What is referred to as the "BVM" UAT actually comes from up here in Wisconsin at Jeff Seymour's shop----> SWB Turbines.....he designed them for his government turbine project planes......the semi-permeable bag is off an automobile fuel pump......you can get them at most auto parts stores....they are too big as they come and must be trimmed down.......any semi-permeable membrane, like on Woket's or Todd's will work......neat technology letting liquid but no gas thru.....originally designed for membrane oxygenators many years ago on heart-lung machines for heart surgery and also used extensively in reverse osmosis units, big and small.....

Of course, we all flew for years with those skinny little saddle tanks in our D/F that were prone to unport and we all seemed to get along with the centered tube in a 2 or 4 oz round DuBro hopper.....if you want the cheapest way to go, that's still it......I built a Roo for my buddy last year and I had a 4oz round tank and no UAT handy at the time......He has umpteen flights on that Roo with literally hundreds of chicken flops, etc. and no flameout due to bubbles....Rob Janiger, Dave Elsinger, Brian French, and I put on over 1000 flights on Rob's old Avonds F-15 with a 2 oz round hopper with centered brass tube, with never a bubble flameout due to the hopper.........

I just like the convenience of the nice 6 mm size nipples on the UAT.....the ability to mount it almost anyway you want from horizontal to vertical, facing direction of flight or backwards......plus the added filtration benefit.....If you want to cheap-charlie it, you can build one up for about $20.00 or less.....too much hassle for me......I've got enough trouble just getting my gear doors and struts to assume the landing position time after time.........I'll let Jeff screw with the UATs

So just pays yo' money and take your pick......

Tom