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Critique my Fuel System.

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gotime242

Joined: 09 Jul 2010
Posts: 52
Location: West Palm Beach, FL

Posted: Thu Jul 15, 2010 9:41 am Post subject: Critique my Fuel System.

Hello all, his is my first post. I recently bought a Kolb FS II and since have been spending a lot of time browsing this forum and some others. It seems the fuel system is kind of a weak point and many people have a lot of good ideas on what the best setup is. I thought about it and kind of decided what I would like to do. 



The Firestar i bought has a very simple fuel system, which is good....but id like to add a little more with a few changes. Currently it has the original Kolb tanks w/pickups made from fuel line w/weights and pickups on the end. Then it just goes to a Y fitting outside the tanks to join the two, then to a aircraft spruce glass fuel filter...and to the pulse pump. Simple and works...however id like to add a back-up pump, not have fuel line in the tanks and eventually a gascolator.  



What i would like to do: 

Kolb Tanks w/ "TNK" all metal top feed fuel pickups -> gascolator -> fuel pump -> fuel filter -> Pulse pump. Using NAPA black auto fuel line throughout the entire systems. 



Here is another thing....instead of having the main fuel line pulling from both fuel tanks (doubling the chance to suck up air for some reason)...i would like to have it only pull from ONE tank, and then have another facet pump to be able to transfer fuel from the 2nd tank to the "main" tank. I like this idea because it eliminates a top-feed that might be problematic and if the pump fails (which it prob wont) you will just have less fuel and can land sooner. And later on i could add an aux tank to the pax seat with the same concept...



A simple picture of all this should be at the bottom.



Will the fuel pump still be able to serve as a backup from this elevated point?



Let me know what you think, thanks!!

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Last edited by gotime242 on Fri Jul 16, 2010 2:19 pm; edited 1 time in total

henry.voris

Joined: 02 Mar 2007
Posts: 116
Location: Pueo Field, Kula, Maui

Posted: Thu Jul 15, 2010 10:38 am Post subject: Re: Critique my Fuel System.

15jul10



Gotime,



   Personalty...



A. I would prefer to have the fuel filter be the last thing before the carbs...



B. I have a fuel pressure regulator after both pumps. I worry about overpowering the carb with two pumps running.



   But I'm no expert...



Aloha,

_________________
Henry
Firefly Five-Charlie-Bravo

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slyck(at)frontiernet.net
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Posted: Thu Jul 15, 2010 11:06 am Post subject: Critique my Fuel System.

A Facet will suck uphill but personally I like to have it below the lowest point on the pickup.

A straight tube with a tapered end is good for a dip tube.  I have an aversion to holes in the bottom of

a plastic jug.  The only thing I can say good about the plastic tank is I don't need a gauge.  I'm aware of their frailty.



I had a regulator.  I removed it because, after some study, realized that if it failed, it would be to zero flow.

A serious regulator would return fuel to the tank as on a FI system.  (bypass)

BB



 

On 15, Jul 2010, at 2:38 PM, henry.voris wrote:



 	  Quote: 	
		   

 

 15jul10

 

 Gotime,

 

   Personalty...

 

 A. I would prefer to have the fuel filter be the last thing before the carbs...

 

 B. I have a fuel pressure regulator after both pumps. I worry about overpowering the carb with two pumps running.

 

   But I'm no expert...

 

 Aloha,

 

 --------

 Henry

 Firefly Five-Charlie-Bravo

 

 Do Not Archive

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=304955#304955

gotime242

Joined: 09 Jul 2010
Posts: 52
Location: West Palm Beach, FL

Posted: Fri Jul 16, 2010 2:18 pm Post subject: Re: Critique my Fuel System.

Thanks for the replys guys.

Looks like im starting to solve this puzzle bit by bit. 



Anyone else have any input on if a Fuel Pressure regulator would be required when adding the Facet 40105 (lower pressure) fuel pump into the series?



I guess in all my reading i hadnt seen much on the use of a FPR...is that because its common sense to have one?...or that not many people are running them?



Thanks again.

lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Fri Jul 16, 2010 3:11 pm Post subject: Critique my Fuel System.

The key is to buy a Facet pump that will not overpower  your carbs, then you can leave the pressure regulator out of the system. In most  cases, less is better.

 Larry

 Note: If you forward this email, please delete the forwarding history,  which includes my email address.

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henry.voris

Joined: 02 Mar 2007
Posts: 116
Location: Pueo Field, Kula, Maui

Posted: Fri Jul 16, 2010 3:43 pm Post subject: Re: Critique my Fuel System.

