The complete radio control model airplane FAQ.
What are Fuel Dots? When do I use Fuel Dots? Where can I get them, and how much do they cost?
(If you want, you can skip straight to the fuel dots links.)
FUEL DOTS are simply plugs for your fuel line, with a fancy method of retaining the end of the tubing.
Fuel Dots are typically used in two ways. The simplest works best if you have a gas (gasoline, as opposed to glow fuel) engine, or a pumped glow fuel engine like a YS, or a normal 2-stroke with a regulated pump like a Perry pump. To use one with these engines, all you have to do is cut the fuel line going from the fuel tank to the carb (or pump, if you have one) and install a T fitting. On the third leg of the T, run a short line out to the fuel dot. Note, that I have purchased two planes that utilize fuel dots, and they both installed the dots on the cowl. While that is nice and clean, it IS a hassle if you have to remove the cowl, because then you have to disconnect the tube. Anyway, that is the line that you use to fill your tank with.
The reason you don't use the simple method with a standard 2-stroke is because the engine can become flooded. With the above engines, there is a valve that prevents the fuel from entering the engine. A typical 2-stroke glow engine's carb has a straight path from the fuel tank to the engine with the only restriction being the needle. When you pressurize the fuel line, like when you are filling your tank, some of the fuel will go into the fuel tank, and some of it will go into the engine via the carb. Unless you want to clamp the fuel line to the carb every time you fill up, there another simple solution to this...
The second method for implementing fuel dots is to leave the line from the carb to the tank intact. You simply add a third fuel line to your tank. When you plumbed your tank, you probably noticed that the stopper had three holes, but only two went all the way through. Just press another brass tube into the third line. From here, you have two decisions to make. Some guys put another clunk on that line. I don't like that, personally, because I don't want it to interfere with the primary clunk at all. I just bend the brass tube to go to the front corner of the tank. It's a little more hassle with tail-draggers because you have to tip the plane to completely drain the tank, but it's worth it to me.
Fuel dots can cost anywhere
between $8 each and $8 a pair, depending on where you get them. I've purchased
them from several places, but Central Hobbies seems to have the best price.
Fuel Dots LINKS
Dots from Central Hobbies
Fuel Dots & T Fittings from PSP Mfg.
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Revised: January 10, 2002 .