Wondering where diagrams of DF Fuel Tank setups can be obtained. Specifically looking for a diagram that uses a main tank and a hopper/header tank. Also, when using an additional line for filling, is it best to have this line fill/enter the hopper tank or the main tank. Thanks.

You want to fill the hopper tank first and let it overflow into the main tank. But you need to make sure you clamp off the fuel line from the hopper tank to the carb or you will flood the engine.

Basic setup is this:

Hopper Tank - 3 connections
1 connection from Hopper to carb on engine
1 connection from Hopper to a fill line (make sure you plug this line during engine operation)
1 connection from Hopper tank to main tank

Main Tank - 2 connections
1 connection comming from the Hopper tank into the main tank - (clunk connection)
1 connection from Main tank to tune pipe or fan preasure

When filling you might want to disconnect the tune pipe or fan preasure line so you will not flood the tune pipe or dump fuel into the jet. Just watch the fuel level in the main tank.

JR Gautreaux

Bob,
Here's the BVM recommended set up. It shows BVM Puffer and standard set ups. Some also use fan pressure. You will get lots of debate but I definitely prefer standard pipe pressure. If the image doesn't come through clear enough let me know and I will email it to you.

Joe

Why a no clunk setup in the hopper tank ?

JR and Joe, Thanks very much for the information. I am also wondering why the hopper tank does not have a clunk. Thanks again. Bob

The pickup in the hopper is in the center of the tank so it only picks up fuel, no bubbles. The hoppers purpose is to eliminate bubbles.

you mean bubbles are located rather near the walls of the tank ? Actually I did not know that....

The bubbles rise to the top. The pickup is in the center so that no matter the attitude of the plane, the bubbles will be away from the pickup. I only ran a hopper tank on one of my DFs and it had a normal clunk in it. It worked fine. I never found bubbles to be a problem with DFs.

As long as your tanks are well foam protected, I 100% agree.

I've run hopper tanks with and without clunks. They work fine either way. The only concern with a clunk is that in a 2 oz. hopper the clunk hose is very short (1 - 2 inches long), so you need to make sure you are using very flexible hose.

Joe

Im thinking about adding a hopper tank maybe a 4oz, with or without the clunk... question, if tank is installed without the clunk and fuel pickup is from brass tube in center of tank.. wont there be left over fuel in the tank after draining for storage? since it cant pickup all the fuel from it being limited to the center of the tank..

probly a stupid question, but knowlegde is golden..

-ron

Ron,

You are correct, there will be a small amount of fuel left. The only way to completely remove all of it would be to remove to the tank and then drain it. Most turbine jet flyers are running a UAT or some other hopper tank and for the most part we leave it with fuel all the time.

JR Gautreaux