DeferredDefect

Hello!

I have a Cox Surestart that is pylon mounted on a scratchbuilt flying boat - there is only one line connection on the engine, and no muffler, so I am lost as to what a fuel tank is supposed to look like for this engine. I have heard of film cansiter fuel tanks, and have one waiting for use.

Do I need a vent line?How is it setup?

Thank you,
Graeme

Tee Bee

I typically use a 1oz Sullivan tank in my .049 birds. Most folks simply install a vent line at the top of the tank which comes out of the plane facing forward. The pickup line can be fixed or clunked depending on your needs. On my Surestart planes, I install 2 vent lines. That way I can fuel up the tank until it overflows out the other vent allowing fillups without unhooking the line to the needle valve. Once it is full, I cap off one of the vents with my finger and blow on the other one with a piece of tubing connected to it until the air is purged out of the main line to the engine. This fills the line with fuel and allows me to hand start the engines without much fuss. With the vents facing forward into the prop blast, the reedie .049s have plenty of vacuum draw to feed the engine without a muffler pressure tap. Good luck.

gcb

Graeme,

You can use only one line if you have a "soft" tank such as a baloon where the sides can collapse.

If you use a film canister or a "pill bottle", etc. you need at least two lines...one to fill, one to vent while filling.

Some use the engine supply line as the vent while filling and fill using the other line. If you use this setup, the plane is usually placed nose down so the supply/vent line is the highest point. That works fine for front intake engines but for the Sure Start you will need to disconnect the fuel line from the engine otherwise overflow will flood the engine.

If you opt to fill using the engine supply line, you must position the plane/tank so the vent line (inside the tank) is at the highest point. Also remember that the vent line should normally run all the way through the tank, that is, if you have the vent line on the top, it should run to the bottom inside the tank so that fuel will not spill out when inverted. If you will only fly upright, this is not necessary.

As Tee Bee said, point the vent(s) toward the prop stream for a little pressure. This will also prevent siphoning while the engine runs.

Now you have several options. Good luck.

George

DeferredDefect

Thanks for the information - going to set up my fuel tank now!

Graeme

ndb8fxe

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I always vent mine out of the front of the firewall. Don't know if it helps, but it might help with a little pressure in the tank.