AN Fittings

BillL said:

I have been on the end of actually doing designs, testing, and writing the test request reports, not retrieving them as public docs - Can you point me in the right direction for these docs?

I know we (when I was at Contintenal, TCM at the time) got sued for a broken connecting rod. The rod was a copy made by another manufacturer. The claim was the FAA filed documentation was followed and so TCM was liable. When I asked if all certs could be looked up by anyone I was told no. So - a little help would be appreciated. Every thing was microfiche then.

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Sounds like you've had some fun over the years. Wait a second, you designed continental engines for living, participated in their certification, but you're asking me where the docs are for the certification standard? :=) Well alrighty then....here's a location for just about everything the FAA certified.

FAA Type Certs

And here's the link to the FAA Part 23 regulating all facets of general aviation small aircraft FAR 23 I recommend 23.1011 Oil Systems as a good bedtime reading.

As a designer of engines, you are probably a member of ASME, so here is a link to the ASME standard for "Pressure Relief Valve for the Lubrication System of an Internal Combustion Engine". Everyone here loves standards, right?

Something to keep in mind, regulations are made by politicians, standards, well those come from engineers. Thanks for helping me on my journey to "gain some knowledge"

rongawer said:

Interesting; I take it you've verified their components don't meet the standard? Or are you just stating your opinion as fact? In reality, you may be right, but there is a big difference between supposition and fact, and what you're doing is impuning a vendor without any data provided. And who says you need to meet an AN standard anyway?

This all comes back to using the right standard for the application. Using 3,000 psi tested stainless braided hoses that were manufactured to a military standard will do the job on my RV-12 brakes, but so will parker plastic hoses with brass compression fittings (that are amazingly similar to the ice maker hose installation on my frig).

Referring to Captain Avgas's story; I'm glad he was able to find a problem and repair it. I have a different story with involves Earl's hoses and fittings on my '69 Mustang. I replaced all of the brakes with {gulp!} reinforced rubber hoses about 20+ years ago - Earl's (now owned by Holley) has been in the business a long time, which says something about their quality. That was the standard for automotive brakes at that time and they still work very well. I purchased, assembled and installed them myself. And before you say "that's a car, this is an airplane", note that the braking service duty of a 2 ton car is much greater than my 750 pound RV-12.

Additionally, noting that the vast majority of failures are human error, when I hear that some product leaks - or failed, my first question is to the assembly of it. The key is to use the right component (standard) for the right service use (application) and then assemble and install it correctly. A high quality hose installed incorrectly is worse than an "AN Fitting From the Internet" hose that was installed right.

I noted that this thread has been viewed almost 3,000 times, yet only a handful of folks have participated in it. My guess is that there are many positive stories about amateur assembled hoses, but those stories are unheard due to reasons that probably include fear of rejection by a few folks on this forum that have very strong opinions. I hope for a more inclusive builder forum that welcomes diverse perspectives. I believe in having an open mind, just not so far open my brains fall out.

There's nothing wrong with failing at an experiment, so I encourage folks to try things - using good engineering practices (if you lack GEP, then please do seek assistance from the fine folks advertising here...). Note that I'm not encouraging someone to make something, install it on your airplane, load up your family and launch off into the clag. There is a substantial difference between my experimental airplanes and my Beechcraft Baron; and anyone who believes their experimental airplane meets or exceeds the certification requirements of FAR 23 is misguided - that is unless you have the certification and testing documents, and you use a certified A&P for your maintenance along with an IA for your annual inspections and major modifications. This is a silly concept. However, do use the best you believe you need, just don't think everyone has to do it your way. That is the entire value and beauty of E-AB, a category I hope does not go away.

And whether certified or not, or whether it was manufactured to a specific standard or you formed it from raw materials into a product YOU designed, any maintenance performed on airplane needs a post maintenance evaluation. Ground run the engine, take a test flight around the field where you can land if the engine quits, fly it for a defined period of time with a good test plan - evaluate the result and make changes if needed. But DO participate in amateur building.

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Ron,

I think it may have gotten lost in a previous post...but when we have builders ask about building hoses themselves, we recommend an Earl's product that is a conductive Teflon hose. It is excellent quality but not a low pressure product.

Unless I misunderstood, you mentioned that you utilized conductive Teflon hoses for your firewall forward kit and implied that high pressure hoses are way overkill and not needed for a less than 100psi system. If you would be so kind as to share the manufacturer and pressure rating of the hoses you utilized for your firewall forward, it would be greatly appreciated. That way if we have anyone who wants a low pressure hose for one reason or another we will be able to give them some more info.

Thanks so much,
Steve

Aircraft Specialty said:

Ron,

I think it may have gotten lost in a previous post...but when we have builders ask about building hoses themselves, we recommend an Earl's product that is a conductive Teflon hose. It is excellent quality but not a low pressure product.

