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Engine basics => Engine set up tips => Topic started by: Jerry Bohn on July 15, 2006, 12:02:48 PM

Title: Plastic Uniflo tank Construction
Post by: Jerry Bohn on July 15, 2006, 12:02:48 PM
I understand the therory of uniflo tanks, as I have used metal ones with good results. I am looking for any pictures of plastic uniflo tanks showing how to plumb them, so that I can try one.
Seems to be an up and coming way to make tanks especially for profiles. At present I am finishing an Oriental profile and wish to use the plastic tank on it with my OS .46LA
Thanks, Jerry Bohn
Title: Re: Plastic Uniflo tank Construction
Post by: peabody on July 15, 2006, 12:05:17 PM
Brad Walker had some great pics....
Title: Re: Plastic Uniflo tank Construction
Post by: Jerry Bohn on July 15, 2006, 02:30:22 PM
Getting close. Where would I find posts by Brad?
Title: Re: Plastic Uniflo tank Construction
Post by: Tom Perry on July 15, 2006, 04:34:58 PM
I understand the therory of uniflo tanks, as I have used metal ones with good results. I am looking for any pictures of plastic uniflo tanks showing how to plumb them, so that I can try one.
Seems to be an up and coming way to make tanks especially for profiles. At present I am finishing an Oriental profile and wish to use the plastic tank on it with my OS .46LA
Thanks, Jerry Bohn

Jerry,

Here's a link to the Tulsa Glue Dobbers Site.  This is how I make mine.  Click the uniflow button by Nils Nordland.

http://www.tulsacl.com/WorkShop.html#anchor_13725

I was having problems finding fuel line as flexible as I wanted so I bought some surgical tubing from the local med supply place.
Title: Re: Plastic Uniflo tank Construction
Post by: Jerry Bohn on July 15, 2006, 06:08:37 PM
Tom, Thats exactly what I was looking for.
If it works for you, thats how I will make one.
Also some other interesting infomation on there site.
Thanks Much, Jerry
Title: Re: Plastic Uniflo tank Construction
Post by: Bill Little on July 15, 2006, 08:09:32 PM
Look over on the open forum at the pictures of Ron King's set-up under "Stunt Plumbing".

PIctures are right here on the board.  y1  (Which, BTW, is the same type of plumbing Bob Hunt and Billy Werwage use)

Bill <><
Title: Re: Plastic Uniflo tank Construction
Post by: Jerry Bohn on July 15, 2006, 08:48:33 PM
Thanks Bill, Good info, similar to Nils but I like the way the uniflow and fuel feed are hooked up to the clunk on Ron Kings. A bit more secure.
Jerry
Title: Re: Plastic Uniflo tank Construction
Post by: Bill Little on July 15, 2006, 08:57:20 PM
Hi Jerry,

Since Billy told me about this method (and I checked with Bob) several years ago, it's the only way I have done them.

A good "tank trim" feature with this set up is that you can loosen the stopper and twist it in relation to the tank.  This allows you to "shim" the tank just like a metal one, but without "moving" the tank physically up or down.  The relation ship of the uniflow to the pick up changes when you twist the stopper.

Bill <><
Title: Re: Plastic Uniflo tank Construction
Post by: Greg L Bahrman on July 15, 2006, 09:17:09 PM

A good "tank trim" feature with this set up is that you can loosen the stopper and twist it in relation to the tank. This allows you to "shim" the tank just like a metal one, but without "moving" the tank physically up or down. The relation ship of the uniflow to the pick up changes when you twist the stopper.
Bill <><

Hi Bill,
This rotation of the stopper does what? In other words what is the result.  Does the engine run richer or leaner as the uniflow is moved higher or lower than the pickup tube. I have heard this before but still don't fully understand which way to move the uniflow to get the desired result?.
Thanks !!
Title: Re: Plastic Uniflo tank Construction
Post by: Bill Little on July 16, 2006, 05:23:19 PM
Hi Bill,
This rotation of the stopper does what? In other words what is the result.  Does the engine run richer or leaner as the uniflow is moved higher or lower than the pickup tube. I have heard this before but still don't fully understand which way to move the uniflow to get the desired result?.
Thanks !!

Hi Greg,
Rotating the stopper up (uniflow above the pick up) is like moving the tank down, and vice versa, as I recall.  We haven't had to do it it so long that I am fuzzy.  It is where the uniflow disperses the "layer of air bubbles" in relation to the pick up.   Since I am fuzzy, be prepared to experiment with it!  **) **)  It's a simple matter to loosen the screw and twist then re-tighten.

Bill <><
Title: Re: Plastic Uniflo tank Construction
Post by: Bob Reeves on July 17, 2006, 09:32:37 AM
Might have posted this before but here is how I do uniflow clunks. Have tried all the other published methods and found this works the best. The main advantage is the clunk tubing remains flexible as possible because the uniflow tubing is allowed to move independent of the pickup tubing. If you hard connect the uniflow tube to the clunk as many how to's show the tubes tend to fight each other and you loose allot of flexibility.
 
Use a Dremel cut off wheel to grind a small slot in the side of the clunk and solder the wire guide in the slot. Bend the wire guide at a right angle about 3/4 inch behind the clunk and use a drill bit slightly larger than the uniflow tubing to form your loop. The uniflow tubing is 1/2A fuel line which is plenty large enough and more flexible than standard fuel line. After you get the fuel lines connected to the hard exit tubes just make sure the uniflow tubing is long enough so it won't come out of the loop as it moves inside the tank.
Title: Re: Plastic Uniflo tank Construction
Post by: Steve Scott on July 17, 2006, 12:58:40 PM
I was having problems finding fuel line as flexible as I wanted so I bought some surgical tubing from the local med supply place.
I also have problems finding fuel line flexible enough to use to plumb tanks.  Closest stuff I've found is the Sig line which appears to be white in color.  It is a pretty close match to the short lengths the tank manufacturers include in their clunk tanks.

For the small (2 oz) clunk tanks, I've used the surgical tubing but it's longevity is nil.
Title: Re: Plastic Uniflo tank Construction
Post by: Bill Little on July 17, 2006, 06:16:35 PM
Sullivan seels the translucent white silicon line that comes intheir tanks.  It's the most flexible tubing I have found that has a good life expectancy.

The pickup tube doesn't have to be nar as flexible as we think it does for any "standard" size airplane.  It is pretty critical in 1/2As.  G forces plus fuel draw will work with some rather stiff tubing on a 40 size profile.  y1  Even the pink Prather on bigger ships.

I have seen some really flexible pick up tubing flip over and "stick" facing front after a reverse pull out on a wing over.

Bill <><
Title: Re: Plastic Uniflo tank Construction
Post by: Tom Perry on July 17, 2006, 08:08:37 PM
I also have problems finding fuel line flexible enough to use to plumb tanks.  Closest stuff I've found is the Sig line which appears to be white in color.  It is a pretty close match to the short lengths the tank manufacturers include in their clunk tanks.

For the small (2 oz) clunk tanks, I've used the surgical tubing but it's longevity is nil.

All it has to last is one season or for that matter half a season.  It's cheap.

The Sullivan tanks I have been buying recently have no tubing supplied with them or at least it isn't very flexible.  On my New old stock the tubing was great.

I want mine flexible so I can use a partial tank of fuel and still be assured of fuel flow.