----- Original Message -----
Sent: Friday, February 11, 2005 2:51
PM
Subject: [FlyRotary] Re: More wild ideas
was Re: [FlyRotary] Re: To Paul SOme diagnosis thoughts
One final thought.....my aluminum sump tank in
not vented. Seems we discussed this at length when I was building this thing,
and since the overflow is pumped into the sump tank, the fuel might just be
pumped right out of the vent.
Paul, this sounds a LOT like a problem I've
experienced.
My
returns go to the main tanks switched by a solenoid. I used to be able to
create a crossfeed situation where I was drawing from one tank, but
returning to the other. The tank receiving the return became full, and I lost
power down to 2500 rpm or so. I was in the pattern when this occurred, so I
just brought it home. I had fuel coming out of the vent. I've seen this twice
when trying to feed the return to a full tank. Maybe the fuel pressure drops
under these circumstances.
In
my case I've rewired the switches to avoid crossfeed and added a
crossfeed warning light.
Regards,
John
Hi, John....No fun pumping
perfectly good fuel overboard. In my system, the unused fuel is pumped back
into the aluminum sump tank. If the sump tank is already full, then less fuel
would be drawn from the main tank, (I presume), or it would slowly just push
the fuel into the sump tank and back up the main supply line back into the
selected tank. ( I have an Andair fuel tank selector, and can select left,
right or both). Of course this system only has approximately 9.5 flight hours
and maybe 10 initial ground/taxi hours, so it is not entirely proven, of
course. I shamelessly copied Ed Anderson's aluminum sump tank, with the
exception that my tank is slightly larger, and is located on the cool side of
the firewall instead of the engine side of the firewall like Ed's. Paul
Conner
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