Unless I misunderstood, you mentioned that you utilized conductive Teflon hoses for your firewall forward kit and implied that high pressure hoses are way overkill and not needed for a less than 100psi system. If you would be so kind as to share the manufacturer and pressure rating of the hoses you utilized for your firewall forward, it would be greatly appreciated. That way if we have anyone who wants a low pressure hose for one reason or another we will be able to give them some more info.

Thanks so much,
Steve

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Sorry I missed that Steve, I do like Earl's Speed Flex hose and Speed Seal hose ends. Very high quality, in my opinion. I've used Earl's stuff for years on various components.

I like to compare products, so I bought 3' from anfittingsdirect and compared it to Speed Flex that I had on hand.

AN Fittings Hose -6 and specs
Specifications:
Pressure Rating: 800 PSI - note: crimp-on fittings are recommended for applications over 500 PSI.

Vacuum Rating: 265 inHg.

Temperature Rating: -100F to 500F


AN Fittings wall dimension

Earl's Speed Flex for comparison with their specs
Specifications:

ColorSilverLength10 ft.MaterialBraided Stainless SteelSize6ANOutside Diameter0.55Inside Diameter0.34Hose Length (ft.)10Hose Outside Diameter (in.)0.547Hose Size-6 ANMaximum Operating Pressure (psi)2,000Maximum Recommended Temperature450 degrees FMinimum Recommended Temperature-65 degrees FOuter MaterialBraided stainless steelPTFE LinedYesQuantitySold individuallyHose MaterialPTFEHose Inside Diameter (in.)0.343Hose ColorNaturalManufacturer's Part Number:610006ERL


My review on the hoses is that they look identical next to each other. The braiding on both is great with no apparent loose strands. The internal tubing looks identical and the wall thickness is within 0.008 with the Earl's being the thinner. I ran a borescope down the hose to look for any pin holes or manufacturing defects and found only a smooth bore through the entire run of both hoses.

As for the fittings, the dimension accuracy, fit and finish quality of Earl's is better in all regards compared to AN fittings. However, I found that AN Fittings Direct were dimensionally compliant according to the spec and passed a blue check on the seat against my genuine 8130 certified AN6 fitting I had on hand. When I say accuracy, the inner diameter of the cheap fitting was 0.373 and Earl's was 0.378. However, the AN standard is 0.375 Approximate, so both actually meet the standard, just Earl's is on the happier side of flow. The threading of both fittings is good, however Earl's thread cuts are more precise and a snug (use oil!). The anodizing of Earls' is much more resilient and less prone to marring with a wrench. There are a bunch of specs for each AN fitting and I didn't measure them all; just enough to know they'd both work if installed correctly.

My opinion is the that for low pressure applications, the AN Fittings hose will work fine. For higher pressure applications, I'd go with Earl's.

rongawer said:

Interesting; I take it you've verified their components don't meet the standard? Or are you just stating your opinion as fact?

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The "AN" fluid fittings do not meet any aviation standard, AN, MS, or AS. Perhaps it would help new builders to know how to tell at a glance.

1. The fittings are unstamped. The standards require AN, MS, or AS, and the manufacturer's mark.

2. These fittings are available with color choice (blue, black or silver). The standards, however, use color as a material identification. Blue for example, means 2014 or 2024 aluminum. Black means carbon steel. Gray means titanium.

3. For their own protection, the seller is not using AN, MS, or AS part numbers. Instead, they use a description based on size, and their own part number. Look close; a -6 elbow, for example, is identified as a "ANF001310".

So, they're obviously not spec fittings.

Want to see a really sad fact? The above ANF001310 mutt is $6.99. The real AN821-6D is $6.56 at Wicks, or $5.90 if you buy 25:

http://aircraftproducts.wicksaircraft.com/item/an-ms-fittings/an821-elbow-fitting/an821-6d

Perhaps it would be best if we all support the quality sources.

PS...any chance you could resize those photos?

rongawer said:

Sounds like you've had some fun over the years. Wait a second, you designed continental engines for living, participated in their certification, but you're asking me where the docs are for the certification standard? :=) Well alrighty then....here's a location for just about everything the FAA certified.

FAA Type Certs

And here's the link to the FAA Part 23 regulating all facets of general aviation small aircraft FAR 23 I recommend 23.1011 Oil Systems as a good bedtime reading.

As a designer of engines, you are probably a member of ASME, so here is a link to the ASME standard for "Pressure Relief Valve for the Lubrication System of an Internal Combustion Engine". Everyone here loves standards, right?

Something to keep in mind, regulations are made by politicians, standards, well those come from engineers. Thanks for helping me on my journey to "gain some knowledge"

Click to expand...

Well, the story is a topic for the OSH/VAF beer gathering. It was waaaay before the internet, 30 yrs ago. So, thanks for the url. ASME member I was, but it was not helpful in the engine design world. SAE and other publications were better. The company I mainly worked for (not TCM) was a leader in the engine field worldwide and had developed their own standards for design, validation, materials etc. They typically led the industry standard committees in guidance. Many techniques were trade secrets, so we seldom strictly followed the standards, per se unless it had no effect on competitive advantage.

