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Sintered Bronze Clunk/Filter

Stuka Stunt Main Forum · 15 of 15 known posts recovered

Peter Hess · Sep 10, 2001 08:27 PM

I want to use an on-board fuel filter, but want, also, to keep the number of connections in my fuel system to an absolute minimum. With metal tanks, there is no real choice but to put a filter in the tank-engine line. However, with clunk tanks there are some other choices. What are your experiences with or thoughts about using the sintered bronze clunk/filters instead of the clunk that comes standard with tanks and instead of putting a filter in the tank-engine fuel line? Thanks in advance for your help.

Peter Hess
Canton, CT

bristunt · Sep 10, 2001 08:52 PM

#1 source

I can see a problem of it drawing air bubbles for a while at the end of the tank. Could be really annoying.

I use crap trap filters between the tank & engine.

Always keep the filter away from the motor especially if it is aluminium.

BRI

Larry F · Sep 10, 2001 09:01 PM

#2 source

Peter --

Pure prejudice here, but I wouldn't put a fuel filter on a chainsaw, go-cart, car, or a model engine. Fuel filters were not designed by engineers, but by salesmen. They SOUND like a good idea, but they don't really make the world better.

When is the last time you ever heard anyone say, "I would not have had this problem if I had a fuel filter."

How many times have you heard a mechanic say, "Hey, Roy, bet the fuel filter is clogged up." -- and it is ALWAYS something else.

Never design systems with built in weak links. A fuel filter is a built in weak link, pretty much sure to do you more harm than good.

Larry F

mcm · Sep 10, 2001 09:35 PM

#3 source

One time (and only one time) in a two-year old pickup truck, I was losing speed on the highway, especially up a hill. I pulled off I-44 into (believe or not) a restaurant/gas station/auto parts store (Missouri). $4.95 and a face full of gas later, I was back on the road. A fuel filter.
That being said, I never have enough room on my stunters to install a fuel filter and I never bother on my profiles. One more connection to create a problem.
However, I borrowed a friend's syringe tonight (for fuel, not heroin) and he had a fuel filter on the tubing from the syringe. I really like that idea.

bristunt · Sep 10, 2001 10:30 PM

#4 source

If I had a dollar for every time I've helped a novice who was having engine run problems and found sh#* in his spraybar that a filter would have eliminated I'd be a rich man.

If the filter is blocked it has served it's purpose by stopping the junk getting to the spraybar and causing a lean run. I've found all sorts of things in them including small grass seeds, bug heads, flakes of tin, slithers of fuel tubing......

If you live in a perfect world where your tank is clean, your fuel is perfectly clean and there is no bugs or dust in the air and you don't need a filter, then one will never clogg up will it?????

Having said that I've also come across probably just as many occasiions where the filter was touching the motor and getting hot, or it was blocked (maintenance sometimes helps) or in some other way the filter was causing a problem, its just a matter of knowing what you're doing.

BRI

Nils · Sep 11, 2001 12:13 AM

#10 source

A filter in a syringe line is fine, as long as you take it off (or turn it around) after you fill the syringe & before you fill the tank. Otherwise the crud you catch coming out of the big jug gets blown into the tank. I guess it would keep the inside of the syringe nice & clean though. Btw, I scratch a "T" on one end of my aluminum filters so I always know which end goes toward the tank. If I have to take the system apart for any reason I know which way to put it back. The T is also handy after I've salvaged parts from a wreck

Nils

Nils · Sep 11, 2001 12:17 AM

#11 source

LAST EDITED ON Sep-11-01 AT 00:21 AM (CDT)

Hmmm, this actually started out as a reply to MCM, I don't know how it got down here. Oops.
Nils

Nils · Sep 10, 2001 10:41 PM

#5 source

I use fuel filters on every airplane I own with a non built in fuel tank (17 at the moment, CL & RC, not counting Cox powered) & have yet to have a problem with one. They've caught everything from bits-O'-bug that came in through the uniflow in flight, to dirt that gets in from the ground. Once I had one catch a little wad of Vaseline when I got carried away lubing a hand crank fuel pump. It was much easier to get out of the filter than it would have been to get it out of the sprayber. I've never had a plugged NVA since I started using filters about 4 years ago, it used to happen regularly. I use the kind that are made of aluminum. They're hex shaped & screw together with a fine screen in the middle. I THINK they're DuBro, but I wouldn't swear to it, since I don't have one NIP at the moment. On my last few airplanes I've taken to putting a layer or two of shrink tubing over 'em. Besides being padding if they get close to something, it also insures that they can't come loose where they screw together, although I've never had that happen anyway in thousands of flights. I've also never had a leak between the fuel line & filter on either end.
Nils

