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Answers that I know listed after question.
Eugene Long
Lancair Super ES
glong2@netzero.net
-----Original Message-----
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of
rtitsworth
Sent: Thursday, May 10, 2007 7:51 AM
To: lml@lancaironline.net
Subject: [LML] Re: IO-550 fuel injection
Eugene,
First a couple silly thoughts (which don't seem to apply since it
mysteriously now works again), but seemed like potential learning
opportunities (for me anyway).
1. Does anyone know the failure modes of the electric boost pump? I
know/believe it is a free flow design but if it's impeller/diaphragm (???)
fails "could' it cause a restriction?
Don't know
1b. How does the Dukes pump work? Anyone have an exploded view diagram for
future reference?
Don't know
2. What is the behavior of a plugged (or partially plugged) gas collator?
Is it a potential restriction?
Possible restriction, but why would it come unplugged and stay that
way?
3. Is your collator drain easily accessible? Do you drain/sump it every
flight? Ever get any H20 from it? Do you disassemble/inspect it at annual
CI?
Fairly easy, it is a large water/contaminant filter. I do not
drain it before every flight, but when done I have not found water or
contaminants in the drained gas. When drained there is only about 2
tablespoons that come out of the drain because the filter is higher than
the tanks and gas is sucked back into the tank. Replace the filter at
the annual.
A couple other questions;
4. Does your wing tip fuel vent line make a vertical turn before going to
the tank (so water would have to go uphill).
Yes, about 2" rise and it is the old 1/4" vent line.
5. Were your fuel tanks both full (maximum gravitational head pressure)? If
not, any chance for similar high h20 condensation on the inside - partially
restricting the gas collator?
About 70 gallons total, 35 in each tank instead of 52. My filter is
meant to trap water, but I have never found water in the filter.
6. What was the approx temp on the ground? (I'm assuming it wasn't too hot
yet at 8:30am) Any idea of the temp enroute? (I'm assuming no bizarre
atmospheric phenomenon, and 8500 doesn't seem all that high anyway from a
fuel vaporization standpoint). Also assuming normal 100LL fuel.
55 on the ground, 43 in the air with 100LL
7. What were your approximate cruise power settings and fuel flow at the
time (assuming 25"ish MP, 2400/2500'ish RPM and less than 20 GHP?
About 24+" MP, 2500 RPM, 12.5 GPH Lean of peak
8. Do you have the original ES fuel-line set-up (sharp 90' fittings at the
tanks, flex line to the fuselage wall, sharp 90' bulkhead fittings, 3/8"
hard line to the selector (Andair), more sharp 90' fittings at the selector,
3/8" line to the boost pump (Dukes) and to the collator (old Lancair style
vs Andair collator).
Straight fittings at the tank and fuselage, solid 3/8" slow bend
lines from fuselage to the Andair selector, 1/2" flex line electrical fuel
pump in the middle of the floor then to the firewall with 90 degree
fitting, 3/8" flex lines to filter and mechanical fuel pump.
9. Where is you boost pump located and how is it oriented? (assuming it's in
the cabin, on the lower firewall, oriented vertically)
At the lowest point in the center of the inside fuselage in the
cabin
10. When the pressure/flow when to zero, did the engine stumble/quit?
(trying to rule out any sort of engine monitor/gauge error)
The engine quit both times and it got very quite except for the
copilot's nattering.
11. Assuming nothing else unique/abnormal about the flight (gross weight,
other???)
Gross was about 3000#, well under the limit
12. Really bizarre thought... Could a restriction in the engine fuel pump
vapor return line cause it to stop flowing and leave the engine pump
cavitating (not able to prime)? Does anyone know approx how much
fuel/vapor cycles back through that circuit (under normal conditions)?
Don't know but the engine primed with the boost pump, started.
taxied, and run-up without the boost. Could be a vent line
restriction but still allow this to happen.
Rick
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