Oil Door Hinge Eating Me

Could someone please give me a boost.
The hidden hinge for the oil door is killing me.
First should it have that big of an offset in the two
mounting areas? If I try to mount it flush on the cowl side,
it does not match the door and it sits way above the hold.
Do I need to build up the cowl side to take up the distance
of the offset somehow. I tried a spaces and the door binds
as soon as you try to open.
I must be missing something real simple here.
I don't have an ego, any help appreciated.



Thanks in advance

You could just put a little more bend in the curve so the hinge will lay flush.

I put the "short" side (L in your pic) on the cowl side (i.e. not door) and built up the gap underneath it with flox. Turned out fine.

It is going to take some glass build up on one side or the other, or both, to get a thick enough flat surface to hold countersunk rivets. Build up the door to what it needs, then do the cowl side to make it fit.

Second, the gap between the door and the cowl above the hinge line will have to be a bit larger than normal. Because of the hinge geometry, that edge of the door moves toward the cowl edge as the door swings open. The door needs to clear the cowl vertically before it moves far enough horizontally to catch the cowl edge.

I had to tweak the bend in the part where the hinge assembly meets the door in order to get the door line up with the cowling.

One other thing to consider. The spring on the hinge may make the door bow out when closed. The door, as received, is fairly thin and flexible. I ended up bonding a thin foam core section covered with a layer of glass to the inside of the door to stiffen it. Worked great.

Then, there's all the filling and sanding on the outside of the cowl to get the door to blend in well........but you already knew that right?

the offset is right

the oil door is thin material, and the place where the hinge mounts on the cowl is the laminated thick section. if anything is off on distances, just bend the angle on the door end a little to match up when closed.

It all works out

Too bad you didn't post this earlier, I was just in your neck of the woods to attend my niece's wedding at the Houmas House Plantation. I could have used an excuse to get away from the chaos for awhile.

I don't have a RV-9, but I can tell you what I did on my RV-10. My oil door was a flimsy piece of fiberglass from Van's. After getting everything to fit, I reinforced the bottom with foam, fiberglass, and some micro. It's pretty stiff, but does seem to bow up about 1/16" when airborne. I've seen several other RV-10s do the same.

I had a hinge from Nonstopaviation. I mounted the hinge to the cowl first, then adjusted everything to fit the door properly. This also helped me located to holes for the rivets on the door. Once the door was riveted, I covered the door with packing tape, then fill in the cowl with micro. The cowl door open as it came from Van's was terrible. It was square or well defined. It took quite a bit of work to make it look acceptable. I also put two latches forward and aft, which seemed to keep the door well secured better against the wind stream.

If that offset is more than 1/8", you are going to have to build up one of the surfaces. The other option is to drill the rivets out and use another hinge and move the piece that attaches to the door higher up on the hinge.



This is the best view of the door after paint that I could quickly find.

I added a strip of aluminum under the hinge to get better alignment. I bent the end of the aluminum strip up and drilled a hole so that I could safety wire the hinge pin in place.

Bruce, elegant setup.