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Mark,
I would not recommend this type of filter
for an airplane.
I couldn’t find a part number for
the replacement filter media for this filter. The filter part number
itself is different depending on whether you want cellulose at 10 microns or
steel at 100 microns. I bought a similar diameter filter that was three
and a half inches long and the filter media was a round flat screen that the
fuel flowed through. The filter media was about three quarters, seven
eighths inch in diameter and would take nothing to plug it up completely, which
it did after about an hour of running. It was a black sludgey material
that I think came from my incomplete cleaning of the fuel hoses that I made up
after cutting to length and installing the hose ends. Anyway after I saw
how easily they were to plug, I got rid of them and installed a fuel filter of
the style of an oil filter. They have a lot of filter media and will plug
very slowly so you should be able to see your pressure or flow dropping for
quite some time before you would lose the engine.
I am not recommending this particular filter,
but it is of the type I would recommend.
http://www.summitracing.com/parts/sum-g1507/overview/
Bill
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Mark
Sletten
Sent: Monday, July 28, 2014 4:42
AM
To: Lancair
Mailing List
Subject: [LML] Re: FW: [LML] Re:
Gascolators and fuel lines.
Gang,
The vast majority of answers on this subject have focused on the
filtration benefits of the gascolator. I think Dennis
Johnson's observations are spot on. If one carefully sumps
the tanks (ensuring the aircraft is sitting on a level surface) prior to engine
start it would be nigh impossible to get a coherent slug of water large enough
and to interfere significantly with engine operation. This is especially true
for fuel injected Continental installations, where a significant portion of the
fuel pumped to the engine is unused and returned to the tank. Is it possible
for a very large slug of water to remain coherent in five gallons of fuel while
agitated by aircraft motion and fuel recirculation? I suppose it is, but it
seems unlikely to me.
That aside, no one has mentioned ever finding water in the gascolator
of their Lancair. Which makes sense, because in order to do so water would have
flow uphill while on the ground, or remain separated enough from the fuel to
fall out while flowing thru the gascolator at something approaching a
half-a-gallon per minute while the engine is running.
Regarding the filtration capabilities of the gascolator; I've emailed
Andair for more information on the specifications (filtration level, filter
material area, max fuel flow, etc.), but they have yet to respond. If anyone
has this information I would greatly appreciate it.
Kevin Stallard suggested the gascolator would appear to be a better
option as a filter than an inline style. The type of inline filter I'm talking
about is not your prototypical one-inch diameter, one-inch long plastic
see-thru filter we've all seen on our lawnmowers. I talking about something
more like this:
This filter is 1.75" in diameter and 6.25" long. If the
filtration media was a simple cylinder that size would yield 30+ square inches
of filtration area. Since the media is pleated (much like your typical oil
filter), the filtration area is actually much larger. Maximum flow rate is 150
gph, which is more than three times that required for an IO-550. That suggests
this filter could be two-thirds clogged with crud and still have adequate fuel
flow. And let's not forget there would be one filter for each tank; if one
clogs I can still switch tanks.
Additionally, this isn't a throw-one-in-and-hope-it-works scenario.
These filters would be installed in a location making it exceptionally easy to
remove for inspection/servicing--something that would occur following every
engine run up to first flight. My reasoning is that such a test regimen will
reveal any problems of the type mentioned here.
On Thu, Jul 24, 2014 at 4:39 PM, John B <2thman1@gmail.com>
wrote:
Like most of you who responded I would not give up the gascolator.
Have done two annuals since flying and both times have found almost a
teaspoon of white fuzzy stuff. Fiberglass particles I'm virtually certain,
and I thought I had done a perfect job of cleaning out the tanks before
first flight.
Adam,
My experience is the same as yours. I often found/drained water out of my old
Cherokee tanks, and MANY rental airplanes as well. All were parked outside, and
I think avgas came with a certain amount of “water added” in the
old days… L
I’ve never found any water in the gascolator of my
IV-P, so the fuel doesn’t have/collect any water…or it’s
going through the engine and being vaporized--which I think unlikely. I know
the gas caps are MUCH better than the old Cherokee “stoppers,” and
I rarely park the Lancair outside these days.
