Quickie Q2 Lite Construction Manual - page 271
HEADER TANK PLUMBING
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Prior to permanent installation inside the fuselage, the
plumbing for the header tank should be installed. The accompanying
drawing shows the location for all header tank plumbing. The fuel
feed to the engine should be patterned after the main fuel tank feed
shown on Page 14-3, including the screen and flox, but omitting the
drain valve. Both the feed line from the main fuel tank and the feed
line from the engine should be made from 1/4" 0.0. Aluminum tubing.
Allow the tubing to extend out from the header tank about 6 inches.
Use liberal amounts of flox to seal the exit points.
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The fuel overflow return tube is made from 5/8" 0.0. Aluminum
tubing. It should extend to near the very top of the aft part of the
header tank, in order to maximize the fuel capacity. Permit it to
extend about 6 inches below the header tank, and seal the exit point
with flox.
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The routing shown for the plumbing is nominal, but will avoid
interference.