Could have been bad!

[Anticept]

Going to side with tom on this, but I also have a suggestion.

 

Check out 4504 beaded tees.

 

 

[Roger Lee]

So moving away from thinking in the box.

Since you say the 7.5mm is smaller in I.D. then when you go to push it on the barbed fittings and other fittings in the engine it scrapes off more inner lining because it's now too tight. Plus if the 7.5mm hose is also fuel injected hose you just made matter even worse by pushing it over those fittings.

Real time research that using real material evidence and not just saying the 5/16" is too big is proved in my video. Show me with a video where it's wrong. 

Plus many here forget this hose replacement for the CT is worldwide and they don't have access to all the hoses either.

[Anticept]

The reason I side with Tom is that I am looking to replace the tee in mine. I am having leaking issues unless I clamp it down real tight. I am using the 5/16ths hose. It's too loose on the fitting. Yes I tried new hose.

I just haven't found a tee that I really like, though the 4504 tee is looking attractive. I might just say screw it, bite the bullet, and build one using AN840s and a female tee.

[Madhatter]

23 minutes ago, Roger Lee said:

So moving away from thinking in the box.

Since you say the 7.5mm is smaller in I.D. then when you go to push it on the barbed fittings and other fittings in the engine it scrapes off more inner lining because it's now too tight. Plus if the 7.5mm hose is also fuel injected hose you just made matter even worse by pushing it over those fittings.

Real time research that using real material evidence and not just saying the 5/16" is too big is proved in my video. Show me with a video where it's wrong. 

Plus many here forget this hose replacement for the CT is worldwide and they don't have access to all the hoses either.

Tubing beads should be smooth rounded to eliminate any scraping. I have tools to make these beads on aluminum tubing used on certified aircraft.  LSA are the only aircraft I have seen sharp barbs for hoses. That said all certified aircraft in the last 70 yrs use AN type fittings for fuel and oil, and for good reason.

[Roger Lee]

4 hours ago, Anticept said:

The reason I side with Tom is that I am looking to replace the tee in mine. I am having leaking issues unless I clamp it down real tight. I am using the 5/16ths hose. It's too loose on the fitting. Yes I tried new hose.

I just haven't found a tee that I really like, though the 4504 tee is looking attractive. I might just say screw it, bite the bullet, and build one using AN840s and a female tee.

What fitting are you referring to?

Using the flared tip fitting works too as demonstrated on the Rotax fuel pump fittings. Same size hoses and zero leaks. These hoses are under 100 psi. They just allow fuel to flow from the tank. Even on the pressure side of the fuel pump it's only 3.5 - 5.5 psi for the carbed engine.

Here is an issue. On the 912iS engine in the CT 912LSi the fitting on the fuel rail just above the #3 cyl. and out of the fuel filter is too small for the hose that FD uses. If you try an Oetiker clamp (even a smaller than normal one) the hose will easily pull off. FD uses a Band-It clamp here so they can squeeze the hose down past its normal point.

I've been doing hose changes since 2008 and use 1/4" and 5/16" and they never leak. I do 15+ hose changes a year and don't have issues. So that makes me think some aren't clamping properly because when done right the 1/4" and 5/16" do not leak. The Oetiker clamps used  for the 5/16" hose on that through the firewall Tee fittings is different than the Oetiker clamp size used on the barbed fittings like on the gascolator.

The proof that .4mm difference makes no difference WHEN CLAMPED PROPERLY is seen in the video. It's irrefutable. 

[Anticept]

The Y fitting in my console for fuel. It's such a small tube that the 5/16ths fits sloppy loose over it and leaks like a sieve if I don't have it clamped stupid tight. It's been a sore point for me and maybe I got the one airplane where someone used the wrong piping at the factory, I really don't know. I'm just done with dealing with it and looking for proper alternatives.

Clamps should not be required to stop a hose leak in low pressure systems, if one has to be used it's against good practice to just "make it work" by throwing clamps on it.

[Anticept]

4 hours ago, Madhatter said:

Tubing beads should be smooth rounded to eliminate any scraping. I have tools to make these beads on aluminum tubing used on certified aircraft.  LSA are the only aircraft I have seen sharp barbs for hoses. That said all certified aircraft in the last 70 yrs use AN type fittings for fuel and oil, and for good reason.

