AN Hardware Question (AN823)

UnPossible · #1 04-10-2011, 10:12 PM

I'm plugging ahead on the FWF section of my plane. I have decided to mount my "Red Cube" to the firewall, between the engine driven fuel pump and the FI servo.

In this location, it appears that a couple of 45 degree adaptors would work great.

However, I am struggling to figure out what to order. It's a 3/8" fuel line from the fuel pump to the Cube and a 3/8" line from the Cube to the servo.
However, all the 45 degree elbows I can find appear to step down to a 1/4" line.

In 90 degree elbows, there appears to be an elbow that is 3/8" in and out.

Please forgive my ignorance with AN hardware, but can someone please point me in the right direction?

Thanks,
Jason

TS Flightlines · #2 04-11-2011, 05:15 AM

Jason--AN823-6D is -6 AN to 1/4 NPT Aluminum, and AN823-6 is for steel
in 45*.
Tom

n8zg · #3 04-11-2011, 06:23 AM

Jason -

If you're having trouble finding fittings, try www.anplumbing.com

I'd strongly recommend steel, preferably stainless, for fuel line fittings forward of the firewall.

Lars · #4 04-11-2011, 07:40 AM

Quote:

Originally Posted by UnPossible

I'm plugging ahead on the FWF section of my plane. I have decided to mount my "Red Cube" to the firewall, between the engine driven fuel pump and the FI servo.

In this location, it appears that a couple of 45 degree adaptors would work great.

However, I am struggling to figure out what to order. It's a 3/8" fuel line from the fuel pump to the Cube and a 3/8" line from the Cube to the servo.
However, all the 45 degree elbows I can find appear to step down to a 1/4" line.

In 90 degree elbows, there appears to be an elbow that is 3/8" in and out.

Please forgive my ignorance with AN hardware, but can someone please point me in the right direction?

Thanks,
Jason

Jason, perhaps you are confused by the fact that the -6 fittings are 3/8" tube in, but 1/4" NPT out. The latter is pipe thread, which for what it's worth has a true nominal OD of 0.54 inches, and is the standard pipe thread size for a 3/8" (-6) AN fitting.

Assuming you are screwing the fittings into the red cube, that's what's required, since it's tapped for 1/4" NPT.

AN822 (90 degree) fitting listings, on Aircraft Spruce's site, for example, typically list fittings with larger and smaller than standard NPT thread sizes. For example, you can get a -6 fitting with 1/8" or 3/8" NPT thread. In those cases, the part number would be AN822-6-2 and AN822-6-6, respectively. Those options are probably available for AN823 fittings as well, at least on paper, but they are less common.

UnPossible · #5 04-11-2011, 07:53 AM

Thank you....I was getting a bit confused by the 1/4" NPT thing..... this clears it up.... there are so many different things you have to get your brain around when building a plane......

Quote:

Originally Posted by Lars

Jason, perhaps you are confused by the fact that the -6 fittings are 3/8" tube in, but 1/4" NPT out. The latter is pipe thread, which for what it's worth has a true nominal OD of 0.54 inches, and is the standard pipe thread size for a 3/8" (-6) AN fitting.

Assuming you are screwing the fittings into the red cube, that's what's required, since it's tapped for 1/4" NPT.

AN822 (90 degree) fitting listings, on Aircraft Spruce's site, for example, typically list fittings with larger and smaller than standard NPT thread sizes. For example, you can get a -6 fitting with 1/8" or 3/8" NPT thread. In those cases, the part number would be AN822-6-2 and AN822-6-6, respectively. Those options are probably available for AN823 fittings as well, at least on paper, but they are less common.