Cowling Installation SNX-P13

The plans and the supplemental sheets in the engine installation manual are pretty comprehensive with how to install the cowling. The first step is to make an adapter plate to go on the prop hub. Rather than machine a 5/32 deep groove in the face of the adapter plate, I cheated and cut a second piece out of 5/32 plywood and glued it onto the plate. This spaces the prop opening in the cowl around the prop hub nicely. There is one picture in the plans where it looks like the cowl goes right up behind the prop hub but this is not the case. One of many emails to Kerry confirmed this. The second shot below shows the first fitting of the cowl, I have started marking the hole for the nosegear. My cowl fit okay along the top edge but was too long at the bottom corner. I had to cut a wedge shaped piece out of the side to make it fit. I cut too much off of it and had to patch it back in. I mixed up some fiberglass and laid it out, letting it set up overnight. Then the right side hinge half is drilled from the inside and clecoed into place.

After the side hinge and southco fasteners are installed the right side cowl is pretty much locked into place. The center lines are marked and cut and then the right side is removed and you install the left cowl side hinge and southco fasteners. Then the right side is reinstalled along with the left side, using the right side to mark the centerlines onto the left side cowl. I used a dremel tool with the shop vac hose held close to make all the cuts.

The cowl halves probably went on and off 30 times to tweak the fit, mark the various openings and hinge halves, etc. Not all of the length of the bottom firewall hinge attachments are used because of the cutout for the exhaust.

12/26/10: I had to move the hole for the oil cooler down, and also had to make the fiberglass tab to allow for a soutco fastener below the hub opening. I cut a piece I had removed for the exhaust cutouts and glassed it back in, then moved the opening down and added the tab. This last shot is when I was riveting the hinge halves onto the cowling halves.