Hey what's the brand of the tool you use for this? I've seen different ones but it seems like field made beaded fittings are one of those things that people hardly do anymore, and I can't tell which one is worth even considering.

[Madhatter]

56 minutes ago, Anticept said:

Hey what's the brand of the tool you use for this? I've seen different ones but it seems like field made beaded fittings are one of those things that people hardly do anymore, and I can't tell which one is worth even considering.

I do them all the time but for aluminum only, it forms the bead from inside. You cannot use it for stainless. That's why the fitting in the CT is machined by undercutting the tube. To do it properly the bead should be slightly larger than the hose ID. This is why I went with AN on all hoses, it's just what I'm used to and I don't have a fitting floating in the firewall. It's OK for lsa but not for any other aircraft since the Wright Brothers. I don't understand why this was done this way, cost is minimal.  Just my pet peeves. 

[FredG]

Interesting discussion.  With the exception of the two ends of the metal tubes that run down the forward pillars from the fuel tank outlets to the engine bay, every fuel hose on my E-LSA CTsw is braided stainless teflon hose with 37 degree AN fittings.  Done once and will last the rest of my flying years.  

Edited April 19, 2023 by FredG

[Anticept]

How much weight did you put on doing that fred?

[Madhatter]

8 minutes ago, FredG said:

Interesting discussion.  With the exception of the two ends of the metal tubes that run down the forward pillars from the fuel tank outlets to the engine bay, every fuel hose on my E-LSA CTsw is braided stainless teflon hose with 37 degree AN fittings.  Done once and will last the rest of my flying years.  

How did you go from the Y tube to the fuel valve

[Skunkworks85]

On 4/16/2023 at 11:05 PM, Roger Lee said:

FD European metric hose is 7.5mm and 5/16" ( 7.9mm). Four tenths of one mm should not make any difference in our hose choice. Think about how small 4/10th of one mm is.The one issue is that FD came out with those fittings really meant for 1/4" hose which is 6.3mm. Later on they came out with larger metal fittings more correct for 5/16" - 7.5mm.   7.5mm for this fitting is technically to big too.

This said if you push the 5/16" / 7.5mm up past the first 1/2" onto the shaft past where the indentation is it fits much better and if you use a smaller than normal Oetiker clamp or a fuel injection clamp 5/16" hose works just fine and has been since 2007 when these metal fittings first came out with the new firewall blanket. FD used to just pass the rubber hose through the firewall. The huge majority use 5/16". Besides 1/4" hose 5/16" is all I use. When clamped PROPERLY it will never leak or come off.

 

You keep talking about "properly" attached incorrect hoses, Problem is, the original post was addressing an Improperly attached hose.  

Lets stop talking about what you think is right, and address the fact that had this been a correct hose installed, The chance of failure (disconnection/leak) would be less. that is enough to convince me that there is NO EXCUSE to use the wrong hose. 

 

Next, 

5% larger hose size is a significant difference. 

Gates manufacturing tolerance as specified in their catalog as well as SAE30r6 hose standard,   for the 5/16 hose is 7.9±0.4 mm. That means that this actual ID will be at 7.5mm - 8.3mm. Combine that with tolerance stack up of the barbed fitting(unknown), there exists the potential for a combination of hose to greater than 0.8mm larger than the designer intended to use for the fitting( assuming all fittings have zero tolerance, which they do not)

that is 10% larger than design. 

Did you do you very scientific test with all cross checks with the tolerance stack up?

Will you repeat your study without any clamps? Can you please use a scale?

 

Edit: anecdotal evidence suggests that 5/16 hose is an issue, as at least 5 members have voiced they have had leaks at this fitting with incorrect hose size. Me included. 

 

[Roger Lee]

"Edit: anecdotal evidence suggests that 5/16 hose is an issue, as at least 5 members have voiced they have had leaks at this fitting with incorrect hose size. Me included. "

That might mean those 5 out of how many CT's in the world (approx. 2K) didn't install and clamp them properly or even use the right clamp or size. You'd have to examine each of those 5 to exclude poor installs. You guys are only going on hearsay and not factual physical proof. There are tens of thousands of times with aircraft hose issues that they weren't installed properly. 

