Flexible fuel lines to wing?

[rockwoodrv9]

Originally Posted by airguy

Truth - I took a couple stabs at it and called Tom Swearingen. I don't need the aggravation.

I did the same thing Greg! I own two expensive flare tools that are almost new, and will never be used by me again!

Thanks Tom for the great lines. I need a couple more so I will be getting with you shortly.

[TS Flightlines]

Well since I too have a vested interest in this thread, with your permission I'd like to comment.

YES ---we build alot of teflon hoses. Started out with engine hoses, mainly to replace the old and heavy 303 series Aeroquip hoses. At one time, the factory was selling components for fabricating 701 hose. After seeing some pictures on this forum of some of the assemblies (how about stems BARELY screwed into the collar because it was 'too hard"), I felt that I might be able to offer some assistance to those builders that enjoyed the process, but felt that they would rather not make their own assemblies.

Builders then began to ask about brake hoses, and the possibility of replacing their aluminum tubing with teflon hoses. Certainly, was the answer. I think we all can agree that in alot of areas, rigid tubing is infact a better option than teflon, especialy where bends are concerned. You can bend a piece of 3003, or 5052O alot tighter than a comparable teflon hose. Just because we build hoses, doesnt mean that we dont use rigid tubing also. The fuel line package for the RV14 is a great example. Yeah, we could have used hose for the valve to wing lines, but after playing with it for a while we decided that YES, aluminum tubing was probably a better product for this application. Yes, a builder can make his own, thanks to some very good plans. We chose to make ours from 5052O instead of 3003, for strength and appearance.

This does bring up a point on the 'other' RV models and tubing versus teflon. I would imagine that if the plans showed a specific pattern of the tube to be bent, many builders would or could do it. Some, however, choose to accomplish the same thing a different way, by using hose.
Tom

[LettersFromFlyoverCountry]

Originally Posted by Toobuilder

Happy to help Bob.

Next time I'm up your way and have a spare 30 minutes I'll build a set of lines for you.

Cheers

That'd be awesome. The next inspection is January 17. Caution: it'll be about -10 and I work in an unheated hangar. It should be no sweat. Literally.

[Toobuilder]

My parents were born and raised in Theif River, so consequently I spent many a Christmas back there. Though it has been many years, I vividly remember that particular brand of cold. No thanks. I'll hold of until Summer and take my chances with the mosquitos.

[sglynn]

What about the dents, scratches, kinks in the rigid aluminum tubes due to less then perfect bending?

I made two ship sets of aluminum fuel lines for my RV-7A and each time saw scratches or a dang kink that I worried would be a stress concentration and potential failure point.

I think I read in the plans, "don't kink them." So I went with flexible fuel hose from valve to wing. I would have preferred the stiff aluminum but only if I could do it pristine, without any flaws.

[JonJay]

Originally Posted by sglynn

What about the dents, scratches, kinks in the rigid aluminum tubes due to less then perfect bending?

I made two ship sets of aluminum fuel lines for my RV-7A and each time saw scratches or a dang kink that I worried would be a stress concentration and potential failure point.

I think I read in the plans, "don't kink them." So I went with flexible fuel hose from valve to wing. I would have preferred the stiff aluminum but only if I could do it pristine, without any flaws.

I don't have a good answer, but I did not accept any kinks, dents, or creases on mine. I recently changed all of my hoses due to life limits to TS Flightlines Teflon (thanks again Tom).
However, I went back and replaced my main fuel line hoses from the tanks to the fuel selector with 5052 hard line. My reasoning, as dumb as this may sound, was to challenge myself. I am much better at bending tubing now than I was when I built the airplane more than ten years ago. It still took me more than one attempt. One was perfect, except as I was installing it I notice a minor crease and rejected it.
So, I now have hard lines and I am glad I went through the exercise for no other reason than I am proud of the accomplishment.

[Maxrate]

A little off topic but I see several builder logs show a return line to the tanks. Did I miss something? I built mine with only one main line out and a vent line.

[jimgreen]

Some injected systems need a return line, others don't.
Carbed engines don't.
Building my 7, I made provision for return lines but ended going with Precision Airmotive's RSA5 servo, so didn't need them.