Ya see, you are looking at logic and standards, I know what happens in the validation tests, so don't get complacent in our other discussion.
Thanks for the links.

DanH said:

The "AN" fluid fittings do not meet any aviation standard, AN, MS, or AS. Perhaps it would help new builders to know how to tell at a glance.

1. The fittings are unstamped. The standards require AN, MS, or AS, and the manufacturer's mark.

2. These fittings are available with color choice (blue, black or silver). The standards, however, use color as a material identification. Blue for example, means 2014 or 2024 aluminum. Black means carbon steel. Gray means titanium.

3. For their own protection, the seller is not using AN, MS, or AS part numbers. Instead, they use a description based on size, and their own part number. Look close; a -6 elbow, for example, is identified as a "ANF001310".

So, they're obviously not spec fittings.

Want to see a really sad fact? The above ANF001310 mutt is $6.99. The real AN821-6D is $6.56 at Wicks, or $5.90 if you buy 25:

http://aircraftproducts.wicksaircraft.com/item/an-ms-fittings/an821-elbow-fitting/an821-6d

Perhaps it would be best if we all support the quality sources.

PS...any chance you could resize those photos?

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sorry for the sizing, i'll have to figure that out.

As for the fittings you reference, they're not hose adapter fittings or the comparable part to what I referenced above. The comparable part on ACS is EATON HOSE FITTING F66000-6, at $62.50 each. That is a substantial cost difference to meet a homebuilt application. I priced out the comparable cost with Eaton (aeroquip) 666 hose and fittings (1500psi application) and it is $1,788, plus tax and shipping versus comparable fittings at $305 from the knock-off shop. I presume your argument is it's worth it. So be it. For reference, the same setup with Earl's fittings and speed flex hose is $685 with tax and free shipping from anplumbing.com (a very good vendor with great pricing).

But for folks buying tools a harbor freight and building on a budget, the cheap option works. You can argue that they don't work or hold pressure or comply with a standard that is not applicable to EA-B, but the proof is that i have -6 hose in a 5 gallon bucket holding 1000# filled with water and pressed with nitrogen through my repurposed pressure tank and a calibrated 2000# pressure gauge. It's been there since yesterday evening and holding. From where I sit, that's good for me.

Oh, here's the fitting made up before testing:

rongawer said:

But for folks buying tools a harbor freight and building on a budget, the cheap option works. You can argue that they don't work or hold pressure or comply with a standard that is not applicable to EA-B, but the proof is that i have -6 hose in a 5 gallon bucket holding 1000# filled with water and pressed with nitrogen through my repurposed pressure tank and a calibrated 2000# pressure gauge. It's been there since yesterday evening and holding. From where I sit, that's good for me.

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Given all your other testing, my main concern in this case would maybe be the type of alloy used and it's susceptibility to fatigue/cracking/etc, but I don't know nearly enough about the subject to weigh in. Given that ignorance I stuck with pre-made aircraft hoses and fittings FWF. But those certainly aren't failure-proof as well.

Personally I have a gut feeling that people like you who put as much thought and testing into their decisions are less likely to have a failure than people who mis-use or mis-installed "certified" hardware, which I believe is probably a much larger cause of failures. It's a mindset - you probably aren't the type to over-torque a fitting, use the wrong sealant in the wrong place, etc.

As long as folks keep making INFORMED decisions, I say have at it.

Chris

YellowJacket RV9 said:

As long as folks keep making INFORMED decisions, I say have at it.

Chris

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Agreed. Thanks for the feedback.

Well, I'm one of those 3000 that are watching and reading this post from the sidelines. I'm glad this discussion has remained civil and supported by logic and testing. When I used to fool around with race cars (formula cars, not converted street cars) I studied at the alter of Carroll Smith a race car engineer, team manager and writer. His series of "How to..." articles in Sports Car Graphic magazine turned into a series of five books on race car design, engineering, materials, systems, and management. His drivers won LeMans, and Formula Atlantic titles among many others. He was an avid supporter of using proper aviation grade hardware on race cars, but an even more avid supporter of Earl Fouts who founded Earl's supply. As Ron noted, Earl's was bought by Holley a few years ago. So when Carroll Smith endorsed Earl's hoses, hose ends and fittings, including some special ones not included in the AN standards, I thought very highly of this endorsement.

Not saying they're "aircraft quality", because as Dan points out, they aren't stamped/identified with markings from those standards. But I would also venture that a race car application has an even tougher operating environment than our light aircraft. ANfittings.com the name of the website that sells Earl's online is perhaps unfortunately named in the context of this forum, but nevertheless, I have purchased some fittings for my aircraft from them and found them an excellent supplier. The fittings I bought were those that solved a space or adapter problem that couldn't be solved any other way. I know which parts they are, I know they are commercial parts, I know they haven't been through as rigorous a QA procedure as an AN fitting. If I could have found an AN fitting that would work I would have bought if from the usual sources but I couldn't. I also used some Swagelok adapters since the AN fittings did not go down to 1/16" NPT size. This was a vent port on a certified aircraft part.

