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
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.
Why would the gascolator need to be on the pressurized side of the
system? The information I've found has not suggested that design as a
requirement. BTW - you have the wrong Mark on the graphic -- (there are
too many Mark's here lately!). The other Mark bought the the fuel
pumps, so I'll need to either go look at them, or ask him what they are
-- unless you remember them (since you had them until just recently!)
I will go review the web address you suggested (Another Mark! Yikes!) &
see how that changes my current design.
Thanks,
Mark (As in Mark & Mark)
The gascolator needs to be on the pressure side because
the pumps have trouble sucking. If you have water drains in the
tanks you probably don't need the gascolator. Is this 25 gallon
tank in the cowl? If so that helps as the pumps now have a head to
work with assuming the high pressure pumps are mounted under it.
BTW Yes I got that figured out. See my last message on last names.
Paul Lamar ...No rotor no motor.
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