JMF


At 02:42 22 January 2014, wrote:
This is not a trivial exercise, a lot of work, a great deal of risk
(Canopy
= $$$) and a really suboptimal place to start learning composite work.

I have about 5 pages of really minor but very important details on this
process that I consult ever time I mount a canopy and this is not my
first
rodeo.

Cut canopies with abrasive cutoff wheels and disc sanders, never with
toothed devices.

Some installers use countersunk metal screws in addition to bonding
(epoxy
+ cotton flox + fumed silica. Screws are mostly to hold alignment and
position while the epoxy cures.

Rubber bands made from bike inner tubes are very handy for holding the
plexi on the frame while it cures.

I cannot think of a more difficult, detail-critical installation than
this.

How far are you from Dave Nelson in MI or M&H in NY?

What a great response! I was away for a while and just signed on again. The words of wisdom and caution are greatly appreciated. I'll show all comments to the aircraft engineer that thinks he might be able to do it. I expect we'll be looking for that special someone who has some good experience. Thanks again.
Guy
Living in Alberta and Nevada

On Sunday, January 26, 2014 1:49:10 PM UTC-8, Guy B wrote:
What a great response! I was away for a while and just signed on again. The words of wisdom and caution are greatly appreciated. I'll show all comments to the aircraft engineer that thinks he might be able to do it. I expect we'll be looking for that special someone who has some good experience. Thanks again.

Guy

Living in Alberta and Nevada

Guy,
I see you live in Nevada some of the time. If you fly Minden, I would be glad to cover the do's and don'ts of cutting, drilling, gluing and painting a replacement canopy. Look for a bat looking sailplane with JJ on the fin and introduce yourself.
JJ