To me, this discussion underscores the need to understand the origin of the parts you are buying, make an informed decision regarding their suitability to the application, seek expert advice if you are unsure, and finally, if in doubt, do your own testing or find someone who can do it for you.

Ron, is that a 3A thread on the hose end?
Tom

TS Flightlines said:

Ron, is that a 3A thread on the hose end?
Tom

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Tom, dimensionally, yes. However, I would classify the fit as RC2 (accurate, but slight movement in thread contact, vice RC1, which would require lubricant to prevent galling) and I cannot verify the hardness of the material. Therefore I would recommend only using these fittings on systems with working pressures less than 800 psi as recommended by the vendor (which would include all of the systems on a small experimental airplane, except maybe a hydraulic retractable landing gear system, if you're so inclined to actually build one). Incidentally, the hose I've been testing is still holding 1000 psi in my garage "test lab" - putting the Experiment in Experimental .

For everyone who may not recognize thread classes, this is a statement of the acceptable pitch diameter - in this case, the distance between the inner bore of the fitting to the bottom of the thread in ratio to the thread pitch. Class 1 would be a loose fit, Class 2 a better fit and likely something I could turn out on my lathe, Class 3, a precision fit and is used for close tolerance applications requiring very good machining. A or B identifies whether the threading is external or internal (these are external on the hose end and internal on the fitting end).

Ron

terrye said:

Well, I'm one of those 3000 that are watching and reading this post from the sidelines. I'm glad this discussion has remained civil and supported by logic and testing. When I used to fool around with race cars (formula cars, not converted street cars) I studied at the alter of Carroll Smith a race car engineer, team manager and writer. His series of "How to..." articles in Sports Car Graphic magazine turned into a series of five books on race car design, engineering, materials, systems, and management. His drivers won LeMans, and Formula Atlantic titles among many others. He was an avid supporter of using proper aviation grade hardware on race cars, but an even more avid supporter of Earl Fouts who founded Earl's supply. As Ron noted, Earl's was bought by Holley a few years ago. So when Carroll Smith endorsed Earl's hoses, hose ends and fittings, including some special ones not included in the AN standards, I thought very highly of this endorsement.

Not saying they're "aircraft quality", because as Dan points out, they aren't stamped/identified with markings from those standards. But I would also venture that a race car application has an even tougher operating environment than our light aircraft. ANfittings.com the name of the website that sells Earl's online is perhaps unfortunately named in the context of this forum, but nevertheless, I have purchased some fittings for my aircraft from them and found them an excellent supplier. The fittings I bought were those that solved a space or adapter problem that couldn't be solved any other way. I know which parts they are, I know they are commercial parts, I know they haven't been through as rigorous a QA procedure as an AN fitting. If I could have found an AN fitting that would work I would have bought if from the usual sources but I couldn't. I also used some Swagelok adapters since the AN fittings did not go down to 1/16" NPT size. This was a vent port on a certified aircraft part.

To me, this discussion underscores the need to understand the origin of the parts you are buying, make an informed decision regarding their suitability to the application, seek expert advice if you are unsure, and finally, if in doubt, do your own testing or find someone who can do it for you.

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Well said Terry. Thanks for joining in and providing your background on Earl's fittings.

rongawer said:

As for the fittings you reference, they're not hose adapter fittings or the comparable part to what I referenced above. The comparable part on ACS is EATON HOSE FITTING F66000-6, at $62.50 each. That is a substantial cost difference to meet a homebuilt application. I priced out the comparable cost with Eaton (aeroquip) 666 hose and fittings (1500psi application) and it is $1,788, plus tax and shipping versus comparable fittings at $305 from the knock-off shop. I presume your argument is it's worth it. So be it. For reference, the same setup with Earl's fittings and speed flex hose is $685 with tax and free shipping from anplumbing.com (a very good vendor with great pricing).

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Can you please post the hose dimensions for what you computed these costs for? How many hoses...diameter, lengths, and firesleeve please. You stated that 666 hose would be $1788, Speedflex $685, and a knock off shop $305.

Thanks,
Steve

Search For the Part's Specification

You can always do a search for the part number that you're interested followed by the word "spec." For example, a search for "MS21042 spec" without the quotes provides a lint to the specification itself at www.everyspec.com. This is a handy site for getting these specifications.

You can read the spec and see what it requires. It'll give the dimensions, the tolerances, the materials and finishes. For fasteners, the strength is usually given but not always. Many of these will be specifications themselves, so there's often a bit of a technology trail involved.

Dave

Aircraft Specialty said:

Can you please post the hose dimensions for what you computed these costs for? How many hoses...diameter, lengths, and firesleeve please. You stated that 666 hose would be $1788, Speedflex $685, and a knock off shop $305.

Thanks,
Steve

Click to expand...

Here you go:
6 feet -6 PTFE hose
18 feet -4 PTFE hose
8 feet -8 PTFE hose
6ea -6 straight hose fittings
12ea -4 straight hose fittings
2ea -8 90º hose fittings
2ea -8 straight hose fittings

For full disclosure, I quoted -3 for Earl's on the brake lines.

