Monday, November 17, 2014

Oil Door

You have to make the oil inspection door on the top of the cowling. The kit gives you a thin piece of fiberglass that becomes the top of the door, but you have to build the hinge and add material for strength, etc. Basically, I didn't even follow the directions for this entire part.

First, I bent a piece of 0.060" aluminum to match the compound curves in the oil door lid. This will act as the structural reinforcement of the door so the door won't bend out from the high pressure engine plenum.

Second, I epoxied the doubler to the door top.

I then started making the hinge. I wanted a hidden hinge for two reasons: it looks nicer and it provides a stop so the door skin doesn't come in contact with the cowling skin (think paint damage).

I used a hidden hinge I found on Mcmaster Carr. I cut most of the hinge part off and remade my own. Then bent legs were really the part I wanted anyway. This custom design allowed me to add a couple torsion springs; they aren't strong enough to open the door but they do keep the door propped up once it is open.

Once I got the dimensions and placement of the hinges figured out it was pretty easy.

Here you can see how the hinge itself provides the stop for the door.

The Camloc KM-610 latch heads are too shallow to protrude through the thick door so I decided to make new thicker latch heads. I drilled holes in a thick piece of aluminum to match the head of the latch and taped them in place.

I also drilled a few holes in the latch top itself so the epoxy will flow down in the holes giving a good solid connection.

I then filled the holes with epoxy.

After sanding the extra epoxy off I popped out the latches. New thicker button heads!

I made some stainless steel latch plates and riveted them in place.

When the oil door closes the latches clasp on the plates.

Here you can see a close up of the finished button heads for the latches. Now I just need a little body work around the edge of the cowling and the oil door is done!


  1. Nice design solution and workmanship! I used a similar hinge and latch arrangement. I used some carbon fiber reinforcement but the door still flexed and flexing eventually causes the latch to wear through metal catches on the cowl. After 8 years of flying and two latch failures I'm headed out right now to see how close I can get to your reinforcement design with aluminum. May need to order a new door first but going to give it a go. Thanks!

  2. ... although the compound curve on the .060 aluminum looks challenging. No magic I assume, just work it I guess.