It will depend on where you "T" in the Facet transfer pump. If the line that
is shared is long, you will develop a pressure drop from the flow of the
return fuel. If it is short the delta p will be minimal.
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
From: <ronmilligan@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, June 29, 2004 12:59 PM
Subject: [FlyRotary] Re: Fuel System Question


> >     Let's look at this logically.  The only time you'll
> > have fuel returning to the tank is when the engine is
> > running (or a few seconds after shutdown).  The fuel pump
> > is creating a negative pressure situation inside the tank
> > by removing fuel.  The engine is burning some of the fuel
> > being pumped out of the tank, so there will always be less
> > fuel coming back than is being pumped out. Therefore, there
> > should never be a head pressure against the return line -
> > unless one positions the return outlet below the level of
> > fuel.  Put the end of your return line near top center and
> > you should never have a problem.
> >
> > Regards,
> > Dale R.
> > COZY MkIV-R13B #1254
>
>
> The tank is vented and assuming it never gets blocked will always be at
atmospheric pressure.  Everyone has a fuel pressure guage before their
regulator.  I want to know what the pressure is in the line after the fuel
regulator.  If it is greater than the pump output pressure of the transfer
pump then I will never be able to transfer fuel.  If that is the case I will
have to plumb two extra return lines to the tank.  One for the fuel
returning from the engine and one for the fuel tranfer (I know this will
work but don't want that complexity).  Anybody know what Tracy did?  I have
Tracy's book, (not with me at the moment) does it give that level of detail
(I can't remember).
>
> Ron Milligan
> RV7 QB Fuse
> Aliso Viejo CA
>
>
> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html