April 6, 2008 - Top Cowl Fitting

Today I turned my attention to the top cowl.  First order of business was to cut out an opening for the oil filler access door.  I marked with a Sharpie where to cut per the drawings.  I triple-checked my measurements because I did not want to make a mistake.  I don't know how much a replacement cowl would cost and I don't want to know. 
 
I made the cutout using the Dremel with the heavy duty cutting wheel. 
 
And sanded the edges smooth.
 
I placed the top cown on the airplane for the first time.  The next step is to trim the aft edge so it butts up against the fuselage top forward skin.
 
The desired gap between the spinner bulkhead and the top cowl is 1/4".  Plus the top of the cowl should be a little lower then the top of the spinner bulkhead because the engine will "sag"  a little in the future.  I duct-taped a wood block on top of the prop shaft to keep the cowl in the proper vertical position.
 
I had marked a 2" reference line from the forward edge of the top forward skin.  Now I used this line as a reference to mark where the top cowl needed to be cut so it would butt up agains the skin. 
 
Now cut along the red line with the Dremel tool. 
 
Then sand it smooth.
 
I taped little 1/4" wooden blocks to the spinner bulkhead to keep the top cowl at the proper spacing. 
 
I clecoed the backing strips to the firewall flange so that the cowl would have something to rest on.  I'm going with the MilSpec camlocs, not the stock hinges.  I had made the backing strips a couple of months ago so they were ready to go. 
 
After at least five iterations of fitting and marking the top cowl, removing the top cowl, trimming and sanding the top cowl, reinstalling the top cowl, it finally fit nicely. 
 
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