REFLECTOR: Dukes 2 speed pump

[Craig and Denise Woolston]

We prime our 550N with 4 seconds of "high", then start with no pump.  We are
at 2350' MSL in the desert.  We definitely use "high" to circulate fuel
(mixture cut-off, throttle open) for "hot starts".  We use "low" on takeoff
and landing for a backup to mechanical failure.  I know I have forgotten to
turn on "low" when landing and never have had the engine quit at idle on
approach and our engine will idle statically around 450 rpm.  "High"
definitely will kill engine at any phase of flight so are switch for the
"high" position is guarded.  FWIW.

 

Craig

XL-5-FG, 550 hrs.

 

  _____  

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Brooke Wolf
Sent: Thursday, December 16, 2010 4:31 PM
To: reflector at tvbf.org
Subject: REFLECTOR: Dukes 2 speed pump

 

Thanks for the info Scott.  

 

The word I got from Cirrus is that they run their TCM 550N's with a Dukes
pump that produces 4-6 psi/19 psi.  I can't verify this information but I am
pretty confident of my source.  

 

My knowledge of the specifics of the 550 is quite limited, however it is my
understanding that they HAVE to be started with the pump on in the high
pressure mode.  After that, the pump is turned on only in low pressure
during critical phases of flight as a backup to the mechanical pump.  I am
told that the engine will not run with the pump in high as it gets
"flooded".

 

Anybody else want to chime in?

 

Brooke

 

 



 

From: Scott Derrick <scott at tnstaafl.net>

Date: December 16, 2010 4:16:27 PM EST

To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>

Subject: Re: REFLECTOR: 2 Speed Dukes Fuel Pump

Reply-To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>



I used to know that as its the same for my 520. The low pressure is between
16-19 psi, The high is think was about 28-30...

It's a b**** to get the electrical backup to work in flight because you have
to change the mixture with any power/rpm change.

I opted to go automotive(racing) single pressure 16 psi carbon vane pump, as
that is the pressure you use for an in flight mech pump failure.

I think I have the data on the Duke at the airport in the overhaul manual.
I can check it next time I'm there if nobody else chimes in.

Scott
-------- Original Message --------
Subject: REFLECTOR: 2 Speed Dukes Fuel Pump
From: Brooke Wolf <bwolf1 at tds.net>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Date: 12/16/2010 05:01 AM




Does anybody know the pressure ratings for the High/Low positions of the

2 speed Dukes fuel pump used in TCM-550 installations?

 

Thanks

 

Brooke

 

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