Help Wanted (with metal fuel line plumbing)

[facthunter]

I don't think so.. I don't like the built up cranks and have made no secret of that. I wouldn't be alone in the engineering game either. The answer is always Rotax know what  they are doing. .  but Lycoming etc don't? I'd still consider a near new Lyc about the most reliable engine out there. Once engines get old there are too many variables of how they have been operated and treated. The Rotax Crank is only available as a totally new replacement assembly..  Nev.

[skippydiesel]

I don't come close to your experience /knowledge Nev but I think in the 100 hp engine range, Rotax 9's have proven themselves, despite what you (possibly others) view as their engineering shortcomings. 

 

There is no suggestion  that LyCon don't know what they are doing (I am sure they do) however Rotax also seem to know what they are doing (even if its diffrent). Despite the engineering misgivings of some, Rotax 9's have stood the test of time, across many and varied  applications.

Edited May 4, 2023 by skippydiesel

[facthunter]

A pressed up crank has large stresses in it even before it starts and all forces cause deflection (Distortion) when applied to something. A normal one piece has no stresses in it if it's made properly till it starts up. .  It's not repairable You replace the lot if it's got runout or any play, Conrods and all. . Cases with separate cylinders lack the rigidity Possible with One piece Blocks. THAT applies to a lot of them.. Can this NOW very old motor take the extra power demanded of the new variants?.  THAT has to be proven.  YET. It's not like it's CHEAP and

 also quite complex. Nev

[skippydiesel]

Would have thought that someone would have offered to sell/lend/hire a proper flaring tool.

[old man emu]

1 minute ago, skippydiesel said:

Would have thought that someone would have offered to sell/lend/hire a proper flaring tool.

Skippy,

Open your purse and get Rodney to do it for you. That way you know it is done right the first time. And you have a bit of warranty on the work.

[skippydiesel]

OME - You will, I am sure, understand the satisfaction, masochistic it may, be from doing it ?) yourself.

 

Then there is the added bonus of being economical with a dwindling resource($).

 

I can not see a down side, unless you count the offended passerby, when the language becomes a tad colourful.

 

(Rodney may lend/hire a flaring tool)

[facthunter]

I can't see that flared al pipe is safe, especially with the normal type nut, Flaring thins the metal a lot and there's a sharp bend  formed where it commences.. You also have the problem of lining it up accurately and accessing it to undo it  You need something to hold the TEE too.  Nev

[onetrack]

I'm with facthunter, aluminium is terrible stuff for becoming brittle, and fracturing with movement. You'd want to do pipe clamping at short intervals to ensure no possibility of movement.

[gareth lacey]

My fuel lines are 6AN braided cotton, tank through to pumps on inside of firewall (2 pumps plus 100micron filter) all an6 fittings(EFI Burliegh) all accessible through hatches in front of windscreen and ss braided in engine area suitably covered in fire proof hose

 

[Area-51]

AL fuel line is not pure aluminium, its a specific grade alloy, and A/C tubing is the best grade alloy tubing to use due to high pressure cycle count.. In over 45 years I have never had a single alloy pipe fail from vibration when correctly fitted... These lines will easily contain 120psi; the Rotax fuel line pressure is 3-5psi...

 

My hydraulic swage and flare tool cost  almost $1000, and its worth every cent, my benders are not cheap either. The stainless steel or alloy end nuts and fittings used are sourced on quality not price.

 

Personally, after the most recent project, i would use braided PTFE or Nylon fuel lines as they will not be affected by ethanol; nylon will dry out though over time and may crack, but again, in over 45 years have never seen a nylon fuel saturated component fracture or crack....

[Blueadventures]

14 minutes ago, Area-51 said:

AL fuel line is not pure aluminium, its a specific grade alloy, and A/C tubing is the best grade alloy tubing to use due to high pressure cycle count.. In over 45 years I have never had a single alloy pipe fail from vibration when correctly fitted... These lines will easily contain 120psi; the Rotax fuel line pressure is 3-5psi...

 

My hydraulic swage and flare tool cost  almost $1000, and its worth every cent, my benders are not cheap either. The stainless steel or alloy end nuts and fittings used are sourced on quality not price.

