This part of the project starts with building a jig to hold the canopy skirt ( frame ) and canopy bubble. There is a lot of trimming that must be done, to have the bubble fit properly into the skirt. This is a photo of the bubble placed on top of the skirt for a preliminary marking and trimming.
Then use whatever tool works best for you. I am using the Rockwell multi tool. The blade vibrates instead of spinning. The tools with spinning blades can sometimes catch in the material, and if that happened, it could destroy the bubble. I am trimming a little at a time. After trimming, I have to place the skirt in the jig, upside down, to be able to put the bubble inside it for a fitting. Here is a photo of when I was trimming the edge of the bubble.
You see the blue tape which is how I mark the line to be trimmed. On the skirt, you can see a line drawn. That was the starting point for trimming. The vertical pieces are sticks covered with tape, to keep the bubble separated from the skirt during trimming. I went thru at least three iterations of fitting and trimming before doing the first trial fit on the plane. This photo is of that fitting. Brother Dave came over to help, as he always does when I need another set of hands and opinions.
This fitting showed us that the bubble was probably fitted into the skirt as it should be. However, some trimming now had to be done to the “bulkhead” in the aft section of the skirt. So we put the skirt and bubble back in the jig, upside down. I do not have any photos of that bulkhead trimming process, but this next photo shows smoothing out the edges of the acrylic bubble after trimming. The trimming process leaves the edges not smooth which can, and will, eventually cause the bubble to crack. Smoothing those out of the edges, takes away those stress points.
I use a small hand held belt sander for this process. I believe that if all the marks that may be left are in line with the edge of the bubble, they will not be the cause of any stress risers.
So, having smoothed the edges, and trimmed the bulkhead of the skirt, the bubble was once again attached to the skirt with clecos and another fitting to the plane was done.
This looked good enough to both me and brother Dave that we are calling it “fit”.
Now to build the frame that attaches the canopy skirt and bubble ( canopy ) to the frame of the plane. Stay tuned.