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Fuel line through firewalls

Old 06-11-2002, 08:00 PM
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Shawnusa
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Default Fuel line through firewalls

He Guys,

Is there such a product that you mount into the firwall for running fuel tubing through? I'm concered that if I just drill a hole in the firewall and ruin the tubing staight through, the vibratrations from the Gas Engine will eventually eat through the fuel line. If there is a product avaliable please send me a link. I guess what I'm looking for is a aluminum/brass fitting you mount into the firewall and connect the fuel line to it on both sides. Anway any tips helpful

Thanks,

Shawnusa
Old 06-11-2002, 08:07 PM
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Buz^
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Default fuel line delema

hi shawnusa, two things come to mind, 1 drill oversizes holes and use goop or any clear poly caulk, goop works great cause it sticks to almost anything. #2depends on what size fuel line, but, drill holes to snug fit a short section of brass tubing,epoxy perm. in place, make sure there's enough tubing to attach line's to on either side,fuel line will have no contact with fire wall
Old 06-11-2002, 08:41 PM
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GrnBrt
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Default Fuel line through firewalls

I go with the brass tubing through the firewall. Drill the holes and run the tubing through and Ca in place and Voila!!!! Do watch out for any burrs on the brass that could cut the fuel line, and get some fuel line clamps from the hobby shop to help keep the tubing from slipping. Have been doing this since Moses was a corporal and have had no problems.
Old 06-11-2002, 08:42 PM
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KidVermin
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Default Fuel line through firewalls

Shawnusa:

I haven't had a fuel line failure yet by drilling thru firewall and
sealing hole as Buz^ stated. I try to limit the number of slip joints
that can be fuel leaks.

And yes I have mastered my mind.
When I talk to myself, I don't pay attention anymore.

Randy
Old 06-12-2002, 03:43 AM
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Texas 3D
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Default epoxy

Just coat the oversized hole with enough epoxy so it is nice and smooth. Nothing will eat up your fuel line then. I think there would be other things to worry about first due to vibration then the fuel line.
Old 06-12-2002, 11:03 AM
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dant-RCU
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Default Fuel line through firewalls

Foremost makes bulkhead fittings in two sizes, standard and large. Standard size are color coded red and green and the large are blue and yellow. These are plastic fittings that secure with a nut on the backside of the fuse. I have used them with no problems. I also just run the lines thru holes and seal with silicone sealer - depends on the model.

The only thing about the bulkhead fittings is that if the front of your tank is very close to the bulkhead then there is not enough room for the fuel lines. The fittings protrude about 1/2 inch inside the firewall. If the tank is too close the the end of the fittings then the lines can/will have sharpe bends and kink.

I get my Foremost fittings at the LHS but I think they are (or were) available at Tower also. I think they are like $4.00 a pair or something.

My experience.

Dan
Old 06-12-2002, 07:07 PM
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Vince
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Default Fuel line through firewalls

I have never heard of anyone having a problem with this. Usually the aircraft doesn't last that long. I just retired a UltraSport 40 that was about 7 or 8 years old, with who knows how many flights on it. It never had a problem such as you are asking about.

Vince
Old 06-12-2002, 07:57 PM
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Buz^
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Default good for you vince

its called preventative maintenance
Old 06-12-2002, 08:32 PM
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MinnFlyer
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Default Fuel line through firewalls

Vince, I'm in the process of refinishing my 10 yr old Ultra Sport! (Love that plane)

Anyway, what I do is, I go to my local Auto Parts Store. They sell 1/8" COPPER tubing that is dirt cheap, (something like 50cents per foot) it bends WAY easier than brass, and because it's so cheap, I buy a few feet at a time. Then, I can run copper plumbing all the way from the tank, through the firewall, and right up to the engine. No more worries about a fuel line leak behind the firewall!
Old 06-12-2002, 10:15 PM
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Vince
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Default Fuel line through firewalls

Again, in all my 30+ years of flying, I have never seen this problem crop up before. I think you guys are looking too hard for things. I honestly do not think it is something to worry about.

