Finally some progress… I know you've all been waiting to see some more blurry pictures of shiny objects, and tonight's update shall not disappoint.
One job I have been putting off until I was sure I needed to do it was trimming the rear ends of the canopy slider tracks. There is a little detail in the plans that shows a relief notch cut into the tracks to let the side skirts clear, with a note saying you should do this "if/as required". I did some playing with aluminum scraps and determined that I did need to trim the tracks to keep the skirts from rubbing, so I guess it is indeed required. First I roughed out the shape with a unibit and hacksaw:
After a bunch of filing and scotchbriting, I had a nice notch cut in each track and all the material for the side skirts to catch on was gone.
By the way, I'm really glad I attached the slider tracks with a nutplate strip instead of nuts and washers – it would have been a huge pain to take the tracks on and off multiple times to get this area to fit correctly.
Then I started on the blocks that anchor the pins that are welded to the aft corners of the canopy frame. Each one is held in place by a U-shaped bracket, which is bolted to the fuselage longeron. I intially drilled the holes only to #30, and temporarily attached the brackets with 4-40 screws in order to be able to fine-tune the fit later if needed.
Next I put the plastic blocks into the brackets, scribbled some sharpie ink in the approximate area where the pins would contact the blocks, and slowly slid the canopy forward. At the spot where the pin touched the block the ink was wiped away, leaving a clear indication of where the drill the hole for the pin. I center-punched the spot and the hole location was marked. Simple.
I transferred the angle of the pin to the top and side of the block so I could have some lines to sight along while getting ready to drill:
The hole you have to drill is parallel to nothing, which makes it tricky to get it lined up. I borrowed a Panavise from work, which made it a lot easier to get the block aligned in the drill press. The pins are 1/4" O.D., but since holes in this UHMW plastic stuff shrink after you drill them, a 1/4" hole in the block caused the pin to be an interference fit. So, I used a 17/64" drill bit I borrowed from Scott to slightly enlarge the holes, and that made everything happy.
Then I drilled the bolt holes in the brackets and longerons to final size, and bolted everything together. But oh by the way, these are also the stops that keep the canopy from rolling off the back of the slider tracks, so in order to remove the canopy and work on anything I had to unbolt the brackets, slide the canopy off, and re-bolt the brackets on. This slowed me down a lot because I kept needing to remove or replace the canopy in order to get anything done.
After that I put the blocks into the brackets, slid the canopy shut (the pins fit in the holes, hooray!) and used C-clamps to immobilize the blocks in the correct position. Then I drilled holes for the screws that attach the blocks to the brackets, drilled the holes in the blocks up to #10 to let the screws fit through the plastic, reassembled everything, countersunk for the flush screw heads, and bolted it all together. Throughout this process I had canopy on and off many many times. Whew.
I may come back and countersink the screw holes a little deeper if I need to later on, but for now I didn't want to wallow out the hole too badly. This will all be covered by the canopy skirts later, so it's not critical.