Tank setup, felt clunk?
 

A dubro tank with the gasoline stopper works for turbine application right? I read a few places that a felt clunk is suggested, is that universal or are there tradeoffs?

I filter my fuel 2 times and just use regular clunk no problems

I've always thought that a felt or paper filter clunk just helps reduce bubbles. I filter the fuel so often it is ridiculous. 1. Pump to JM tank 2. JM tank to main tanks in the plane. 4. UAT 5. Jetcat filter. 6. Filter in motor. This stuff is probably so clean that you could drink it by the time it hits the injectors. So felt clunk as a filter? Maybe. Bubble reducer? Probably, more than likely why I would do it.

The nice thing with the felt clunk is that it will get ALL the fuel out of the tank.

The only down side is... the Walbro clunk that will fit in the Dubro tank isn't very big. I don't know if I would use it on anything bigger than a 20lb engine.

FYI... I use them, with a 2 or 4 oz tank, and make my own bubble tank for about $10. AND... it's Walbro P/N 125-527-1

Dr Honda is nearest. It should never be thought of as a filter, its like people who don't fit filters because of having a UAT!
Its biggest plus is the sponge affect and it allows moments out of the fuel with fuel being drawn from the felt (like in a low power dive) Tillotson clunks need the centre hole drilling out to 2.8mm, or we use our two sizes of Hi-Flow clunks.
The thing with most dubro tanks is that they are long and thin, so a felt clunk is ideal.
(Before installation attach a piece of tube and suck the loose fibre out and they run for years without issues)
http://www.rcuniverse.com/forum/atta...mentid=1937259

Hello friends:

But, if you use a clunk with filter, you no can fill the tank throw the UAT, because you will put all dirty into the main line and the filter not help you.
I use metal clunk in my tanks and always UAT tank, but the question is...where can I get a clunk more heavy ? I need find clunks of more weight, 30gr up. Do you know where can I get it ???

many thanks in advance.
Carlos Marquez
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www.cmjets.blogspot.com

My fuel system has no dirt in it...so I fill through the bubble trap without a problem.
You will have to have something made at that weight, even our heavy std clunk is less than 20g

Hi Dave, thanks for your answer. You know if is necessary install 6mm tygon into the tank ? Or 4mm is enought, because the 6mm tygon need a lot of weight for move free the clunk. For big turbines of course.
BR.
Carlos.

Carlos - around 28g this one.....

http://www.gbr-jet.com/catalog/produ...products_id=83

marcs

Hi:

cool, but if you fill the tanks throw the UAT all possible dirt fit into the filter in the main line and return to UAT. (Outside the bag).
If possible that I would buy one like thus for test.

thank you.
carlos.

Carlos not sure with other UAT's but if you fill the CAT via the fill barb any dirt will potentially end up in the tank as you correctly say, however when the fuel is drawn out of the tank assuming the dirt comes with it which it will with either a felt filter, paper filter or no filter it will be stopped at the filter in the CAT before it goes to the pump.

marcs

Yep... what Marc said.

If you use a felt clunk... you should fill the tank from a vent hose. (like when using a UAT) That way... the dirt will be outside the felt, and it will work as a pre-filter. If you fill thought it... then the dirt gets trapped, and then goes into the fuel system when started.

All this talk of adding dirt! I have never changed a felt clunk or cleaned a fuel filter in 10 years. Not one. If your fuel has dirt in it, filter in more, if you tanks have dirt in them clean them before use (blowing glass tanks out with an airline will not clean it!)

Fuel from my MAP header tank is flushed through the inside of my felt clunks. I can count my flame outs, its a binary number...

I don't think of a felt or paper clunk/tank as a filter unit....its not.

Sorry missed this!

Dave, thanks for your answer. You know if is necessary install 6mm tygon into the tank ? Or 4mm is enought, because the 6mm tygon need a lot of weight for move free the clunk. For big turbines of course.

Bigger is better, but 6mm o/d 3.2mm I'd is OK up to 160N. Above 160N its better to go 8mm o/d 4.1mm I/d if the tank/clunk is long enough

Dave

Thank you very much.

This felt clunk works great and has enough weight to pick up in all tank positions.
http://www.taildraggerrc.com/1-8-bar...el-tank-clunk/

I too fuel via an extra fuel line too bypassing the felt clunk. One of the resons is that by doing this I reduce the risk of flooding the engine if the solenoid is broken. Also I like the fuel to always pass through the felt in the same direction at all times. I use the felt clunk purely as a bubble trap. Still if there are large FOD in the fuel it will be cought before messing up the fuel pump. So even if not seen as a filter it can help. Works very well for my micro turbines without any hopper tank.