Since the fuel tanks in my Bede BD-4C airplane are in the wings, I very much want to get it safely and securely from the wings to the engine. The plans call for running “hard line” through fully enclosed channels in the corners of the fuselage. Fabricating and installing the hard line is difficult, no two ways about it. The rigid aluminum tube lasts darned near forever, though, and having it surrounded by the square channel provides added mechanical protection. I like the notion that the gas will stay where I want it to stay and not go randomly flowing around parts of the airplane where it doesn’t belong.
I was pretty intimidated by the notion of bending hard line. I had read and heard horror stories about what a PITA it is. YouTube and Google turned out to be reliable resources and I found good instructions. Ultimately, it turned out to be pretty easy. I started with about six feet of 3/8″ straight tube and bent it four times. Here is what it looked like before it went into the plane. (Click on the photo if you want to see me the tube in more detail.)
This photo shows where the line runs. I have removed the square channel so that I can fit the line.
Test fitting the line to the fuselage confirmed that I had the bends in the right places. Then I drilled holes in the channel and installed the hard line in the channel. Here are a couple of pictures taken part way through the process.
Once I had run the line through the channel, I clamped it in place with a padded Adel-style clamp. Then came the tricky part: re-installing the square channel in the fuselage. This channel is a major component supporting the spar (the large tube at the top of this photo). I ended up using a scissors jack to lift the spar back into position so that I could bolt the channel in place! Here is the happy result: one fuel line installed.
With the taking of that photo, ten days after I initially bent the tubing, I was half way done. I needed only repeat the job on the left side of the fuselage. I had learned a lot on the first hard line so the second one went much faster: only seven hours spread over two days. This is one job that I am very glad to have completed!
Glad to see your success with the solid lines, Art. My plans call for rubber lines. It doesn’t take much imagination to realize they would be a major inspection and maintenance nightmare. In fact, they would almost certainly be due to be replaced by the time I got my 640 finished. I was a little intimidated by the idea of trying to use solid lines and thought I might go with teflon hoses instead, which are significantly more expensive. You’ve convinced me to give solid lines a shot, especially since I’ll have nearly a straight run to a bulkhead fitting at the wing root. Thanks.
Good luck with the hard lines for your Zenith. I still have a couple of more bends to make, when I install the fuel selector. But it went so well the first time that I would not hesitate to do hard lines again.