Hopefully most of you know the importance of putting a fuel filter on every airplane you fly. In my book I wouldn't think of having an airplane without a fuel filter between the tank and spray bar, to me it's as important as a good glow plug. junk gets into our fuel tanks, even if you clean things well and are careful you would be surprised by what can sneak in through a vent while you are flying. I've found bug parts, dandelion fuzz and other unidentifiable junk in my fuel filters all of which would have ended up in the needle valve resulting in crappy engine runs.
 
Now that I hope I've sold you on the importance of fuel filters, I discovered Master Airscrew filters some time ago (see photo) and have been using them every since. They are small enough to fit most any installation, priced right, made of plastic and weigh nothing.. They do have one little problem.. They tend to leak where the two plastic parts are put together. It's just a press fit and depending on the tolerances can be loose enough for an air leak.
 
My solution is to pull the filter slightly apart, run a bead of silicon gasket sealer around the edge, push it back together then wrap the whole thing with a short piece of heat shrink tubing. Once the heat shrink is shrunk it forms a tight seal plus eliminates any chance of it coming apart at an inappropriate time. The one on the left out of the package has been treated with my heat shrink trick.

These filters are available through Tower, Brodak and probably your local hobby shop..

I prefer the Sullivan crap-trap filter, easy to see when it needs a clean or replacement, and the dual screens help maintain good fuel flow... http://www.shopatron.com/product/part_number=S187/102.0.329.337.0.0.0

Fuel filters on planes create far more problems than they've ever prevented.  Filter your fuel before it goes in the tank.

Your experiences sure must have been different than mine, I have a sealed fuelling system that never sees anything but what goes in the can and it's filtered before it goes in the tank. Even with that I trap junk in my engine filters that would surly make me have a bad day at a contest. Please tell us what problems fuel filters cause that I haven't addressed in my original post...

Filter leaks, fuel line/filter connection leaks, filter clogs caused by micro fiber accumulations that would otherwise flow thru the engine, reduced fuel suction draw caused by restrictive filter, and of course the inevitable putting a used filter in backwards.

Even with filters they need to be checked once in a while.  Ask me how I know.  James flying my Original Magician with Brodak .25.  I have lost count of how many flights are on the combination.  About the sixth flight the plane was leaning out more and more.  The last flight he said he was tired and I couldn't get the engine to richen up.

Anyway, got home and cleaning up the planes and decided to check filters.  I mean it was put on the plane a year ago.  Also cleaning the OS 35FP that went straight into the mud.  The filter was full.  I don't even see how the engine even started.

But, on the blue filters, I put a copper wire tie around the ends to make sure it doesn't come apart.  Oh, by the way James filter was one of the little metal take aparts.  I also had one of the metal filters leak.  Found it by putting pressure on it with a shringe.  Tightened with pliers and problems solved on that plane. 

I have always sworn by filters, even when Perfect was only filters at the time.  DOC Holliday

    .......Last I knew, John Brodak was having the former H&R threaded filters reproduced.  These are the best bet.  Tom H.

Tom,
Do you know if the H&R type is the BH-935 "Brodak Fuel Filter", aluminum with 80-mesh screen?  From the picture in the catalog, it looks like the smallest threaded filter I've seen.  My Smoothie could use a filter that small, as it was obviously designed before fuel filters came into use. 

Thanks,
Kim Mortimore

This is the filter you are talking about... They are really small and I have a couple of them in places the Master Airscrew is a little long to fit well. I have had these leak but discovered a copper washer from a glow plug makes a great gasket.

Fuel filters on planes create far more problems than they've ever prevented.  Filter your fuel before it goes in the tank.

  Oh, good Lord! I agree that you should filter the fuel as it comes out of the can because you can pick up crud from handling, but I would NEVER EVER fly without a fuel filter *in the airplane*. Of course you can have the occasional problem with a filter (mostly, leaking air) but that's a tiny fraction of the problems with crud getting into the fuel. If nothing else it catches the bug parts that go into the intake, or residual carbon or epoxy bits that get into the tank through a pressure line, or whatever the tiny threads that somehow get into the tank. With the little filters as sold by Dave Shadel there's no excuse for not using one, they are no larger than the fuel tubing. If someone is worried about them leaking, use silicone sealant on the threads.

   I would also note that unless you are using some off-brand of fuel, there is *little or nothing* by way of contamination in the fuel as it comes from the factory. After on the order of hundreds of gallons of SIG and Powermaster all through several filters in the extraction path, I have never found so much as a *speck* of anything in any one of the progressively finer filters in my fuel can "up" line. Filtering the fuel before use by decanting from can to can is only going to cause an issue.

   I also recommend this fuel can fitting:

     http://www3.towerhobbies.com/cgi-bin/WTI0001P?I=LXRS88&P=8

    It's aluminum and plastic, no brass to fall apart from corrosion, and it's entirely air-tight because the aluminum "probe" seats in an o-ring. Leave it in the car, and if the fuel heats up, it will hold the pressure so the fuel doesn't "breathe".

