PA18 Aux Tanks

[markc]

Folks

Looking at the possibilityof Installing Aux Fuel Tanks in the PA18.

I guess there is an option of a Fus Tank, requiring a boost pump and additional tanks in the wings.

If installed in the wing, are they available as tip tanks or do additional bays need to be created in each wing.

What is the best method of connecting:

Fuel Selector (AUX L & R MAin L & R)
Gravity Feed via Interconnect in same wing
Left Aux - Right Main (Cross Feed), etc using gravity or a pump??

I am sure that there has been discussion over the years on many aspects of this matter and that by now a lot of those projects are in the air and there may be some valuable experience that can be passed on.

Can any one recommend suppliers?

Many thanks

 

[Crash]

Aux. wing tanks

Extra tanks in the wing have been tried for years. They stink!!! Go with either larger tanks(Dakota 24 gallon or Atlee Dodge 30.5 gallon) or a belly tank. Extra tanks in the wings went out about 1972, bad mod. Crash

 

[cubdrvr]

Listen to Crash. When I rebuilt my cub I reinstalled the aux tanks that were in the wings. I am going to now remove them....they leak and never did feed properly. So I will be back to the standard 36 gal. and do what we did years ago......throw in a 5 or two in the back if range is a problem.

 

[Dave Calkins]

Mark C., here's strike 3 for the 13 Gallons per side Aux. tanks in the wings.

Mine are leakers. They'll come out at next rebuild. Why we didn't take 'em out last time escapes me. Back then, Atlees tanks were available, but not what we wanted. The Dakota 24's have only recently become available (last couple of years).

The 24 Dakota Cub Aircraft fuel tank mod may just be the ticket.

The belly pod is another workable option. In my opinion, made better, by the Airglas combination baggage/fuel pod.

 

[flywhatever]

Aux. wing tanks

Extra tanks in the wing have been tried for years. They stink!!! Go with either larger tanks(Dakota 24 gallon or Atlee Dodge 30.5 gallon) or a belly tank. Extra tanks in the wings went out about 1972, bad mod. Crash

agreed!

 

[flywhatever]

Listen to Crash. When I rebuilt my cub I reinstalled the aux tanks that were in the wings. I am going to now remove them....they leak and never did feed properly. So I will be back to the standard 36 gal. and do what we did years ago......throw in a 5 or two in the back if range is a problem.

or throw in a couple Airframes overpriced fuel bags in your belly pod.

 

[mvivion]

I've flown a couple Cubs with two extra18 gallon tanks--one of the old "polar bear hunting special" solutions. Neither of those systems were really bad, but that's a LOT of fuel, and not that easy to verify you're getting it all to feed, therefore I always had more gas than I really needed, due mostly to paranoia. When all tanks were full, the plane felt pretty ponderous in roll....

Atlee 30.5 main tanks: Lots of them around in AK anyway. Again, 60 gallons useable is a lot. If I were to own/operate a Cub with these, I'd be sure to install a fuel flow computer system, again, to have a better handle on fuel on board. Those big flat tanks hold a lot of fuel, even when the balls in the gauges are near the bottom.

My preference, if starting with a stock plane, would be to install a combination fuel/cargo pod. I believe those hold about 18 gallons, which is a lot of gas added to stock tanks. Once the initial installation is done, it's not that hard to remove/re-install the pod when needed. And, you gain some cargo space as well.

Second choice would be Dakota tanks, the ONLY reason being that that installation may be more involved and cost more. Or not. I like gas in the tanks, available with little to no messing around to get it to the engine. While the pod requires a pump to move the fuel, my experience with those setups has been positive, with few if any issues.

MTV

 

[TR Dunn]

The mission should drive the decision. If maneuvering is required with full fuel (wildlife research for example), the fuel belongs on the longitudinal axis for best roll authority. I run an Airglas 32-gallon belly tank on my Cub, augmenting the stock wing tanks. I also run an ASC combination 26-gal fuel/cargo pod on our 180H with factory long-range tanks. For sucking seat cushion prevention, I also installed EI fuel flows that are dialed in tight. If fueling from your own bulk tank, it is also appropriate to calibrate your bulk tank meter at least once per year to ensure a gallon is really a gallon, just a tenth off per gallon results in a 10-gallon error on 100 gallons. I'm not a fan of additional weight (fuel) in the wings if maneuvering flight is required as roll control is degraded as supported by physics.

TR

 

[planenuts]

TR, on your PA18 belly fuel pod did you run the fuel line to a new port in the left tank, as instruction say, or did you run it to a
T with your left top fuel gauge port? Would be a lot of work to pull tank and weld in a boss, rather than just fitting in the fuel gauge.
Thanks
Bruce

 

[TR Dunn]

TR, on your PA18 belly fuel pod did you run the fuel line to a new port in the left tank, as instruction say, or did you run it to a
T with your left top fuel gauge port? Would be a lot of work to pull tank and weld in a boss, rather than just fitting in the fuel gauge.
Thanks
Bruce

Bruce, I pulled the tank and TIG'ed a female boss for top fill as instructed. This is more work but a more appropriate and correct install. I placed a piece of clear (fuel compatible) tubing above the check so I can easily see bubbles as the pump starts pulling air indicating empty.

TR

 

[TR Dunn]

An additional tip for those desiring to maximize external tank capacity. The placement of the filler neck on the Airglas 32 does not allow for filling to full capacity when in a 3-point attitude, extended gear and large tires only exacerbate this issue. An air slug sits at the front of the tank and has no way to be displaced by fuel resulting in one thinking their tank is full when in reality it is not. Two solutions; Place the tail on sawhorses while filling to bring the filler neck above front of tank (a real PITA), or drill into the most forward portion of tank as near top as possible and epoxy in a 1/8" quick drain which you can open while filling allowing the air to escape. Once fuel pee's out the quick drain, you know you have a full tank. Close the drain and press on knowing you are at maximum capacity. Note, the ASC fuel pod for the Cessna series does not have this issue as the filler is far enough forward to allow the air to escape resulting in a full fill. This is by no means a slight on the Airglas tank as their products are exceptional IMO.

TR

 

[skywagon8a]

I don't know how easy this would be to do after the tank is already built? I made several aluminum belly tanks with an internal vent tube starting at the forward upper right corner running along that seam to the the filler neck and up to the top of the neck. It solved the air trap issue.

 

[TR Dunn]

I don't know how easy this would be to do after the tank is already built? I made several aluminum belly tanks with an internal vent tube starting at the forward upper right corner running along that seam to the the filler neck and up to the top of the neck. It solved the air trap issue.

Easily accomplished installed on the aircraft. Have done a few. I can't take credit for this "fix" as it was recommended by Gary (as I recall), at Airglas, while I was living up North and working my Cub. I required every drop of fuel I could get in there and this was his solution. It works.

TR

 

[TR Dunn]

Here is a shot I had in my phone, can see the little quick drain at top of tank, does the job of purging air when opened. Was really required when on extended gear and 31 ABW's or skis. TR