re-contouring the oil door?

[claycookiemonster]

We did a really nice job of locating and cutting out the opening for the oil door on my Showplanes RV-8 cowl. The extra piece of fiberglass fit the opening perfectly, right up to the point we actually installed it and put the spring on the hinge. Now it's not perfect anymore. I think small stresses around the hinge and latches have caused the smooth exterior to be pulled out of alignment. Question Time:
1. I may be able to adjust the hinge to alter where the fiberglass portion rests against the frame. It feels like opening a can of worms to play 3D chess with that.
2. I can certainly add a layer of glass and flox on the inside of the door to thicken it, and then simply sand away the parts that lay a bit proud of the mating surface.

Are there any other options?

 

[wirejock]

Door

I used the cutout but modified.
The door and hole were drilled for clekos before anything was cut. After cutting out the hole, I bonded the hole to the door using the cleko holes. When closed, the hole centers the door and makes it really stiff. Holds the original shape.
Since you're past that, I would add flox and glass and just sand to shape.

 

[Webb]

Here is a possible alternative. I used the fiberglass door as the frame for a 0.063 aluminum door. After glassing it in place and sanding it smooth, i was very pleased with the result.

I didn’t like the fiberglass door so this was my solution.

 

[Stevea]

fiberglass oil door

...The extra piece of fiberglass fit the opening perfectly, right up to the point we actually installed it and put the spring on the hinge.

Yep. Been there, done that.

Adding only a couple of layers of fiberglass on the inside will help.....but only a tiny bit. You really need to add a thin foam (or balsa wood) core on the inside surface, and then glass a couple of layers over the top of the foam. Make sure you can clamp it to the cowl to hold it to the desired shape while curing. This will add a lot of stiffness to the door, and it will not bulge out because of the spring hinge, or the air pressure differential in flight.

Here are photos of mine.

 

[agent4573]

I added a bit of thickness and then sanded the outside smooth. You don't need a super stiff door, you just need to sand it while it's under load from the spring and held closed by your latches.

 

[Desert Rat]

If the issue is that isn't stiff enough theres a bunch of ways to make it more rigid.

I'm going to be working on this in a couple of weeks and my plan is to sandwich in a few coffee stir sticks with just a single extra ply on the inside. that should make it rigid like apiece of corrugated cardboard with almost no extra weight.

disclaimer- this obviously won't work if it needs stiffness in two directions, or if they get in the way of whatever latch solution I come up with.

 

[Scott Hersha]

I was able to make my thin fiberglass oil door lay down firmly with two fluted ribs riveted and glued to the door. I think I used .025, bent with 1” sides, and it takes about five minutes to get a good fit with your fluting pliers. I’ve done this on my last two builds.
Might have to zoom in to see the fluted ribs.

 

[EdH]

I was able to make my thin fiberglass oil door lay down firmly with two fluted ribs riveted and glued to the door. I think I used .025, bent with 1” sides, and it takes about five minutes to get a good fit with your fluting pliers. I’ve done this on my last two builds.
Might have to zoom in to see the fluted ribs.

View attachment 43945

View attachment 43946

Scott, that is a beautifully finished -6! Got any photos of the interior?

 

[wirejock]

Oil door

Here's a photo of the inside. The section bonded to the door is the hole cut out of the cowl so it holds the door to the correct shape.
Second photo is a shameless finished photo.

 

[toolmanmike]

Spring oil door latch

Larry,
Where did you get the hardware for your oil door? I like the Cessna type latch and spring hinge. I know I’ve seen them somewhere.

 

[johnbright]

I was able to make my thin fiberglass oil door lay down firmly with two fluted ribs riveted and glued to the door. I think I used .025, bent with 1” sides, and it takes about five minutes to get a good fit with your fluting pliers. I’ve done this on my last two builds.
Might have to zoom in to see the fluted ribs.

View attachment 43945

View attachment 43946

Great minds think alike except I riveted the 0.025 fluted ribs to the door with soft rivets.
.

 

[vlittle]

I was able to make my thin fiberglass oil door lay down firmly with two fluted ribs riveted and glued to the door. I think I used .025, bent with 1” sides, and it takes about five minutes to get a good fit with your fluting pliers. I’ve done this on my last two builds.
Might have to zoom in to see the fluted ribs.

View attachment 43945

View attachment 43946

Here's a photo from my RV-9A archives, circa 2006. Adjusting the flutes changes the shape of the oil door for a perfect fit.

 

[Scott Hersha]

Did the same thing on my latest RV6 build. I used the RV14 hinge setup.