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-   -   Fuel line firewall fittings (https://vansairforce.net/community/showthread.php?t=144429)

s10sakota 11-29-2016 05:10 AM

Fuel line firewall fittings
 
I would be interested to see how you guys pass the fuel line through the firewall. Do you use the blue aluminum AN fittings or Steel fittings?


Auburntsts 11-29-2016 05:19 AM

I used steel.

Mark Dickens 11-29-2016 05:24 AM

I used steel for all of the fuel line connections fwf.

s10sakota 11-29-2016 05:25 AM

As a follow up question: if you used these, either alum or steel, what washers did you use? I didn't see any washers listed on AircraftSpruce with the fittings, and I don't really want to use cheap Home Depot washers.

snopercod 11-29-2016 06:17 AM

AN960 washers
 
Quote:

Originally Posted by s10sakota (Post 1130294)
...what washers did you use?

I used steel fittings, standard AN960 flat washers, and steel AN924 nuts. One thing I would like to mention is that in order to keep the bulkhead fitting from spinning, you will need will need a backup wrench on the back side of the fitting. Be thinking ahead about how you are going to get a backup wrench on the back side while you are torquing the B-nut on the front side. Also, if you are going to install sound insulation on the aft of the firewall, that can block access. Like they say, PLAN AHEAD

DanH 11-29-2016 07:34 AM

Quote:

Originally Posted by snopercod (Post 1130306)
Also, if you are going to install sound insulation on the aft of the firewall, that can block access. Like they say, PLAN AHEAD

Don't apply sound insulation to the cabin side of a firewall. Doing so creates a flame transfer system, defeating the reason for having a firewall in the first place.

Toobuilder 11-29-2016 08:13 AM

Quote:

Originally Posted by DanH (Post 1130328)
Don't apply sound insulation to the cabin side of a firewall. Doing so creates a flame transfer system, defeating the reason for having a firewall in the first place.

+1

Thanks largely to your "foot stomping" of this issue Dan, I have spent considerable time scraping the foil and foam insulation off my Rocket (applied by the builder, not me).

I also did a burn test on the remnants and WOW! what an eye opener!

Not only did it burn readily, but it produced enough acrid smoke that I almost passed out watching it burn in the yard. Even without fire, I would almost certainly been overcome immediately in an enclosed cabin.

rapid_ascent 11-29-2016 09:44 AM

I know some will say no need and that I unnecessarily added weight but I made my doubler out of stainless. I don't want the aluminum spacers melting and the fitting becoming loose. I also plan the run stainless tubing back to the fuel filter.

David Paule 11-29-2016 10:20 AM

Here's the requirement for certified airplanes:

"23.1183 Lines, fittings, and components.
(a) Except as provided in paragraph (b) of this section, each component, line, and fitting carrying flammable fluids, gas, or air in any area subject to engine fire conditions must be at least fire resistant...."

There's considerably more to it than this excerpt.

Dave

snopercod 11-29-2016 11:32 AM

Flame Retardant per FAR 25.853a Appendix F, Pt1
 
Quote:

Originally Posted by Toobuilder (Post 1130338)
I also did a burn test...

That was prudent since you didn't know what the original builder used. The "Super Soundproofing" that ACS sells is flame retardant per FAR 25.853a Appendix F, Pt1. Whether that's good enough, I don't know (and hope to never find out). All I do know is that without the soundproofing, ATC was unable to reliably hear my transmissions due to the high cabin noise.


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