mduslick

My Feedback: (1)

I need help with fuel line plumbing. As you all know, the remote needle valve is at the rear of the .46 AX and this places the fuel inlet right up next to the firewall. I do not have enough room to place an inline filter between the tank and needle valve without creating a kink in the line (with the needle valve oriented so that the fuel inlet is horizontal) or without creating a big loop (when the needle valve is rotated 90 degrees and the fuel inlet is vertical). My question is, would it be feasible to place the inline filter between the remote needle valve and carb, or does the filter have to be placed between the remote needle and fuel tank? I was considering not using an inline filter at all because I use two other filters already (a filtered clunk in my gallon fuel jug and the other filter in the fuel probe that is used to fill the tank) but I'm still concerned about contaminates that come from the pressure feed from the muffler to the tank.

jaka

Hi!
Don't use a filter in the plane!!! Never !!!
Filter the fuel when filling the tank and use a good comercial filter, not those tiny hobby filters with just a tiny metal screen inside, they are nothing but useless.
I use a filter I bought in a motorcycle store, a plastic filter, approximately 3cm in lenght.

Regards!
Jan K

macdona

My Feedback: (3)

Been flying R/C for 40 years, and I have yet to use an in line filter. I filter the fuel when I fill the tank.

JohnBuckner

My Feedback: (1)

I would agree with the other responders concerning the in line filter, they are a reliabilty contributor but make nice "hobbystore eye candy" to sell (an appropriate phrase someone coined in a similar thread) new folks and right up there with in cowl refueling valves.

With a rear needle like you have where it is difficult to remove the line from the needle housing next to the firewall, the solution is easy. Just make a loop out from the needle housing and cut where you can get to it. Insert a 3/8ths piece of brass or alum tube and this is where you refuel from. It makes no differance whether or not the engine is cowled or open, Just make the loop long enough to reach.

Here is an example of this on the same type of needle close to the firewall and you can see the line to the needle and where it is split and fueled from.

John

da Rock

OK, we got 3 who don't like filters.

I'm one who likes 'em. And to actually answer your question, yeah, they work great on a 46AX between the remote needle and the carb.

Matter of fact, a World Champion aerobatics flyer once gave me a tip about filters. It was that they help to reduce fuel flow problems if they're located as close as possible to the spray bar. Seems he felt they served as a "sump" and their screens helped break up any stray bubbles that had gotten that far.

He also suggested that if you were smart, you'd check them every 20 or so flights when you also looked over everything else. He was WC about 3 times I think, so he must have known something. Me, I always "block check" my models every so often.... grin.... not as often as he did, but then, each and every one of my flights isn't for blood.

da Rock

BTW, relying on prefiltered fuel can let you down, but it depends on how "clean" you handle your fuel.

There is a guy at our field who is a RABID anti-filter guy. He has them all over his fueling rig, but loudly repeats all the arguments you just read above. The other day, one of his engines shut off on him on two or three flights. I wound up helping him trouble shoot. When I discovered that there was some kind of restriction between his remote needle and the engine, I got about three choruses of "why he doesn't use a fuel filter". And I hadn't said BOO to him about a filter or anything.

Turned out that there was some kind of residue of some sort that seemed to be pressured into a plug that was either in the inlet into his carb needle or in the end of the fuel line going into the carb. I got no idea if it had collected just inside the carb or in the end of the hose. I also got no idea what it was or where it came from.

After finding it in that last section of hose, I swapped clean, new hose in. I then blew the needle clean by giving the carb mouth-to-mouth. (I made sure nobody had a camera before I did that. chuckle) And after having to listen to him go through his song a couple more times, got to see him fly "to prove that was it". Engine ran like a top. Strong and steady.

And while he was on the proving flight, I pulled the filters he had in his fueling system. Guess what was in those filters. And one of them had fallen off the line. No wonder he didn't rely on filters on any airplane.

The things we use only work as good as we use them.

da Rock

One of the "no-filter on the engine" guys at our field should be a poster boy for "using a filter on the engine" advertising posters.

I don't remember how many times I've picked up his fueling hose, wiped the clay and grass off the nozzle and stuck it up on his fueling rig (I couldn't bring myself to stick the nozzle into the jug). He's a perfect example of one who shouldn't be relying on the filter in his delivery hose.

To make the "no-engine-filter" deal work, you really need to work at it. Nothing works automatically without your attention.

fredscz

My Feedback: (47)

I'm another of those who would not be without a filter. While I always wash/rinse out fuel tanks before using them. It seems those little plastic "hairs" left over from manufacturing have a way of getting into the needle valve at just the right[wrong] time.
FEB

muzzlemaggot

My Feedback: (7)

I filter my fuel while pouring into my filling can, the pick-up tube has a filter on that, and I have another filter on my filling hose after the fuel pump. In addition, I run a filter between the tank and carb. Guess what I still occasionally find in the filters on my planes? Yep, lint and plastic leftover thingeys from who knows where. In my opinion, it's cheap insurance to prevent a headache from inconsistent running. I've seen too many spray bars get trash in 'em where the guys were meticulous about cleanliness.

muzzlemaggot

My Feedback: (7)

....but didn't use filters.

onewinglow

My Feedback: (1)

Try this put it in the tank. I do and dont have any problem. it also helps keep the clunk at the bottom of the tank.
Just my 2 cents.