Prapan

I have a question and want to get comment from friends here. Normally I saw several peoples in here used the stock clunk that comes with gas tank. For example steel or brass clunk that supplied with DUBRO 24 Oz tank. However my friends in here they used OS Clunk with Filter. The reason they used that OS clunk with filter is that all fuel inside the gas tank will be consumed all until it is finished and during some manuevers, clunk filter can absorb some fuel and to help for smoothen the throttle and engine running.

Do you have any comment on this?

ram3500-RCU

My Feedback: (221)

I do not use filter clunks. I filter all gas going into the tank from the can and then use a clunk for large fuel line. They are heavy enough to keep the line in the fuel. I have found that with time, the filter clunk will deteriorate and the tiny fibers will travel to the crap trap in the carborator and clog it. The very thing the filter is supposed to prevent. I have had this happen.

pe reivers

The felt filter will effectively prevent gas bubbles from entering the fuel line. Fuel foaming inside the tank will no longer influence fuel draw, and the tank will be emptied to the last drop.
Be sure to prepare the felt element by cleaning it well with fuel and flowing a generous fuel amount through it before you fit it in the tank. This gets rid of all loose fibers, and improves the soaking action.

Prapan

In fact, I also have bad experience before by using filter clunk inside the fuel tank. After several times used, I recheck the filter clunk and found a lot of tiny fiber inside the tank. Also the filter is clog and does not draw the fuel to the fuel line effectively so I decided to use normal clunk. Thank you for your ideas and comments.

Tired Old Man

My Feedback: (1)

100's of engines and 100's of felt filtered clunks. Never had a problem. I've never had a problem with inspecting and cleaning a carb screen every once in awhile, though. Kinda like changing the oil in my car. Good preventative maintenance and everything lasts a lot longer.

Prapan

Hi Silversurfer, So you mean using filter clunk does not create any problem to you right?. Just make sure it is cleaned before insert it into the gas tank.

Tired Old Man

My Feedback: (1)

Don't want to argue with you. Not in the mood. Everytime I lite up an engine for work it runs about 12 to 15 hours. The filtered clunk gets changed after 100 hours. Only about 70,000 hours of experience so far. How's your experience with filtered clunks stack up? BTW, we don't wash any of them first.

Nogyro

My Feedback: (10)

Prapan,

If the filtered clunk is clogged, then I guess it's doing it's job, right??????????

I've been running the felt clunks for years and never a problem.....Like SS, I don't prewash them either. I'm sure Stihl, Husky, Poulan etc, don't prewash them either. I've got an echo stringer that's 14 years old(at least) that I took the carb apart the ther day....Nothing on the screen inside the carb......The felt clunk is doing it's job.

You still need to filter your fuel going into your gas can and out of it.....

ram3500-RCU

My Feedback: (221)

Opinions and experiences vary and I too don't want to step on any toes here. I have great respect for my fellow modelers and there ideas and opinions.

Personally, I stopped using filter clunks and instead, filter the fuel as it is dispensed. We don't have bubble problems, always land with a good reserve of fuel, and see no problem with fuel draw during my rigorous style of flying. I just don't see the need for the felt, and the restriction it can cause. I used the felt filters for maybe 5 years and found it to be a false sense of security. I was not as careful with the purity of the fuel I was loading because I had the 'filter' in the tank. Truth is, that is not where you want to stop crap. It should be stopped BEFORE it gets on board, as in full scale. Your tank and the rest of the fuel system should be as clean as it can be.

I am a member of two clubs and have many other friends with giant scale and I would say that about 3/4s of them do it this way. I don't know of any major problems either way. We have talked about this among ourselves in the past. Other than a hand full of guys in this area that have had the same experience as me with deteriorating felt clunks, either way has not been found to be problematic, as long as clean fuel is always loaded.

Changing the felt filters, and cleaning the tank, as part of the 'annual' would probably prevent even these occasional crap trap clogs, but I don't take my tanks apart each year. I check the stopper for softness, look for signs of any leaks, and lines for brittleness and leave it at that.

I am however using air filters now and see no lose of power with them. I like the idea of clean air to go with my clean fuel.

