Jim,

What I was envisioning is a simple electrical solenoid controlling fuel transfer.  Forget all the lines from bottom of A to top of B, etc.  Some sort of fuel level sensor could tell the solenoid when to open and close.  (Some of you electronic whizzes will have to step in here.)  This would free up the pilot to do other things, like watch for traffic. 

 

Mark S.

 

 

 

<... you'd want two lines.  One from the bottom of B to the jet pump.  Another from the mid level of A to the top of B ... A full B empty... B full A empty ... A & B half full ... A & B full ... parked on a hill ... >
Sounds a lot like a ten-cent tail wagging a forty-dollar dog here.  Didn't we set out to simplify something?  How about just ONE line from B to A with a Facet pump.  To get fancy, you could have a momentary ON for the pump that would cause it to pump for 2 or 3 min or something and then turn itself off. 

Just trying to stay on message ... Jim S.

PS  Has anyone actually seen the two-line-jet-pump and watched it actually WORK ??
(the devil made me say that )


Ernest Christley wrote:

Thoughts on the jet pump:
<>

Fuel tank levels needs to be controlled in order to eliminate a 'heavy wing' which is very fatiguing on a long cross country.  Aileron trim can do it but that adds drag.  A valve can be used but that adds to the complexity again.

Tracy

Looking over the diagram in the PDF that Ed sent.  The jet pump works all the time, constantly pumping fuel from the bottom of B into A, where the main pump can pick it up.  An important element to this is that there is a large return path for fuel to go from A to B.  If the tank is half full or more, all the fuel moved by the jet pump just flows back over.

In the airplane transfer, you'd want two lines.  One from the bottom of B to the jet pump.  Another from the mid level of A to the top of B.  The lines need to stay below the tanks.  At no point will the the sides ever be more than 1/2 a tank different.  Consider:

A is full, B is empty
   Fuel will flow from A to B via the return line, until A is half empty.
B is full, A is empty
   Fuel will flow to A via the jet pump, until B is empty.
A and B are both half full
   Fuel will flow to A.  If A gets more than half full, fuel will flow back to B.
A and B are both full, and you park sideways on a hill.
   Fuel will flow to the ground until the high tank is empty. Doh!!

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