Aux Fuel Tank Plans

[Gunther]

Hello to all. Does anyone know where to find the auxiliary fuel tank plans that Steve/Sonex #892 posted on the old yahoo site?

I searched the yahoo archives and was unable to find them. I would greatly appreciate if anyone could point me in the right direction.

A big thanks to Steve for originally posting and sharing his great idea.

Gunther

[sonex892]

Hi Gunther

When Sonex said they were closing sonextalk. I removed my files from there and loaded them in the files section of the old Yahoo group, Sonexbuilders. Alternative wing rigging drawings are also there in the files section. If not already a member you may need to sign up.

https://groups.yahoo.com/neo/groups/sonexbuilders/info

Cheers Steve

[Gunther]

Thank you for replying Steve. I signed into Sonexbuilders successfully but can not open the files section. I must be doing something incorrectly. Is there any other way that I could access the plans?

I really like your tank idea. As an alternative to the fill spout, do you think it could be filled by allowing back flow from the main tank?

Thanks,
Gunther

[tonyr]

Hello Gunther,

I have copied Steve's Aux tank plan file to this location, top of page:

http://sonexaus.wikispaces.com/Ideas+for+more+fuel

Cheers
Tony

[Gunther]

Thank you Tony!

Gunther

[GordonTurner]

I really like your tank idea. As an alternative to the fill spout, do you think it could be filled by allowing back flow from the main tank?

I was wondering also if this would work. Should be plenty of gravity....how fast does 5 gallons free flow through AN6 tube?

[sonex892]

I really like your tank idea. As an alternative to the fill spout, do you think it could be filled by allowing back flow from the main tank?

Hi Gunther

I'm sure your idea could be done, personally I wouldn't as I see more reasons of why not to do it, than reasons to do it. Time to fill being the main reason, it could be quite time consuming. I think knowing when its full and venting could be other problems.

The way I fill the tank, inside the fuselage is one feature I don't particularly like. I don't use the tank that often so 95% of the time its removed from the plane. If I were to use the tank more often or not remove it at all I would consider installing a filler in the turtledeck with a rubber inlet tube to the tank.

Choice of plumbing to the carb may vary with your carb choice. Regardless you will need to pump from the aux tank. Its too low to gravity feed.

I have a Jab 3300 and retained the bing so plumbed from both aux tank and main tank to 3 way valve then to engine. Cannot feed from one tank to the other, this I don't mind as its impossible to pump fuel overboard out the vent. I use the electric pump only to prime the line initially after connecting the tank and for take off and landing. The standard jabiru mechanical pump draws fuel from the selected tank.

If using an aerocarb would be easiest to pump and transfer fuel from aux tank to main. I think Aaron K does this with his.

Cheers Steve

[GordonTurner]

Old thread, would like to throw this idea back out there...

I have looked at the idea of gravity filling an aux tank behind the seat. It looks to me like AN-8 hardware will gravity flow 3.5 gal/min with an 18”drop. AN-6 is just less than half that. So I envision the main line out of the tank being AN-8 hardware, already found a oops-like fitting in AN-8, to a T, one branch through a valve to the aux tank pump (w/ a check valve), and then to the aux tank sump. There will be a bypass around the pump with a valve for filling the aux tank.

Continuing from that T, forward to the main fuel shutoff valve, through the firewall to gascolator and carburetor. All of that can be AN-6.

I will vent the main tank to the aux tank and the aux tank to atmosphere. This should solve some of the other venting problems i have read about with the standard vent, and provide overflow back to the aux tank if you transfer too soon. The fuel transfer from aux to main will be back up the same AN-8 line, essentially backflowing into the main tank.

Comments?

[NWade]

What does this do to your CG?
What does this do to your safety in a hard landing or a rollover?
Are you comfortable routing multiple fuel and vent lines through the cockpit (keeping in mind that fuel vapor in a vent line is inherently more-flammable than liquid fuel)?

I'm not approving or condemning your idea; just some things to consider before making a decision.

--Noel

[GordonTurner]

Hi Noel

All points to consider. CG seems like it will work out in my rough calcs with the slightly heavier corvair on the nose.

As far as fuel lines, everything will be proper lines with AN fittings. It’s a little late in my career to start worrying about those....the fitting that concerns me is the main fitting on the bottom of that plastic fuel tank that’s sitting in my lap. The tank will be well secured of course, and not used on every flight, and only full at the beginning of a flight. At some point we pays our money amd takes our chances.

Anybody have any experience with filling an aux tank by gravity from the main tank? Anybody have anticipated problems or remarks about venting the main tank to the aux tank?

Gordon