Tired Old Man

My Feedback: (1)

Air filters are good. Whenever you see scratches on the side of a piston you know that an air filter was not used.

Bob Pastorello

My Feedback: (198)

As with so many others, my belief is "filter in the JUG, not the plane", and I do my best there. My fuel jugs have lawn-mower in line filters as their "klunks" in the jug pickup line. Then, on the "Fill" line on each airplane, I have inline filters for gas from Madison products, and in the TANK I use their "ceramic filter klunk".

My system may be overkill, but years ago I ran YS 4 stroke glow motors..... learned about "fuel filtering" from that experience. So it was logical to apply those principles in the gas realm.

Many ways are effective to skin this cat of fuel impurities..... I guess the important thing for all of us is that we're doing SOMETHING.... and there are guys who don't do ANYTHING...

rc bugman

My Feedback: (30)

I guess that I am worse than most. I filter gas from the jug, use a filter on the clunk and in the line. No problems ever.

Elson

Uncas

My Feedback: (1)

Where do you get air filters?

Tired Old Man

My Feedback: (1)

Make your own out of the same stuff used in chainsaws. Zip tie it over the opening of the carb. Too add a few drops of oil or not to trap dirt is up to you.

altavillan

My Feedback: (1)

UNCAS;

Here is a place to start, http://www.aircraftinternational.com/
Or you can get a velocity stack from tower, Cut the top off a plastic bottle and slip it on the stack, then zip tie some foam over the wide opening.

dirtybird

My Feedback: (5)

I found this was the only way I could keep my SPE 26 running reliably.

dirtybird

My Feedback: (5)

Double post.

ram3500-RCU

My Feedback: (221)

I use the 3W ones as well. They make many sizes.

JoeAirPort

My Feedback: (41)

Also filtering the vent line is good too. It can suck in debris from the flying field.

ram3500-RCU

My Feedback: (221)

Here is a 3W air filter on an Extra.

JoeAirPort

My Feedback: (41)

Cool Gary. Does this work on rear induction engines?

ram3500-RCU

My Feedback: (221)

Sure does Joe. Use this linc http://www.aircraftinternational.com/ and then click on 'motor parts'. Scan down and you will find all their air filters for both side and rear induction.

Tired Old Man

My Feedback: (1)

The type of induction doen't have much of an impact except for fit clearance between the carb and a firewall. Sometimes you may have to compress the filter element a little to make the squeeze. That's where just using a zip tie to hold the element in place comes into play

Prapan

Hi Silversurfer,

To answer your question, I have experienced with filtered clunk for the glow plug power like YS110 and found out that the filter was clogged inside the fuel tank and after that never use it again. I have entered into gas airplane since last two years and never used filtered clunk before. Given the feedback from my friends in the field here they have experienced with filtered clunk in positive way. But I am in dount about long run after several hours of running. For me so far, I only use normal clunk and never have any issue about too much air bubbles. However I always filter the fuel before pumping to gas tank all the times by using micro filter. Just want to try how filtered clunk is effective in terms of air bubbles reduction. I have read the story in web of Toni-Clark about cotton felt clunk and they always recommend that type of filter.

So far I am still happy with normal clunk.

Tired Old Man

My Feedback: (1)

Prapan,

One of the great things about a good felt filter is their ability to use fuel in a tank down to the last possible drop. They also break up most of the air bubbles that can crop up. Not all, but most. To be rid of all of them requires a header tank. Filtering down to 20 microns is also a good thing. Most filters, with the exception of the paper type, don't do that well. I don't have any experience with the ceramic types so I can't go there. The average filter used by many engine owners is about as effective at stopping crud from entering the carb as a tennis racket is at stopping wind. Any filter is better than none, but for what many pay for a sub standard filter they can obtain a very good one at about the same price.

The Walbro felt filter/clunk is extremely effective and I have not seen or heard of fiber issues in a carb screen in thousands of hours of running time. They are also heavier than a standard clunk, making them better in keeping the fuel supply constant to the engine. A must for 3D!! Something else to watch for. Many gas tanks come with tiny plastic fibers in them from the manufacturing process so clean a new tank out before it's used.