Blue fuel line. Why? Why the love affair with this garbage in the ultralight community? Change it every year? Why not use something reliable? Alum tubing? Auto fuel line? Think I've read it might shed particles from the inner surface? Similar is used in certified AC right? Without problems? In all my 20 year old vehicles I've never had a bad fuel hose or filter plugged with any containment. Just lucky? But I think the odds would be in my favor with auto fuel hose vs blue fuel line. Why do we try to build to AC standards and use AN harware,etc only to use a fuel line that will fail in a year or two?

Hi. I use what your talking about, aluminum line as long as I can with small pieces of Baricade line from Leading Edge which you can get at the auto parts store, that goes to the tank, filters and carbs. I've used blue, yellow, and clear and clear lasted the longest, I could go 2 years with it and when I went to the aluminum and rubber line never have to worry about it any more. I do use the little tool that puts the bead at the end of the aluminum tube to help hold the rubber line on. How often do you change the line on your car? I just make sure its soft and no cracks in it and check the clamps now and then. Now all my flying buddies are going the same route.

I do use the little tool that puts the bulb at the end of the aluminum tube to help hold the rubber line on

   I'd be curious to see this tool. Do you have a pic or link?  I've seen a tool that will put a bead on a tube but I dont think it was available in ~1/4 or 3/8" tube size. Or maybe it was super expensive? Been a while since I was looking for one.

Edit
  This one?  https://www.aircraftspruce.com/catalog/topages/ezbeader.php?clickkey=102006
Looks like 3/8 OD tube may be just what I need.  Pricey, but not "super expensive"

Look at pegasusautoracing.com they have them for 5/16 for $24

I did mine with 3/8 Ali tube but I did use some Polyurethane flex hose (Blue ) for the connection to the tanks.

Cheers, Mick

Loose the blue junk Mick, friends dont let friends fly blue fuel line. Wait....is this THE Mick Dundee?

Tnx for the Link Bill

Blue line sucks!  A friend ended up with 15 gals of gas in the cockpit of his Kitfox due to Blue line failure....lucky still on the ground.

If you want to use a flexible fuel line that lasts for many years then the thick wall pulse line is great.

https://www.aircraftspruce.com/pages/ap/fuel_line/heavypulseline.php

What's the weight difference per foot (Not to mention the low weight of plastic Tee's with worm clamps vs. REAL aluminum AN 37° fittings like shown in the photo above?
  With all the talk of guys worrying about being LEGAL Part 103 (OR ELSE!) and pulling staples out of their builds and all other manner of weight saving tricks, (Not that it's a bad thing to lighten the load), BUT I have always been of the mind set of to Hell with 254 pounds if it means building with products (Just like you are talking about, Blue Fuel Line), that seem to (increase risk). I'd rather stand or (be heard) in a hearing arguing about how I was in VIOLATION only in the name of SAFETY!

What I am suggesting is maybe THAT'S why the use of the crap blue line for so many for so long. God forbid you build your HiMax (or any Max) to such a quality level as to be/look like a REAL aircraft & still be able to fly under the (freedom) of Part 103 with regard to registration, inspection & maintenance & licensing.
NOT looking to argue with anyone about MY views here! Just stating them.                  TTT  

PS: Nice looking work there Mickvds
PS: I think you can get those (flare ) tools to put the "bump" on the line at Harbor Freight for cheap. No link, Just seem to remember. Think it's called a "Bubble Flare" & is the first step to making a "Double Flare" for Brake line applications.

That is a great looking fuel system you have there. May like to suggest that you use a gromet at the point where the line comes into the cabin through the wing root. It would be difficult to enlarge the hole in the wood at this point but a sharp #11 blade and careful work could get you there. Cut thru one side of the gromet and put it on the line the work into the hole with the cut siide up. Really nice work that you have done with the adel clamps. Best wishes  

maybe THAT'S why the use of the crap blue line for so many for so long

                   My guess?  Its an "ultralight thing", "what everyone has been using forever", "tradition".
AND I FELL INTO THE TRAP/mindset !  Fortunately for me the project is still in the project phase, wasn't flying when it failed, was working on the fuel drain/gascolator and  the fuel line crumbled in my hand.
   37 degree AN flared fittings? I'm thinking 45 degree brass fittings from the auto parts store or hardware store will be just fine unless one of you can educate me that its a bad idea.

