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One example of a in-tank pick filter can be seen here: http://www.jayracing.com/index.php?main_page=product_info&cPath=2_5&products_id=16724
Any rust and junk will be picked, but once the pump is turned off, there is no more suction and the junk falls to the bottom of your fuel tank. Hence the comment "self cleaning"
My son's Nissan had been sitting for six years, and the fuel tank was full of rust. Enough flaky rust that he could drive one mile, pull over and wait, and drive another mile. Made it home OK, but took a while.
Someone mentioned it previously, but just how small of a particle can be
easily passed through an injector? If you are using common Mazda Injectors, you really do not want to filter anything smaller than the Mazda filter does. If the injector passes a 100 micron particle without problems, there is little need for a filter that filters down to 10 micron as it will just clog rapidly with poor gas.
My Land Cruiser spent years in the Nevada, with the amount of dirt ingested to the tank. When I rebuilt the carb there was a lay of fine mud in the bottom of the float bowl. Filter passed the finest stuff so it would filter the big stuff. Admitted it was carb'd and not injected... but even if you let dirt through to the injector it might not close completely for a few cycles, but would blow the dirt out of the nozzle. Engine would remain
running.
As part of your annual, just pull injectors and bench flow test them. I have them squirt into graduated cylinders, and with a simple injector driver, you can compare if they are all squirting cleanly and flow the same rates. Rather than Gasoline, I prefer using mineral spirits and Techron injector cleaner. Less volatile but same specific gravity, and does a decent job of cleaning the deposits.
Tom
From: Dave <david.staten@gmail.com>
To: Rotary motors
in aircraft <flyrotary@lancaironline.net>
Sent: Monday, August 6, 2012 8:57 AM
Subject: [FlyRotary] Re: Fuel Filters. Was: Rotary Forced Landing
For the ignorati among us, I must ask.
How does a filter "Self clean"? How DO the car manufacturers
overcome eventual filter clogging/saturation? Just by making it so
dang large it never reaches that point?
Dave
On 8/6/2012 8:48 AM, Al Wick wrote:
<how small of filtration do we need?
<size of a particle that will fit through the injector
nozzle easily?
Excellent questions. You have one resource that stands WAY
above others. What do the OEM vehicles use? They know precisely
what the optimum surface area is, optimum filtration size. Too
fine, it clogs needlessly. Too coarse, you increase risk of
injector clog. Too little surface area, it won't last. They even
take into consideration unusual needs, like people that operate
at super high flow rates.
A few decades ago, cars would periodically suffer clogged
filters. Never happens any more because they have new tools to
optimize designs. For example, their course filter screen has
around 10 times more surface area than any airplane filter. Self
cleaning, screen size optimized. So debris can't affect your
car. It's just brilliant.
I really worry about builders copying marginal fuel designs.
Unaware of how close they are to the failure threshold. You can
fly for years with marginal design, tell everyone "works great
for me". Unaware you are promoting failure.
-al wick
----- Original Message -----
Sent: Sunday, August 05,
2012 1:35 PM
Subject: [FlyRotary] Fuel
Filters. Was: Rotary Forced Landing
So my next question is how small of filtration do we need? ie,
what is the size of a particle that will fit through the
injector nozzle easily?
I was using the Earls sintered bronze element at 35microns, but
I also could use the SS screen version at 85 mic. The Peterson
in line 600 series is MUCH more expensive and comes in 45, 60,
and 100 micron SS screens.
http://www.jegs.com/p/Peterson-Fluid-Systems/Peterson-600-Series-Fuel-Filters/1528539/10002/-1
Those do have more surface area but will be a hassle for me to
retrofit, and not sure they are worth 4x the price of the
earls. Lots of other brands I have not explored yet.
I like the sintered bronze for strength and durability. Other
opinions?
Dave Leonard
On Sun, Aug 5, 2012 at 12:42 PM, David
Leonard <wdleonard@gmail.com>
wrote:
Yea, mine is an Earls cleanable high
pressure with maybe 10 sq cm worth of area. Will look
into the Peterson. Thanks Tracy.
