azrv6
Well Known Member
In a previous post (http://www.vansairforce.com/community/showthread.php?t=91946) I showed a way to make some compound curve fairings from aluminum. Today I was looking at the gas tank quick drain and thought I'd give that area a go. Here is what it looks like:
I'm a little constrained by the shape of the cutout in the bottom of the gas tank skin, so I needed a fairing that would deal with that.
Made a pattern and using a chisel and a gouge I dug out the desired shape in a piece of 3/4" thick MDF. Depth of the hole, at the deepest point, is 5/8". Took about 30 minutes to shape the cutout including finishing off with some sandpaper. One nice thing about this approach is that you can customize the shape and size of the fairing to meet your specific need.
I used a piece of 0.040" thick 3003H14 aluminum. I annealed the area in the center where the most shape must be hammered in, but I really don't think this was necessary. In the picture, the piece is held in place over the cutout with 4 screws. I found out I needed more screws and ended up adding one on each side in the center to help hold the piece in place during shaping.
About two minutes of hammering and the shape is almost completely in. The small end of the nylon hammer was a little too big to get down into the tighter radius areas so I polished up the end of a small ball peen hammer (using a scotch brite pad in the right angle grinder) and used that instead.
Piece removed and ready for some planishing.
Planished, polished up with the scotch brite pad, flange trimmed and center hole drilled out with a unibit.
I'm happy with the end result.
Just to be honest it doesn't always work out on the first try!! These pieces were 6060-0 aluminum which was just too soft. Also, as you can see, the material was not thick enough to endure that amount of stretching resulting in a material thickness of "Oh-two-thin".
I'm a little constrained by the shape of the cutout in the bottom of the gas tank skin, so I needed a fairing that would deal with that.
Made a pattern and using a chisel and a gouge I dug out the desired shape in a piece of 3/4" thick MDF. Depth of the hole, at the deepest point, is 5/8". Took about 30 minutes to shape the cutout including finishing off with some sandpaper. One nice thing about this approach is that you can customize the shape and size of the fairing to meet your specific need.
I used a piece of 0.040" thick 3003H14 aluminum. I annealed the area in the center where the most shape must be hammered in, but I really don't think this was necessary. In the picture, the piece is held in place over the cutout with 4 screws. I found out I needed more screws and ended up adding one on each side in the center to help hold the piece in place during shaping.
About two minutes of hammering and the shape is almost completely in. The small end of the nylon hammer was a little too big to get down into the tighter radius areas so I polished up the end of a small ball peen hammer (using a scotch brite pad in the right angle grinder) and used that instead.
Piece removed and ready for some planishing.
Planished, polished up with the scotch brite pad, flange trimmed and center hole drilled out with a unibit.
I'm happy with the end result.
Just to be honest it doesn't always work out on the first try!! These pieces were 6060-0 aluminum which was just too soft. Also, as you can see, the material was not thick enough to endure that amount of stretching resulting in a material thickness of "Oh-two-thin".
