AN and Racing fittings

[RVG8tor]

I could not find a post on point. I need an adapter to tie into my fuel line for a purge return line. I found what I needed at Summit Racing. My question is has anyone used these fittings, will they screw into the AN male connectors on the Andair fuel selector? I guess I am asking if you can mix and match them. I have read about the differences and I know there is some difference the the thread design but no the pattern, it seems there area a lot of posts with recommendations to Summit Racing fittings.

I would like to hear from those flying with the fittings and if there have or have not been problems.

Cheers

[Sam Buchanan]

Originally Posted by RVG8tor

I could not find a post on point. I need an adapter to tie into my fuel line for a purge return line. I found what I needed at Summit Racing. My question is has anyone used these fittings, will they screw into the AN male connectors on the Andair fuel selector? I guess I am asking if you can mix and match them. I have read about the differences and I know there is some difference the the thread design but no the pattern, it seems there area a lot of posts with recommendations to Summit Racing fittings.

I would like to hear from those flying with the fittings and if there have or have not been problems.

Cheers

I made my fuel and oil lines from "speed shop" AN-type fittings and braided hose over ten years ago. The hose has been replaced in order to meet service life requirements but the fittings were reused. They have worked flawlessly with the occasional AN fitting in the engine compartment.

[RVG8tor]

Sam,

Thanks, I finally found a thread from a couple years ago when someone received fittings that did not have the "AN" markings, in that thread I read enough about "Non-AN" fittings that I feel safe to use them. The fittings I can get from Summit will keep me from having to make more fuel lines.

On another note, I am considering flexible line going out of the fuselage to the wing tank, this is the connection in the wing root. Is this the way you did yours or did you use the stock aluminum tubing?

Cheers

[Sam Buchanan]

Originally Posted by RVG8tor

Sam,

Thanks, I finally found a thread from a couple years ago when someone received fittings that did not have the "AN" markings, in that thread I read enough about "Non-AN" fittings that I feel safe to use them. The fittings I can get from Summit will keep me from having to make more fuel lines.

On another note, I am considering flexible line going out of the fuselage to the wing tank, this is the connection in the wing root. Is this the way you did yours or did you use the stock aluminum tubing?

Cheers

Sort of--I used more of the "speed shop" components (actually Aeroquip) to make braided lines for the wing roots. One end has the "AN" fitting for the tank AN fitting, the other just clamps over the aluminum line protruding from the fuse. I did use a special tool for putting a bead on the end of the aluminum line but I don't feel this is necessary if carefully clamped. There is no reason you couldn't run braided line from the fuel valve to the tank with AN fittings on both ends. This would really be easier than hard lines on -A models.

[w1curtis]

Try this place for AN fittings.

http://www.anplumbing.com/shop/

[szicree]

Originally Posted by RVG8tor

On another note, I am considering flexible line going out of the fuselage to the wing tank

I recall reading a long time ago that the aluminum tubing is specified because in a crash it tends to crimp shut as it breaks. Hose would simply be cut and continue to pour fuel. Obviously this is making a lot of assumptions about the nature of the wreck, but it does make sense.

[Toobuilder]

Originally Posted by Sam Buchanan

Sort of--I used more of the "speed shop" components (actually Aeroquip) to make braided lines for the wing roots...

I'll agree here that as long as they are 37 degree fittings (as opposed to the 45 degree you get from the hardware store) and the right thread, then they are likely perfectly acceptable for use in a homebuilt. I use plenty of "speed shop fittings. Interestingly enough, Spruce often has better prices for the mil spec parts than Summit has for the "generic" hot rod parts.

Originally Posted by Sam Buchanan

...One end has the "AN" fitting for the tank AN fitting, the other just clamps over the aluminum line protruding from the fuse. I did use a special tool for putting a bead on the end of the aluminum line but I don't feel this is necessary if carefully clamped.

