jerry@mc.net wrote:

I get the impression, the readers/writers of the fuel system design
are fully confident a header tank pick-up will never be uncovered.  No
one has ever written this possibility, or have they?  I have missed it
if written.

It depends on the shape. If the bottom plates are set at a 45 degree
angle it is unlikely. If you don't have room for that it is more
likely in say something like a practice stall or slip.

It is also perceived there is high heat build-up, in a fuel bay, from
return fuel.  I fail to see the threat of possible heat transfer
because of the enormous heat sink within any fuel bays, metal or
composite.  This should shed most of the heat returned.  If it
doesn't, I question the judgment to fly in that environment.

I think people were referring to and concerned by returning the hot
fuel to the sump tank. I totally agree there would be no problem 
if you returned the hot fuel to the main tanks except perhaps when
you were down to your last gallon.

It seems the slosh bays in a low wing airplane could be increased to
equal the the volume of most header tanks.  That is the time to be
putting the gear down and refilling the wing bays.  45 minutes of fuel
remaining is nice number for slosh bay capacity since it equals the
capacity of the original Lancair header size.

I believe the most serious challenge to low wing kit builders is to
design and install a vent system that addresses a multitude of
infamous venting problems.  We know fuel can be supplied with brute
force (electric) or pulled by  mechanical force and still limp home or
land at nearest suitable.  The true limit, one which cannot be
purchased, is good venting.

I am also one to follow Tony Bingelis' lead when he says, "the safest
fuel system is the one where the pilot is not in the loop".  How nice
it would be to light the fire and fly for 3 hours and never touch fuel
handling controls except throttle.  This is where we have to take the
future airplanes and those we are now building.  We need to address
how to do that but first we have to get the basics aligned and behind
us.

Jerry Grimmonpre'       L320

That is possible. Except in a high pressure pump failure mode or perhaps 
during take off when you want to run both pumps. The Mooney has a boost 
pump that is run on takeoff only. Ironically the forced landing I had to
make was caused by the boost pump failing and particals from that
failing the other pump. Perhaps pumps in series is not such a good 
idea.

Paul Lamar

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