beachbrada

My Feedback: (17)

I need some help setting up my exhaust pressure line to also act as my overfill line. Normally you would just pull off the line from the muffler and once fuel starts coming out you can stop fueling it. But in my situation I can't get to the exhaust line because of the cowl. Theres a guy at the field where I fly that uses a brass fuel tee, the end that points out connects to the muffler and the end that points down he runs a longer line that sticks out the bottom of the cowl that he unplugs to let the fuel drain out before it hits the muffler. I want to run this setup but I cant seem to find metal tees on the normal hobby websites. So I was just wondering what types of setups you have or if you know where to buy metal tee's. For now I have been filling the tank up until fuel pours out the muffler, but this wastes fuel and makes a mess. I have plastic tees but Im worried it will melt from the heat of the exhaust.

RCKen

My Feedback: (9)

The plastic tee's will work fine. For most setups like this you can just pump until it comes out of the muffler. On the setups that I have I can actually hear the fuel hit the muffler almost a turn before I see it coming out of the muffler. So I stop when I hear the fuel in the muffler. But if the muffler is pointing downwards you won't waste much waiting until you see it coming out.

Ken

carrellh

You can get aluminum tee fittings from PSP:
http://www.pspmfg.com/TFittings.html

JohnBuckner

My Feedback: (1)

Here are Tee's and connectors:

http://www3.towerhobbies.com/cgi-bin...&I=LXFU81&P=ML

When using tee's there is no need at all to use metal tee's and plastic type are commonly used. You can also find these very cheaply at a good hardware store that stocks plumbing for swamp coolers.

In a sideways monted engine in the case of a two stroke I agree with RCKen its just easier and makes more sense to just let it come out the muffler, it will be instantanious and there is no need for the tee. In some other orientations the tee set up can be useful.

jetmech05

that could be alot of fuel you're loosing in the line....why not run a simple 3 line setup

beachbrada

My Feedback: (17)

Which 3 line setup are you referring too? I have a 3 line setup, one to the carb, one to the muffler, and one for filling.
And just to make sure everyone understood me, you're saying the back pressure from the muffler going through the plastic tee will not melt it?

JohnBuckner

My Feedback: (1)

I am the one saying that and yes a plastic T will work fine in the installation you described.

For what its worth I never use third lines and consider them redundant. Here is a simple airplane with a side mounted engine and a muffler/pressure line that is not to accessable. The carb line is a little longer and as you can see is used for filling, the overflow when tank is full instantly runs out the muffler with no excessive loss over just looking at the pressure line when popped off. When filled the line is plugged back together, done it works well and more reliable that most other setups bar none.

In addition contrary to what everyone will say is the slightly longer carb line will cause running problem and this is simply not so. As long as the fuel tank/spray bar relationshop is maintained there will be no change in running. It will require you to flip the engine over a few times to fill the line while your finger is blocking the muffler outlet to pressurize the tank.

KISS is always the best method and philosiphy. Veiw the photos from left to right:

beachbrada

My Feedback: (17)

Thanks for the tip John. Also, Im seeming to have a problem with the carb flooding because the tank is higher than the carb. A guy at the field told me to try running the line so that instead of going straight down to the carb nipple, and some slack in the line so that it can go up then go back down like a upside down "U" then run it to the carb so that its not just gravity feeding whenever it wants. Will this work?

bigtim

My Feedback: (13)

yes that method works, a tip for you, use a zip tie to make sure the fuel line stays in position, around the engine mount through the fuel line, it doesn't need to be tight, so the loop stays high in the engine compartment.

I use the plastic "T" from the local ace Hardware they have a barb which works well for fuel line and there just a few cents ea.

opjose

Yup that cures the siphoning problem that occurs when your plane is on the ground, caused by any tank height differences.

Once the engine is running, the minor offset produced by running an inverted engine becomes inconsequential, and tank height turns into a non-issue with most ARFs.

CGRetired

My Feedback: (1)

Some clubs require the use of overflow collectors, that is, don't allow spilling fuel on the ground or on the benches. In that case, requires adding a setup that forces the overflow through a different tube.

If you don't have access to the muffler because of the cowl, perhaps some sort of bypass valve would be useful, but I'm not familiar with a setup like that, only that something like that exists.

If someone here knows of such a setup, perhaps he/she could describe it to us.

This stuff can get pretty complex!!

CGr

JohnBuckner

My Feedback: (1)

In that case even with a tee and a dot there is still gonna be some that gets into the muffler, the solution is simple set a rag under the mufflers outlet.

This stuff only gets complex if you fall into that trap. KISS is always the best system

beachbrada

My Feedback: (17)

The guy that told me about the tee setup from my field has a small bottle that he connects to the overfill line and as soon as fuel starts going into it he shuts off the pump, then he connects the bottle to the fuel filler and sucks it back into his gallon jug. I was pretty impressed because he doesn't waste a drop of fuel. Also John, if you look at the pic I positioned the tee lower than the muffler fitting so that if the fuel wanted to go into the muffler it would have to fight gravity, so Im pretty sure it will just run straight down the line.

CGRetired

My Feedback: (1)

Yeah, even with my cowl equipped aircraft, I have access to the muffler tube using a pair of forceps. I have a pair with long curved jaws that gets right up to the muffler nipple. Works great. And, keeps it real simple. I attach my fuel supply overflow directly to the tube, which solves the flowing-on-the-ground issue, if I were to fly at a field that has that demand.

CGr.

beachbrada

My Feedback: (17)

I found the fuel bottle that the guy used to catch his fuel from the overfill line. Its just a 1 oz fuel bottle that he outfits with the normal fuel stopper and two lines going into it. One for catching the fuel and one for sucking it out. [link=http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFU33&P=0]Fuel Bottle[/link]

CGRetired

My Feedback: (1)

Yeah, that works just fine. I use the system I described becausd the fuel supply came with it... and when I remember to use it.. Otherwise, I let it spill down out of the vent/pressure tube when it is filled.

CGr.

bigtim

My Feedback: (13)

my set up look just like yours beachbrada, other that the large loop, the "T" is about even with the muffler pipe.

when fueling, I pull the little extra fuel line out of the bracket, so its lower than the muffler, I unplug it and when fueling put my finger over the end of the exhaust pipe to ensure that the exess fuel exits the vent tube, the bracket I made ensures the little screw/plug doesn't whip around and bash my cowl or plane when flying.

the reason I went this way was my exhaust pipe was a little long to exit the cowl and I had no access to the pressure line like you,and my muffler sits prety flat so it loads up with fuel, and then dumps all over the place when the engine starts,this has stopped it from happening.