     I have two filters in my airplane - one in the fuel line (usually a Sullivan Crap Trap, but if it's tight, a Shadel filter) and one in the pipe pressure line to keep pipe debris out of the tank.

    Brett

That looks just like the ones Melvin used to sell until he was told they were not being manufactured any more.  Pliers and prop/plug wrench cured the leak on mine.  Only thing now is after I tried to clean it I lost the wire screen.  It is in the shop somewhere.  DOC Holliday

Ya... I have an RO-Jett filter I lost the screen out of.. Not sure why I'm hanging on to it, pretty much worthless without the screen. Finding a screen much less figuring out how to cut it would be more trouble than it's worth.

I had some interesting problems with Sullivan Crap Trap filters, although I don't think the filter type was really the problem.  What appeared to happening was that the fuel would precipitate what must be very tiny globs of jelly like material, it was totally invisible.  This stuff would build up on the filter in between flying sessions and then start to come out of the filter and plug the NVA during flight.  I could not see anything in the fuel, filter, or NVA, but after opening the needle valve, flushing it, and trying again, the motor would run fine at exactly the same old setting.  Eliminating the filter pretty much solved the problem, but I've now taken to flushing out the fuel line and needle valve with air after flying.

    I think all you are seeing are things the Sullivan filter caught, and the others didn't. I have seen the "clear globs" in fuel jugs during the "bad castor scare" and the "1995 SIG Fuel Disaster NATS". I don't know what it is for sure, but it stopped showing up in my fuel in the late 90's . If it's the same thing, I don't think you are helping yourself by letting it through - we had a bunch of bad runs and a few ruined connecting rods when trying to use fuel with the clear globs.

     Brett

I tracked down Dave Shadel following Brett's recommendation of his very small fuel filters.  I found him listed in the PAMPA membership directory and emailed him.  Here is his reply:

"I'm the right guy.  The bad part is that the filters aren't available right now since the co. that was making them went out of business,  I'm making the parts now to supply these again.  They should be available in about 4 weeks or so.  Check the website, www dot pspec dot com (Performance Specialties--primarily RC Pylon Racing supplies).  When we have them again, you can order them online.

Thanks for the inquiry.

Dave"

Hope this helps,
Kim

I use the Sullivan Crap Trap filters but a chance discovery on a web page showed me that they should only be fitted one way because of having two different sized meshes.

Hopefully most of you know the importance of putting a fuel filter on every airplane you fly. In my book I wouldn't think of having an airplane without a fuel filter between the tank and spray bar, to me it's as important as a good glow plug. junk gets into our fuel tanks, even if you clean things well and are careful you would be surprised by what can sneak in through a vent while you are flying. I've found bug parts, dandelion fuzz and other unidentifiable junk in my fuel filters all of which would have ended up in the needle valve resulting in crappy engine runs.
 
Now that I hope I've sold you on the importance of fuel filters, I discovered Master Airscrew filters some time ago (see photo) and have been using them every since. They are small enough to fit most any installation, priced right, made of plastic and weigh nothing.. They do have one little problem.. They tend to leak where the two plastic parts are put together. It's just a press fit and depending on the tolerances can be loose enough for an air leak.
 
My solution is to pull the filter slightly apart, run a bead of silicon gasket sealer around the edge, push it back together then wrap the whole thing with a short piece of heat shrink tubing. Once the heat shrink is shrunk it forms a tight seal plus eliminates any chance of it coming apart at an inappropriate time. The one on the left out of the package has been treated with my heat shrink trick.

These filters are available through Tower, Brodak and probably your local hobby shop..

Before I use the Master Airscrew filters I pull them apart and put Canopy Cement around the outside diameter of the piece that fits inside the larger half.  The canopy cement bonds them together permanantly.

I recommend the Du-Bro Final filter, I never had any problems with them.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD742&P=7

    These are pretty notorious for leaking air where the plastic insert goes into the metal part. I have seen a bunch of them that just came apart in flight.  If you crimp the aluminum "can" to keep the filter element in, and then pour epoxy around the joint to seal it up, they are OK. They're huge but that's OK if you have the space.

     Brett

I use the Sullivan Crap Trap filters but a chance discovery on a web page showed me that they should only be fitted one way because of having two different sized meshes.

HI
The crap traps have the filter cones in a dome shape and force the debris to the outer edge and trap it there.
I have all of the filters mentioned here, and  more, I use the crap traps, they do not leak like many shown, do not crack or split, and are very easy to clean, and you can see if they are full, plus they hold way more than the other filters if they have too.
There was a few that said they had troubles with leaks on the  20 years or so ago, but I have never seen that.
It is easy to tell, if you can spin the ends, the filter may leak, just shrink the clear tubing with a heat gun. Other advantage is the are not much bigger diameter than the fuel tubing and will fit most any plane

Randy

Randy and I have argued this point for years. I have replaced 3 crap trap "leakers" (one on a world class flyers ship) and solved problems.

