Fuel Line - Is this safe?

[Craig23]

I have been working on some of the fuel lines for my RV-8 and had a question about the line I've got going from my fuel pump to the firewall. I was having trouble getting the proper bends in the short piece of aluminum tube that was required, so I thought about doing a loop with the tube. Then I remembered that I had a spare fuel hose Brett Bonaco made for me and tried it. It fit fine, but I wanted to put a picture of the arrangement here and ask all of you out there who have more knowledge and experience than I if it is safe or prudent to have a full loop in the fuel line there.

Here's the picture. Fire away.

[scard]

My comments: That is a little bit of stress at the straight fitting. Also this bend radius looks like it is pretty close to minimum. There is a spec for minimum bend radius for this hose, what is it? That big loop up there will have a tendency to take vibration/rotational loads unlike a shorter fixed pipe. Either secure the top of the loop, or "be at peace" with it. Also, is the hose loop touching the firewall? I'm guessing not, but if it is, that would be a no-go for me.

[craigvince]

Why not just send the hose back to Brett @ Bonaco and have him make it the exact length you need? I can't imagine it would co$t you much.....

[ThisOne]

Originally Posted by Craig23

I have been working on some of the fuel lines for my RV-8 and had a question about the line I've got going from my fuel pump to the firewall. I was having trouble getting the proper bends in the short piece of aluminum tube that was required, so I thought about doing a loop with the tube. Then I remembered that I had a spare fuel hose Brett Bonaco made for me and tried it. It fit fine, but I wanted to put a picture of the arrangement here and ask all of you out there who have more knowledge and experience than I if it is safe or prudent to have a full loop in the fuel line there.

Here's the picture. Fire away.

Craig S.,

In a word...NO.
Tell you what....seeing as how I will be working Sunday I will give you a call in the AM and we can then take it from there. Also....can you please send me some pictures (from the top down), and make sure you have the distance from the nose of each fitting (this will help when we talk on the phone).

[Norman CYYJ]

This looks like a good place for vapor lock or air. Don't do it. Make a piece up the right length.

[Craig23]

Thanks for the answers. Having a loop there didn't look quite right, but I wanted other eyes to verify it for me. I've only got about 3.5 inches between the firewall fitting and the forward end of the pump, with an offset of about 2 inches. How have you guys been able to get the right bends in such a short piece of aluminum tubing and still put the fittings on and flare each end?

[lightning]

i don't know what # line the fuel is... but about 2 hours ago i was dealing with the same problem... only my problem was O2 lines, they are #5 line. anyway, what i did was take a piece of line longer than i needed, made the appropriate bends, as per my notes and measurements, then cut the excess line off, (O2 doesn't flare we put sleeves and B-nuts.. although flaring would be much easier and leak less )... it worked for making the whole piece the right shape and still fit the system....

it waste's a bit of hardline but the results were right..

good luck

[allbee]

Seems to me you should have some scap aluminum line and than get a couple fittings and make a straight shot to that point.

[Larco]

Why not just move the pump or fitting to align the two? Larry

[N941WR]

Originally Posted by allbee

Seems to me you should have some scap aluminum line and than get a couple fittings and make a straight shot to that point.

Once you make that short pipe, you and loosen up the bulkhead fitting, slip it into place and tighten the bulkhead fitting back up.