Certified Aircraft's Parts

When I graduated as an aerospace engineer, I went to work for a now-defunct general aviation airplane manufacturer. One of the things that was quite interesting was that very often they sourced components from the same industrial sources that are available to us now, like McMaster. They'd specify a certain part number and at first I'd think that that was all. Then I realized that they'd frequently modify it in some way. For example, they'd add a hole or shorten it or something. And then this part would become a proprietary part for them.

They didn't release data on how to modify the original part or what the original part was. If you needed one you'd have to buy it from them as a fully-approved part. And you can't blame them, really, they did make changes, after all.

The point to all this is that if you're dead certain, and I use that phrase intentionally, that a commercial part will work for you, then it's satisfactory.

Please remember that after a designer specified the part and any changes, that the stress analysis team would review it. So would the design chief and probably some other people, and then the project manager. Those reviews were what makes a commercial part into the design of a certified part. Don't neglect that sort of care.

Dave

David Paule said:

When I graduated as an aerospace engineer, I went to work for a now-defunct general aviation airplane manufacturer. One of the things that was quite interesting was that very often they sourced components from the same industrial sources that are available to us now, like McMaster. They'd specify a certain part number and at first I'd think that that was all. Then I realized that they'd frequently modify it in some way. For example, they'd add a hole or shorten it or something. And then this part would become a proprietary part for them.

They didn't release data on how to modify the original part or what the original part was. If you needed one you'd have to buy it from them as a fully-approved part. And you can't blame them, really, they did make changes, after all.

The point to all this is that if you're dead certain, and I use that phrase intentionally, that a commercial part will work for you, then it's satisfactory.

Please remember that after a designer specified the part and any changes, that the stress analysis team would review it. So would the design chief and probably some other people, and then the project manager. Those reviews were what makes a commercial part into the design of a certified part. Don't neglect that sort of care.

Dave

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Interesting post Dave. I like the history, but you lost me after "intentionally using a commercial part". Are you advocating that it's ok to use non-certified parts in lieu of parts that are required normally required to be certified if they are validated to be a comparable part? You could can actually, legally, do that as an Owner Produced Part under FAR 21.303.b.4 as long as, as the Owner, you verify the correct dimensions and materials are used - assuming all liability for the manufacture. I've done that several times for things like replacing an engine baffle with a new part I made, and then having an A&P sign off on it as a repair in the appropriate log book. But that's all about certified aircraft and was never the intent of the original post here.

This thread is regarding experimental aircraft, where the parts are determined by the builder. In the eyes of the FAA, the builder is the manufacturer and is held wholly responsible for the design, and who sometimes is the actual designer. This builder is generally the person determining which parts to use, so I'd expect that it would normally be the same person anyway.

But if you're advocating that we should use certified parts in building our experimental aircraft, well ok then, that's an interesting perspective. Not one I'd advocate, but certainly a valid perspective.

We seem to cross the certified and experimental streams here often. I try to make sure I don't confuse the two.

rongawer said:

....you lost me after "intentionally using a commercial part". Are you advocating that it's ok to use non-certified parts in lieu of parts that are required normally required to be certified if they are validated to be a comparable part?

Click to expand...

That's not exactly what I said. I said

David Paule said:

....The point to all this is that if you're dead certain, and I use that phrase intentionally, ....

Click to expand...

I was intending to express the seriousness of using a commercial part, and in the remaining part of the posting, to describe the very serious manner in which commercial parts sometimes get approved in the design of certified aircraft.

For us, we ourselves have the responsibility as the builder to verify that a commercial part is indeed suitable in a particular application, if we're going to use one. If a part is specified by the factory, then unless you're certain that your proposed substitution is adequate, use the part that is in the design.

Dave

i'm probably going to get in trouble for doing this,

but I emailed ANfittings.com, with this question:
'Are the fittings you have class 2 or class 3 threads?'

Their reply:
Hello,

Thank you for your inquiry. We are the manufacturer of this product although production occurs overseas. They are standard AN threads with the specifications listed here: https://en.wikipedia.org/wiki/AN_thread

Thanks,

(name ommited by me)
Customer Service
AN Fittings Direct, Inc.
www.anfittingsdirect.com
[email protected]

