Main Fuel Tank

[Soaringpilot]

Pulled the main fuel tank out of my BC-12D due to leaking. My welding shop said it needs to be replaced, so I purchased one from Wag Aero. I just found out from another mechanic, who purchased one recently, that it may not fit. Anyone out there can add to that information? Is there any data available to modify it for an easier fit?

Thanks,
Ed K

[NC36061]

Re: Main Fuel Tank

Ed,

If you look at your old tank you will see depressions (dents) in the upper forward area of both sides of the tank. They are necessary to give clearance to the fuselage tubes in that area and are not built into the tank, you gotta make 'em yourself. Other than that it should fit if you ordered the right PN.

Dave

[Soaringpilot]

Re: Main Fuel Tank

Thanks Dave,

That new tank does have those depressions. Are you saying that they have to be modified (made larger) in order to fit? If so, what do you suggest on how to do that?

Thanks,
Ed

[Soaringpilot]

Re: Main Fuel Tank

Thanks Dave,

That new tank does have those depressions. Are you saying that they have to be modified (made larger) in order to fit? If so, what do you suggest on how to do that?

Thanks,
Ed

[NC36061]

Re: Main Fuel Tank

I haven't bought or installed a main tank from Wag Aero, just remember that they were being made without the dents and guys were having to make them to get them to fit. I did get new W-A wing tanks for our '41 project and they were perfect. Why specifically does the mechanic think it won't fit? I have never heard anything about their tanks being a problem. I would just give it a try, you might need to massage the depressions with a length of small diameter pipe or wood dowel and a rubber mallet or something if there is not enough clearance with the fuselage tubes. You want enough clearance for a piece of felt or rubber between the tube and tank. If there is any other issue, W-A should make it right for you. Again, never heard of a problem before.

[Guest]

Re: Main Fuel Tank

Pulled the main fuel tank out of my BC-12D due to leaking. My welding shop said it needs to be replaced, so I purchased one from Wag Aero. I just found out from another mechanic, who purchased one recently, that it may not fit. Anyone out there can add to that information? Is there any data available to modify it for an easier fit?

Thanks,
Ed K

What was the cause of the non-fit?

That's a pretty vague comment I would get some details if I were you.

It sounds odd.

You could also call WagAero and ask for Jonas and tell him your concerns. He may have insight or offer guarantees.

Dave

[McRay7ac]

Re: Main Fuel Tank

After trying to repair my main tank after several times welding and pressure checking i found out its best to buy a new one - order one from Wag Aero it fit just fine filled full fuel leak check it for week all check out.

Ray

[McRay7ac]

Re: Main Fuel Tank

After trying to repair my main tank after several times welding and pressure checking i found out its best to buy a new one - order one from Wag Aero it fit just fine filled full fuel leak check it for week all check out.

Ray

[woodmw]

Re: Main Fuel Tank

I replaced the main tank a few years ago with a replacement from Wag Aero. The indents were there, but not exactly in the right place. Couldn't get the new tank into correct position. Gentle but persistent persuasion with rubber mallet and wooden blocks fixed the problem.

Did the recommended test of filling the tank with water and letting it sit for some time before installing in plane. No leaks. Installed tank, plumbed lines in from wing tanks and out to gascolator. Put in 5 gals fuel. Saw no leaks. Two days later, saw fuel stain at bottom flange weld. Very small pinhole in weld.

[Hank Jarrett]

Re: Main Fuel Tank

The dents in the tank are not a myth. These planes were built with some kind of "loose" tolerances in some places. One was the tubes along side of the fuel tank. The guys saying to just "dent it in" are absolutely right. Just don't pierce the tank!!! You want a bit of passing clearance with the tubes for a spacer. They originally used a piece of rubber or felt, but I don't like the felt. It can hold water and corrode through the tank. A piece of split rubber tube works well and I have seen a few planes that just had electrical tape (which I also don't care for.

As for leak checks you should check the whole system to the gascolator but DO NOT PRESSURIZE THE TANK!!! Even a low pressure from a compressor will damage the tank. I used a condom and blew into the tank through the carb fuel line. Your lungs will not put too much pressure on the system when the condom inflates, but you need to get over the obvious weird feeling of blowing up a condom on an airplane. I don't suggest having any of the ramp rats around when you blow it up. That much laughter tends to draw a crowd, which the condom will anyway. If the condom stays inflated for and hour you have a pretty tight system. Better to find a leaking fitting BEFORE you put the boot cowl on (not after like I did!).

Good luck and don't forget to post photos. Just try to not giggle too much blowing up the system.

Hank

[Hank Jarrett]

Re: Main Fuel Tank

The dents in the tank are not a myth. These planes were built with some kind of "loose" tolerances in some places. One was the tubes along side of the fuel tank. The guys saying to just "dent it in" are absolutely right. Just don't pierce the tank!!! You want a bit of passing clearance with the tubes for a spacer. They originally used a piece of rubber or felt, but I don't like the felt. It can hold water and corrode the tank or tube. A piece of split rubber tube works well and I have seen a few planes that just had electrical tape (which I also don't care for).

As for leak checks you should check the whole system to the gascolator but DO NOT PRESSURIZE THE TANK!!! Even a low pressure from a compressor will damage the tank. I used a condom and blew into the tank through the carb fuel line. Your lungs will not put too much pressure on the system when the condom inflates, but you need to get over the obvious weird feeling of blowing up a condom on an airplane. I don't suggest having any of the ramp rats around when you blow it up. That much laughter tends to draw a crowd, which the condom will anyway. If the condom stays inflated for and hour you have a pretty tight system. Better to find a leaking fitting BEFORE you put the boot cowl on (not after like I did!). Also even TINY amounts of fuel will ruin the condom and it will tear where it goes over the filler neck.

Good luck and don't forget to post photos. Just try to not giggle too much blowing up the system.

Hank

[Soaringpilot]

Re: Main Fuel Tank

Thanks everyone. I think I have enough information to continue. I temporarily installed the tank today before sending it to the welders to put a few extra fittings on (vent line and such). It almost fit, which told me I could make it work. I'll get a broom handle and mallet to increase the clearance for the upper tubes.

Cheers,
Ed K

[astjp2]

Re: Main Fuel Tank

Is your original aluminum or tern plate?

[Bruce Caldwell]

Re: Main Fuel Tank

I just installed a main tank from W/A and it was really tight but did manage to get it in with quite a struggle. I didn't put any kind of rubber in between the tubes but I will work on that.

Bruce
N95893
46 BC-12D

[Bruce Caldwell]

Re: Main Fuel Tank

I just installed a main tank from W/A and it was really tight but did manage to get it in with quite a struggle. I didn't put any kind of rubber in between the tubes but I will work on that.

Bruce
N95893
46 BC-12D