Canopy Warped

[racaldwell]

I finally got to the point in the project of unpacking the last of the big boxes. The canopy has not been unpacked since leaving Sonex in 2014. On removing from the box, the edges were scary looking, like it have been trimmed with a hammer & chisel. Many chips and serious rough edges. I immediately sanded the edges but no way to sand out the chips. Using the masking tape applied by Sonex, I marked the centerline front and back. I aligned the canopy centered on the fuselage and so far no cracks. But I noticed that the bubble is not symmetrical. The pilot side is lower than the passenger side. Here is a picture.

Has this been encountered before and if so, is there any way to correct it to get a symmetrical canopy?

I tried pushing on it but the right side bulge is not moving. The picture shows it strapped down to moderately hold it's shape in hopes the 100+ heat of my hangar helps the canopy remember that shape.

Rick Caldwell
Xenos 0057

[Area 51%]

It's been said more than once on this site that no two snowflakes are alike.

I placed our canopy in position last week and found the factory tape line well outside the actual border. Didn't bother to cut at the factory tape as that would only have added a step in the process. Made my own tape line + 1/2in and started there. Unless your chips are 3in long, I'm sure they will not be a factor.

On to the snowstorm. After the required three dozen fitting sessions, I started to pilot the canopy to the frame. All was going well, except about an hour ago when I drilled the last of the rear bow-to-canopy holes. I stepped back to admire my work and noticed the canopy had a distinct bulge on the co-pilot's side. Asked the wife for a ruling. She pointed out that we have a spare canopy in the trailer, and if I wanted to go through the fitting process again, only to find it too might be misshapen, she was there for me.

I've decided not to pursue a relationship with the second canopy at this time, but to include a note in the shut-down checklist to leave the propeller in the 10 or 2 o'clock position to block the view.

The canopy I'm fitting is not a 2014 model, but one I picked up at Sonex 3 weeks ago today. I'm thinking, either we both got the only two canopies ever produced with a goiter, or they all have that bulge to some extent.

Good luck with reshaping the plexiglass. It has quite the memory below 100 degrees.

Oh..and thanks for this post. It probably IS my fault the canopy isn't symmetrical, but it's nice to have someone/something else to blame.

Plodding along here @Area 51%

[LarryEWaiex121]

Your 100% certain that the canopy isn't 90 degrees out of kilter?

Larry

[Area 51%]

I don't know about Rick's, but mine was marked Front. I don't think a 90deg off canopy would even cover the hole.

[bvolcko38]

I took 3 days to fit my canopy... I wanted it perfect. Clecoed on, it did look almost perfect, good enough.

Riveting changed everything. Rivets have a much stronger pull than clecos. I'm living with it.

[racaldwell]

Thanks for the replies back. There is some comfort in knowing I'm not the only one with asymmetrical canopy issues. I put the frame inside the upside down canopy before I fit it over the fuselage. It was not even close to matching the shape of the frame. I thought the markings must be wrong. Then I measured and the markings are right, it will not reach all sides if rotated 90 deg. So after sanding, it was pretty flexible and draped over the fuselage enough where I have extra to trim off all the chips and then some. I marked the inside of the canopy with a sharpie on masking tape to get the trim lines close and then sand for final fit. I'll start that Saturday.

At least I'm not over 68" so I get the low side of the canopy and I'll have room under the canopy for taller passengers.

I did notice that the left and right side bulges are of different strengths to push them somewhat straight with the fuselage. I can understand why so many crack when pushed to the side framing. I think I'll go with the idea of making an aluminum sheet joggled to hold the plexi instead of riveting it directly to the frame.

Rick Caldwell
Xenos 0057

[sonex892.]

I did notice that the left and right side bulges are of different strengths to push them somewhat straight with the fuselage. I can understand why so many crack when pushed to the side framing. I think I'll go with the idea of making an aluminum sheet joggled to hold the plexi instead of riveting it directly to the frame.

Hi Rick. Sorry its a bit off the warped canopy topic. Attaching the canopy with aluminium sheet is similar to what I did except I didn't joggle, I used a spacer. Used no rivets just 3mm screws, tapped into the frame and nyloc nuts on the plexi attach. Can easily get 2 -3 mm more edge distance at the plexi holes compared to attaching to the frame. I also relocated the hinge to attach to the bottom of the frame instead of the side.

[DCASonex]

Glad to see you are not going to rivet your canopy. When assembly sees very hot or very cold, the plastic and aluminum expand at different rates, and a lot of stress is put on the rivets. Do make sure to avoid even the tiniest scratch, especially on the inside of lower edges.

David A.

[racaldwell]

Thanks, good info to know. I like the screw idea instead of rivets. I think someone said that they did not use any fasteners or sealant on the plexi, it is just clamped between two sheets of aluminum. That sounds like a good idea. I'm sure with the canopy secured front & rear it is not going anywhere that the airplane doesn't.

I have the swing back frame already finished so I have no hinge to deal with. I'll be making both sides mirror images of each other. My exterior canopy locking device is below the longeron so I have nothing in that regard to interfere with the side skirt.

Anybody make the side skirt extend down past the longeron like the RV design?

I'm thinking of making a rear skirt to rest on the turtledeck like I did on my RV sliding canopy. But still formulating plans in my head for the canopy skirts.

The other Xenos here has the rear bow higher than normal so the canopy actually rests on the turtledeck. That's too much of a step for my liking.

Rick Caldwell
Xenos 0057