 

Personally, after the most recent project, i would use braided PTFE or Nylon fuel lines as they will not be affected by ethanol; nylon will dry out though over time and may crack, but again, in over 45 years have never seen a nylon fuel saturated component fracture or crack....

How would the coiled soft alloy tube go that I believe is used in cars at times?

[rgmwa]

Vans supply this for the RV's: https://store.vansaircraft.com/aluminum-tube-035-x-3-8-x-29-coil-at0-035x3-8x29-ft.html

[Thruster88]

8 hours ago, facthunter said:

I can't see that flared al pipe is safe, especially with the normal type nut, Flaring thins the metal a lot and there's a sharp bend  formed where it commences.. You also have the problem of lining it up accurately and accessing it to undo it  You need something to hold the TEE too.  Nev

Every Cessna, Piper and Beechcraft has it in their fuel system. There is also one aluminium flared pipe attached to each cylinder head on every Lycoming engines as the oil return line, doesn't get much harsher in terms of vibration. They have been doing this for at least 60 years now.

[old man emu]

22 hours ago, skippydiesel said:

OME - You will, I am sure, understand the satisfaction, masochistic it may, be from doing it ?) yourself.

Most assuredly, but sometimes one must look to the end result. I'm sure that Rodney would be happy to teach you how to use the tool, and to use it at his place. That mob have always had the custom of providing free advice to homebuilders because the original owner built his own Pitts Special and was hoping to build a GeeBee replica before he got crook.

[facthunter]

It's the type of flare I'm talking about and the quality of the tube..sharp bends etc.  Nev

[Geoff_H]

My flaring tool.  The brass piece is the substitute for aircraft angled flaring

[rgmwa]

That's similar to the one I have. I found the serrations in the clamp tended to score the soft aluminium tubing which I wasn't very happy about, but a single wrap of masking tape around the tube helped a lot.

Making good flares is definitely an art. The number of pieces of tubing I threw away could almost have built another plane.

 

[facthunter]

When you repair a flare you have to shorten the length and you need room to do this. You'd need Big "S's" to allow for it and a large access. Nev

[Area-51]

There's only one option left... we start our own insurance company of Cheats & Dobbers & Co, where we can freely tell each other to go get stuffed without fear of accountability and repercussions!! 🤓 

[Area-51]

On 05/05/2023 at 12:31 PM, Blueadventures said:

How would the coiled soft alloy tube go that I believe is used in cars at times?

You would need to know specific material's data specs to make any worthwhile assumptions.

 

Pic below, precision flaring tool; does just about everything... the other type above is for single flare on copper pipe.

[Geoff_H]

Nice set of tools.  The above set was made for copper.  By making the adaptor piece o made the device work on Aircraft fuel systems including aluminium pipe and fittings.  I made an adaptor system for my air compressor that uses aluminium tube and holds 100psi air.  I like you set better, just like the cost of mine.

[old man emu]

"Single flare"

There's something that tinkles a tiny bell. Am I wrong in saying that the flaring on piping used with aviation fittings are double-flared? 

[Thruster88]

No they are single flare. There is a backing part that is inside the nut. The nut should turn on that piece so the pipe flare is just being clamped. 

[Geoff_H]

I have only single flared fuel lines.  My 100 psi air line would benefit from double flare. One day I may make a tool for double flaring.  What are others using on fuel lines?  Maybe I should remake the fuel lines.

[onetrack]

Only brake lines are double flared, because they have to resist substantial pressure levels. I have a Rothenberger RoFlare double-flaring tool, it's the dux nuts for perfect double flares on Bundy tubing. I've only ever done double flaring on steel (Bundy) or copper lines, I've never used or tried double flaring aluminium tubing.

 

Copper is unsatisfactory for brake lines as it "work hardens" with vibration and the pulsing of brake pressure, so it must not be used in that application.

 

https://www.amazon.com.au/Rothenberger-26033-RoFlare-Compact-Flaring/dp/B002JASATC

 

Edited May 7, 2023 by onetrack