You forgot already about the oil hose that came off the oil thermostat and caused an engine failure. So with you assuming hose only comes off if it's the wrong size then you are saying it was too big, but we do know the clamps weren't tightened.

Since all hose installed on the USA CT's are all metric and come from Europe that NO USA hose substitute can be used. It won't be the same millimeter. It will either be too big or too small and it isn't exactly the same size as ours.

On this initial post it wasn't a clamp / hose failure, but a failure that the clamp wasn't actually on the hose. A MIF (mechanic induced failure), not the hose or clamp just a missed clamp install.

The video proves that 5/16" is as good as the 7.5mm and 15 years of use prove it too. Not to mention the thousands of planes that use the 5'16" hose on their planes that came from Europe.  Go get some REAL PHYSICAL evidence that 5/16" will not work and stay away from hearsay. This is why I do so much real time physical testing. I have shown aircraft MFG's and even Rotax some things are wrong because they failed to test them and only thought it might be an issue.

Start showing physical proof of why things happen. Why they work or don't work.

[Roger Lee]

 

"5% larger hose size is a significant difference. 

Gates manufacturing tolerance as specified in their catalog as well as SAE30r6 hose standard,   for the 5/16 hose is 7.9±0.4 mm. That means that this actual ID will be at 7.5mm - 8.3mm. Combine that with tolerance stack up of the barbed fitting(unknown), there exists the potential for a combination of hose to greater than 0.8mm larger than the designer intended to use for the fitting( assuming all fittings have zero tolerance, which they do not)

that is 10% larger than design. 

Did you do you very scientific test with all cross checks with the tolerance stack up?

Will you repeat your study without any clamps? Can you please use a scale?"

 

"Will you repeat your study without any clamps? Can you please use a scale?" 

This is irrelevant because we do not use hose without clamps. If we did most of our hose would come off. So the test need to be done as they are used in real life.

How do you explain away FD using the wrong fuel injection fitting for the larger hose size that will only stay on when crimped past its normal limits.

The other issue is the metal fitting is a poor design, but works when clamped properly.

Plus did you guys order your 25mm coolant hose from Europe or just buy 1" local or use the 1" that a service center supplies. Did you buy 13mm oil hose from Europe of use local service center hose? Did you use US 1/4" hose for some of the fuel or order European millimeter hose. They are all different sizes.

You can carry this debate as far as you want, but without physical proof it's just a he said she said debate.

[Roger Lee]

The original post was about a hose where the installer had missed the hose with the clamp and not that it was clamped and just slid off.

[Madhatter]

Sorry can't take this anymore. It's not rocket science on securing hoses, it's either tight or not tight, screw clamp or band clamp, doesn't matter. If someone can't figure that out then they have no business working on any plane, stick to lawnmowers. This hose and tube assy is a pita and that's why I changed the design for my plane. There are a lot of issues on aircraft that are much more difficult than this.

[Tom Baker]

This is the fitting in 5-16" hose. I know it said 4 pounds, but there wasn't much tension. That was mostly the weight of the scale as I started to pull it taught.

[Tom Baker]

This is with 7.5mm hose. 8 pounds of pulling force. the fitting is sliding in the hose, but slowly. In my opinion, the hose is sealed on the fitting.

[Tom Baker]

This is how loose the fitting is in the 5/16" hose.

[Towner]

Corey said it isn’t a pressurized system. Sure didn’t seem that way when the fuel was unexpectedly pouring into the cabin!

[Anticept]

Hey now, I said LOW pressure system!

Tom: that's about what mine looks like. I had to put two clamps on mine to make it stop leaking and I hate myself for it. However, until I find an alternative and get it approved, I have to work with it.

Madhatter: Aye I'm looking for a beaded tube tee. It's why I'm starting to look at just using AN adapters. I do not like barbed fittings for things I have to take apart from time to time and I've seen what it does inside of the hose.

That said I really should fill out an SDR.

