Fuel tank upgrade

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Includes: Highlander, Escapade, Summit and SuperSTOL.

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Re: Fuel tank upgrade

Postby z987k » Tue Jul 17, 2018 8:31 pm

danerazz wrote:Just cap off the spars and fill them. Should be able to get about 11 gallons in all four spars (total).

Aaannnnd....comment!

I mean, I like the idea. Sounds like a leaky nightmare, but I like the thought.
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Re: Fuel tank upgrade

Postby Clark in AZ » Tue Jul 17, 2018 11:24 pm

What a CG nightmare!
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Re: Fuel tank upgrade

Postby danerazz » Wed Jul 18, 2018 7:51 am

Not really, about 36 lbs slightly aft and the same slightly forward

Now that I think about it, you could make tubes that slide in from the wingtip and fit in the cutouts in the ribs. If you did it before the wings were covered, you drill a hole in the outboard end of the wing tanks, install a connecting tube with a check valve so fuel only runs inboard from the tubes.

Then again, I forgot about the drag/anti-drag tubes...
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Re: Fuel tank upgrade

Postby danerazz » Wed Jul 18, 2018 8:05 am

External wing tanks that attach to strut brackets and have electric pumps

Wing tip tanks that are profiled to wing shape, and could attach by telescoping tubing that extends into spars (they would “plug-in” to the end of the wing)

Belly pod with electric pump


I’ll admit, the wet spar was sarcasm, but now I am seriously considering some of the other options...
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Re: Fuel tank upgrade

Postby av8rps » Sat Sep 22, 2018 11:16 am

I think there is an opportunity for someone here. Someone should build a auxialary, easily removable belly tank for the Highlander and Super STOL that can be installed as needed.

I have small tanks on my Highlander, and most of the time they are fine for what I do (fwiw, in 2007 we flew two Highlanders on amphibs from WI to Sun-N-Fun and back on the 9 gallon tanks, stopping every 3 hours for fuel). So one can certainly make them work. And frankly, I really don't want to add more weight to the plane when I really don't need it. And I really don't want to tear my wings apart to put bigger tanks in. But for the times I want to take more fuel it sure would be nice to attach my belly tank and gain another 10 to 15 gallons of fuel without carrying it around in bags or cans.

My vision says it would be molded fibreglass to closely conform to the fuselage shape so as to reduce drag, much like you might see on a Alaskan SuperCub, that is attached to the fuselage right at the CG. It would have a small fuel pump to either power direct to engine or to pump into header or wing tanks. It could even pump into a seperate header tank? But then again that would be more weight in the fuselage that would be there even when you didnt have the belly tank attached. Hmmm? But maybe that could be used for more fuel when you don't need that extra 10 to 15 gallons? A 4 or 5 gallon header tank by itself would help all of us with the small tanks since that's another hour of fuel typically.

I will probably add some bladders in my amphib floats with pumps, as it seems that when I fly on floats is when I want more fuel. Plus, amphibs typically move your cg way ahead, so I would place the bladder tanks in the floats behind the cg in an effort to offset the normal forward cg you get when going to amphibs.

There you go guys, there's the solution as well as the challenge to someone that has more time than I do to produce this.

Oh, and for someone not wanting or needing more fuel, the fuselage drop tank shell could be configured for more baggage area. Or maybe just to carry a gas bag or two, again, keeping all the weight on the cg.

I may have had a little too much coffee this morning... :wink:
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Re: Fuel tank upgrade

Postby marl59 » Fri Sep 28, 2018 11:48 am

I built a removable aux tank set up using a Summit Racing 8 gallon oval track tank. I made a cradle with lift handles for easy removal. It sits directly behind the seats. I plumbed it into my fuel line upstream of the fuel pumps via a T fitting. It has an inline shutoff switch and a quick disconnect that seals at both ends when disconnected. The tank comes with a port to install a vent. So on a long trip I burn it out first then switch to my wing tanks. It works great. I recently flew from Central California to Central Idaho with only one fuel stop. I have a Bonanza with 4 separate tanks so I'm used to fuel management with multiple tanks. When I'm flying local I remove the aux tank and run the wing tanks. The Aux tank when full moves the CG aft a little bit but doesn't affect the flight characteristics much at all. If anyone asks I can post pics. The whole thing cost me less than $300 including the AN fittings.
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Re: Fuel tank upgrade

Postby Clark in AZ » Fri Sep 28, 2018 5:42 pm

marl59 wrote:... If anyone asks I can post pics. The whole thing cost me less than $300 including the AN fittings.


YES! I would love to see some pics.

Thanks,
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Re: Fuel tank upgrade

Postby marl59 » Mon Oct 01, 2018 10:37 am

Hi Clark,
Here are some photos of the tank.
Attachments
Highlander Aux Tank 2.jpg
Highlander Aux Tank 1.jpg
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Re: Fuel tank upgrade

Postby Clark in AZ » Mon Oct 01, 2018 10:42 am

Cool! Thanks for posting!

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Re: Fuel tank upgrade

Postby av8rps » Sun Oct 14, 2018 10:54 am

Could I impose on you to show us a pic or two of how it fits in the aircraft?
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Re: Fuel tank upgrade

Postby marl59 » Mon Oct 15, 2018 11:52 am

Sure,
I reinstalled it Saturday for the High Sierra Fly-in. I'll take some photos after work today.
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Re: Fuel tank upgrade

Postby marl59 » Tue Oct 16, 2018 12:07 pm

Sorry, I'll have to take the time to convert the files to JPEGs. This site does'nt allow HEIC files.
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Re: Fuel tank upgrade

Postby BDA » Tue Oct 16, 2018 5:34 pm

How much does it affect the weight on the tail wheel in that location?

Does tail feel really heavy?
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