So---since there is a big discussion of AN grade, or not AN grade, they seemed to sidestep the question by referring to the definition of AN Thread, and its comparison to JIC, instead of saying whether or not theirs was a class 2 or class 3 thread. Also their statement that "production occurs overseas" isnt a surprise to me, based on the pricing of the fittings.
I am NOT knocking companies that produce components overseas that use MIL SPEC standards, including the prints, the materials, the manufacturing procedures (like thread rolling for 3A thread), and the quality control inspections with the appropriate certifications and documentation. I am not comfortable with companies the say this is a 'AN fitting' when it isnt. Manufactured to a MIL-SPEC drawing is different than to MIL-SPEC. What materials were used?
If you REALLY want to dig into this, request the MILL report on the materials that were used to manufacture the fittings. Then get an independent lab to verify that report. Then examine very carefully the machining, the threads and the common dimensions of the fitting. Then, in the case of a teflon hose end, the Nut will probably be Mil-Spec, the body and OD and ID will 'probably' be within a range margin. The crimp area, or the screw collar area will be different, because thats where the individual company that has the manufacturing rights (lets say Eaton Aeroquip, Parker Stratoflex, Smiths-Titeflex, and some others including Earl's Performance) differs from their competitor. They are certifying that the materials, the connection part of the fittings meet the "AN" Mil Specification for that fitting. NOT necessarily the way the hose attaches to the fitting. Aeroquip's design is different than Stratoflex, which is similar but different than Titeflex, that is also different than Earl's. Why? copyright or patent infringement stuff.

So---with all that, does Stratoflex, Aeroquip, Titeflex, Earls, etc meet AN Spec? They certify they do. Does Earls; they say AN fittings, so they say ( I assume) that some part DOES meet the AN spec. Others---um--maybe in the name 'AN fitting' but maybe not AN grade as per the Mil Spec. It may look like it, smell like it, assemble like it, resemble a "certified" fitting by the way the components integrate, (like the brass olive over the liner, under the braid, squeezing onto the stem design that was pictured in this thread.) But, calling it an AN fitting with a brass olive isnt exactly right. Aeroquip's 'certified' design has a stainless olive. And class 3 threads on the stem and collar, not class 2. AND--swivel stems--Aeroquips design has the stem is part of the body of the fitting, with the threaded collar and a male threaded nut to capture the olive to the hose and stem. It 'can' rotate during assembly if indexing is necessary BEFORE final assembly. NOT a live swivel that is sealed by an O'Ring, and lock wire that not only 'can' rotate after assembly, 'can' leak under not nominal conditions. A Mil SPec live swivel has redundant seals around ball or needle bearings to allow the fitting to rotate.

So---when talking about "AN" or not 'AN" is a gray area. IF the fitting is stamped 'AN" or has a MilSpec number on it, it IS a true certified fitting. And, somewhere there is the traceability information on that fitting. IF there isnt, it may be manufactured to the PRINT of an AN or MilSpec fitting, but may NOT meet all the criteria. Steve and I just spent the better part of 2 years dealing with this.

I certainly dont mean to stomp on anyone, and if I have I certainly didnt mean to. We build experimentals because they give us some latitude in things we can do. What a particular builder puts on his or her aircraft is up to them, under 'suggested' guidelines, either published ones, or from similar applications. We all want to use the best materials we can, given the conditions we operate under. For most of us its a budget. There are many applications where a builder has a choice whether to use a certified component, or something that does the same job that is 'experimental'. In the long run, I think we can all agree that safety FIRST is the mission.

Tom

rongawer said:

Here you go:
6 feet -6 PTFE hose
18 feet -4 PTFE hose
8 feet -8 PTFE hose
6ea -6 straight hose fittings
12ea -4 straight hose fittings
2ea -8 90º hose fittings
2ea -8 straight hose fittings

For full disclosure, I quoted -3 for Earl's on the brake lines.

Click to expand...

Ron,

So, breaking this down into assemblies.

-4 hose str/str average length of 36"= QTY 6

-6 hose str/str average length of 24" - QTY 3

-8 hose 90/str average length of 48" -QTY 2

These materials from Earls would cost $685 according to the quote you received. For the fun of it, I decided to run these assemblies through our hose pricing algorithm on our website. The cost of the hoses as built by us or Tom would be $686.04 plus shipping. One large difference is that you are receiving an assembly that is professionally built and tested with a 10 year warranty.

Again, I am not trying to convince anyone NOT to build their own assemblies. The Earl's product is very high quality and we highly recommend it to customers who really would like the experience of building their own hoses. However, a lot of people do prefer to buy professionally built and tested hoses, especially when the cost difference in negligible.

Proper fabrication technique is critical, and is also the reason why some of the OEM manufacturers we work with decided to get away from either building their own hoses, or having their customers fabricate the assemblies themselves. The correct crimpers, dies, hose cutting and testing equipment as well as multiple CNC machines (for rigid tube assemblies) is not inexpensive for the type of assemblies we do. Fabricating hoses can definitely be done safely by an individual if they are careful and follow good practice. A space suit and clean room is not required to fabricate hoses correctly. However, having the proper equipment and experience is definitely very helpful.

Steve

Buy or build

Steve, thanks for taking the time to price this out for me.

I obviously hit a nerve making a review of a vendor for parts, which is supposed to be part of amatuer building of airplanes. There's an obvious concern for safety present, and that's fine. However, just because you do something yourself with materials you choose doesn't mean it's unsafe. I am reminded of why EA-B exists, "recreating while learning". Making an airplane, understanding that "the major portion of which has been fabricated and assembled by person(s) who undertook the construction project solely for their own education or recreation." It's supposed to be fun.

