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An Fitting Question

C

ClarkieSr

Active Member
I'm installing the red cube fuel transducer between the fuel servo and the fuel injector distributor. The red cube ports are for as AN816-6D fittings. I need to know what fitting I can use to reduce down to 1/4 inch tube hose fitting


Thanks

Tom Clark
N646LC
 
Are you asking about reducing to a -4 AN, or to 1/4" tubing of some other sort?

I suspect that you're looking for 1/4" NPT to AN-4 flair adapters. Try here:
https://www.anplumbing.com/index.php

and look through the AN aluminum adapter section. Probably their #981644.

You can also get them on ebay, Amazon, etc.
 
Please consider using steel AN fittings on fuel lines FWF..

Red cube...wires up and outlet higher than inlet to get air bubbles out..
 
Ulrich said:
Please consider using steel AN fittings on fuel lines FWF..

Red cube...wires up and outlet higher than inlet to get air bubbles out..
Click to expand...

+1 Especially since this is getting mounted to the engine.

Are you sure the cube uses -6?? Mine needed 1/4" NPT male ends the cube side. -6 hose is to the servo, but from the servo was smaller. Isn't that the standard 1/4 NPT to 37 deg -4 flare AN fitting? [correction - no - the standard is 3/8 NPT to -6 tube flair - sorry for creating confusion]

Correction: Scott, in total, is better than 99.9% correct, this time is the 0.1 % where he is not - OSH fuzz probably. The Standard AN816 nipple for 6D is 3/8" NPT - 6D line. However - fact - the hose from the servo to the spider is 4D in size. From the factory, via Vans, IO360 M1B. (also per Jesse below) The red cube does use female 1/4 NPT fittings. The one needed is a 4-4 size from Spruce.

No confusion on NPT - pipe uses sizing designations based on hydraulic flow diameter for a rough inner surface. 1/4" pipe has 1/4" inner flow diameter, not the mechanical dimension. 3/8" tube - -6, is the outside diameter and the inner can vary by the wall thickness.

Man -it never pays to give a twitter abbreviated answer here.

Sorry for not being more definitive in the original. Won't happen again.
 
Last edited:
ClarkieSr said:
I'm installing the red cube fuel transducer between the fuel servo and the fuel injector distributor. The red cube ports are for as AN816-6D fittings. I need to know what fitting I can use to reduce down to 1/4 inch tube hose fitting


Thanks

Tom Clark
N646LC
Click to expand...

Don't confuse the size of the two ends of the fittings....
An AN816-6D is sized for a -6 line or hose on the fair end (6 X 1/16"; or 3/8ths). The other end is 1/4" pipe thread (the size of the female port on the red cube).

Hopefully you aren't reducing a line diam. for feeding fuel to the engine, to 1/4". That would be too small for all of the engines we use on RV's.
 
The line from the fuel servo to the spider is #4. What you would need in this case is a fitting with 1/4" NPT to AN4 flare, which is the AN816-4-4. Aircraft Spruce sells them. As already mentioned, get the steel fittings for FWF.
 
Jesse said:
The line from the fuel servo to the spider is #4. What you would need in this case is a fitting with 1/4" NPT to AN4 flare, which is the AN816-4-4. Aircraft Spruce sells them. As already mentioned, get the steel fittings for FWF.
Click to expand...

Not that it does much good, since the red cube is aluminum, but it's good practice.
 
Fittings

airguy said:
Not that it does much good, since the red cube is aluminum, but it's good practice.
Click to expand...

Yep steel fittings for me on everything FWF and the Red Cube wrapped in large fire sleeve.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
airguy said:
Not that it does much good, since the red cube is aluminum, but it's good practice.
Click to expand...

The steel fittings are used not only for fire protection, but are less prone to cracking due to engine vibration. That's what I use them for.
 
The FlowScan transducer that came with my JPI EDM-700 specified steel fittings only. They didn't say why.
 
More options

Not to muddy the waters but the racing guys are always trying to connect something from some non aviation application to another application, maybe aero and maybe marine or whatever. Take a look at these guys and their catalogue. I've found them the best at cross use applications. The old AN and current MS certs are good but with today's CNC equipment any reasonably equipped machine shop can produce parts that easily meet the aircraft specs and supply certs for the materials used.

http://www.xrp.com/
 
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