I included a fuel pressure regulator in my system based on no empirical evidence what so ever.  The decision was made using darker forcesâ€¦ rumor, innuendo, fear, and commercial interestsâ€¦



I had read in several sources, that it was advisable to include a regulator when adding a Facet pump to a pulse system. My sources (CPS leaps to mind) had a commercial interest in me buying said regulatorâ€¦ I have not read such a requirement from either Rotax or Bing (I havenâ€™t been looking.). I would appreciate any real data on the subjectâ€¦



Until thenâ€¦ The repeating vision of the Facet pump overpowering the float valve on the poor little Bing, sending a torrent of raw fuel down the throat of the (normally) thundering 447 was too much for me. I caved and installed the regulatorâ€¦



I suspect the mechanism is simple, so I expect high reliability. I havenâ€™t heard of any failuresâ€¦ (I havenâ€™t been looking.)



I have not tried to calibrate the pressure delivered to the carb. However I do know that it is possible to turn the regulator down enough to starve the engine. (Donâ€™t ask me how I know thisâ€¦ or how long it took me to figure it outâ€¦).



I agree with Larryâ€¦â€  In most cases, less is better.â€ And would happy to be persuaded that itâ€™s OK to get rid of the regulator.

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Firefly Five-Charlie-Bravo

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lcottrell

Joined: 29 May 2006
Posts: 1494
Location: Jordan Valley, Or

Posted: Fri Jul 16, 2010 5:39 pm Post subject: Critique my Fuel System.

Henry,

    When I first started with a 447 I used a  regulator that I had previously used on a truck mounted welder and set the  pressure at 5 pounds. After an unknown number of hours, I discovered that Facet  makes pumps that will only put out 5 pounds of pressure. ( you can get more  pressure if you want) at that point I took off the pressure regulator and ran  out the 447, a 503 and am now working on a HKS. All happily without gasoline  squirting every where. 

   You do what makes you feel good, as always all this  information is just that, not even a hint of suggestion or recommendation should  be derived from the preceding message. 

 Larry

 Note: If you forward this email, please delete the forwarding history,  which includes my email address.

 [quote]   ---

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Dana

Joined: 13 Dec 2007
Posts: 1047
Location: Connecticut, USA

Posted: Fri Jul 16, 2010 6:29 pm Post subject: Critique my Fuel System.

--------------------------------------------------

"henry.voris" <henry_voris(at)yahoo.com> wrote:

(15/07/2010 14:3

 	  Quote: 	
		   A. I would prefer to have the fuel filter be the last thing before the carbs...


	


i Understand the logic, but I think it's more important to protect the

pump from any crud coming into it.  If the pump is producing crud, 

it's likely to fail anyway. 



-Dana

henry.voris

Joined: 02 Mar 2007
Posts: 116
Location: Pueo Field, Kula, Maui

Posted: Fri Jul 16, 2010 11:37 pm Post subject: Re: Critique my Fuel System.

Larry 



Thanks for the infoâ€¦ Got off my butt and looked around a bitâ€¦ My Rotax Manual sez my thundering 447 requires 3 to 7 psi  from the fuel pumpâ€¦ Facet claims a max pressure of 6 psi . I think it is safe to ass-u-me that, 6 psi is more than the output of the pulse pump. But, I wonder if the pressure from the pulse pump might add to the total pressure at the carbâ€™s float valve. If not, I can chuck the regulator. I think I need to put a pressure gauge next to the carb, do a run-up, and take a lookâ€¦

Dana,



I worry about crud fouling my fuel pumps too. After my fuel leaves the tank it falls into a sump (lowest point) before it gets sucked out by the fuel pumpsâ€¦ In a former life, the sump had been a gasolator â€¦ Hawaii went to ethanol in the fuel, so I had to make a new gasket and chuck the paper filter. It seems to work great just operating as a sump. Occasionally Iâ€™ll catch a bit of crud when I take a squirt from the sump, but the filter (next to the carb) has remained clean. With the sump protecting the pumps, Iâ€™m OK with the filter last in line, next to the carb, where IMHO it is most effective, standing between the carb and all sources of contamination, including the fuel pumps. 



Thanks guysâ€¦ You help me sort this stuff out.



Aloha,

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Firefly Five-Charlie-Bravo

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rickofudall

Joined: 19 Sep 2009
Posts: 1392
Location: Udall, KS, USA

Posted: Sat Jul 17, 2010 6:37 am Post subject: Critique my Fuel System.

