Wednesday, December 29, 2010

Installing a gas tank in an ultralight aircraft (such as the FAR Part 103 Belite!)

Another easy task is mounting our 5 gallon, spun aluminum gas tank in our ultralight aircraft, the FAR Part 103 Belite aircraft.  These tanks weigh less than 5 pounds, are extremely rugged, and are painless to mount and use.  They are clearly preferable to heavy plastic tanks used on certain earlier ultralight aircraft.

(If you are new to this blog, you'll find several other detailed construction posts on other topics [such as building carbon fiber wings].  Just poke around the search box until you find them.)

The major component of this tank installation is the aluminum tank.  We use an off the shelf 'dune buggy' style tank.  They are available from many different vendors online.

Before starting installation, consider the usage of a fuel sender -- this requires tank modification before
installation.  I'll cover that in another post someday.

I like starting with a picture of what the job looks like when it's done.  Here's a view of everything, all done:



The tank is mounted to our aircraft frame by bolting the circular fuel tank straps to the pre-existing steel straps on the fuselage:




Insert a brass right angle fitting into the tank (use gas-proof teflon tape).


Then connect the fuel line to the barb fitting.  Seal with safety wire.  The fuel line is then routed to the quick release fitting on the lower corner steel gusset:


You don't have to use a quick release fitting, but we sure like them.  It makes it easy to drain the tank at the end of the flying season.

Important note:  We always drill a small vent hole in the middle of the filler neck.  This provides a safety vent, in case the gas cap vent gets clogged.

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