Clunk Line

[XJet]

	Quote: Originally Posted by JoeAirPort
	What brand neoprene was this? I hope it wasn't the Hayes stuff. I never noticed anything like that in my tanks. I even had an in-line filter on it for a little while and nothing was in the ultra fine screen when I opened it up.

Dubro.

I tried in two tanks and got the small particles appearing in both.

It might be something specific to our gasoline perhaps.

[bodywerks]

	Quote:
	I've been contemplating the Aerotrend Aquablue. Is there any difference between Easyflex and Aquablue, except the size?

The aquablue is similar in stiffness to your average tygon tubing, maybe a little stiffer. It is still gas compatable and will outlast chinese junk.

	Quote:
	To say that the Aqua Blue or "standard" stuff is stiff, is to participate in an example of extreme understatement. The EasyFlex is very similar in it's flexibility to other commonly used fuel line types albeit a bit stiffer than say Tygon or neoprene.

Hmmm, can't say I disagree, necessarily since I haven't used tygon in a while, but I seem to remember tygon being noticeably stiffer than easyflex. All I know is that the easyflex stuff flops around quite readily inside the fuel tank, and blue looks cooler

[RCAddiction]

defintely...everyone knows that the blue looks cooler. Use blue for supply line and yellow for your vent line. Very cool.

FLEX
I have both Tygon and Aeroflex in my workshop (and Hayes and Viton and silicone). When new, the Aeroflex is slightly more flexible than the Tygon in the same size. The Aeroflex also tends to stay flexible longer than Tygon when used inside the fuel tank. Yes, it hardens also, but seems to take longer to harden using the gas blends I've run in Chicago and Charlotte.

Hayes is THE softest and the most flexible, but you usually need a stiffener as has been mention, like a length of brass tube, etc so that the Hayes line itself is not much longer than 2" or so.

Viton 60 duro initially is as flexible as yellow Tygon, but stays that way in fuel. Downside....it is far more expensive to use. I use it for clunks, and for the lines in my fuel jug, so that i never have to replace them.

[smokin]

i lost a SUPERXTRA at the bottom of a very low inverted flat spin due to my engine quitting.....
i found out after much searching that my tygon tubing in the tank could be used to pole vault with! i then made the switch and will never go back!


AEROTREND TUBING

get it at TBM or AIRWILD.


this is THE stuff!

[Zeeb]

	Quote: Originally Posted by RCAddiction
	4. Genuine 1/8" ID Tygon tubing from McMaster. It comes in large rolls and in a real Tygon box. http://www.mcmaster.com/#search/5552K23 I hope these links are helpful.

Hah, there it is....

I knew the number had a bunch of 4's in it

I couldn't remember the number for the Tygon you can use as fuel line, but this link RCAddiction provided shows it in the specs;

"Tygon formulation F-4040-A"

If it doesn't say that on the tubing, it isn't the right stuff. As I noted before, Tygon comes in lots of flavors and we used to use it quite a bit for various things in the air ambulance transport modules we put into aircraft and helicopters. IIRC, only the F-4040-A is gasoline compatible. Then there is the fact that other manufacturers produce yellow tubing. Who knows if any of that is gasoline compatible?

Nick is right on the EasyFlex as I just went and compared some to Tygon, it is just a tad stiffer but almost un-noticeable. I don't have any of the AquaBlue around anymore and maybe the package I got was bad or something, but it wasn't a whole lot more flexible than brass tubing.

And yes the EasyFlex will get stiff over time, but I usually change my lines each year and I've yet to find a piece of it that was stiff where I used to find Tygon stuff that was getting marginal after a year.

I think the OP has enough info to take action now...

[RCAddiction]

Okay, I've done some "flex deflection" testing.

• Precisely measured 4" lengths of new samples of the fuel tubing were fed thru a 1/4 ply plate. 4" seemed like a reasonable length for a moderate sized fuel tank.
• The plate is thick enough and holes fit tight enough so that the tubing did not flop around in each hole
• 4 identical fuel clunks (same weight, brand, etc) were applied to the end of each piece of new tubing.
• The Aerotrend had a bit of a curve to it which I oriented laterally, to minimize any effect on the direction of the deflection test. The Tygon had a smaller curve to it.
• Except for the 3/16" Hayes, the other tubing is nominally 1/4" OD.

Photos:

1. Tubing hanging vertically with clunk at bottom, left to right.
2. Tubing hanging vertically with clunk at bottom, front to back.
3. Tubing plate rotated counterclockwise to observe amount of deflection of each tubing with the same weight on it
4. Tubing plate rotated back clockwise to observe the amount of deflection in the opposition direction
5. Tubing returned to vertical hanging position once more to ensure nothing had moved significantly.