Vince
Old 06-12-2002, 10:27 PM
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Buz^
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Default VINCE HAS A POINT

WHAT VINCE IS SAYING IS TRUE, THE ODD's OF VIBRATION CHEWING UP A FUEL LINE ARE ALMOST NIL, I GUESS I SHOULD HAVE KEPT ON A BIT MORE ABOUT THE GOOP ,IT DOES INSULATE AGAINST RUBBING , BUT , IT's AS OR MORE IMPORTANT AS A SEALER , TO PREVENT ANY FUEL FROM GETTING INTO THE FUEL TANK AREA. AN OUNCE OF PREVENTION , YOU KNOW THE REST
Old 06-13-2002, 05:24 PM
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Default Fuel line through firewalls

Ok . . .I'm suprised no one has offered this up . . .so I will. I have been using rubber grommets. I drill the hole for the right size grommet then push it in. works great, looks professional, and solves the problem of chafing the fuel lines. I have purchased them from several sources including TNT landing gear, radio shack, and home centers. The TNT variation seem to be just the right thickness for most fierwalls. I even get some that are thinner for running wires etc through bulkheads.

Take it with a grain of salt, but I am Anal, and these things make the installation just perfect.

PBH
Old 06-13-2002, 06:17 PM
  #13  
Steve Collins
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Default Fuel line through firewalls

Vince has got it right. You guys are going to some extra time and trouble to fix something that never breaks. Do any of you honestly know of anyone who had a fuel line chafe through to the point of leakage just because it passed through the firewall?

In my 20 years of flying just about everything except helicopters I have never seen any instance of this happening nor, for that matter, any instance of any significant fuel or oil passing through oversize holes in firewalls.
Old 06-13-2002, 06:33 PM
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jelaird
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Default Sounds like a Gasser here..

Shawnusa, if you are running a big gasser I can understand your concern. There's 90,000 acres burning in Colorado right now. If so... use Tygon for your run through the firewall with good clearance...it's tough stuff. I'm almost positive neoprene could be a problem rubbing against wood over time in that environment.
Jack
Old 06-13-2002, 06:34 PM
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Default Fuel line through firewalls

I use the gromets because they give a great finished look . . .I agree though, I have never had a failure in my pre gromet days . . .heck some of the things I do today are miles ahead of when I first started building 20 yeas ago (I was 11 at the time) and I have had only 1 failure (a wing of a Sr falcon came off because I did not glue it correctly). The main reason I use the grommets is vainity not function.
Old 06-13-2002, 07:01 PM
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Shawnusa
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Default Fuel line through firewalls

Gentelmen,

I appricate all your comments and find the grommet Idea to best suit my needs. I fly the big gassers as someone asked. I'm only doing this as a precaution and nothing furthur. Best to always error on the side of saftey than chance a Colorado wildfire . Serouiously, thanks for the posts. Cudos to the grommet idea. Will be using that one

Cheers,


Shawnusa
Old 06-14-2002, 11:18 AM
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jelaird
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Default I know where your at!

A big gasser changed my thinking, thought I was the only one worried about stuff like that. I was in a house fire one time and was lucky to escape. I don't want that stuff ruining my good time flying or taking off on the landscape. Flying sites are hard to find.
Jack
Old 06-14-2002, 06:12 PM
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RandyL
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Default Fuel line through firewalls

Geezzzz Shawn, Ya never know where a good thread pops up! I'm running Tygon through a slightly oversize hole. My rear carb mount makes my fuel inlet on the carb very close to the firewall.
Old 06-14-2002, 06:20 PM
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Shawnusa
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Default Fuel line through firewalls

Yea, you never can tell what I'm up to on here. Always looking for new ways to do things. I liked that grommet idea. Going the the Hardware store today to get some. I ordered that router tool you have. should be here today. I know I will get good use of it.

Shawnusa
Old 06-14-2002, 10:38 PM
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Default Fuel line through firewalls

I used rubber grommets for the cuns to go through the nose glass but the fuel line will just go through an enlarged hole on mine. The grommets look nice.
Make sure to use the router before glassing the airframe. It works great on wood and much less so on fiberglass...just like the instructions say. Just wanted to mention it.
Old 06-18-2002, 12:25 AM
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crosswind
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Default Fuel line through firewalls

Another two cents. I also have been flying more than 20 years and have a bipe with ten years flying on it with never a problem of a fuel line chaffing on the firewall hole. I certainly have no arguement with the several suggestions, but what I would add is to not forget to look out for where the chaffing DOES usually occur, and that's where it connects to the brass tubing if indeed you're using brass tubing. Be sure to not leave a sharp edge on it because it will cut the fuel line. Especially if the line angles away from the tubing sharply, as is often the case with a tank front close to the firewall. Happy flying!

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