Extra fuel - to bag or not to bag...

[BDA]

I saw these and found them to be an expensive but interesting substitute for the Alaska Airframes fuel bags.
https://www.advdesigns.com/gilogasbagfu ... gIe1PD_BwE

https://www.airframesalaska.com/Liquid- ... 5.2bag.htm

https://www.skycowboysupplyco.com/produ ... inment-bag

I will need some sort of extra fuel bag because it is a LOOOONG way between airports here. Will have to build some kind of a rack or box for them I guess. I have considered building a tank that bolts into the passenger seat position.
My cabin is 3 hours from my house at 100mph, so extra fuel is a must.

Anyone else have any other fuel ideas??

[BDA]

BUT...

A fuel bladder under the floor in the baggage area might be better!! Header tank replacement?????
http://atlinc.com/rangeextender.html

https://www.youtube.com/watch?v=taNoJS2AkYg

[BDA]

Has anyone deleted the stinger down the center on the bottom and just covered it flat across so that a belly pod could be mounted like the supercubs do?

A belly pod the same shape as the normal Superstol belly could hold a fair amount of fuel. Roughly 11 gallons if it was 3' long.

If it was made so that it came up through the floor boards on both sides of the control rod to make the baggage floor flat it would be around 21 gallons!

[danerazz]

Two words:

Drop Tanks

[Clark in AZ]

I've recently seen a pic of a SuperSTOL with long range tanks installed in the wings. Can't find it though, I'll keep looking.

It had aluminum tanks (smaller than the regular tanks) maybe 5-7 gallons each? They were in the next bay out on each wing.

Clark

[alan]

I bought a 10 gallon plastic fuel tank from Summit Racing several years ago. Mounted it using a couple of 1"x 1/8" aluminum straps right behind the seats. Plumbed it into the electric fuel pump system and used it first on every flight. It worked perfectly. Then my original fiberglass tanks started to dissolve. With 26 gallons of new aluminum wing tank fuel the auxiliary tank became redundant so I removed it. I can't find I picture of it anywhere.

Alan

[BDA]

Clark, that was Chris Wallen I believe, that put those in.

Before I covered my wings, I made a mock up and was about to weld some up - but after talking to Troy decided not to.

Weight in the wing is more "over-center momentum" when on the brakes as the fuel sloshes forward.

Supercub guys have proven that the belly tank is the best way to carry extra fuel - down low, and as far forward as possible.

Alan, I really liked your setup and had planned to do that - still might - but its hard for me to give up that space. When we load Moose quarters into the plane it is hard enough to get them over and behind the seats (my baggage door is not big enough for Moose quarters).

At this point I will most likely take the first baggage floor board out, and build a tank that goes under the control rod (and around) to make the new floor level above the rod, so it does not have that goofy cover over it. Moose quarter is going to crush that thing.

I wish I had thought about the belly pod thing before I covered the bottom.

[BDA]

Dane,
Drop tanks like the ones Hal is using? WW2 style?

[SheepdogRD]

Drop tanks like the ones Hal is using? WW2 style?

If you have drop tanks like those, you probably need to add invasion stripes to your paint scheme...

[danerazz]

I still like my idea of removing the wingtips and building tip tanks that “plug in” to the ends of the spar and are just 12-18” extensions to the wing. Easy on, easy off. Have to put a port in the outboard of the wing tanks, and a fuel line with a check valve so they just gravity feed to the mains. Even conservatively a 12” extension would easily be 5 gallons per side.

The whole thing could just be sealed aluminum riveted construction with tube mounts that telescope into the end of the spar tubes. Add a filler and vent and you are good to go. Just have to make sure the mains are vented in such a way that they do not gravity feed and overflow when everything is full.

Could plumb the tips separately into the header with shut off valves, only to open after the mains are burnt a bit.

[R Rinker]

Dane, I can tell you the experience the C-185's have had with the flint tip tanks. MAF used them in their 185's, and told me they caused the spars to develop stress cracks due to the long arm and pressures produced by that long arm in turbulence. And the 185's have a hefty built wing, and over 3000 lbs not terribly reactive to turbulence. Your airplane is very light and is highly reactive to turbulence. I put the flint tanks in our 182 and always tried to burn them off as soon as I could. Also, it's good practice to pick & choose the conditions you will actually fill them up and operate in. The light tube spar in the Just aircraft would certainly limit extra mod's in the wings for me. This is one of the frustrations of an extreme light weight airplane, which is an ultralight but designed like a utility airplane. Because of it's light weight it achieves extreme short field performance, and that makes folks like us who want to use it in remote operations try to configure it to do so. But at the same time that light weight construction does limit modifying the airframe. I guess the next step would be to develop a design that is a true utility airframe, sacrifice some of the exteme performance and make it with the structural integrity to do what a utility airplane must do and have the usable range to do it. I lived 100 miles above the Arctic Circle for years at Old Crow. Fuel....both in tanks usable for long range flying, and ability to transport fuel in cans for skidoo's, boats, etc., was our #1 issue always. Every time we came home from a supply trip to town, we were a flying bomb.
Of course, the discussion here is what is practical for Just aircraft. To me the best options are belly, baggage, or remove the right seat and tank that area. The concerns to be dealt with are obvious.

[danerazz]

Understood and considered. The Flints added somewhere around 14 gallons per side. That is 84lbs of fuel plus the weight of the tank. I am suggesting 3-5 gallons, 18-30 lbs of fuel. Obviously consideration would have to be given to the conditions, but if you are just wanting an extra hour or so of fuel I still think it could be done without any adverse effects.

With that being said, I think a belly tank with 5-7 gallons and an electric pump to transfer would be better. Most of the highlanders have an extra, unused gear attach point at the back, you could build a simple tubular tank (preferably with internal baffles) and figure out a forward attach point, punch a hole in the belly for a hose and power to a pump, maybe a sender.

[R Rinker]

I'm in Canada. I saw a quality boat tank yesterday at Canadian Tire, for less than $90 Canadian, about $60 US. It was 12 gallons and a flat profile, very heavy wall tough built with tie down grooves molded in. It had a quality filler set up with the ability to open or close the air vent easily. (Must remember to open this vent when pumping) It had a built in quick release boat type fitting for the gas line connection. This tank could easily be strapped down, just mount a 12 volt pump with a quick release connection. Tee in an access line to one of the wing tanks at the wing root. Use quick release fittings for the hook up, and it can be quickly removed or set up when needed. Two could be set up for long range use.
I used to have a similar set up in the baggage area. The pump was permanently mounted on the airframe and the tank plumbed to the pump. You would fly on the right tank to drain it down, then switch to the left tank, then pump the aux tank into the right tank. If you didn't switch to the left tank, but operated on the right tank while it was being filled, when the aux tank ran dry and pumped air into the line, the engine would instantly quit but would also instantly restart when the line was switched left. Greatest way to scare a passenger to death. Recommended to wire a warning light into the panel to remind pilot when the pumping sequence is active, since it has to be manually turned off.
My flint tanks were 12 gallon tanks. My point being the Cessna wing being built much heavier, the effect of a 5 gallon tip tank on a Just aircraft wing would be similar stress. The idea of putting baffles in a homebuilt tank, especially if it was long & skinny is a point that must be remembered. Very important. I can't imagine the effects of fuel sloshing in a half filled tank when rotating the aircraft without baffles!!