I recently threw together a quick profile plane to test out an engine I built.  I figured that a balloon tank would work best for this application, but I wanted something that would be easier to fill than the ones I used previously.  Kind of like my bladder tanks with a check valve on the back of the bladder.  I’m sure I’m not the first person to do it this way, but I’ve never seen this described before anywhere.

I used a standard 9” party balloon, a section of medium fuel tubing, two bladder fittings from Texas Timers, a section of small tubing, a fuel tube stopper, an a couple of pieces of wire. 




First thing I did was make a nick at the end of the balloon.  I then use a hole punch to take a couple of nibbles out of the medium fuel tubing, then put a fitting on each side of the tube and slid it inside the balloon.  The small side of the bladder fitting is a tight fit through the nick.  I changed my mind about using the pieces of wire and just used a small cable tie on the fittings on both sides.  I slipped the small tubing on the large side of the balloon, which will be the back where I fill the balloon.  The other side fitting will be attached to the tube from the engine nipple.  The fuel tube stopper will plug the back after filling. 







I pumped up the balloon with a fueling syringe and capped it off with another stopper.  The volume was more than I would use for fuel on a normal engine run.



I left it for a half hour and it stayed pumped up, so if it will hold air for that long then it’ll hold fuel for a five minute run.  Yes, yes.  I know, it's a balloon tank and isn't pressurized...

Just another way to do it.

Mark