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Rob's REBVAIR Project
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Date:  9-20-2017
Number of Hours:  10.00
Manual Reference:  
Brief Description:  Fuel system design and install (part 2)

There is little room between the wing and the fuselage for the fuel system plumbing. My setupis reminiscent of many other designs, but robustly attached to the fuselage, rather than off the NPT fittings on the wing. There's so little space in fact that I had to use commercially available elbows in most places to keep the arrangement compact. 3003 grade aluminum 'versatube' was used in final connections to the wing since it could be bent to more acute angles than 5001 grade tubing (used everywhere else). Since these are all 'vent' connections (not fuel delivery to the engine), I'm not concerned about sharp bends in the plumbing.

This layout implements Wayne's suggestion to have the cross-tank vent pass through the forward part of the fuselage, instead of just overhead the pilot and co-pilot seats (as described in the plans). This places the vent closer to the true apex of the fuel tank. More importantly, doing so creates more space in the very congested area where the top wing vent and the sight gauge need to connect. There's also a J-tube ram air vent, which also precludes the need for special welding/brazing of the fuel tank caps.

The order of construction is noteworthy: I worked from the cross-vent backwards. With the 90 degree bulkhead fitting installed in the wing-root on the fuselage, I selected the approximate location of the sightgauge top hole, and prepared a small piece of 3/8" tubing (flared, with blue AN nuts) that bridges the forward fitting with the two sequntial tee fittings (black) and the second black elbow. Once everything is connected, you can assess where to drill the second hole for the AN to NPT elbow.

That black fitting has the 1/8" NPT threading poking through the fuselage. On the inside, I use a female NPT elbow to connect to the sight gauge fittings (Straight 1/8" NPT to hose barb). With NPT threads, there are always 'exposed' threads between two fittings even though the connection is tight. That gap is t
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fuel system vetn plumbing

fuel system vetn plumbing

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different view

different view

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cross tank vent

cross tank vent

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