Previously enquired about ideas on taking extra fuel for longer trips - excellent ideas in return.

As I really don't want to open up the wings for another tank, add tanks to struts or internal tanks; ...has anyone thought about making - say the first section of the inboard slat - a "wet slat  tank" by using pro-seal or some other product?? Not looking for a lot of fuel and weight - just five gallons - so area from inboard end to first rib would be about 2.5 gallons ( 15 lb) per side.  Very little added weight - fuel lines, sight gage, vent  and valves. 

Had the outboard section of slats opened to add strobe / wig wag lights ( LED kit from Crazedpilot.com 39.00 bucks for landing?,  wig wag and wig wag strobe) and it fueled, pun intended, the thought - simple. not much cg change, fairly strong area close to  centerline, gravity feed, short run to fuel system etc.

Still grinning !

Phil Smith

CH 70wonderful

Buhl, ID

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In lieu of installing auxiliary fuel tanks any other way, I think it's a great idea and cannot foresee any reason not to.  You may be blazing the trail on this, and I look forward to seeing how it turns out. 

although you didnt want inboard tanks I had contemplated getting a pair of 5" Al irrigation pipes welded up with end plates and fuel hose fittings to mount vertically in the rear baggage shelf  on each side.

inserted in existing fuel lines (mine run from aft wing root down rear door corner posts) and a fuel pressure warning switch could be added to the top if desired.

the main function is to give a header tank to each wing tank (the standard configuration is susceptible to unporting)

Phil, I know you are reluctant to open the wing ..BUT a fairly easy addition is to add the OLD zenith 5.5 gallon tanks outboard of your mains , they fit between the ribs and extend back only about10 inches and are tight to the spar so on CG ,you only have to put a "T" fitting in the main  tank outlet and a electric solenoid between the two tanks to block the  aux. tank, you can use a dual tank switching valve from NAPA and plug the normally open port , with this set up you need NO gas gage because the main tank will read fuel until the aux. is empty , I switch on the aux. at half tank on main ,I have right and left toggles only on dash for the two tanks , and it works flawlessly . 

Bob,

Sure would like to see pictures or sketch of your setup - also maybe some part numbers etc that would get me on the right track.  Seems five gal tanks are available from Zenith or could build my own.Did you do this like I willl as an after thought or from the beginning??  Trying to visualize the system setup: T fitting would go to main tank and aux at the rear outlet of the main, is the electric solenoid in the line between tanks or between main tank and T or where??  Any info would be appreciated

Still grinnin !!

Phil

madriver42 at gmail.com

PHIL, THE "t" FITTING GOES IN THE OUTLET FROM THE MAIN TANK , THE DUAL TANK FUEL SWITCHING VALVE GOES IN THE LINE BETWEEN THE AUX. AND MAIN , YOU PLUG THE {NORMALLY OPEN   PORT ON THE SWITCH VALVE]  THE FUEL THEN ONLY PASSES THRU WHEN YOU ENERGISE THE SOLENOID,.. SINCE THE AUX. TANK ENDS UP HIGHER ON THE WING , [OUTBOARD OF THE MAIN AND CLOSE TO THE SPAR  IT GRAVITY FEEDS THE MAIN AND PASSES FUEL THRU THE "T TO THE ENGINE .., SINCE THE MAIN TANK FUEL IS IN THE LOWER HALF OF A HALF FULL TANK , THE AUX. FUEL ENDS UP ABOVE THE MAIN FUEL LEVEL , THAT WAY THE MAIN TANK FUEL GAGE IN THEORY WILL READ FUEL UNTIL THE AUX IS EMPTY , AND ALSO THE MAIN TANK FUEL  WILL NOT ALLOW AIR INTO THE EMPTY LINE FROM THE AUX.TANK IF YOU DONT CLOSE THE SOLENOID  

Loren,

Just seemed like an easy solution - further thinking leads me to a couple of things: first one could seal up as much as you wanted  - within weight reason - and then easily plumb it down the front "A" pillar to the regular fuel line.  Think about this: vent the tank with an inverted "L" vent, install a fuel pump to back-fill the tanks during refueling thus no cap, then use it as required by valving  the lines from the "slat tanks", make a sight gage on the inboard slat cover and you could still fly while you are whooping all this up with the slats removed - further checking the capabilities of the 70whatever you have.

Just my thoughts

Phil

In the spirit of experimenting, another idea I imagined is to plumb the slat tanks to the main tanks so that it will fill and vent with the main tank.  To do this,

Replace the elbow fitting coming out of the bottom of the main tanks fuel supply with a "T" or "Y" so one branch flows as it normally does, and the other goes to a high area of the slat tank.   This, in theory, would allow the slat tanks to fill at the same time as the main tanks.  As for venting, let it vent out the top as a wing tank would.  

Then, using a "T" or "Y", plump the slat tanks supply outlet (low point) to the wing tanks supply outlet.   Isolation valves or plugs are optional.  Not sure I'd even bother with a sight gauge.

 

After thinking on this matter some more, I'd just replace the elbow fitting coming out of the bottom of the main tanks fuel supply, and plumb one branch to a low point on the slat.  This should allow for filling of the slat when the wing tank is being filled, and suppling fuel to run the engine through that same line and fittings. You'll still need to install a high point vent on the slat, but that's easy.  I believe the existing brackets should be able to support the extra weight, but that also needs examined. 

Loren

The slat tank would probably fill - but at a very slow rate most probably much slower than the fuel hose from the FBO  pump.  I thought that one could use a fuel pump of reasonable volume to pump fuel on board to the slat tanks - maybe while taxing to the pumps.  Anyway the fuel lines wouldn't  have to be extra large to make it work. Just have to match the flow from the pump used to make a reasonable flow / time. 

Right now vinyl covering my cowl with a carbon fiber pattern - sure not as easy as it looks on Utube but it came out really well - not commercial quality but OK from 25 ft.

I have the top done and by using a lot of gained knowledge will start on the bottom tomorrow.  BTW look up the crazedpilot.com website and peruse the strobe / wig wag / landing lights.  Put mine the outboard slats.

Phil

I meant to say "I'd replace the elbow coming out of the tank with a "T", with one branch going to the slat tank."  I do not believe filling the slat tank would take long because it's so small and narrow compared to the larger surface area of the main tank.  After all, what is the normal gravity feed of a typical fuel supply line?  Once filled, the slat tank would essentially be a part of the main tank, as if there were just a baffle in between.   No level monitor would be necessary.  

Loren

Didn't mean to get your hackles up -  right now I'm on a different project of vinyl wrapping cowl - coming along nicely - lots of learning curve though.

I agree with you - but still want to go out and check the actual positions of the units as they would be in normal parked attitude.  Also though that I might want a little more control of the fuel - right now all I have is both lines from the tanks leading to the "Zenith Cascolator - read small metal tank" to a Zenith supplied fuel valve and then on the firewall gascolator and engine  912ULS.

ttfn

Phil

No hackles, I just wanted to correct a mistake I made, and express why I no monitoring of the slat level would be necessary.  

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