If I ever get some old hose, I should split it open and peel the rubber back to show all the little cuts that barbed fittings do to hoses when clamped down. I'm OK with barbed fittings that have a flat spot for a clamp, but things like the in line fuel filter are terrible.

[Tom Baker]

27 minutes ago, Anticept said:

Tom: that's about what mine looks like. I had to put two clamps on mine to make it stop leaking and I hate myself for it. However, until I find an alternative and get it approved, I have to work with it.

Why not use the correct size and specification hose? I bought 10 meters of the 7.5 DIN spec hose back in December for $7.66 per meter, and the 9.5 was even cheaper. That is less per foot than the Gates hose. Using the incorrect hose makes no sense what so ever given the economics and legality. Back in 2010 when I did my first hose change, and the hose was $65 per meter from Flight Design, I could see the allure of using the much cheaper 5/16" hose. However things have changed since then.

[Madhatter]

41 minutes ago, Anticept said:

Hey now, I said LOW pressure system!

Tom: that's about what mine looks like. I had to put two clamps on mine to make it stop leaking and I hate myself for it. However, until I find an alternative and get it approved, I have to work with it.

Madhatter: Aye I'm looking for a beaded tube tee. It's why I'm starting to look at just using AN adapters. I do not like barbed fittings for things I have to take apart from time to time and I've seen what it does inside of the hose.

That said I really should fill out an SDR.

If I ever get some old hose, I should split it open and peel the rubber back to show all the little cuts that barbed fittings do to hoses when clamped down. I'm OK with barbed fittings that have a flat spot for a clamp, but things like the in line fuel filter are terrible.

When it comes to serious safety issues on LSA I do them regardless of the beurocracy. They usually wait for the incident,  it's called tombstone legislation. I don't have patience for this if they drag it out. Just me

One thing very important on fuel plumbing, all flow must be downhill or level at all places.  There can never be a low spot as water will collect and freeze in winter. The routing from the "Y" to the fuel valve is more difficult when using AN fittings . It must not rise above the "Y" tube. I had to keep it flat and use a 120 degree fitting. 

[Anticept]

There's a lot of lovely things LSA brings, but maintenance and the wild west it's treated as, even by the manufacturers (flight design isn't the only model that I've run into "good enough"), is really something else.

I can say a lot of good and bad things about repairmen work that I have seen, just like I can about other A&Ps. What surprises me is how much of a different focus there is on what is acceptable and what isn't, and some of this is a result of the way regulation is written. It puts all the onus on manufacturers to maintain airworthiness and leaving no wiggle room for the mechanics, but we all know how long term product support tends to go and who the owner is going to blame while things sit around waiting on the simplest of things...

I am dreading to see what happens in the coming years when manufacturers are trying to shed their old LSA product responsibilities like Cessna tried to shed their 400 series!

[Anticept]

4 hours ago, Tom Baker said:

Why not use the correct size and specification hose? I bought 10 meters of the 7.5 DIN spec hose back in December for $7.66 per meter, and the 9.5 was even cheaper. That is less per foot than the Gates hose. Using the incorrect hose makes no sense what so ever given the economics and legality. Back in 2010 when I did my first hose change, and the hose was $65 per meter from Flight Design, I could see the allure of using the much cheaper 5/16" hose. However things have changed since then.

Forgot to answer you, sorry.

First, a bit of background:

I am still fuming mad that a manufacturer's fiscal irresponsibility and straight up lying to our faces about the state of their business has led to my inability to get any work done during that time period because I needed parts. Since my airplane was being used for rental and I still had the mortgage to pay on it, it set in motion a lot more problems that I STILL have to deal with today, and I lost a hell of a lot thanks to them.

Only reason I would even recommend a flight design following those events is because of the new lift-air management and how aerojones is willing to step in if need be. If it was still under the old company, I'd be telling people never to touch a flight design.

None the less, I try to get entire specifications approved as substitutes for anything that isn't a purpose built part, so that I can use anything that meets those specs.

I'm not doing maintenance anywhere near as much as I did since I shifted towards the pilot profession, so extra would just sit on the shelf and rot. But, if things have changed enough that this stuff is readily available, I'll buy the correct hose and keep it simple.

Where are you buying the hose? Is Tulsa the only place?