I also use all brass fittings, a plastic 90 or tee would be easier to fail, the plastic gets brittle with age, the brass won't. I run a redundant electric fuel pump so I have a lot of fittings in the system.

37° is the flare angle that is used for aviation applications vs. 45 degrees for automotive. (SAE vs. AN).
I wouldn't say from a safety point of view it really makes any difference if it's flared 45 or 37 degrees.
Like so many things aviation related, there are higher standards for quality control & material
specifications for anything that's called out as "AN" (Army Navy) . But when you are walking the fence
between Building Part 103 Air Vehicles & (trying) to use only REAL airplane parts & building practices
where it REALLY matters, I don't think these different flare angles come into play. As long as YOU KNOW what it is.
You wouldn't want an aircraft being serviced by a certified A&P mixing & matching up these two very similar looking parts.
That would be a disaster!
Here are a couple of quotes from a Kit Plane Magazine article...

" The tube is prepared for joining by slipping on an AN818 nut and an AN819 sleeve and then flaring the end using
an aviation flaring tool. Please note that automotive flaring tools are set for a different angle and are not acceptable
for aviation use".


" Do not be tempted to buy a less expensive automotive double flaring tool. It produces a 45-degree
flare and not the recommended 37-degree flare used for aviation".

BUT that's for "AIRCRAFT" not "AIR VEHICLES" !!   So in the ultralight world you are free to use the easily available
at the local auto parts store 45° fittings & the cost is probably 1/100th of true AN 37° fittings & flare tools!

But if any REAL A&P or knowledgeable piglets (um pilots) ever get a look at those 45° fittings on your fuel line connections....

                 THEY'RE ALL GONNA LAUGH AT YOU                      TTT

aeronut, I just have to ask.... Where is the line coming in through the wing root that needs a grommet?
I keep looking at the photos & I only see a stop valve with a short stub sticking out towards the rear.
Or are you (suggesting) that when he gets around to adding some type of flexible line from that stub
to the tank he should use a grommet? Which from what I am seeing of attention to detail & build quality
I have ever confidence he would most certainly be doing. If not that, I just can't figure what you are suggesting.
Just curious....                                           TTT  

In picture one and two it appears to me that just before the shut off valves that the fuel line enters the cabin through the plywood of the wing root. I could be seeing it wrong.

Hmmmm, Ya know, Ya could be right. I was seeing it as a stub out with a bubble flare on the end waiting to connect some
flexible fuel hose to. I guess it could just as easily be a sharp 90 heading through into the root. 400% zoom in &
I still can't tell     Can't imagine if it were to be a 90 in that he would have missed putting some sort of protection
(grommet) there but only Mick can answer that one I guess.
What's the deal there Mick?

Looks like a hose fitting to me.
Micks rolling on the floor laughing, seeing how long we will go back-and-forth pondering this.

Gday everyone, sorry for the delay in response. Work and life have gotten in the way of most things these last couple of months.

Flydog

Is this the Blue hose you are talking about?(see photo attached)
As far as I'm aware it is suitable for fuel line. I only use 2 short lengths from my shut off valves to the tank connection. I'd be interested to hear the short comings of this stuff.

aeronut/ TTT/ Flydog

The pictures were taken before I fitted the flexible fuel line. What you see is a 1/4" NPT to 1/4" hose barb, brass fitting, which is screwed into my shut off valves. From that fitting I have about a foot and a half of flexible line running to the tank fitting. My wing roots are open to the cabin so the hose just runs in through the opening.

As well as answering some questions here I also managed to get up in my HiMax today which was very nice.

Cheers, Mick

I used to use it. It's ok, but will start rotting after a while. It is recommended to be changed every couple years.

Keeep it on your preflight and post flight check list and replace it every couple of years as Puff suggested. I hope that you get more time to enjoy some more flight time in your creation.Best wishes

https://www.lonesomebuzzards.com/cgi-bin/forum/Blah.pl?m-1638747519/
This hose about two years old. Visually looked OK. Crumbled in my hands while working near the gascolator. Parked in a garage so minimal UV exposure.
Ask yourself what is the Risk vs. benefit?

Yeah fair enough flydog, that is pretty ordinary. I'll look have a look at the flex pulse line mentioned earlier on in the thread.

aeronut, I managed just over 1 hr today in beautiful smooth air this morning but I had a good look at the fuel line before take off. It was still nice and pliable and looked ok
but I will start looking for an alternative.

