Friday, October 3, 2014

Oil Door

I decided to do a single post on my oil door installation.  There are several days worth of pictures here but this should show the process.
First step was to cut a hole in the cowling for the door.  If you look at the picture above you can see both a white circle and an area of the cowling where the surface looks different.  That different surface area is where Will did not put in the honeycomb support structure when he molded the cowling.  It allows me to cut a hole and not have a bunch of honeycomb pockets to fill.  So, using that white circle I measured a 5" x 5" opening and then proceeded to cut it out with my dremel cutting wheel.  For the door Will was nice enough to include a separate piece of molded fiberglass that was about a foot square and was molded to match the contours of the cowling in this area.  This picture was actually taken after I had cut the hole and door and added the flange underneath.

Next up we lay up the "flange" that the door will sit on on the under side of the cowling.  I used 3 layers of glass and overlapped the edge of the hole by about 3/4" of an inch.  Eventually, after the layup had hardened, I went in with my Dremel sanding drum and trimmed that back to a quarter of an inch.

After trimming this is what the opening in the cowling looks like.  The door is sitting to the right of the opening.  I did come back and add a very thin layer of micro slurry to the lip to smooth it out.  I have to be careful not to build it up to the point where the door will sit proud of the cowling once its painted.

Next I added a layer of 9oz carbon fiber fabric to the back of the door to stiffen it up a bit more.  I have read accounts of the door popping open in flight due to the door flexing under the pressure of the air inside the cowling.  This single layer of carbon fiber really stiffened up the door.

Next I used some flox and the door hinge to create a level "pad" for the hinge to mount to on the under side of the cowling.  I used clear packing tape all over the hinge to make sure the epoxy mix did not attach itself to my hinge.

Hinge is drilled and cleco'd to the door and the cowling.  The latch is drilled and cleco'd to the door and if you look close you can see a small notch where I will be installing a small steel striker plate for the latch.

Another view of the door all cleco'd together

And the under side of the door with the steel striker latch cleco'd on and the door closed.  Now I have to wait until I paint the inside of the cowling before I rivet this all together.