Fred,
I recall your non standard engine, but am confident in the quality of
your testing and evaluation.
I don't intend to start a gascolator war, because they are a fine piece
of equipment for tractors, metal high wing aircraft with no prime pumps
and constant water problems or aircraft with low wings and the
gascolator installed and tested with a thirty year track record like a
Piper. They are fine for the aircraft with tank drains, and long runs
of line that fill with water while sitting. I prefer Andair's
gascolators as they work well up to high pressure, seal well, but they
are not a visible junk trap. His filters are built into the unit and
replaceable. On the ones we've installed in RVs, we put them on the
engine side of the aux fuel pump and have had no problems. His pumps
are great also.
You=99re A&P friend is correct in having a high volume / low
pressure pump feed the engine pressure pumps. The Facet pump indeed
sucks well. (So does a Piersburg). On the initial installation of fuel
injected engines, we used to have to have a header tank. Auto and
Marine experience now shows a primer pump at the tank bottom level, will
feed the volume needed. However, the volume of the high pressure pumps
must be satisfied and proper plumbing to prevent circular flow when one
pump fails. Your EFI manufacturer should have that information. As you
know, autos now have the high pressure pump in the fuel tank and run
pressure lines forward to the engine with the regulator after the fuel
rail which prevents starvation and priming problems. Problem with our
little aircraft is the fuel selector has to be forward of the pumps
because they are not normally pressure tested and submerged fuel pumps
are not possible. You probably have already reviewed SDS for their fuel
system installation notes, but if you haven't:
www.sdsefi.com<http://www.sdsefi.com/>. They really helped us with an
RV as well as the Jason Parker engines. Their stuff works. See their
cute little surge tank in their tech section. Small and affordable.
Cleaning the fuel line used to be done with denatured alcohol but since
auto fuel is now filled with ethanol and excellent cleaning and plastic
ruining addatives, I use plain old ethanol laced auto fuel for my
flushings. It does stain if you get a leak and it stinks a bit, but boy
does it clean the crud out of fuel lines that may have been sitting on
the shelf for a while. Not uncommon to get brown fuel out of an R-14
fuel injection hose.
Our procedure:
Start with clean gas cans and fresh fuel always.
1. We fill the tank nearly full, about 15 gallons (and watch for leaks
in the fill neck and bosses).
2. Slosh the plane around
3. Lift the tail and disconnect the fuel line from the engine pump or
fuel regulator.
4. Look for static leaks again.
5. Turn on the electric boost pump (pumps about 30 gal per hour or
more).
6. Calibrate the fuel flow and sight gauge as appropriate.
7. Change 5 gallon tanks out.
8. When the fuel stops flowing out of the main, switch tanks and
exhaust again.
9. Refuel through a Mister Funnel or similar filtering fuel funnel.
10. Repeat two more times.
Repair anything that is wet with fuel. Use care not to overtorque fuel
clamps and use the proper type if using other than automotive hose
(cheap kind you throw away after a few years).
Cheers Fred
Bud
----- Original Message -----
From: Fred Klein<mailto:fklein@orcasonline.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Saturday, April 18, 2015 10:55 AM
Subject: Re: Europa-List: First Fueling
Budyou wrote:
Gascolators do not prime well. I would check for an air leak.
Andairs are well made and pull a vacuum. The standard diaphragm pump
does not pull air well enough for some brands.
Budnow we begin to descend down the rabbit hole of the
testing and operational phase of a one-off, non-standard engine
installation...recall that my engine is MPEFI=99edmy two
(in parallel) fuel pumps are hi-pressure type and (apparently) do not
have the ability to =9Csuck=9D fuel on the input side..
If it won't prime the engine with 2.5 gallons on the ground, will it
do it in the air?
An excellent questionfor which prudence requires an answer
=9Con the ground=9D.
Ground Test war story: Ran the main dry, flipped to aux and it
would not self prime without more head pressure. Could not find a leak
but the gascolator was installed slightly above tank bottom level. With
10 gallons it would prime. It was a trigear. I know they have used
gascolators in a/c for ever, but they should be the lowest point in the
system. That is, the bowl outside, below the belly.
With my mono resting on the LG & tail wheel, I=99m preparing a
diagram with measured elevations of the various points in the fuel
system starting from the tank outlet to the hi-pressure fuel pump
outletsHowever, by eye, it is apparent that the high point in
the system is the selector-valve-main-tank-outlet(selector
valve having been installed as per manual). At this stage of the game, I
have concerns that if main tank runs dry to exhaustion and I move
selector to reserve, will fuel continue to flow?
That is why I don't use them and won't install one. To easy to
screw up. Besides, water does not condense in the tanks and filters
work as well.
I=99ve been unaware of your thoughts on gascolatorsI
confess to have one solely because of the frequent mention of them on
this list and their apparent widespread use.
Most experimental takeoff accidents are fuel and engine related.
I am indeed aware of that fact.
Make them flawless then test for fuel exhaustion, on one side then
switch and hopefully keep running.
Exactly my intention...
Clean your fuel lines before hooking to the engine. A common
assumption is the filter missed some dirt/ debris and the gascolators
just prior to the engine caught it. Flush and flush again.
And what do you recommend for a cleaning agent?
My two cents.
Grossly undervaluedyour knowledge is priceless
Many thanks,
Fred
PS: A local A&P recommends adding a Facet pump to ensure that fuel
gets to my hi-pressure pumpsmy engine builder recommends
bleeding the lines just upstream of the hi-pressure pumpsfor
the moment, I=99m looking for simplicity and reliability.
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