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Fuel lines

bob888

Well Known Member
Anyone have thoughts re pros/cons on Aeroquip flexible tubing vs stock aluminum tubing for the line from wing to tunnel?
 
Anyone have thoughts re pros/cons on Aeroquip flexible tubing vs stock aluminum tubing for the line from wing to tunnel?

Stock Aluminum is easy and inexpensive. IMO, you should make them from the outside in, rather than inside out as the plans call for.

What I mean by that is to make the two 90 degree bends outside the fuselage, add the hardware and flare that end. Then, feed the un-flared end towards the tunnel, get that length right as you fit it, and cut, add hardware, and flare the tube at the tunnel. The plans have you leaving the "outside" ends unfinished until it is time to mount the wings, which makes that a much more difficult operation, IMO.
 
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My thought.....that line is easy to make, and aluminum tubing is cheap and lasts forever. Upgrade to 5052 if it floats your boat, but flexible tubing is just money down the drain.
 
My thought.....that line is easy to make, and aluminum tubing is cheap and lasts forever.
I agree!

I added a couple of 90 degree bulkhead fittings for ease of installation.
One in the lower fuselage portion terminating near the tank pick up source
and the other in the tunnel wall. This will greatly simplify your tubing installation and allow you to complete the fuel lines except for a short piece
from the fuselage to the wing tank pick up fitting.
 
Thanks guys. Regarding Kyle's suggestion that the bending should be done first...can the tubing be installed (slide in from outside) with the wings on?
 
Yes - there's room to slide it in from the outside with the wings on. I just did this month or so back.
 
My thought.....that line is easy to make, and aluminum tubing is cheap and lasts forever. Upgrade to 5052 if it floats your boat, but flexible tubing is just money down the drain.

+1 -- Compared to making the brake lines, the fuel lines were a piece of cake. And I upgraded to 5052.
 
Plenty of discussion on the pro and cons of hose on this forum, but I would caution anyones use of multiple 90 degree fittings on the suction side. Might not be a big deal for most people, but if you intend to operate in very hot weather, high altitude, or with auto fuel, you really increase your risk of vapor lock issues. Every 90 is a restriction and creates a cavitation hazard, so use them sparingly. If you have to use a bulkhead fitting, see if a 45 will work instead.

I'm rebuilding my fuel system for the Rocket right now and since I plan on running auto fuel, I'm trying to eliminate all 90's in the system.
 
Lots of discussion on this topic over the years. While we are in the hose business, there are places where rigid tubes are better, and yes, less expensive. We do combinations of both. Its really up to the builder and what her wants for his plane.
Tom
 
good point

Plenty of discussion on the pro and cons of hose on this forum, but I would caution anyone use of multiple 90 degree fittings on the suction side. Might not be a big deal for most people, but if you intend to operate in very hot weather, high altitude, or with auto fuel, you really increase your risk of vapor lock issues. Every 90 is a restriction and creates a cavitation hazard, so use them sparingly. If you have to use a bulkhead fitting, see if a 45 will work instead.

As you see in my tag line.
My 10 is set up for auto fuel and I do operate in very hot weather and high altitudes and without any issues.
I do agree that 90 degree elbows should be avoided but the 2 elbows in my fuel system along with multiple other 90 degree "corners" to and from the Andair fuel selector have not cause any fuel delivery issues.
 
Thanks for that data point Ernst. I hope everyone reading this understands that my words were not to be taken as an admonition not to use 90's, but more as a reminder that if you have a choice, think it through. Much like the general guidance to "build light", the penalty for taking the slightly easier path during construction will stay with you forever.

Homebuilts have a notoriously bad record when it comes to fuel delivery issues. I just want everyone to stack the deck in their favor - even for something as insignificant as your choice of fittings.
 
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