I was looking through the Lancair Legacy manual pdf
and found this fuel pump. Anybody know what brand it is?
Apparently it has the pressure regulator
built in. Since it is a mechanical fuel injection system I don't
know what the system pressure is yet.
Sure simplifies the low wing fuel plumbing and loses the external
pressure
regulator. The two layer selector valve is still used to reroute
the return fuel to the tank that is being drawn from.
An essential feature.
Paul Lamar ...No rotor no motor.
Paul,
I think it is a Dukes pump, AKA 2-speed Continental fuel pump. You
can
get one from Lancair for $745.
Mark S.
Is that all? :) Do you know the system pressure Mark?
Of course you will pay a couple of hundred for a good fuel
pressure regulator anyway.
Paul Lamar ...No rotor no motor.
Paul,
Not sure of the pressure, but I was told that Continental fuel
injection
systems run significantly lower pressures than auto systems. I
don't
have any sources to verify that though.
With the Dukes pump, wouldn't you still have the same problem with
air
getting trapped between the tank and the fuel rail causing engine
stoppage? This is why I installed a bleeder circuit that bypasses
the
regulator. Tests show that it solves that problem. I read a
flight
report done during the 40-hour fly-off period of an ES that almost
had
to do an emergency landing on I-70 in Colorado after intentionally
running a tank dry, and then being unable to get a restart.
Activating
the high pressure circuit of the Dukes pump finally got it started.
Mark S.
Yes I guess you could get air trapped between the pump
and the injectors but it should escape through the injectors
when they are pulsed. On the other side of the pump it
is a different story.
High pressure pumps are notoriously hard to prime. That is why
they must be as close to the tank as possible.
The ultimate is having the pump in the tank like they
do it in the automotive world.
Paul Lamar ...No rotor no motor.
Ok, so apparently add another thing I need to plumb into the fuel
delivery system -- a pressure regulator. It's a real problem that I am
so clueless on EFI fuel delivery system design -- I keep discovering
things I need. This area is a missing piece on the website, Paul -- not
a word to be found. What little I have found elsewhere on the web is of
little use as well. Ah well... I suppose I will muddle through it all
eventually.
Here's my design so far -- those who have a clue, please chime in & tell
we where I am going astray...
Mark Supinski
Very important. Please ask. Not everything is on the web site
yet. Mark Wrathal has a good do's and don'ts on his web site.
http://members.aon.at/wrathall/rotary/
Looks like the high pressure pumps need to go next to
the shut off valve before the gascolater. The one way valves
are built into the pumps. What brand of pump are you
using?
Paul Lamar ...No rotor no motor.
Paul,
Just for the record, the schematic shown was not of my fuel system.
Close, but no cigar. My system has two wing tanks, with water drains and
finger strainers in each, followed by a two-level Andair valve. The
Andair outlet splits, feeding two fuel pumps (connected in parallel)
followed by a separate filter for each pump, the two lines then tee
together to feed the primary and secondary fuel rails, returning through
the pressure regulator which has a bleed-bypass circuit. Each return is
directed back to the tank in which it was drawn from. Note: The Andair
valve does not have a "BOTH" setting, only LEFT, RIGHT and OFF.
Mark S.
OK I see what happened. Please sign your full names Marks :)
That was Mark Supinski's skematic. Not Mark Steitle skematic.
What you describe above sounds OK. Watch out for that Andair valve
as the detents are not very strong. No "BOTH" position is a good thing.
Paul Lamar ...No rotor no motor.
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