I’ll try and not include too much detail here. First you must clean the inside of the cowl very good. It has some sort of compound on it. I used lacquer thinner & a toothbrush. Otherwise the epoxy won’t stick! Next make a cowl ring. I made mine by sandwiching two pieces of 1/8” plywood. It should be about ¾”-1” in width all the way around when finished. Next, mount it to F1 (I used (4) 6/32 bolts & blind nuts from the inside of the cowl) and trace around the fuse. Remove & cut the access off. Now is the time to decide how much you need to trim off the rear of the cowl. Make it a rough cut leaving 1/8” extra to trim later. Next remount the cowl ring onto F1 but put some scrap 1/8” ply between the ring and F1 to act as a standoff. Now center the cowl and epoxy it to the top portion of the ring. Now you can epoxy all the way around the sides leaving the bottom free for now. This could take many epoxy sessions.

Because the cowl is designed as a slip-over, its perimeter is larger than the perimeter at F1. Therefore you will have to cut a pie shaped wedge out of the bottom of the cowl for it to match F1. Once this is down you can epoxy the bottom to the ring. Remove from fuse. Next, using some strips of fiberglass cloth, epoxy them in the corner where the ring is glued to the cowl (on the inside) to reinforce the ring to the cowl. Once that has cure you can sand the rear of the cowl flush with the ring. Now you have a flush cowl!

Next is to split it. I epoxied a strip of 1/32” (1/16” is good too) plywood ¾” wide from the cowl ring to the front of the cowl on each side (on the inside of course). Next cut the cowl in two cutting down the center of that ¾” piece of ply. I used a hand saw. A dremel would work fine, just be sure no to remove too much material. Once it is in two halves, glue a second piece of 1/32” ply ¾” wide on directly over the piece on the bottom half. Now you have a lip for the top half to bolt to. I used 7 #2 sheet metal screws per side to mount the two halves together. I also put 2 screws on the lower half at the leading edge to eliminate the ply strips from breaking free due to all the high vibration/buffeting that occurs at the leading edge of the cowl. Not a single problem after 160+ flights.

Doing this is a bit of work but well worth the effort. It makes for a clean looking model because of the flush cowl. It also makes life easy for putting the cowl on when using any twin engine. The split cowl also offers better options of cutting out for mufflers, carb intakes etc. because the cowl does not have to be slid over the engine to be installed.

Hope this helps.