Sonex Aux Fuel Tank

1

I have had several people ask about the details of my aux tank to extend the range of their Sonex. So I thought I would put together my parts list and how it is setup. The list does not include the various brass NPT fittings to connect the hoses to the tank (main or aux).

The site with all the tanks is: 12G Tank

(Note: I have updated the link to my new 12 gallon aux tank. The pics are still showing the 6.5 gal. Nothing has changed other than tank size).

They also have several other sizes that fit behind the rear seat well. I measured and the following fit comfortably. The 33″ is tight but possible and adds several more gallons.

They also sell the two brackets needed: Brackets

To mount it, I used 6061 aluminum “L” bar and mounted it by first resting it on the rear spar cap, then riveting it on the bottom and double rivet on the top. You have to notch toward the bottom and taper the top for the seat back (see pics below).

1

Here it is installed with the notches highlighted from the first picture.

2

I bought blue fuel line from Amazon and three quick release valves so it can be disconnected at two points for removal/emergency cutoff. One is by the passenger just below the air vent inlet, one between the fuel flow off the tank and the fuel pump, and the other is on the fuel cap so the cap can be properly vented yet still easily removed for filling.

I bought a one way check valve from mcmaster carr to prevent any fuel to flow back from the main tank.

I bought a 10’ length, not 5ft: Fuel Line

The 3 quick release safety valves: Valves

  • One by passenger knee, one by fuel pump and one at fuel cap

3

Fuel pump of your choice: Pump

Here is a simple bracket I fabricated to hold the pump steady.

99

 

I bought a generic fuel cap from the auto parts store with no valve button on the top. I think it was a 96 dodge caravan. I drilled and tapped it for a ¼” barb fitting from Home Depot. To double secure it, I then epoxied it.

89

The fuel cap vents out the bottom of the airframe through a rubber grommet. I also added a little fire sleeve to protect against anything in the cargo bay cutting it

 

The fuel cap vents out the bottom of the airframe through a rubber grommet. I also added a little fire sleeve to protect against anything in the cargo bay cutting it.

17

I wired the aux fuel pump to a 3a breaker on the panel. You can see when the tank is empty by air bubbles at the quick release valve by the passenger knee. It takes about 25min to flow all 6.5 gallons into the main tank.

With the Aerovee Turbo I can cruise at 135mph for 350 miles with extra reserve fuel on board.


Leave a comment