This evening I started to fit the Plexiglas bubble on the canopy frame. I started by putting tape over the canopy attach angles and the latch tube so the bubble does not get scratched up as I put it in place on the frame. I also put some drafting tape over the forward bow of the canopy frame. This tape is to help identify the point of contact along the forward bow where the Plexiglas bubble rests on the bow.
I set up a small table in the garage and put a small moving blanket over the table. Next I moved the Plexiglas bubble from the shop to the garage. The shop is air conditioned with the house so I was concerned that the bubble might be too cool to work on. I have learned from reading in the RV-12 forum on the Vansairforce website that the canopy is subject to cracking if it is drilled, cut and sanded when the temperatures are low. Since it has been sitting on the floor of the shop for the past several months I was concerned about the temperature. I am sure it didn't take long for the bubble to take on the temperature of the open garage. It was 95o so there should not be a problem with working on the Plexiglas. After I have completed the canopy I am going to build the fuel tank while it is still warm. The Pro-Seal tank sealant works a whole lot better when it the temps are higher. I prepped the edges of the canopy bubble by removing the plastic cover about 3" from the edge and I installed tape on the inside and outside of the Plexiglas.
I set the bubble in place on the canopy frame. Initially it seemed to fit pretty well. One of the steps in the instructions is to mark and drill a 5/8" hole in the top aft section of the bubble for the latchtube. I was happy to see that the hole was drilled at the factory. It appears to be in the right location. With the bubble in place I looked closely at the fit. I discovered I will need to do some trimming to get it to fit better.
I used some gaffer tape and 2-small clamps to pull and hold the lower edges of the bubble in place. On closer examination I have discovered that I will need to remove an 1/8" material along the forward bottom edge on both the left and right sides of the Plexiglas.
I will also need to trim (sand) the notch at the forward corners on both sides.
I will also need to remove some of the material along the aft edge of the bubble. There is supposed to be a 1/32" gap between the forward edge of the rear window and the aft edge of the canopy bubble. It appears the bubble is tight against the rear window all along the edge from the lower left side to about ½ way up the right side. At that point it begins to open to about 3/16" at the bottom on the right side. I will need to sand the aft edge of the canopy to achieve a 1/32-1/16" gap across the width of the joint. That should prove to be a good challenge.
