Fuel lines

I am the current owner of an RV6A that was built by another. The plane flies great and I have close to 200 hours in it since purchase last April. There are a few things I want to change (imagine That), One of which is the fuel selector valve. The current one is not the smoothest and you have to position it in the off position as you change from left to right. I have also had it reposition itself in flight resulting in an engine shut off. Obviously got it repositioned and the engine started and then fixed the loose nut. At Sun N Fun I saw the Andair valves and loved the smooth action of the valve so when I saw their booth at Oshkosh I took advantage of the show special and got one. I talked to Andy (The Guy in the booth) about the retrofit and he was pretty sure it wouldn't just slip in. So was I by the way. He recommended flexible steel braided fuel lines to attach the valve to the existing lines. That makes a lot of sense to me, but I haven't seen anyone using them on this forum in fact some of the "spaghetti bowl lines" I have seen lead me to ask why wouldn't you use flexible? Is there something I am missing?

Funny, I had this very same conversation with Andair at the show.

Assuming that you used an aircraft quality hose, either would be technically acceptable. Now on the practical side, in a small area -6 flex line isn't so flexible and with end fittings will be bulky in an already tight area. I just remade my lines from the fuselage fittings to the valve using the 3003 aluminum tube as I didn't like the way the original builder had done them. Not my favorite choice of alloys, but these lines only see static pressure and the soft tubing lends to tweaking the bends for final fit much better. A tubing bender is highly recommended if not required to prevent kinking the line.

The other option would be transitioning hard lines to flex at some point adding fittings and a union to the mix, again in tight areas.

I am going with the Andair valve as a replacement and think the tubing route will be what I will do.

I doubt that you would be able to use flex lines to go from the valve to the existing hard lines. Just not enough room. At the very least, you might be able to run the flex lines away from the valve and find a convenient spot to cut and re terminate the existing hard line. By then however, you are almost as much work as making new hardlines. After all, you already have the existing lines to use as a pattern. I'd suggest using 5052, as it's less prone to tooling damage than that butter soft 3003 garbage.

You might be able to do it with a single flex line and careful choice of angled hose ends at the fuel valve end.

One thing to keep in mind, flex lines have a defined service/replacement life while the hard lines have no service life limit in this application.

Andair Fuel Valve

I was able to install the Andair fuel valve in my RV-6 with just a little bit of tweaking of the fuel lines. The valve has worked great for several years with no trouble.

Danny Parker
RV-6
N360DP

TS Flightlines - Tom Swearengen

Tom made me a set of lines for my RV 6 that started rigid, went to flex, back to rigid, and then back to flex. Allowed very narrow radius bends from valve to fuselage fuel fitting. Call him. He does absolutely excellent work.

Here is a thread about the fuel lines Tom made for my RV-7.

http://www.vansairforce.com/community/showthread.php?t=110008&highlight=tsflightlines

I am sure he can make lines that will work for your airplane.