Dave Leonard
On Sun, Aug 5, 2012 at 10:48
AM, Tracy <rwstracy@gmail.com>
wrote:
Al probably means the filter that's on
factory in-tank pumps. OK, but very hard to
implement on RV wet-wing tanks. I used a
gascolator for low side filter on my -4. Worked
OK and when it clogged, switching on the backup
pump with main pump caused the screen disk to
collapse and let fuel bypass it. which is
better than no fuel at all but not an ideal
solution.
On the -8 i used a cleanable Peterson filter
with TONS of filter area, works great. That
was a replacement for the Summit Racing fuel
filter with a filter element disk the size of a
nickel. It clogged up in about about 5 hours of
flight.
Yes, it was the high side filter. I
don't have any low side filters. Would be
interested in a source for the
self-cleaning fool-proof low side filters
that Al mentions.
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
On Sun, Aug 5,
2012 at 6:34 AM, Tracy <rwstracy@gmail.com>
wrote:
I assume Al is referring to the
pump intake side filter. So
for the record, was it the inlet
side or the high pressure side
filter that clogged? ( Both are
needed ) >From the symptoms I'm
guessing high side but not sure.
BTW, nice job!
Tracy
Sent from my iPad
As long as your are
rebuilding, tremendous
safety improvement by
using same fuel filter
method that all cars use.
No matter how much foreign
material you throw at it,
it can't clog.
It minimizes pressure
drop, so lower risk of
vapor lock. Self cleaning
filter. Self priming
pumps.
-Al Wick
Cozy IV powered by RDM
Subaru 3.0R.
Expert at failure
prevention methods, N9032U
240+ hours from Portland,
Oregon
Glass panel design, Subaru
install, Prop construct,
Risk assessment info:
http://www.ez.org/pages/alwick/index.htm
----- Original
Message -----
Sent:
Saturday, August 04,
2012 1:38 PM
Subject:
[FlyRotary] Re: Rotary
Forced Landing
Dave, having gone
through recently what
you just experienced I
would like to say GOOD
JOB on getting down
safely and with such
little damage. Anyway
at 1500 AGL there
isn't a lot of time
... obviously you made
the right choices.
Jeff
(Rebuilding my Ride)
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Sigh..
Yup, that was
me. I have been
meaning to fess
up. We were at
about 1500 agl
when the fuses
blew on my fuel
pumps. I was in
a close
formation of 40
aircraft at the
time too. I
think I got some
bad MOGAS
somewhere in
Iowa as I did
notice my fuel
return flow
creep downward
but didn't think
it was a big
problem.
On the incident
flight, a one
hour formation
flight from SQI
for a mass
arrival at OSH,
the return fuel
flow drifted
down to zero. I
actually though
it was a sensor
problem. I
didn't have the
ability to give
it a lot of
attention
because we were
in a loose
formation. Soon
after we pulled
it together for
a tight
formation power
switched off. I
tried to find a
road, but
quickly ran out
of options and
put it down in a
bean field. With
the beans
hitting the
flaps it brought
me to a stop in
about 200ft,
just before I
would have gone
into the full
grown corn. As
mentioned, wheel
pants broke in
half but no
other damage
besides pulling
bean leaves out
of every nook
and cranny. The
farmers were
very nice, and
the stories are
true... they
have attractive
daughters. They
were out there
barefoot in
their Sunday
best enjoying
the excitement.
Helped me clean
the fuel filter
and replace the
fuses. Within a
couple of hours
I was able to
take off from
one of their
driveways as
they all waived
good bye (but
strangely, no
one took me up
on my offer for
a ride).
Landed at OSH
just before dark
to a reserved
parking space
and a very warm
reception from
the formation
group and
friends. Great
support from
everyone all
around, though I
am trying to
avoid the
obvious new call
signs they are
trying to give
me.
--
David Leonard
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David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
--
David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
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