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Luscombe Fuel Cells

Disclaimer: PopularAviation.com makes no claim or warranty as to accuracy of these articles. You and your mechanic are responsible for your aircraft.

By: Mike Culver
Posted: Wednesday, January 16, 2002

Fuel cells have been used in aircraft since at least the 1940s, as evidenced by many Luscombe 8E models that need attention due to leaks. The purpose of this technical artical is to explain the differences between various materials, as well as provide some guidance on installation. Much of the content for this article is pulled from a publication by Eagle Fuel Cells, in Eagle River, Wisconsin.

Before proceeding, an important point. The author purchased a new fuel cell in the spring of 2001 ($800), but had problems getting the work signed off. Seems that the manufacturer (Eagle) made the cell on a form 337, when in fact as a manufacturer it's required to use the PMA or STC process. The mechanic notified the FAA, and an ugly war started. Eventually everyone agreed to be adults, sign the paperwork, and never do things this way again. But what a mess in the meantime! If you order from the Luscombe Foundation, your cell will be manufactured under a STC.

Diagnose the problem before removing any fuel cells. Check gaskets, connections, cracked tubing, etc. Inspect the cavity for fuel staining, and have a very good idea where the leak is coming from before removal. This will be a nasty job (although the author found that it wasn't THAT bad).

Unscrew the many screws around the filler neck, remove the fuel guage, then remove the fuel lines. Careful! You WILL get a face full of fuel from the rear line. (There are two lines: one out the rear, and the other out the front of the bladder.) Remove your belt buckle and cover the wing with paper in order to avoid scratches. Finally, pull the bladder out thru the opening.

Preparation For Installation
Remove your belt buckle and cover the wing with paper in order to avoid scratches. Carefully inspect the cavity for rough edges and objects that could cut the bladder. As long as you're in there, look at the wing spar -- this is an area that has probably never been inspected. Tape any rough edges or rivet heads with duct tape. Never use glue or gasket cement, or you risk something moving, eith the result that the fuel cell is now glued in place.

Make certain the new fuel outlet tube will fit thru the spar. This hole is too small from the factory, given that new and repaired cells have a better (larger) tube coming out.

Old fuel cells stored for extended periods of time may shrink. You can fill it with warm water (120 degrees or more) to expand. The water needs to be in the cell for two to four hours for this to work.

The fuel cell needs to be warm! Easiest way to do this is toss it on the floor of your car, start the engine, turn heat on full blast, and go have lunch.

Fold and roll the cell, then insert thru the hole. there are snaps on the top of the cell that have corresponding snaps on the upper wing skin. They are convenient in that they hold the bladder in place. Work slowly, pushing the bladder out from the center. This will take you most of an hour before all the wrinkles are gone.

The fuel indicator is the most frustrating part of the job; specifically the bolts that hold it in place. Use some extra-long bolts as dowels to line everything up, and plan on several hours just to fight this one issue.

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