I think it's great that you offer good quality parts and service at a reasonable price and there is certainly a need for your business here. It seems like you could build my hose sets for me at a good value. If the day comes that I need to replace the hoses on my Baron, I will keep you or Tom in mind for possibly making a set of hoses to spec as Owner Produced parts.

As for me, it's about the journey and process. If I want a certificated aircraft that I know is 100% FAA Part 23 Certified (although technically CAR3 in my case), I currently have one built by Beechcraft sitting out in the hangar. But I enjoy building, experimenting and doing things myself with my own hands and I do not intend to stop, nor would I dissuade folks from doing it their way either. There is a contingent that would rather buy pre-built components and simply assemble them together - possibly as a way to achieve having a good airplane at a reasonable price - and that's fine and well. But I enjoy the amatuer building, designing, modifying, making-it-my-own aspect of it. And I know that there are folks like me (even lurking here on VAF!), as well as those who just want the parts and having fun putting it together so they can go flying - both are great aspects of the deal.

It's Friday, have a great weekend!

rongawer said:

Steve, thanks for taking the time to price this out for me.

I obviously hit a nerve making a review of a vendor for parts, which is supposed to be part of amatuer building of airplanes. There's an obvious concern for safety present, and that's fine. However, just because you do something yourself with materials you choose doesn't mean it's unsafe. I am reminded of why EA-B exists, "recreating while learning". Making an airplane, understanding that "the major portion of which has been fabricated and assembled by person(s) who undertook the construction project solely for their own education or recreation." It's supposed to be fun.

I think it's great that you offer good quality parts and service at a reasonable price and there is certainly a need for your business here. It seems like you could build my hose sets for me at a good value. If the day comes that I need to replace the hoses on my Baron, I will keep you or Tom in mind for possibly making a set of hoses to spec as Owner Produced parts.

As for me, it's about the journey and process. If I want a certificated aircraft that I know is 100% FAA Part 23 Certified (although technically CAR3 in my case), I currently have one built by Beechcraft sitting out in the hangar. But I enjoy building, experimenting and doing things myself with my own hands and I do not intend to stop, nor would I dissuade folks from doing it their way either. There is a contingent that would rather buy pre-built components and simply assemble them together - possibly as a way to achieve having a good airplane at a reasonable price - and that's fine and well. But I enjoy the amatuer building, designing, modifying, making-it-my-own aspect of it. And I know that there are folks like me (even lurking here on VAF!), as well as those who just want the parts and having fun putting it together so they can go flying - both are great aspects of the deal.

It's Friday, have a great weekend!

Click to expand...

Ron,

Not at all! No nerve hit. We build because it is a fun and an enjoyable experience. I am on my third kit right now and who knows how many more we will end up doing. This thread has taken so many turns and weird twists that it is hard to keep up. There is some very good and thought provoking information in it. As a vendor of a component that is critical to flight safety, we have a vested interest in making sure that people buy quality components. (It doesn't have the be from us) The Earls product line that you mentioned is a very high quality product line and that's great. The reason that it is important to us is that if people utilize improper components or fabrication techniques it could give non certified components a black eye. That would be unfortunate, because I think we can all agree that in many cases non certificated items are equal to if not superior to certificated components. That is a privilege of EAB. It is all of our responsibility to make sure we do it safely.

Steve

Aircraft Specialty said:

Proper fabrication technique is critical, and is also the reason why some of the OEM manufacturers we work with decided to get away from either building their own hoses, or having their customers fabricate the assemblies themselves. The correct crimpers, dies, hose cutting and testing equipment as well as multiple CNC machines (for rigid tube assemblies) is not inexpensive for the type of assemblies we do. Fabricating hoses can definitely be done safely by an individual if they are careful and follow good practice. A space suit and clean room is not required to fabricate hoses correctly. However, having the proper equipment and experience is definitely very helpful.
Steve

Click to expand...

This is a very relevant comment and it indicates that there are two different issues being discussed in this thread in parallel. The first issue is about the pedigree of hose assembly components. Many people on this thread have been at pains to stress the importance of using components with traceable quality control (whether the hoses are "professionally" assembled or builder-built).

The second issue is about the wisdom of assembling one's own hoses (whether using pedigree parts or not).

My experience has been that using auto or commercial grade components is riskier than using genuine AN aviation products. My experience has also been that it is considerably riskier for the novice to assemble his own hoses than to get them assembled by a professional. And of course if a builder opts to buy cheap Chinese components AND then assembles his own hoses... then the combined risk is greatly multiplied.

It may well be true that building your own aircraft should be "fun" and that it should be "educational". But more important than either of those....it should be SAFE.

I fabricated 2 of my own hoses on my RV7A. They were fuel hoses between the wing tanks and the fuel selector (Vans plans call for aluminium tube in these locations). I installed hoses to facilitate the removal of the wings. I assembled the hoses from aviation grade Aeroquip hose and end fittings. And I used a Koultool to facilitate the assembly of the end fittings and ensure higher quality. And finally I tested both hoses hydrostatically to proof pressure.

