Anyone who has a UAT would be able to answer this question.

I'm familiar with Ducted fan Hopper tanks and the like, but want to be clear on how to setup and run the lines for the BVM Ultimate Air Tank.

I have a 50 oz main Dubro Tank with standard clunk and open overflow. I've run the main tank clunk line to one nipple on the UAT. The other nipple is my fill line that I plug with a fuel dot. Then I have the membrane line going to the Turbine fuel pump.

Finally My Question: Am I supposed to plug the main tank overflow, creating a fully closed fuel system? How would the pump pull fuel?

How is your UAT/main tank set up?

Thanks.

Your plumbing is ok. Just leave the main tank overflow line open.

Regards

Ben

Hi,
Leave your large "feeder" tank vented outside of the plane, put a piece of tubing on it so you can connect to an external fuel tank clunk line.
Now when filling overflow into a ground unit.
Then after start up you can run on the external ground tank until you are ready to launch, leaving your onboard fuel cell full.
Good Luck,
John Roth
Chicago

Great Idea and info. Thanks guys for the quick response!

Just as important, when de-fueling the aircraft, remember to leave the UAT full of fuel. If drained, the membrane will dry out, requiring you to go through the saturation process all over again.
The BVM Ultimate Air Trap can also serve as the final filter upstream of the pump.

When re-fueling, please don't make the mistake of leaving the UAT fill line unplugged. If you have an air leak at the fill line plug, you will soon have a flame-out because the pump will pull all of the fuel from the UAT instead of from the main tank(s) and header.

I use a Festo 6mm one-way checkvalve instead of the plug that comes with the UAT. You could also use a Festo 6mm ball valve if so inclined. Turn it on to refuel, turn it off when full.

Regards,
Harley Condra
BVM REP

Harley is absolutely spot on with the air-leak scenario.

I previously used a one-way check valve. I recently had my first ever flameout, and was incredibly lucky to have it happen a hundred feet or so into the takeoff roll, rather than a couple of seconds later. Turns out that air had leaked in through the one-way check valve.

I replaced it by a 6mm ball-valve, and additonally use a stub of fuel tubing with a plug in it which I push in to the outer end of the ball-valve. This gives me a level of redundancy - if the ball valve leaks, then the plugged stub may save the day.

Lemme know of the above description is unclear - if so I can take a pic tomorrow & post it here.

Regs,
Gordon

NS? You must be livin' clean my friend.

Remind me to have you setup my fuel system for me......

All the comments posted make great sense to me. After thinking about it, I think I will replace the slightly loosely fitting fuel dot for a ball valve.

Anyone have a favorite source for these parts?\

Thanks

I just mail order connectors direct from Festo. The ball valves were $8.50 the last time I bought them.

Gordon