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Have you seen the fuel pump modules in late module autos with the 6" white sock on the intake nozzle of the pump, that's the self cleaning, no cartridge around the sock just your entire fuel tank swishing fuel around & washing the filter , heavy debris on & off. David R. Cook RV6A Rotary
From: "Dave" <david.staten@gmail.com> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net> Sent: Monday, August 6, 2012 9:57:19 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.nethttp://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.
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David Leonard
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David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
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