Bladder tanks Guys

John Goddard wrote:no one ever used one?

I think rusty had one on a CL plane.
Indra

Rusty used a balloon of some sorts and a cigar tube. I believe it was on his chopped stuntman. Ask him when he comes online.

I have used a pressure-less bladder and a pressure bladder. I answered in the thread in the general questions forum about the pressure bladder. It works great, just makes fueling a little more of a pain, but not much once you get your routine down. If anyone is interested I can answer more about the pressure-less balloon too.

Here is a video demo of the balloon tank. Fast forward when I start cranking it, but be sure and catch the first and last couple of minutes of the video:
https://www.youtube.com/user/rastus10?feature=guide#p/u/7/VMPlgF81fgc

I have refined it since I made the video.

Thanks Rusty
Just one question, do they only work with balls out full throttle
Or could one be utilised with a r/c throttle?
J

The pressurized bladder has to run wide open screaming. When the needle is set, fuel is forced through the NV at a constant rate regardless of the engine speed. So if you throttle down, the same amount of fuel is still being forced into the engine. If you stop the engine with fuel in the bladder, you have to clamp it off quickly or it can fill up the crankcase.
With pressure bladders, a bored venturi can help performance because it lets more air in, and vacuum is not needed to get the fuel to flow. The bladder does all the work.

Though I have never used a throttle, the pressure-less balloon bladder should work well with one because you only fill it full without stretching the rubber, and there is no forced feed. You just have to make sure you evacuate all of the air before pushing the fuel in with your syringe. It's all engine vacuum that pulls the fuel in. I tried it with my TD .049 and it worked pretty well, but I bet a Medallion is probably the best engine for this system since it has larger less finicky orifices than a Tee Dee. If you use a pressure-less bladder on a Tee Dee, be sure and use a stock venturi, not bored, because you want the best vacuum you can get so it pulls the fuel in efficiently.

Top Man Rusty
Many thanks
J
Love the vid BTW

Just discovered this excellent video, Thanks Rusty if you don't
mind me getting personal on such short aquaintance.
So that,s what the medallion is, excellent!
Always love peeks at other guys workshops too and their models.
John
Oops! couldn't find spell check, shouldn't use big words!

proctor wrote: Just discovered this excellent video, Thanks Rusty if you don't
mind me getting personal on such short aquaintance.
So that,s what the medallion is, excellent!
Always love peeks at other guys workshops too and their models.
John
Oops! couldn't find spell check, shouldn't use big words!

That's okay, I called a cylinder a piston twice in the video.