Author Topic: an fitting/bung size for main fuel line  (Read 1104 times)

Offline noslin

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an fitting/bung size for main fuel line
« on: November 08, 2017, 08:34:05 PM »
i got 1 1/8th .062 wall for suction tubing from tank to pump.  what size fuel line from that to the pump?  since it is 1" ID thats probably a -20?


Offline Paul New

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Re: an fitting/bung size for main fuel line
« Reply #1 on: November 09, 2017, 06:47:59 PM »
AN size is in 1/16 so 1” it would be 16/16ths -16

Offline noslin

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Re: an fitting/bung size for main fuel line
« Reply #2 on: November 10, 2017, 09:45:13 AM »
thank you sir

Offline noslin

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Re: an fitting/bung size for main fuel line
« Reply #3 on: November 11, 2017, 12:10:43 PM »
for returns to the tank, 3/8" ID (-6 AN)  or 1/2" ID (-8AN).  need to buy return alum fuel line.

ty
dean

Offline noslin

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Re: an fitting/bung size for main fuel line
« Reply #4 on: January 20, 2018, 02:39:44 PM »
so, looking at main feed fuel line and male bung ID.  my main feed is 1" ID tubing.  i purchased a -16 male bung to weld to the 1" ID alum tubing. the bung ID is shy of .875 (more like .801) .  the -16AN male bung ID is not 1" ID even though -16an is 1" ID.     surface area is .785 for 1" and .500 for -16 male bung i purchased.  that's a 36% reduction in fuel flow between the two based on surface area. 

my concern is flow, were not gonna make that much hp. prob 1300 max.  will the .801 ID bung support that?  im thinking about getting -20 bung as it would be 1" ID based on the -16 bung i purchased being shy of 7/8".

ty
dean

Offline denverflatheader

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Re: an fitting/bung size for main fuel line
« Reply #5 on: January 22, 2018, 07:21:21 AM »
Dean - AN flexible hoses and fittings were developed many years after rigid tubing to provide us another alternative.  Rigid tubing sizes were already standardized by the tubing outside diameter.  As Paul wrote, the system for AN numbers are based on sixteenths of an inch.

To answer your question, AN hose sizes are designed to match the inside dimension flow rate of rigid tubing.  There lies the confusion, rigid tubing measured outside, AN flexible tubing measures inside flow.

SIZE     O.D.       I.D
6AN…….3/8”………0.34”
8AN…….1/2”………0.44”
10AN…..5/8”……..0.56”
12AN…..3/4”……..0.69”
16AN…..1”   ………0.88”


Before further designing your main fuel feed line and parts, you may want to read Spud’s FIE article on the Perfect Fuel Tank especially the “EXIT” fuel line segment.  You may come to conclusion a -20AN line too large for your application and may cause other issues.  Alan