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[Rusty]

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[Russell Shaffer]

For the Twister, try a Hayes standard plastic tank.  Just fasten it to the fuselage with the big flat side against the fuselage, and drill out the extra vent so you can fuel it. Put a 1/8 shim under the rear corner of the tank to tilt it out.  My Twister/LA 40/Hayes runs dead steady through the whole tank.  The only possible problem is that there is no warning at all for low fuel.  It just quits abruptly.  The credit for this setup goes to Mr. Dirty Dan Rutherford.

[Garf]

Hello Gents:

Is there a chart (like a prop chart) that one can use to determine the best tank for different planes?

Since I have been flying there is a thing called "uniflow" tanks.   Huh??? 

Anyway, I have a Jr. Ringmaster with OS 15 I need a tank suggestion on; and

a Twister with OS LA 40 I need a tank suggestion on.

All my metal tanks are old and I know they have residue in them.  I am sure that is why my engine shut off Saturday.

Thank you. 

PS:  Is there a cleaning shop for metal tanks like a radiator shop?

Rusty

Fill the tank half full with R/C fuel. Cap all vents. Shake for about 5 minutes. Drain. Repeat until fuel coming out is clear.

[Clint Ormosen]

Fill the tank half full with R/C fuel. Cap all vents. Shake for about 5 minutes. Drain. Repeat until fuel coming out is clear.

......and then throw the tank out and buy a new one.



Sorry Phil, I just think using old corroded tanks is a recipe for trouble. They're just not worth it.

[Steve Helmick]

On the other hand, brand new tanks can be rusted inside, it seems. They're all trouble. Take the back cover off and see if the tubes are in the right places...and copper...., no rust present. Re-assemble and check for leaks. Be sure there are none. Plastic tanks don't have rust issues, but there are potential problems, like leaks, and leaky clunk tubes.

The .15 should be well stocked with go-juice if you use a 2 oz tank. The .40LA will probably get by with 4 oz, but maybe not quite long enough for contest work, depending on the venturi size, nitro content, oil content and type, prop load, muffler restriction, etc.  Normal deal is to use a tank large enough plus some excess. Then, you fill the tank and remove the amount that will then result in the perfect run time. This will sound like a hassle for sport, learning the pattern, or practising, but it will be good experience and also make it unlikely that you will crash due to running out of fuel in the overhead stuff at the end of the pattern. That is assuming you want to do the pattern.    Steve

[john e. holliday]

I agree with Clint,  Get a new tank that will fit the plane.  Also a fuel filter to go between tank and engine.  Even new tanks have some garbage in them.   When flying check the filter every two or three flights at first.   The .15 will probably need a little over 2 ounces to start with.   The bigger LA 40, go for 4 1/2 ounces to start.  As they break in the economy will improve in some cases.  Don't forget to get decent fuel for them.  

[Randy Ryan]

I agree with Clint,  Get a new tank that will fit the plane.  Also a fuel filter to go between tank and engine.  Even new tanks have some garbage in them.   When flying check the filter every two or three flights at first.   The .15 will probably need a little over 2 ounces to start with.   The bigger LA 40, go for 4 1/2 ounces to start.  As they break in the economy will improve in some cases.  Don't forget to get decent fuel for them.  

Nothing can ruin a day like fighting fighting tank problems. There's enough trouble sometimes just getting a new tank to work right let alone compounding it with an old cruddy tank. Its just not worth it.

[Chris Edinger]

I second Doc and Clint's opinion.. am building the same plane I crashed 35 years ago,,, even have the tank that was in that plane...
I opened up the old tank to find lots of things that would cause many problems... throw them away... tanks are cheap compared to the problems they can cause..

Doc... email me when ya get rested up.. I'll come and take ya to coffee... or whatever ...LOL>

[Tim Wescott]

Since I have been flying there is a thing called "uniflow" tanks.   Huh??? 

I looked around a bit on the net to find a good reference for how a uniflow works, and this is the closest I could find:
http://www.cadclassics.net/uniflow%20tank.html

It's hard to put into simple words what a uniflow does -- so let me start by saying what a regular tank does.  You fill a regular tank, and you launch.  As you maneuver, the fluid pressure on the needle valve changes because the engine changes position with respect to the tank.  Also, as the fuel runs down, the fluid pressure on the needle valve changes because the position of the top of the fuel load changes with respect to the needle valve.  So you have two fuel pressure related things affecting your engine run -- the airplane attitude, and the amount of fuel in the tank.  To compensate for the varying amount of fuel, you have to run a bit rich at the beginning of the flight, and lean at the end.

What's different about a uniflow tank is that it submerses its vent in the fuel.  This doesn't do anything about the fuel pressure on the needle changing with maneuvers.  What it does stop is the fuel pressure changing with respect to the amount of fuel -- as long as the vent stays submerged, the tank will act as if it has just the right amount of fuel to just touch that vent.  Always.  So now your fuel pressure only* depends on the airplane attitude, not on the amount of fuel.  Until that vent gets uncovered, the plane acts the same from the beginning of the flight until the end.  Build the tank right, or mount it right, and that vent won't get uncovered until the very end of the flight.

So with a uniflow, the flow is uniform with respect to the amount of fuel in the tank.  It means that when you dink with the needle valve, you're not trying to adjust against variations in the amount of fuel -- you're only adjusting for the variations with maneuvers, and if you're smart you can do that adjustment to your advantage.

I hope this helps -- a proper explanation really needs about 27 eight by ten color glossy photographs, with circles and arrows and a paragraph on the back of each one, and all I'm giving you is words.  But once you get your brain wrapped around the concept it really does make sense in a helpful sort of way.

* And any ram air effects on the vent tube.  Thank you Mr. smarty-pants.  That's a question for another day.

[John Stiles]

Nuthin like a tank you can take apart and clean occasionally.

[Garf]

The last 2 "BRAND NEW" tanks I bought both split the rear solder seam the first time out. It was an easy repair, but my 30 year old tanks are still going. Yes, I have replaced most of the tubing and soldered the ends of the vents in place, but they are still going.

[Tom Rounds]

Where is a good source for the Hayes tanks that are being talked about in this post? I have not seen them in my local hobby shop.
Thanks,
Tom

[Russell Shaffer]

Tower has Hayes stuff.  And they fall into the parts express cheaper shipping class.

[andrew stokey]

Rusty,
Try Aeromanics web site.  Lots of good info, including how to uniflow plastic tanks.  I have had good luck for 10 yrs with Sullivan tanks and there are less that $5.
Andy

[Andrew Tinsley]

Hello All,
  There are some strange tanks about! Went flying with a friend on Friday. He had a Cardinal with what appeared to be a conventional tin tank (i.e. an oblong tank with a triangular section on the outer side). Looking closely, there was a small oblong let into the triangular wedge. On querying this, I was told that the oblong bit was a chicken hopper! The runs on LA40 power were extremly good.
 At the end of the session he flew a Peacemaker (small Flitestreak) with a PAW 19 diesel for power. This had a what looked like a conventional tin tank, with one side having a triangular section. This was fitted with the triangular section to the rear! The fuel pick up being to the back outer side of the triangle! So there are some very odd things around which work well!

Regards,

Andrew.