Like you, I was meticulous in cleaning/keeping the fuel
tanks/lines clean during fabrication and through flight test. I still collected
some small amounts of carbon fuzz, and a few bits of aluminum in the gascolator
during testing, and at the first two condition inspections. Almost undetectable
bits of something for the last three, not enough to even identify when poured
onto a piece of white paper… So the gascolator/filter is probably not
serving a useful function today…but deleting it would be like throwing
away the spare tire in my car, IMHO… I carry a few critical spare parts
in my airplane for the same reason…
Bob
From: Lancair Mailing List
[mailto:lml@lancaironline.net]
On Behalf Of Adam Molny
Sent: Thursday, July 24, 2014 1:30
PM
To: Lancair
Mailing List
Subject: [LML] Re: Gascolators and
fuel lines.
Hi Mark –
Our planes are kept in a heated hangar so there’s no
opportunity for water in the system from rain or condensation. Back when I was
renting Cessnas and Pipers I did occasionally drain water from the gascolator.
Those planes were kept outside.
The lowest point in the Legacy fuel system is the fuel selector
valve, but it’s not designed to capture water or sediment like a
gascolator. Your notion that the fuel flows too fast for water to settle out is
difficult to prove or disprove. I always envisioned tiny globs of water flowing
out of the fuel tanks and coalescing into a large glob of water in the gascolator.
The real test would be to pour a cup of water into one wing tank, run the
engine at high power, and see where the water ends up (in the gascolator, out
the tailpipe, or back to the fuel tank). However, deliberately adding water to
the fuel system seems like a bad idea so I’m not going to try it.
I think you are saying you want fuel filtration but there’s
no point in having water separation since a gascolator won’t work. Can
you be 100% certain that you will never get water in your system? What about
flying through rain with a loose fuel cap? What about being parked outside at Oshkosh for a week? If
you do get water in the system, where will it go? I hate to fall back on the
“It’s always been done that way” argument, but gascolators
exist for a reason.
For all the Legacy drivers out there: Have any of you ever
discovered water in the gascolator?
Good discussion!
From: Mark Sletten
[mailto:mwsletten@gmail.com]
Sent: Thursday,
July 24, 2014 9:15 AM
To: Adam Molny
Subject: Re:
Gascolators and fuel lines.
Adam,
I wasn't
questioning the value of fuel filtration, just whether a gascolator is the best
choice. As I understand it, the gascolator provides a means to filter the fuel
and a low point to catch water that may have gotten into the fuel system. There
are several arguments against using one for the Legacy.
- In the Legacy the gascolator is not the lowest
point in the fuel delivery path from the tank to the engine, so water in
the tank should not flow to the gascolator before turning on the pumps. (I
believe the same is true of the RV. Has your wife ever drained any water
from her gascolator?)
- Given the high fuel flow rate and recirculation
of unused fuel to the tank, it's unlikely the gascolator will remove any
water with the engine running.
- The gascolator in the engine compartment provides
a large surface area to add heat to the fuel which can contribute to vapor
lock. Lancair combats this with a heat shroud and blast air, adding weight
and complexity.
- The gascolator requires numerous fittings and
breaks in the fuel lines, adding to complexity, weight and the possibility
of fuel leaks.
Since the
gascolator appears to be rather useless at removing water, it's primary
function for the Legacy is filtration. With so many other filtration options
available, it seems illogical to put a gascolator in the engine compartment.
On Thu, Jul 24,
2014 at 7:12 AM, Adam Molny <Adam@validationpartners.com> wrote:
Mark –
The gascolator provides a large reservoir for capturing water and
sediment. It also contains a fine screen with a fairly large area that acts the
final filtration element to keep junk out of your carburetor or injector(s).
Case in point: my wife’s RV6-A started showing small amounts
of debris when sumping the fuel tank drains and gascolator. We opened up the
gascolator and found a small amount of debris at the bottom of the bowl, and
the screen was about 5% blocked. There was no immediate danger, since the bowl
would have to completely fill with debris and the screen would have to be 100%
blocked in order to kill the engine. It turned out to be bits of fuel tank
sealant flaking off.
My point here is that the gascolator acts as a buffer and gives you
lots of warning and lots of time to head off any potential fuel contamination
problem.
What is the argument for omitting the gascolator on fuel injected
engines?
-Adam Molny
Legacy N181AM 255hrs
From: Mark Sletten
[mailto:mwsletten@gmail.com]
Sent: Wednesday,
July 23, 2014 7:35 AM
Subject: Gascolators and fuel
lines.
Gang,
First:
Gascolators. There is a great deal of debate around the web on the benefits of
a gascolator in fuel injected systems. What's the consensus among
Lancairians?
Second: I'm
considering making my own engine compartment fuel lines. I plan to build them
up from scratch including the fire sleeve (or not if the hose is sufficiently
fire resistant). Anyone have a recommendation on the type of hose to use?
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