Charlie,

For what it's worth, your proposed fuel system is essentially the same as I
am using with the exception - that I have a very small (like 1/2 pint)
header tank at the junction of your "T".  But, I see no reason to believe
that you proposed set-up would not work perhaps even better - no header tank
on the FWF to absorb engine heat.  Mine has worked for 10+ years.

However, I would suggest that you include a facet pump between the tanks and
your set up - probably after your selector valve - for a couple of reasons.

In the early days of my testing when I was doing power on stall testing, I
discovered the combination of high power settings and low air flow through
the cowl - could get my fuel in the header tank hot enough to percolate -
never got vapor lock, but I could see the fuel pressure varying considerably
and the engine would complain.  Turning on the facet pump apparently
provided sufficient pressure to stifle the percolation.

Plus it sort of "ensures" that you have a pump that will "Pull" fuel out of
the tanks.  I always have it on for take off and landing.

FWIW


Ed

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW

http://www.rotaryaviation.com/Rotorhead%20Truth.htm

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Charlie England
Sent: Sunday, June 06, 2010 9:47 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: high/low pressure pumps question

Hope this helps...

On 6/6/2010 2:21 AM, Todd Bartrim wrote:
   

Hi Charlie;
Hmmmnn, I gotta say a picture (or drawing) is worth a thousand words.
Todd (sent on my new-fangled google phone with a really damn small
keyboard)

     

On 2010-06-05 8:46 PM, "Charlie England"<ceengland@bellsouth.net
<mailto:ceengland@bellsouth.net>>  wrote:

Hi Todd,

My thought is to set up the fuel path thus: fuel source through a T
into injection pumps, through filters, through combining T, through
the regulator(in cockpit), through firewall to engine. The
regulator's bypass port (in the cockpit) would be plumbed just like
yours, except no heat exchanger since the bypass fuel would never see
the heat of the engine compartment. The bypass would still T into the
supply to the injection pumps, like your system. Obviously, a
manifold pressure line would be required through the firewall into
the cockpit to the pressure regulator.

My original plan (different injection that didn't require a return
line) was similar to your selector setup: main tanks feeding stock
van's selector, with the 3rd port on it being fed by a 2nd vans
selector to select either of the 2 aux tanks. No transfer pump would
have been required,&  no crossover valve. Failure of the primary
valve could have been a 'show stopper', but the newer valves seem to
be rock solid reliable. Going to this system using the gear type
pumps requiring a return line forced re-thinking. Using your idea to
return the bypassed fuel at the pump inlet effectively eliminates the
'return' issue,&  tempts me to return to the original fuel selector
layout, with the addition of a Facet boost pump. The fact that the
optical sensors will work looking into the side of a fuel line (the
T), instead of needing them in the tank&  that they still give almost
a full minute's warning, is very encouraging. I'll start looking for
a convenient place to mount them.

I hope that Tracy will chime in on how he plumbed the regulator on
his -8.

Many thanks for the extra details.

Charlie



On 6/5/2010 12:32 PM, Todd Bartrim wrote:

     >
     >  Hi Charlie
     >     Not sure I understand correctly what you mean? Can you
     sketch it out quickly? I'...

     >  *From*: Charlie England<ceengland@bellsouth.net
     <mailto:ceengland@bellsouth.net>
     <mailto:Charlie%20England%20%3cceengland@bellsout.
     <mailto:Charlie%2520England%2520%253cceengland@bellsout.>..

     >  *Subject*: [FlyRotary] Re: high/low pressure pumps question
     >  *Date*: Sat, 05 Jun 2010 08:38:09 -0...



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