Cowling Sanding – The Saga Continues

Yesterday afternoon was spent sanding and tweaking the lower cowling half. Was able to finish off sanding both sides and then test fitted the upper cowling to see how the parts mate. During the test fitting discovered a little more material needed to be removed in the area where the side of the cowling transitions to the joggle … plus the edges of the jogle needed a little cleanup as well. As mentioned in a previous post, even using 80 grit sandpaper, it takes a lot of sanding to work the 1/8" excess (Van’s suggests leaving) down to the trim line.

The joggle on the left side of the lower cowling after trimming and cleanup. Note what looks like a light area in the round port … that is a tall ridge of resin that needs to be sanded down.

Sanding the 1/8" excess material Van’s suggests leaving down to the trim line takes a fair amount of elbow grease. The long edge my left hand is on is finished … and the edge of the cowling that will go over the firewall shelf is almost done. Then it is on to the other side.


As with the upper cowling, the sanding is not being done to the aft edges of the lower cowling until the overall fit has been checked first with the back plate for the spinner in place. I was running out of good light so did not mark and cut the oval opening in the lower cowl half. The trim line in this area is barely visible and only if holding the part at the correct angle to the light. It appears roughly a 1/4" or so of material needs to be removed all the way around, so that will be the starting point for the next work session.