filtering an overflow line

[my c210]

hi, could someone please explain to my dad why we put filters on our gas plane's overflow lines dangling out of the cowl. he thinks that all it will do is add weight.

[ken crane]

keeps the crap from getting in the tank from the vent line that is blowing around tthe bottom of the plane

[wylieruneyjr]

Sure , First I buy mine from Dons Hobby Shop, They are self cleaning. If you fly from a grass landing , runway, your prop kicks up dust and debris. As gas flows to the engine, a vacuum occurs on the vent line, which will suck debris into the tank. The vents only weigh a few grams. Now if you run a filter somewhere between the tank and engine, you may feel that the vent filter is unneeded, however it prevents the main filter from clogging up prematurely. They are expensive at $ 10.oo a piece. I run them, my friends don't.

[my c210]

THANK YOU!! what now dad!

[sinergy]

Can't say I run one or would bother personally. I burn a lot more fuel then the average modler and can't say I have had a problem in the last 5 years.

[hpapilot]

I don't, and don't really see many people who do. In theory it's a good idea, but...

[rc4flying]

I have been running gas planes for way to many years and have never seen the need for one or issues due to not using one. I fly both off grass and pavement.

[Tired Old Man]

Why bother?

When you filled the tank you left a bunch of sticky fuel/oil residue inside the vent line. The likelyhood of dirt making it up the vent line without sticking to that residue is less than nil. BTW, the suction through the vent line is very slight. The rest of the time the plane is in the air, away from the most dirty environment. Since I know your not using an air cleaner, the vast amount of dirt ingested by the engine is through the carb. In the microscopically small chance that any dirt did make it up the vent line, the filter inside the tank (you DO have one right?) prevents it from getting into the carb. Between a filter in the gas can ond one in the plane's tank the odds of getting debris into the carb is, well, at best remote.

As for keeping filters cleaner longer, I've got a bridge for sale. A good Walbro felt clunk filter runs about $2.99 and will last for 100 hours or more. For most, that's once a year or a little longer. Change the filter the same time you change the plugs and you're good to go. Yes, the plugs last 100 hours or more as well...IF...you tune the carb. Not tuning the carb (and using Lawnboy) can cost you a set of plugs every week.

People are too hung up on bling and gimmicks. Makes the sales vendors real happy though. I think you're Dad sees through the smoke and mirrors pretty good if he can't find a reason for one. Said more than you wanted to hear but it's all related in a way.

[zoomer260]

I gotta admit the first time I ever heard of one was today in another thread on FG. An engine having issues and the thread starte was asked if he was filtering his overflow line. It never occured to me to do so until then.

Kinda made sense but I thought the vacuum is so weak and the monster filter clunk I run would catch any debris so I thought no more about it until this thread.

I say do it if it makes you warm and fuzzy inside.

[aviti]

I think your dad is right

[classclown]

Nothing but extra weight.

[MODE 1]

Yep pointless

[my c210]

yeah, a 20 gram plastic filter is just going to completely destroy my hover pull out power. come on, it cant do anything but help out.

[sinergy]

More like it won't do anything period.

[Tired Old Man]

Because (name your superstar) uses one is not a valid reason for doing it yourself. Once you meet up with someone that has some proof of vent filter viability and effectiveness there's no reason to even think there is a benefit of having one. Someone that theorizes what might be happening is only dreaming and without any type of factual support for the theory.

Next week I might hang a small cowbell from my landing gear and then tell people that it cleans up the radio signal....