Cheers, Mick

My suggestion would be any good quality automotive (black rubber compound) type fuel line of the necessary internal diameter
to fit your barbs size. While you cannot (see) the fuel flowing through it, (And that really should not be a necessity), you can
likely be assured of a much longer service life with confidence it will not just brittle up & fall apart from a few years of use or
exposure to elements. There were long ago stories told of the inside of some auto grade fuel line degrading to a point where
small pieces of black particles were flaking off & clogging up a fuel filter. (or something along those lines). That may have been
around the time (they) started adding the ethanol to fuel & the rubber compounds just couldn't handle it. Same issues that are
had by old rubber o-rings & all the other issues you probably know about caused with the introduction of ethanol to our fuel.
But most fuel (handling products) these days are manufactured to tolerate or resist the known additive to the fuel (ethanol).
So there really should not be any big search to find an alternative , flexible type fuel line. That's your better choice between the "blue stuff"
or something else. Next is going with solid fuel lines but that's gonna be an extra hassle to bend/form & make proper flared connections.
Plus only "Real Airplanes" bother to use that!   LOL.  And if your going to go that route, Remember you must flare 37° for aircraft, NOT
45°. That's strictly automotive flare angle. God forbid you use the less expensive , automotive 45° flare tool & fittings.
Remember post #11 above (They're all gonna laugh at you).  

You can go one step further and go with the more expensive auto high pressure rubber line made for fuel injection. About $5 a foot, it has a extra layer of hard rubber on the inside. It will be there till the cows come home. How often do you change the fuel line on your cars or trucks?

Agree Bill, For the short length that is involved you probably should use the best quality hose.
I just had to go back & look up some info because of my comments about flaring 37 vs 45 degree (automotive vs. aviation).
I had read some info. & quoted it from Kit Plane Magazine where the author advised not to use the automotive grade tubing
flare tool because it flared 45 degrees vs. the "recommended" 37 degree for aviation systems.
Then I was just reading some info. I have about "SAE J514" (That's Society of Automotive Engineers), which relates to flare specifications for
HYDRAULIC systems/connections. And for those we are back to a 37 degree specification for the flare.
So I have to wonder the reasons for the different flare angles? Are we back to just what the standard convention has been for X # years
and so we continue on with it. Or is there an actual mechanical/physical reason? I have a hard time imagining how one over the other
could yield a more robust connection. I get that a hydraulic system line/connection is going to be under extremely higher pressures than a fuel
line system/connection.
Anyway, just had to go back & see that what I was posting was correct. Well what Kit Planes Magazine was saying was correct.
I understand the need for having "standards" in various systems/industries. I just happened to be reading that SAE J514 flare specification of
37 degrees & it's relation to AUTOMOTIVE by it's very designation of "SAE" & a buzzer went off in my head about what I had previously posted
so I was just doing a little fact checking.
Would appreciate any thoughts on the subject.....The possibility of a mechanical strength difference? That it's just the difference to distinguish
between hydraulic fittings & fuel or other types? That it's just how things developed over time & is how it has stayed that way over the years?
Then we can talk about why Railroad tracks are the distance apart they are!!!!!!!   LOL  

UPDATE: Looks like most questions are answered in this link.
No need for anyone to go into an educational history here for me..... I was just thinking out loud before I got a Google education
on the subject matter. This is obviously subject matter that comes up pretty regular with differences & why it's the way it is among
students and the like
https://blog.parker.com/site/u.....ts-the-difference-us

https://blog.parker.com/site/u.....p;   

Just to muddy the waters a bit. Brake lines use 45 degree fittings and is a hydraulic application.
I feel 45 deg brass fittings from the hardware, or auto store will be just dandy. A project that is on hold 'till warmer weather.

Well all righty then Mr. Mississippi!!!!!
Funny you should have posted that...I was just watching YouTube Videos on Bubble flares & Double flares.
None of them ever mentioned what the various tools they were using had for flare angles.
I guess it's just understood in the brake line (Automotive) trade that 45 is the flare angle.
But that's a "Hydraulic" fitting isn't it, So one would think it would be subject to the SAE J 514 standard
for a 37° flare..     Yeah, sometimes it seems like (they) do this stuff on purpose just to "muddy the waters".