Bill Freeman wrote:

Rich,

What exactly are you looking for?  I have some and can scan,
but will be on vacation and too busy for a week.

As an example - the C185 is fuel injected, high-wing (of course)
and has two pickups in each tank, T'd together, feeding a
common sump which feeds back to the top of both tanks (T'd)
and each tank has its own vent.  No selector valve, both tanks
(all four inlets) feed the sump all the time.  The pump
draws from and returns to the sump.  This is a simple system.

Bill,

 Where is the sump located?

The C185 sump (incidentally called a "vapor separator and fuel
accumulator tank" by Cessna, is located on the lower firewall.  It is
vented back to the top of the fuel tanks with a T so the vapor/fuel
can return to either/both tanks. This system is normally unvalved
(i.e.on "both" all the time, with only a fuel shutoff valve) but there
is an optional L/R/Both/Off valve listed.

                         snip

Actually, the inboard & outboard tanks level each other out. That
is why I think that returning to the inboard tank won't cause an
overflow thru the vent. Is this logical?

Does the wing have no dihedral? Perhaps I missed something early
on (I started out thinking it was a low wing), but aren't we back
to the problem of overfilling the inboard tank if you start off on
one of the others and fuel is returned to a full inbd tank?  If you
do the Bonanza fuel system deal by always starting on the inboard
and burning it down to 1/2 then going to others, periodically
going back to the inboard to pick up the returned fuel, it should
work as far as fuel return goes.  Fuel feed and vapor separation are
still issues.  Cessna has found large vapor bubbles flowing upstream
back to the tanks on some systems and increased line size to
accomodate this reverse flow.  Are the vented caps made with
fwd facing standpipes?  If not, they may not actually vent if
flush on the top of the wing.

Would it be any easier to photocopy? I can send you an SASE. Let me
know what the postage will be. At this point I'll look at everything
I can to learn from.

Rich

The primary issue is that I am going on vacation from Friday thru
Wed.  I can scan at a friend's house about as easily as photocopy,
and you get it quicker, plus someone else may benefit online.
I looked at your excellent schematic again, and if you replace the
selector valve with a sump, the return lines can be a single
T'd vent/return line, I think it will be OK, altho unporting can
be a problem, which is why most hig wing Cessnas have duel
pickup ports, one front, one rear (decent/climb).  The C185
sump/vapor sep looks like about a gallon capacity, with the return
line in and out coming off the roof shaped top and all the fuel
in from tanks and out to pump from the bottom (vapor on top).
The sump appears to be welded aluminum with 4 fittings, fuel in
(all lines from tanks T'd together outside of sump), fuel out,
fuel return to sump and vapor/fuel return to tanks (T'd, enters
top of both tanks).  All gravity feed to the vented sump.

Bill
Long EZ builder & pilot
mechanical engineer

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