Left to right and front to back - the Hayes is the thin black tubing. The Viton 60 durometer is the thick black tubing, then the Blue EasyFlex, then the yellow genuine Tygon.

Results

• Within the realm of our use, the Tygon, EasyFlex, and Viton are very close to identical when brand new. The EasyFlex ultimately had slightly more deflection but it was not immediate.
• The Viton reacted more quickly to a change in direction than the other 2. If I had 3 hands, I would have taken a video to display this.
• The Hayes is significantly more flexible. It has the advantage of being smaller in diameter, with thinner walls, and is a softer material.

[krayzc]

way to go RCaddiction i love test results....

[RCAddiction]

Heck....I'm not an engineer for no reason, buddy!

[rcign]

Never saw 3/16 ID Hayes....3/16 OD, yes....3/16 OD Hayes will run ANY gasser WE USE on the planet, no need for large ID fuel line...
No, I'm not an engineer, just been doing this for most of my adult life....

[JoeAirPort]

Nice test. The Hayes flexibility is as obvious as it gets in those pic's. And it stays flexible so that's why I use it for clunk line with a short brass tube in the middle. I never use the Hayes outside the tank, it's too precious for that. I use the Dubro yellow and the Aerotrend blue outside the tank. The yellow is easier to see the gas in the line and that's the only advantage for my use.

[RCAddiction]

	Quote: Originally Posted by rcign
	Never saw 3/16 ID Hayes....3/16 OD, yes....3/16 OD Hayes will run ANY gasser WE USE on the planet, no need for large ID fuel line... No, I'm not an engineer, just been doing this for most of my adult life....

Ralph - I don't believe I mentioned Hayes being 3/16" ID. If I did, that would have been a typo. Medium Hayes line sold thru Great Planes is 3/16" OD. That's the size hole I drilled in the plywood for it to pass thru for my extensive test rig (grin).

Engineer - it's what I do. I make no excuses for my degree but also make no claims to be smarter than anyone else. I take experience over a degree any day. However, unlike yourself, Ralph, I have not reached my "Adult" life yet, but I have been designing stuff for 25 yrs since engineering school. Did a few years as lead engineer for a division of Walbro for fuel injection systems. I'm definitely no expert but I do know a couple of things as a result of my career.

Joe - I've had the Hayes fall off and/or tear off brass tubing and barbs in tanks of a couple of planes. Their neoprene line is not great for cut and tear resistance. Might have been due to additives in the gasoline where I have lived. Various fuel mixes may be one reason why people have different experiences with these products. So, as a result of my experiences, and to avoid further problems, I only use Viton inside tanks and for the fuel dot line, with transparent blue/yellow stuff for vent and supply lines. Pretty bullet proof setup if one can spend the $3.50/ft for the Viton.

[zzw26n]

	Quote: Originally Posted by RCAddiction
	Clunk Lines: 1. Viton 60 durometer 1/8" ID, 1/4" OD @ McMaster http://www.mcmaster.com/#search/5119K41 2. EasyFlex @ Aerotrend http://www.aerotrend.com/shop_subcat...ea0cd769085af9 3. Hayes medium neoprene line at TowerHobbies http://www3.towerhobbies.com/cgi-bin...&I=LXK824&P=ML Vent Lines and other lines external to the fuel tank: 4. Genuine 1/8" ID Tygon tubing from McMaster. It comes in large rolls and in a real Tygon box. http://www.mcmaster.com/#search/5552K23 I hope these links are helpful.

Nice Post Lee! One-stop-shopping.

[RCAddiction]

[StevL]

As you can see from my first post starting this thread I was in need of some help with clunk lines. I decided the Hayes seemed like the best idea. I also haven't flown much in December since I'm in retail. Put about 6 flights on my yak this past Sunday, after defueling I noticed some fuel in the tank (much more than normal) but loaded up and went home. Took a much closer look today and saw the clunk laying in the corner of the tank. Pulled the tank and opened her up, the Hayes line had broken off right at the clunk. I gave the line a gentle tug and it broke off the brass end. I then proceeded to break it in half with another gentle tug.

I'm not sold on the Hayes idea any longer.

I changed back to genuine Tygon on both my gassers today. I may try another line but not till summer.

All of this may be because of fuel additives, oil, etc. but something has to change. Before someone ask I'm using Saber Pro mixed 80:1 and I'm sure my gasoline has some ethanol content.

[Tired Old Man]

No matter the line type you should change it once a year. Even the best, Viton, wears out.