Fit is Important
The sliding canopy is the premier eye catching item in the design in my opinion and the final result is worth a lot of watchmaker precision and extra effort. The rear gaps will allow cold air to enter.
Rear Skirt installation and sealing - I followed the information in the Orndorff video but I do not remember the details exactly (the details are important in this part of the airplane - canopy) but I followed them very carefully and the skirt came out very well. One of the "tricks" was to block up the rear of the frame to get a little interference fit between the skirt and the fuselage skin, then trim for the final fit. I don't remember if I did most of the final trimming with clecoed skirts or pop riveted. Down on the sides at the rear corners there was a gap that may have been as much as 1/4" altough that seems a little big. I tried reforming it for a closer fit with limited success. The main thing I wanted to do was to bring it within a range that I could seal upon closure. I kept doing very fine trimming until I had a fit that no longer scuffed the fuselage skin upon closure. Then I used the soft white rubber "P" strip for a seal. I glued mine to the underside of the skirt set back from the edge enough to conceal the rubber, provide a seal and prevent abrasion of the the fuselage skin by metal to metal contact. This has worked very well in actual operation for around 160 hours.
I had been made sensitive to the draft prone nature of the sliding canopy design by Ken Scott many years ago so I really focused on making sure mine was air tight during the build. I'm going to tell you what I did in each area and you can evolve your own solutions or fly only in nice weather most of the time which is a solution also.
The center canopy rail track hole in the rear skirts - I made a loose fitting hat for the skirt hole over the rail and a plug to slide on the rail that seals the hole upon closure as I am told Tracy Saylor did (I have never seen his design). I had a lot of things to learn to evolve this system into a reliable operating closure seal. My plug is laminated balsa wood covered with fiberglass with sealing rubber in a central band around the plug. The plug is pushed back by the plastic block that guides the canopy upon opening. The Plug is pulled into the closure position by four individually tied waxed nylon wire bundle lacing tape (flat nylon string with a waxy impregnation - available from Aircraft Spruce and Specialty) and there is piece of clear plastic tubing on the pairs of strings (two from each side of the plug) to keep them from dropping into the gap where the skin is cut and bent down under the rail and wearing and breaking. Two eye hooks are made from very fine safety wire (.020"?) for tying the pull strings to the plug. These eye hooks need mechanical security so they are pushed through the plug then a "U" is formed and the wire is pulled to embed the bent back hooks into the block. I actually formed the "eyes" with needle nose pliers after the pull wires were anchored in the block. With the canopy off and inverted, and the strings tied to the plug hooks and routed through the plastic tubing,I layed the plug in the hat where I wanted it to rest at closure and tied the pull strings to the canopy plastic guide block attach bolt. The canopy is more difficult to install because I now have to get the plastic block on the rail and then get the plug on the rail before I can install the frame on the side roller plugs. Once the canopy is in place I had to add a small silicon drag bump at the rear of the rail (I put it on the last screw head) to allow the plug to pass if pushed but keep it from flying off the rail during normal opening.
Front end sealing - I glued a continuous piece of the soft white rubber "P" strip between the roll bar and the fiberglass that extends back from the windscreen over the slider. This simple seal fit and works perfectly.
Side sealing back to the end of the roller guide extrusions - There are on continuous straight line mating surfaces between the side canopy skirt and the fuselage through the full range of opening and closing travel of the canopy. I observed that the extrusion's outer curved surfaces are perfectly straight and aligned with the canopy motion throughout the full opening and closing travel. What was needed was a mating surface on the canopy. I made a rib out of 3/16" aluminum bar stock to conform the the side skirt contour (I used the fuselage contour outboard of the final position of the extrusion in making the patterns) on the outside leaving the natural straight edge of the bar stock aligned with the maximum radius of the outer each of extrusion. Using the normal techniques for aligning the ribs with the maximum outward extension of the extrusion outer radius I double flush riveted them in place on the inner surface of the canopy skirt. I then used the patterns for the ribs to cut over wide ribs out of sheet rubber for a seal. These are glued to the underside of the aluminum ribs which places them in alignment with the curved extrusion surface just a little below the maximum extension point of that extrusion curve so any attempt to force air into the canopy at this point forces the rubber tighter against the extrusion.
Sealing the area between the side roller extrusion and the upper aft Fuselage Skin - The drawings show this skirt skag hanging down over the side of the fuselage to cover this hole. I reasoned that an extension up from the fuselage behind the skirt would achieve the same thing. I cut a piece of 1/16" aluminum angle for each side that extends from the aft end of the extrusion to inside the upper aft fuselage skin on top of the longeron and riveted them to the longerons and the skin. This area is a fairly tight fit with insuficient room for a rubber seal so I coated the fuselage side of the interface to prevent sticking and applied silicon ruber RTV to the mating canopy skirt area and closed the canopy to achieve a formed fit.
The canopy is snug and the small gaps that occur between the rear skirts and the fuselage are not only not a problem some is necessary to prevent scuffing the skin/paint and assure a seal.
Bob Axsom