Joe Bellcrank · Sep 10, 2001 11:21 PM

#6 source

Ok, Some use them, some don't. I personally have used the sintered bronze filters. They worked fine. No tendency to suck bubbles that I ever was aware of. I still use them when using an RC clunk tank.

I also use them when fuleing. I have one of thosesetups that allow you to fuel with out taking the cap off the jug. I use the sintered bronze filter at the bottom of the pickup line in the jug.

I tend to agree that it's better to use a filter somewhere in the fueling process. Either in the tank or fuel line, Best in my opinion, or at least in the syringe or pumps lines.

John

Brett Buck · Sep 10, 2001 11:26 PM

#8 source

>Pure prejudice here, but I wouldn't
>put a fuel filter on
>a chainsaw, go-cart, car, or
>a model engine. Fuel filters
>were not designed by engineers,
>but by salesmen. They SOUND
>like a good idea, but
>they don't really make the
>world better.

Always, always, always, run a fuel filter. The potential downsides are negligible compared to the positives. I've seen an incredible number of instances with crud in needles, and only a few where the filter was the source of the problem.

I personally prefer the Sullivan Crap Trap to most of the two-part filters.

As an aside, most cars have at least 3 fuel filters, most lawn-mower at least 2, and my 16-engined satellite has 34.

Brett

Scott Riese · Sep 11, 2001 12:53 AM

#12 source

USE ONE ALWAYS You got some time and money invested with your plane so why not protect it. I use an in line fuel filter and also use an air filter. Rather spend $5 then rebuild an engine.

captcurt · Sep 11, 2001 06:46 AM

#13 source

Its interesting to note how many planes I see with fuel filters (we have alot of control over what goes into the tank) Vs. how many with fuel filters and no air filters (we have little control over what goes in the carb or venturi)

Just an observation.

I DO understand the difference in the failure mode though!

Curt

Howard Rush · Sep 10, 2001 11:23 PM

#7 source

Those sintered filters dissolve in fuel.

I wouldn't be afraid of connections. Mr. Walker's B-17 stunter has 45 fuel tubing connections. It's had some fuel system troubles, but not from loose connections.

Fuel filters are particulary necessary if you get your fuel in plastic jugs. The jugs contain jive which clogs even big filters after a couple of gallons. Should you not use a fuel filter, I recommend that you not fly a stunt plane you don't mind crashing. Combat planes have kinetic energy to coast long enough after flaming out to enable recovery from any maneuver; stunt planes don't.

Howard Rush

Howard Rush · Sep 11, 2001 12:02 AM

#9 source

I should have mentioned that it is prudent to use at least one filter on the fuel jug and another filter on the airplane. That way the filter on the jug catches most of the jive. You can get a filter from a car parts store that will go longer without clogging than the little ones do.

Howard Rush

Peter Hess · Sep 11, 2001 07:39 AM

#14 source

Thanks, guys, for all your your comments. All things considered, I think that I will use a filter in the tank/engine line on all tanks and stick to the standard clunk on clunk tanks.
Larry: I am sure that there is more than an ounce of truth in what you say about filters being as much a product of the sales departments rather than the techies. But, I am one of those about whom gremlins gather and if there is a way that I can ward off even one of them, then I'll use it.
Nils: Your point about making sure to reverse the filter on the syringe so that fuel always flows through the filter in the same direction is a good one. On my fuel syringe I have two filters and different color tubing on the opposite ends of the plumbing. One color is always closest to the source of the fuel, be it the jug or the syringe. After filling the syringe it is an easy matter to reverse the whole tubing/filter line. This also makes it easy to know in which direction backflushing should be done to clean the filters every so often.

Peter Hess
Canton, CT