Sam, I respectfully disagree with this. A hose clamp is "sometimes" acceptable, but a beaded end is a requirement. The bead creates a tightening action as the hose tries to move off the end of the tube. One should not rely on friction alone to secure a hose; especially one that carries fuel. I doubt a DAR would let that one pass. Aside from that, not all braided hose can be effectively clamped with a worm drive band clamp due to the resistance that the outer braid has against crushing or due to the construction of the inner hose itself for the same reason. Some hose has metallic strands imbedded to not only resist burst pressure, but also collapse from suction. A worm drive band clamp often does not provide enough force to deform the hose assembly enough to provide an effective seal on a tube - especially if the tube is not beaded.

Originally Posted by Sam Buchanan

...There is no reason you couldn't run braided line from the fuel valve to the tank with AN fittings on both ends. This would really be easier than hard lines on -A models.

Easier yes, heavier, absolutely. It's good practice to avoid flexible hose except where absolutely required. Solid tubing is the accepted standard for moving fluids through an aircraft because it is light, inexpensive, and highly reliable... As the polar opposite, braided hose is a specialty item and used by exception.

[Sam Buchanan]

Originally Posted by Toobuilder

Sam, I respectfully disagree with this. A hose clamp is "sometimes" acceptable, but a beaded end is a requirement. The bead creates a tightening action as the hose tries to move off the end of the tube. One should not rely on friction alone to secure a hose; especially one that carries fuel. I doubt a DAR would let that one pass. Aside from that, not all braided hose can be effectively clamped with a worm drive band clamp due to the resistance that the outer braid has against crushing or due to the construction of the inner hose itself for the same reason. Some hose has metallic strands imbedded to not only resist burst pressure, but also collapse from suction. A worm drive band clamp often does not provide enough force to deform the hose assembly enough to provide an effective seal on a tube - especially if the tube is not beaded.

Hence the emphasis on "carefully". Agreed, a bead is the best way to secure a clamped hose. We were talking about a connection that carries no pressure other than head pressure and is subject to no motion.

Easier yes, heavier, absolutely. It's good practice to avoid flexible hose except where absolutely required. Solid tubing is the accepted standard for moving fluids through an aircraft because it is light, inexpensive, and highly reliable... As the polar opposite, braided hose is a specialty item and used by exception.

After you have tried to snake solid fuel tubing around/through the gear towers of an -A model RV you might be willing to pay whatever it takes to install flex hose.

[Toobuilder]

Originally Posted by Sam Buchanan

Hence the emphasis on "carefully". Agreed, a bead is the best way to secure a clamped hose. We were talking about a connection that carries no pressure other than head pressure and is subject to no motion...

..I'll agree under the premise that "carefully" means that the type of hose in use is correctly evaluated for use with a hose clamp... You can "carefully" apply a hose clamp to a hose that will resist all efforts to deform enough to create an effective seal, let alone generate enough "grip" to resist slippage. In other words, some hose is just too stiff for the relatively weak hose clamp. As for the un-beaded end... I would only consider its use acceptable if the hose slipping off the end of the line would cause no harm... So fuel lines, pressurized or not, are out of the question. I don't have a 43.13 or a 1-1A-8 in front of me at the moment, but I'll bet they would read very similar.

Originally Posted by Sam Buchanan

...After you have tried to snake solid fuel tubing around/through the gear towers of an -A model RV you might be willing to pay whatever it takes to install flex hose.

Well, I have spent most of my adult life working on military aircraft that were designed with almost no regard for the maintainer, so my "pain threshold" for a one time installation of a hard line is pretty high. Besides, as long as I have use of my legs, I can't see myself building an RV with training wheels.

[chaskuss]

Originally Posted by Toobuilder

I'll agree here that as long as they are 37 degree fittings (as opposed to the 45 degree you get from the hardware store) and the right thread, then they are likely perfectly acceptable for use in a homebuilt. I use plenty of "speed shop fittings. Interestingly enough, Spruce often has better prices for the mil spec parts than Summit has for the "generic" hot rod parts.

I'll second Michael's findings that Aircraft Spruce often has better prices than Summit, Jegs, or the local automotive speed shop. Another possible issue with automotive fittings is that some brands have a smaller inside diameter [more restrictive] when compared to the AN units sold by ACS and other aviation outlets.
Charlie Kuss