Fitting the fiberglass cowling was not as hard as I was dreading.  It did take a lot of time, and installing and removing the bottom cowling by myself wasn’t fun.  But with a little patience, I ended up with a pretty good fit.

Top Cowling

I started by making the marks aft of the firewall, just like the directions say.  I also made a mark for the center of the top of the fuselage.

After I had the spinner backing plate temporarily installed, I clamped the front of the top cowl into place.  I used spacers between the backing plate and the front of the cowl, and c-clamps to hold it in position. 

I then marked the middle of the aft end so I could align it with the center of the fuselage.  And transferred the marks for the firewall.

Instead of removing and having to re-clamp the top cowling, I used a 2x4 block to raise the aft end up off the fuselage.  This allowed me to trim and sand with the cowl still in place.

I made the initial cut, then removed the 2x4 to check the fit, marked where I needed to sand, inserted the 2x4, and sanded.  I repeated this process until I had a good fit between the top cowling and the fuselage.

Then I drilled and clecoed the top cowling to the firewall hinge. 

I temporarily held the lower cowl up to see how much overlap I had for the seam between the top and bottom cowlings.  My fiberglass cowling was flush at the front, but overlapped by about two inches at the firewall.  So I knew I had some room to trim either the top or bottom cowl to get the line looking the way I wanted.  The bottom of the top cowling was aligned horizontally with the main axes in the in-flight position.  So all I needed to do was clean it up.  I used a thin aluminum strip with a straight edge to mark the bottom.  Then sanded it until I had a straight line.

Bottom Cowling

With the top cowling installed, I placed the bottom cowl into position as best I could.  Because the sides overlapped with the top, I couldn’t make it perfectly to start.  I aligned the front and held it in place with duct tape.  I then wrapped a strap around the aft end to pull it up into position.  I had one side out of the top cowl, and the other inside the top cowl. 

I started trimming on the bottom side of the cowling.  I trimmed only enough to go around the curves of the firewall.  Again I trimmed a little, fit it, sanded, and refitted.  It was a pain removing and installing the cowling every time, but it was the only way to get a good fit.

After the bottom was pulled up into position, I marked and cut the sides and back 1/8” larger than I thought I would need.  Then I reinstalled the fiberglass cowling and checked the fit.

I realized the front of the lower cowling was a little too far forward, so I trimmed a little off the back edge.  Then I noticed the bottom wasn’t fitting flush (up and down) with the belly of the fuselage, so I trimmed a little off the tops.  I went on in this fashion until I was happy with the fit all the way around.

I finally drilled the rest of the hinges onto the firewall and the hinges to connect the top and bottom halves.

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