I fabricated these hoses because the pathway between the fuel selector and the wings tanks is extremely convoluted on an RV7A as it has to snake its way through the landing gear mounts. The most practical way to get the job done was to fabricate one end of the hose and instal it, and then cut and fabricate the second end to fit.

I spent a LOT of time researching how to fabricate those hoses and buying the appropriate tools, hoses, and fittings. I am satisfied with them bearing in mind that they are a zero pressure hose and that if one fails there is redundancy with the other.

Initially I was going to fabricate all of my hoses myself but after fabricating the first two I decided that I was going to get Aviall to manufacture all my FWF hoses. What I learnt from my experience is that there are a lot of important little tricks in fabricating hose assemblies and in retrospect I now understand that this is not an area where you want to "learn as you go". In particular the consequences of a FWF hose failure is just too severe.

So in the end I went to Aviall and had all of my FWF TSOd hoses fabricated from PTFE hose and with swaged stainless end fittings. I believe that it is superior to have steel fittings FWF but that's another topic.

So my advice to novice builders is to get your hoses professionally assembled from aviation grade components. Believe me, a professional who is doing hose assembly every day will do a better job than you.

Incidentally, in post 56 the OP has a photo of his preassembled hose and fittings sitting on a table that is literally littered with swarf. I wouldn't put my hose fittings on that dirty table, even if was just for photographic purposes.

Captain Avgas said:

Incidentally, in post 56 the OP has a photo of his preassembled hose and fittings sitting on a table that is literally littered with swarf. I wouldn't put my hose fittings on that dirty table, even if was just for photographic purposes.

Click to expand...

Wow, really? whadaya say we stop throwing gasoline on the fire and let this die?

Captain Avgas said:

So my advice to novice builders is to get your hoses professionally assembled from aviation grade components. Believe me, a professional who is doing hose assembly every day will do a better job than you.

Incidentally, in post 56 the OP has a photo of his preassembled hose and fittings sitting on a table that is literally littered with swarf. I wouldn't put my hose fittings on that dirty table, even if was just for photographic purposes.

Click to expand...

I admit my fault. You've shown me the error of my way. I'm a changed man. Do not build your own hoses. You should not trust yourself - that is unsafe, just do the smart thing as your told and buy them. Buy your airplane too - building it yourself is very dangerous - as is aviation. You can't possibly understand how to do this, nor learn, and can't be trusted - leave it to professionals who do it every day.

Oh gee

"I admit my fault. You've shown me the error of my way. I'm a changed man. Do not build your own hoses. You should not trust yourself - that is unsafe, just do the smart thing as your told and buy them. Buy your airplane too - building it yourself is very dangerous - as is aviation. You can't possibly understand how to do this, nor learn, and can't be trusted - leave it to professionals who do it every day. "

I personally think this has gotten out of hand, and completely away from the original intent of the first poster. He was simply making a comment of a supplier he used. Since then we've had all sorts of explanations, data, and frankly alot of good information that the BUILDER can use to make his own determinations.
But I think to say that " You should not trust yourself - that is unsafe, just do the smart thing as your told and buy them. Buy your airplane too - building it yourself is very dangerous - as is aviation. You can't possibly understand how to do this, nor learn, and can't be trusted - leave it to professionals who do it every day. " is taking the intent of this thread, AND experimental aviation and making a mockery of them.

Very sorry if that offends anyone. A very smart man once told me that "Cant never could". The Wright Brothers were told they couldnt fly, but they and others have. I think that too was experimental aviation. If you get down to it, EVERYTHING we do in life is or was an experiment at one time. We learn from it, and apply what we learned.

Tom

Bob---we understand that in Australia as in some other parts of the world, the resources have some limits. In the US, there are many more resources to choose from. Aviall is a great company, and a vendor of ours. Glad to know that they have a facility in AUS to help supply you with certified assemblies for your planes. it does save shipping from the US, although I dont know how much pricing difference there is.

We looked at setting up a shop in Australia and other places, but with the world trade climate situation right now, we probably wont do it. BUT, for those looking for alternatives, we have several solutions.

Tom

TS Flightlines said:

" You should not trust yourself - that is unsafe, just do the smart thing as your told and buy them. Buy your airplane too - building it yourself is very dangerous - as is aviation. You can't possibly understand how to do this, nor learn, and can't be trusted - leave it to professionals who do it every day. " is taking the intent of this thread, AND experimental aviation and making a mockery of them.

Very sorry if that offends anyone. A very smart man once told me that "Cant never could". The Wright Brothers were told they couldnt fly, but they and others have. I think that too was experimental aviation. If you get down to it, EVERYTHING we do in life is or was an experiment at one time. We learn from it, and apply what we learned.

Tom

Click to expand...

Thanks Tom, your comments capture the actual intent of my original comment of this thread.

The comment right above, well, that is absolutely intended sarcasm and mockery indeed, hence the green lettering. I'm too old to take myself too seriously.

I'm done here. On to new threads.