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TXFlyGuy

Well Known Member
Is it ever acceptable to use solid brass fittings (hose barbs / T-fittings) in a fuel line? We are having a debate...one friend and RV-8 builder says NO! And another builder claims it is very safe.

Who is correct?
 
Lots of vintage aircraft use brass fittings in the fuel system. What specific application in the fuel system are you referring to?
 
Mike H said:
Lots of vintage aircraft use brass fittings in the fuel system. What specific application in the fuel system are you referring to?
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Coming out of the fuel tank, between the fuel pre-filter and the fuel pumps. A brass T coming off the filter, then going to the pumps via a hose barb. All safety wired.
 
I suspect that the bigger ones are what caused their bad reputation; the wall thickness vs total size tends to suffer as they get larger. Brass wouldn't scare me if I could make sure it wasn't 'stressed' by static loads, and vibration wasn't an issue. Using one on an engine does get a little more dicey. A fried just lost a Cessna 195 to a brass 'L' in the oil system (a certified part, BTW).

If you're really concerned, you can probably get the same part as an A/N fitting in your choice of materials, or at least a stainless plumbing part.

Charlie
 
rv7charlie said:
I suspect that the bigger ones are what caused their bad reputation; the wall thickness vs total size tends to suffer as they get larger. Brass wouldn't scare me if I could make sure it wasn't 'stressed' by static loads, and vibration wasn't an issue. Using one on an engine does get a little more dicey. A fried just lost a Cessna 195 to a brass 'L' in the oil system (a certified part, BTW).

If you're really concerned, you can probably get the same part as an A/N fitting in your choice of materials, or at least a stainless plumbing part.

Charlie
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As this is well back of the firewall (at the fuel tank), I do not think it will be an issue. The fittings are 3/8".
 
TXFlyGuy said:
Coming out of the fuel tank, between the fuel pre-filter and the fuel pumps. A brass T coming off the filter, then going to the pumps via a hose barb. All safety wired.
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It's not what I prefer to use but I does not sound like a safety of flight issue either. Lots of vintage and very light aircraft use hoses with barbed fittings and clamps. I prefer to use flared fittings.
 
Alot of planes had brass, but they also used rubber push on hose too. Several LSA aircraft still use it. Costs less than AN hardware, and is easier to install.
But---its still brass.
Tom
 
TXFlyGuy said:
Coming out of the fuel tank, between the fuel pre-filter and the fuel pumps. A brass T coming off the filter, then going to the pumps via a hose barb. All safety wired.
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I've always heard to stay far, far away from hose barbs, clamps, and the like in aircraft fuel systems. Also that fuel system issues are a primary, if not leading, cause of "eventful" first flights. Please be careful here. Sticking to the most common fuel system materials and the plans is one way to ensure reliability.

(Note that I'm not saying don't do this, you'll fall out of the sky, or anything like that.)
 
Brass and fuel? No, no problem there - just that the brass is not as strong as a steel or aluminum AN fitting under vibration.
 
its not the life expectancy of brass using fuel. Its the hose, and what the additives may do the the hose liner. Brass was used for years, and still is in some cases. BUT----things do change---
Tom
 
TS Flightlines said:
its not the life expectancy of brass using fuel. Its the hose, and what the additives may do the the hose liner. Brass was used for years, and still is in some cases. BUT----things do change---
Tom
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The fuel line for the low pressure side and return line is fine. But we are looking for fire sheathed type lines for the FWF.

Any suggestions?
 
TXFlyGuy said:
The fuel line for the low pressure side and return line is fine. But we are looking for fire sheathed type lines for the FWF.

Any suggestions?
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Call the guy who's been responding - Tom S. at TS Flightlines. It's what he does, and he does it darn well. Lots of us flying with his gear.
 
Brass

Certified Pitts uses a brass elbow to connect to the early style Lycoming oil pressure port where there is a clearance problem between the fitting and the engine mount. Never heard of a problem with one of these. I have the same setup on my new Lycoming powered homebuilt. No AN fitting will work in that area.
Many AN fittings are available in brass.
 
Wow, I did not know a DAR could do that. My engine compartment is FULL of brass fittings, who was that DAR?
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Brass

TXFlyGuy said:
Local DAR said "pull them out!". Replace with aluminum fittings.
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As I said before there are many AN fittings available in brass. Melting point of aluminum 1218 F, melting point of brass 1700 F.
Piper used brass fittings extensively for many years may still use brass fittings in primer lines on carburetor airplanes.
This is clearly outside the authority of the DAR.
 
An email from the DAR...

Hi TXFlyGuy,

That is tight for sure.

Ultimately, you want a flared fitting and aluminum/stainless tube assembly. And, I recommend that Adel clamps be used in lieu of aluminum strap with gasket material.

Also... I never recommend the use of thread putty or Teflon on tubing/fitting connections. One of the highest risks associated with Amateur-built aircraft is the likelihood of fuel system failure, especially early in the Phase 1 flight testing. My goal is to never see a builder experience fuel system issues.

All the best,

Tom Willis
EAA Technical Counselor At-Large
 
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