   I have seen exactly two leakers over the 25 years or so they have been around. The most interesting was on Bruce Perry's PA40 at the 1995 NATS. He was having all sort of problems with inconsistent runs, etc. And that was when we we also having all sorts of problems with SIG fuel, which confused the issue considerably - David's PA40 wore out a connecting rod during the week apparently due to fuel problems, I was having all sorts of funnies, etc. At any rate, about half the week went by with us monkeying with the pipe length, sealing the header joint, leak-testing pipes. Finally, Bruce put the airplane in his much-maligned "R/C Stand". This is the full R/C "Club dork" toolbox, with deployable legs, a thing to hold your fuselage while you adjust the reeds, change tubes in the receiver, or whatever RC guys do. And all the stickers, too. Eventually he decided to fire it up with it in the stand, upside down, with the cowl off. About 5 seconds into the run, sure enough, a stream of bubbles in the crap trap. Pull it out, and when they were pushing the end fitting into the tubing, part of the tubing folded under, causing a leak. Replaced it with a new one straight out of my tool box, everything works.

    But that was one issue over thousands of flights. If you have a problem, check the filter. But the number of problems caused by not having a filter are so huge and pervasive that I stick with my recommendation to never fly without one. I like the crap trap because it's relatively small, hard to clog , but still offers superior filtering. The two elements also seem to catch the fibers better than a single-element filter. The Dave Shadel filters are good if you have a very tight installation but the filter area is tiny and thus much more prone to clogging.  Any of the screw-together types are prone to leaking (much more likely than the crap trap) but that's a problem that can be dealt with.

      Brett

How many leaking crap traps in this post alone?

   A tiny fraction of all those used. They are the best filter currently available. 

     Brett

The Skylark I flew at VSC (4th owner?) had a tiny filter in it that I'd never seen before. I asked, and somebody said it was a RO-Jett filter. I was removing the .40FP and installing a .46LA, and it didn't take me much thought to put in a Crap Trap. It's still there, has given no problems at all. The tiny filter, whatever it is, resides in my field box, ready to loan to Ward-O when he comes to one of our contests.

   That's the same as the filter Dave Shadel sells. Very tiny indeed, tiny filter medium (something like 3/16" diameter little chip of mesh). Like all screw-together filters it's prone to leaking around the threads, but still very useful if you have a small space.

    Everybody knows that that the screw-together types also have a right and wrong direction, right? The part with the male threads is the inlet end.

      Brett

How many leaking crap traps in this post alone?

w

An incredible TINY TINY fraction of those out there, and  WAY WAY less  than the  plastic pushed together or screw together filter,
You really have to abuse a crap trap to make them leak. I know about 40 people I sell them to that simply have ZERO problem with the Crap traps, plus they will hold ten times more than what it takes to stop up one of the tiny screw together filter.
If you have a leak in a crap trap 99% of the time you can just heat the tubing to reshrink it back onto the metal fitting. I have not had to do that in over 25 years now.
I have seen leaking filters for decades, almost every time I see one it is a screw or push together filter.
The little tiny screw together one people are talking about was made by John at Jayson Headers, he is now out of business. There is a chance Dubb Jett  will  make these now.
AS alway  use  what works for you, and what you are comfortable with.

Regards
Randy

Using paper coffee filters to decant fuel from the "jug" isn't very satisfactory.  The fuel only drips very slowly through the filter, and I end up with fuel all over the bench top!

I have lots of silk covering material.  Is that too coarse to do the job?

    Aye carumba,  silk as a fuel filter. Billions of silkworms are spinning in their cocoons!

    Just don't filter it at all.  Decanting it can only ADD stuff, not subtract it, if you use a quality fuel. Use a filter/filters in the "up" line of the fuel can fittings so you run it through ever finer filters as you draw it out of the can. I use the plastic Du-Bro can fittings. The pickup has a pretty coarse filter in the pickup. I then run it through a "Russkie" filter I got from Dirty Dan, then through a Crap-trap, then out the can. As I mentioned earlier, I *never* found more than the tiniest specks of matter and the occasional bit of fuzz.

     If you use a ketchup pump, then put a huge automotive filter on the outlet end, that will catch whatever comes out.

    Brett

I have three filters on the output of my ketchup pump: a lawnmower filter I got at the car parts store, a Dirty Dan Russian filter, and a little one like Bob shows above.  I probably got it from Melvin.  I gotta flush the little one every few tankfuls, so there is jive coming from somewhere.  It may be coming from the paper lawnmower filter, but my environment is saturated with cat hair, so it could well be cat hair.  I have a skinny filter I got from Dub Jett in the airplane.  I had to flush it a few times recently when I installed a new metal tank.

Air Filter...a perfect use for one of the Master Airscrew (plastic push-together type, weigh almost nothin'), grafted on with a short piece of fuel hose. Keep the bugs and seeds and grass clippings out of the fuel system.  Steve