FYI--- Gas Caps

[M Towsley]

Re: FYI--- Gas Caps

Hank,

I have a good wing tank cap on my plane I can use as an example, but would really like to borrow a good correct main tank cap.

I really would like to get to my old BC-12D but it has moved since the last time I talked to the owner and it just isn't possible at this time. I know it had correct main and wing tank caps.

Do the tubes look like steel?

Let me know. Thanks.

[Hank Jarrett]

Re: FYI--- Gas Caps

Looks like a copper or brass tube (nice and soft, easy to bend) and is brazed in. I need another main cap so if the caps you found look the same send me a couple and I will make one for each of us to match my original. I'll check with the engraver to see what he wants to engrave the markings.
Hank

[M Towsley]

Re: FYI--- Gas Caps

Hank,

I ordered three caps today to see what they look like. I will let you know when they get here and after I compare them with one of my wing tank caps. There are several people who have PM'd me wanting caps. I wanted to see how these go and plan from there. I will e-mail you this weekend to work out the particulars. Thanks!

[M Towsley]

Re: FYI--- Gas Caps

Here is a picture of the caps. At first glance they look like the same exact cap used on the Taylorcraft. I think they sent the wrong gaskets, though. I will call them next week to find out.

I found out I have a friend who has a plasma cutter, (he owes me favors), so I think I will get the dimensions on the tabs and let him cut-out a batch for me.

(Hank, I will then do some quick checking around here on engraving and get back with you.)

[Ron Coleman]

Re: FYI--- Gas Caps

I have a set of original caps. The text does not appear to be engraved. They were stamped. You can stamp the caps in about 10 minutes, I did, when I made duplicate caps.

RonC

[M Towsley]

Re: FYI--- Gas Caps

Hi Ron,

I know they were stamped, however, unless you have a steady hand they will look like one of my tank caps. The bottom of the word "GAS" is stamped off of the small flange and looks like, well, that it was stamped on by a guy that had a bad night before work. Plus, I haven't found a set of stamps that big locally.

If I can have them engraved quickly and cleanly, (and cheaply), that is the route I am going to take. If that doesn't look right I will search for some hand stamps. But from prior experience that can be tedious if I end up doing a lot of caps. I have had many PM requests for caps....

Thanks, though!!!

UPDATE: I checked the fit of the caps and compared them to my original tank caps. These are just like the originals.

[cvavon]

Re: FYI--- Gas Caps

Marty

took a look at my caps they are original the numbers are stamped and the vent tube is copper and is lead soldered to the cap will take photos if you need them just let me know chuck

[flyguy]

Re: FYI--- Gas Caps

Have no idea how much is original if any. Tube isn't I'm sure as it is stainless. Tube and tab brazed on. BC12D 1946. Guess I should strip and paint it,LOL.

[M Towsley]

Re: FYI--- Gas Caps

Yes, that cap is missing a tab and the tube doesn't look to be original. Thanks for the pic, though...

Chuck or Hank. Can one of you guys take a picture of the 12 gal tank cap, top and bottom and give me dimensions of the tube protusions on top and bottom, also the diameter inside and outside of the tube if possible.

If I remember correctly from my first BC-12D there was an angle cut in the bottom of the tube. I wonder if that one is copper, I would think probably a harder material. I may do that in stainless if that can be brazed, or whatever, to the cap.

As always, thanks for whatever you can do!

[cvavon]

Re: FYI--- Gas Caps

Marty

here are two photos of my caps that i took this afternoon after striping paint to see if they had stamped tabs new paint is wet so will take measurements when paint dries. It does have the angle cut on the bottom of the tube for the main tank float tube Chuck

[cvavon]

Re: FYI--- Gas Caps

Marty

Paint dried and took the dimensions of the small tube in main gas cap

The inside tube is cut on a bevel long side measured from cap is 7/8 " the short side is 7/16" the diameter is 3/16" ID the top protrudes 5/16" hope this helps Also the float wire is 15 3/4" long with a 5/8" long 90 degrees bend on the top the airplane was marked O indicated 2 1/2 gal in tank with this float
set up Chuck

[Robert Lees]

Re: FYI--- Gas Caps

Don't forget there is a little hole at the back of the tube in case the tube gets blocked by an insect:

[cvavon]

Re: FYI--- Gas Caps

Robert

the small hole makes good sense but on the day my caps were made the old boy in the factory was feeling lazy and forgot to drill them but can be fixed easy Chuck

[M Towsley]

Re: FYI--- Gas Caps

Rob,

I am not a wing tank gas cap expert by far, but your caps are the only ones I have seen with that hole in them. I have seen a few, but never with the hole.

I saved this photo when I first saw it several weeks ago and plan to use it to show the guy who hopefully will braze on the tabs for me.

[Hank Jarrett]

Re: FYI--- Gas Caps

Hey guys, I have been out of town for a week and looks like I missed a lot of the research fun.
First to Darryl (FLYGUY), I have a cap just like that with two tabs that was original on my 41 wing tank. I understand that some planes had trouble getting the fuel to start transferring from the wing tank and the larger vent tube was supposed to provide more ram pressure. Remember that the vent for the wing tank is in the LOW PRESSURE area of the wing (pretty close to the LOWEST pressure on the airfoil). That means the cap is seeing lower pressure and the fuel doesn't get pulled down the transfer tube as much by the net force (pressure head of the fuel LESS the partial vacuum from the upper wing). I wonder if they didn't put the caps with the big ram port on planes with poor transfer. My tank was TERRIBLE to get started.
That brings another point up. I also have NEVER seen a vent hole at the back of the tube. It helps defeat the purpose of the ram tube! I would solder the hole up and I put a vent cover over the tubes with large "REMOVE BEFORE FLIGHT" flags on them. One thing I plan to do is put NUMBERS on my warning flags. You know, "1 of 9", "2 of 9"...... I REALLY hate it when someone chases me out to the run-up area waving their arms trying to let me know my Pitot cover is still on! I chased a guy half way to the runway with his gas cap last fall. It flew off just as he began to taxi. Ever seen how fast the gas blows out of a wing tank with the cap off? You land REAL QUICK, whether you want to or not! We lost a Citabria that way just short of the runway. The plane was a mess, but luckily the pilot walked away.
Hank

P.S.
How about if we used fairly thick Hobby Shop brass for the tabs and soldered them to the cap along with the copper or brass vent tube (my tubs are awfully soft to be brass). The brass would be a LOT easier to stamp or engrave (you don't even want to ask the engraver to engrave steel!) and brass would still be plenty strong as a twisting tab in the same thickness. If you bend or break the tab in brass there is something wrong with the fit of your cap!