Sonex Fuel Tank & Oops Fittings

[GordonTurner]

I have just received the tools from Ben.

Who's next?

Gordon

[rizzz]

OK, so far so good.
I filled the tank and left it overnight, no leaks.
I then went for a fly, did some aero's and pulled quite a few G's, still no leaks.
The fix seems to work so far.
I will report back here in a few weeks time with an update.

For the people interested in how this fix is done, the pictures I posted show the idea but just in case here's an explanation (of course this is not a Sonex approved fix and should be done at your own risk!):
1: make little plates out of 1/8 6061, about 1" larger than the fitting they will go around. You can make these plates square or octagon shape or something like that, the idea is you can use a spanner on them to tighten them against the tank.
2: drill and tap a hole so the plate can be screwed onto the NPT fitting. make sure you tap it far enough so it can be screwed all the way to the back.
3: with the plate on the NPT fitting, cover the contacting side in Permatex #3 Aviation Form-a-Gasket and screw the NPT fitting into the molded fitting in the tank, tighten as per normal.
4: turn the plate back on the fitting until it contacts the tank & molded fitting, tighten slightly using a spanner.
5: leave overnight before putting fuel in the tank (I did anyway).

[Waiex 49]

Hi Michael,

Nice job on that repair!

Professional looking workmanship.

Thanks for sharing this.

[BRS]

OOPS!

When I renovated my Sonex-A I had installed a fitting in the fuel tank outlet with plans to eventually replace it. It needed to be replace with a screened fitting.

Today while making that change I ran into a delima. The fitting would not come out (did I use loctite? Don't remember). So I could keep pulling on the wrench and either it would give or the fuel tank insert would give. Either way, there needed to be a screen in there. Well since I'm posting on this thread, you can guess it was the insert that gave in first. Spun two flats.

Good thing, I pre-emptively purchased a set of OOPS fittings a few years ago. Bad thing, the AN fitting is still in the tank insert and is in the way. So now what? All I can think is to drill through it with a 1/2 step bit at which point it should break off. Any other ideas?

Also, after reading the instructions and the first 5 pages (10 pages to go) of this thread I'm still questioning the need for the 1" drill bit. My Step bit stops at 1" then can be just pushed through. Will that not leave a clean enough hole?

Thanks!

[Bryan Cotton]

I preemptively installed oops fittings. I took a regular fitting and drilled a hole in it to use as a guide for a holesaw. Worked great. You could do something similar.
viewtopic.php?f=33&t=1916&hilit=oops+fitting&start=40

Either a bushing, or a stepped rod that matches the ID of the AN fitting.

Edit: here is another picture.

Oops fitting holesaw setup.jpg (50.83 KiB) Viewed 16293 times

[BRS]

Thanks Bryan,
I had seen your post as I read through the thread but didn't realize what you were showing. I understand now. Might do it that way.

-brs

[Bryan Cotton]

The holesaw will either go around that AN fitting or saw right through it.

[DCASonex]

I have the OOPs fitting tool kit that I made up some years ago. Many others have used it and added to it. PM me your mailing address, and I will send it out Priority Mail. (assuming you are in the US). When returning, just include cost of my shipping it out.

David A.

[Bryan Cotton]

I have the OOPs fitting tool kit that I made up some years ago. Many others have used it and added to it. PM me your mailing address, and I will send it out Priority Mail. (assuming you are in the US). When returning, just include cost of my shipping it out.

David A.

That tool is awesome! Glad to see it is still making the rounds. Thanks David!

[BRS]

I have the OOPs fitting tool kit that I made up some years ago. Many others have used it and added to it. PM me your mailing address, and I will send it out Priority Mail. (assuming you are in the US). When returning, just include cost of my shipping it out.

David A.

Thank you David. Yes your tool seems to have quite the reputation. PM sent.
-brs

PS. I'm not sure what all is in your kit. Should I hold off on drilling my hole unti it arrives?