N247BR

Engine Cowling - Air Vents & Hinge

I live in Texas and it gets really hot here in the summers so engine cooling is a constant concern which is why I made every provision to ensure adequate engine cooling.  The first change was to make a pressure cowling for the engine.  I have detailed the pressure cowling elsewhere.  I also decided to add air vents on the side of the cowling to pull the cooling air out of the cowling.  This was also made necessary by the four into one exhaust system which will close down some of the rear opening of the cowling.  Finally, I have added a piano hinge to join the cowling sides together.
Thanks to the internet and Google, I was able to locate some light weight aluminum vents that were the perfect size for what I needed.	I located the vents on the sides low down below the cylinders.
After locating the position for both of the vents, openings were cut and the vents were clecoed into place.  Pop Rivet holes were drilled evenly spaced around the opening.  Filler was used to smooth out the edges between the glass and the vent.
The rivets were recessed leaving a relatively smooth surface but it still required substantial filler to make a smooth transition between the cowling surface and the vent.  I filled, sanded, and filled again.  The process is repeated until a smooth seamless joing is obtained.  Like every other modification to the standard there are many hours invested.
It's hard to see how well the vents and hinges ended up but the finished product looks really good.
In addition to the vents, I added a piano hinge connection to join the top and bottom of the cowling.  This also turned out to be real fun with a capital "F".  The issue with using the hinge was getting the joint between the top and bottom to fit correctly.  The joint between the cowling top and bottom is normally an overlap.  The overlap resulting in different thickness between the parts caused an issue with the hinge bonding at different levels.  I had to cut the cowling and add filler to the top to match the thickness of the bottom.  Some filling was then required on the outside using some layers of glass.  I finally got a good match.