CorvAircraft> facet pumps gascolator, systems design, , , have at it!

[601corvair]

Yesterday I posted the question below and got lots of good info.  I have not figured out
how to respond to a string so i included it below.  Mark was especially helpful with his link to 
his fuel system.  I am looking for more insight into my last two questions.  Do i really need a selector
valve ( Mark votes no), and two do i really need a gascolator?  

I have posted the link to the facet pumps so as to document their technical spec.
At this point we do NOT have a header tank in our design, just two wing tanks with individual sumps and an MA3 carb.
But, we can change any or all of this.  After all this is EXPERIMENTAL and we are all putting our own styles into the
designs and power plant.  If we had wanted to be aircraft Assemblers ( and rich ) we 
would have bought an RV quick build it!  :-).


Thanks for all your help. phill

------------------------

From: corvaircraft-bounces at mylist.net
[mailto:corvaircraft-bounces at mylist.net] On Behalf Of 601corvair
Sent: Saturday, August 25, 2007 2:15 PM
To: corvaircraft at mylist.net
Subject: CorvAircraft> facet pumps gascolator, systems design,,, have at t!

Ok guys I've got some fuel system questions for corvair builders.  We are
building an Zenith 601 hds with a corvair and I am purposely asking this
list because of all the KR2 guys  who I think have insight here.  There is a
WW zenith set up that lots of people follow and  but I am hoping to get
answers the questions rather than links to the WW XL.  I have great respect
for WW, but I don't have an XL and I would like general answers to
questions.  Here we go.

According to the Facet web site
(http://www.facet-purolator.com/solidstate.asp) all their pumps have check
values, but when you read the specifications only a few do.  The one that
came with the kit is 40105 and the one recommended by WW on the XL is 40108.
They are comparable, only slightly different pressure, but differ in pipe vs
AN fittings.  According to the application chart, nether have check valves,
but according to the narrative both should.  Does anyone know for  " my life
depends on it for sure'?  Here is why this is important to me, and why I
need some insight.  The  plans for the HDS call for a fuel selector valve,
our hds is a low wing plane with leading edge wing tanks.  If the pumps have
effective back flow check valves, can we use the pumps as fuel selector
valves?   Can I place one pump in each wing root , then go to a "T"
connection and on to a third common boost pump?  Do I even need a fuel
selector valve?  This would be simpler and ,lighter, plus i
 could place the lines so as to avoid fuel  in the cabin ( not that I really
care).

Question two. Gascolator.  Each tank has a sump.  Do I really need a
gascolator?  These originated in the days of header tanks with no sumps.
Some current fuel system designers have questioned the need for them --- I
fully expect to get flamed on this one.

Question three.  If you install a gascolator, where does it go?  There have
been several versions of fuel system plans from Zenith, some of the older
ones have it after the fuel pump  (i.e., pressurized).  Some folks say it
should come before the pump.  If the pumps are in the wing root this could
be problematic, or we could have one in each wing.  However, it seem silly
to have one 3 inches after the wing sump.

I should mention I have a MA3SPA carb.

OK, have at it.  I would rather be educated on the ground.

phill

 
       
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