Tuesday, March 17, 2015

38-06 Upper Cowl fitted

Lots of work, but it was worth it.  It took about 6 hours of work just to do this page today.  (I’m writing this at 2:30 AM, so it’s still “today” for me.)

The upper cowl has 4 edges with hinges.  The upper ones went on first and weren’t too bad to install / remove when they were clecoed together.  After I riveted, I couldn’t get the pin to advance no matter how many times I fiddled and tried to get it slide.  I finally realized that I had inadvertently crimped 2 of the eyelets (during riveting) such that the eyelets were no longer round.  Damn!  It took some serious thinking to figure out a repair.  I didn’t want to drill out and replace the entire hinge as the likely hood that I would not damage the cowl was somewhat better than winning the lottery.  I couldn’t get a drill bit in there because of the close set spacing (1/2” gap) between the eyelets.  I finally came up with taking some of the hinge material (guaranteed to be the correct diameter), bending a ~5/8” 90° “tooth” to slide into an eyelet and then grinding the tooth to be flat on one edge (of the 5/8” length).  That left two sharp edges on what had been a round pin.  The sharp edges were enough for me to shave the inside of the eyelet back to being round and permitting the regular pin to pass.  Viola!  Much better than trying to remove a section of hinge and replace.


Below, you can see the installed upper and lower cowl.  I’m not happy with the gap forward of the hinge pin, but there’s not much I can do with it.  I might learn some tricks with epoxy & fiberglass in the future.  For now, it won’t prevent me from being airworthy so I’ good with it.

IMG 4123


IMG 4122

Cowls, installed 

IMG 4124

Cowls, installed (front view)

When I return to the project, I’ll install the nut plates on the front, sides and bottom and tackle making the oil door.  Those should be fairly straight forward.  Then, back to the cooling system where the cooling duct goes inside the lower cowl.  That will require my first venture with ‘wet’ fiberglass (e.g., laying down fiberglass) vs. just trimming & sanding dry pieces made by somebody else.

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