Tony, The Walker Firebaby was also the earliest use of a non-pressure balloon tank that I can remember, and may be the first use ever.
Tim, balloon tanks are easy to make, easy to use, and work flawlessly! Toy balloons work great, and come in a large variety of shapes, colors, and sizes. Texas Timers used to sell them, and any other free flight builders site should have instructions, and materials to make them. Instructions are probably on this site if you search.
One thing to remember is that a syringe or squeeze bulb are necessary to fill them. You need to draw all the air out of the balloon before (or after) filling, so your engine does not draw air bubbles while running. No vent or overflow tubes are necessary, because the balloon collapses while draining to close the space occupied by fuel as it's used by the engine.
Never overfill the balloons with fuel, or you will likely flood the engine while starting! Just enough fuel to inflate the balloon, or just a measured amount for whatever flight time you desire. The balloon does not have to be full, because it contains no air for the engine to draw.
I'm told balloon tanks don't last a long time, but mine on the Firebaby lasted a very long time (using diesel fuel), because it drained naturally after a flight just by pulling the fuel line from the spray bar. It may help to drain all the fuel after flying with a syringe or bulb.
When you see how easy and fast they go together, you can make a half dozen spares, and store them out of the sun until needed. Sun destroys rubber balloons in short order.
Another advantage of balloon tanks is they can adapt to almost any size tank compartment such as an old 35mm film can, plastic bottles, or balsa tank compartments. Fuel proof the wood compartments with fuel proof dope, or thinned epoxy just in case.
Good luck!
Bill
Topic: source for 1/2A bladder material (Read 2576 times)