Gas Tank

You might be familiar with, or have even used the expression "if they made it that way 100 years ago, we can do it now."  If I've learned anything working on old airplanes, it's that this is not always true.  Todays manufacturing environment demands low labor costs with production efficiencies.  Just look at the complex ways things were made long ago.  Companies would not think of doing it that way today!  In 1928, labor was cheap and they built equipment and machines to do just about anything.

The gas tank I just completed is a good example.  This was one of the more difficult things I've ever had to fabricate.  It would be interesting to go back in time to 1928 and see how Lincoln-Page made it.  Fortunately, my friend Mark helped out a lot.  The size of the metal sheets and overall size of the tank made it about impossible for one person to manipulate.

Original tank - 40 gallon capacity

Interior of metal skins showing corrosion

New metal skins and baffles

 Here you can see what I started with.  I initially thought it may be useable, but after looking inside with a borescope there was too much corrosion.

Close-up of baffles

After taking it apart, the level of corrosion was very evident.  Once apart, the old skins could be used as patterns for the new ones.























New metal skins were cut out from 22 ga. galvanized steel.






















There are 2 internal baffles that prevent the fuel from sloshing around too much.  These are held in with rivets.

The fore and aft portion of the tank

Baffles riveted to the side and top skin

Side/top skin being fitted

 As you can probably tell in the pictures, the tank is made from 2 pieces of sheet metal that are curved and held together with a seam.  So the first step was to form a 90 degree flange and a bead on the fore/aft skin.  This was done on my bead roller.

Fore/aft skin being fitted

Almost there!

A 90 degree flange was then formed on the side/top skin.  The baffles could then be riveted on.  The rivets are steel as they have to be covered with solder once the tank is complete to prevent leaking.












The 90 degree flange makes curving the sheets virtually impossible without kinking the metal.  It took lots of careful stretching in the stretching machine to get this piece to curve around correctly.












Just the opposite on the fore/aft skin as it required shrinking to curve correctly.  Had to work a little bit at a time here - a little shrinking, then fitting followed by more shrinking and fitting, etc., etc.












This is about as far as we took it.  Too much shrinking and stretching puts a lot of stress on the metal and I wanted to avoid any cracking.  Hand-fitting from here.

Rivets soldered over to prevent leaking

Ok, so I'm skipping a lot of steps here.  Believe me, it was not pleasant!  Getting all the flanges and seams to line up correctly was difficult to say the least.  the 90 degree flange of the fore/aft skin is formed over the side/top skin by rolling it over 180 degrees.  This was done by hand with a hammer and dolly.

Prior to assembly, the edges were tinned with solder.  Once crimped, more solder was added to make a nice, tight, leak-proof joint.  The baffle rivets could then be soldered over and all the other attachments soldered in place.

Filler neck and gas gauge mount soldered on

Here you can see the filler neck and mounting flange for the gas gauge soldered on.  The filler neck is a Ford Model "T" radiator filler neck.  It uses a threaded radiator cap as a gas cap.

Fuel outlet riveted and soldered

Here's the fuel outlet.  It was riveted first, then soldered as it has to withstand more stress when attaching the plumbing.

All done!

Here's the final product.  In spite of the grief it gave me in building it, I'm pretty happy with how it came out.  It was built exactly like the original.

 I still need to leak test it - screw on the cap with a good gasket, cover the gas gauge flange and attach an air hose coupling to the fuel outlet.  Pressurize the tank to a couple of psi, spray some soapy water on the flanges and hopefully, no leaks.  Probably not too big of deal if there is, just more heat and solder.

Besides the tank, the OX-5 is mostly done.  I'll do a final post on it soon.  For now, its back to airframe work in earnest.  Please check back soon...