Henry, Imagine a beautiful Saturday afternoon at a fly in after a morning of hanging out with the guys and gals of you EAA chapter, watching the kids take Young Eagles rides, having one of those great all you can eat fly in breakfasts, and all the other good things that happen at airports. It's finally time to head for home. You line up, take off and because your Kolb climbs wonderfully, your at pattern altitude by mid downwind and suddenly things get far too quiet. Now it's not such a happy scenario. For me it was crud, a piece of plastic, that got stuck in the fuel selector valve that was installed before the filter. The temporary cure, to get me home, was to put a filter in the line coming from the tank pickup. The full cure was to put pickup screens on the bottom of the tank pickups.

 The point is that your fuel system is a series of constricted passages and if it gets in there it's trouble. Filters have a fairly large area where a piece of crud can lodge and fuel can still get around it and get to your engine (water on a paper filter as you've described is the exception to this).

 



Rick Girard



On Sat, Jul 17, 2010 at 2:37 AM, henry.voris <henry_voris(at)yahoo.com (henry_voris(at)yahoo.com)> wrote:

[quote] --> Kolb-List message posted by: "henry.voris" <henry_voris(at)yahoo.com (henry_voris(at)yahoo.com)>

 

 Larry

 

 Thanks for the info… Got off my butt and looked around a bit… My Rotax Manual sez my thundering 447 requires 3 to 7 psi  from the fuel pump… Facet claims a max pressure of 6 psi . I think it is safe to ass-u-me that, 6 psi is more than the output of the pulse pump. But, I wonder if the pressure from the pulse pump might add to the total pressure at the carb’s float valve. If not, I can chuck the regulator. I think I need to put a pressure gauge next to the carb, do a run-up, and take a look…

  

 

 Dana,

 

 I worry about crud fouling my fuel pumps too. After my fuel leaves the tank it falls into a sump (lowest point) before it gets sucked out by the fuel pumps… In a former life, the sump had been a gasolator … Hawaii went to ethanol in the fuel, so I had to make a new gasket and chuck the paper filter. It seems to work great just operating as a sump. Occasionally I’ll catch a bit of crud when I take a squirt from the sump, but the filter (next to the carb) has remained clean. With the sump protecting the pumps, I’m OK with the filter last in line, next to the carb, where IMHO it is most effective, standing between the carb and all sources of contamination, including the fuel pumps.

  

 Thanks guys… You help me sort this stuff out.

 

 Aloha,

 

 --------

 Henry

 Firefly Five-Charlie-Bravo

 

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JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sat Jul 17, 2010 11:20 am Post subject: Re: Critique my Fuel System.

Your Fuel Diagram looks very good, you have definitely done your homework and put thought into your fuel system.  Very impressive, most people just copy what ultralight guys have been doing since the early 80's without putting any thought into it.  These are things I have been saying for years here on the list.  According to EAA, half of all engine failures in experimental aircraft are due to a problem in the fuel system.  You have hit on some very important points,



Use high quality fuel injection line from NAPA, 3.75 a foot, not the cheap 1.50 dollar a foot stuff from NAPA or other places.  The injection line has much more resistance to crushing and pinching than the cheap stuff.  The worst stuff in the world is the clear ultralight fuel tubing, it has a very short life, cracks easily, and pinches and cuts very easily also.  With a properly designed fuel system, there is no requirement to " See " the fuel in the lines.  How many certified airplanes use cheap fuel lines for some misguided reason such as to " See the fuel go through the lines ", ZERO ?  There is a really good reason for that.



NEVER suck fuel from above the fuel level of the tank, that just just asking for a fuel related engine failure.  Now in the top draw tanks that Kolb uses, you can use the metal draw tube, and bring it down over the top side of the tank with top quality fuel injection line and a fuel injection clamp that puts pressure evenly around the line, not a cheap 1 dollar home depot clamp...  Not perfect, but good enough if you use the metal tube and top quality fuel line down to the gascolator below the fuel level.  Drilling a fuel pickup on the bottom of the tank not dis not designed for it can be dangerous and the source of a big leak.  I use the metal tubes feeding down over the side described above, I have great confidence in it.   Mount your gascolator and fuel pump below the level of the fuel tank, this way a pinhole leak in the hose connection, gascolator gasket, etc. will be a slight wet spot instead of air flooding into the system.  Once the fuel is under pressure,  it wont suck air..  Your fuel filter can be mounted higher if you like.



There is no need for a pressure regulator, the Facet pumps can be bought that are rated to deliver the correct pressure for the Rotax engine.  Adding a pressure regulator that is not needed just adds extra complication and is just something else to go wrong.



What I do not like is your fuel filter, those filters are made in China, with very cheap materials, there have been a lot of massive and sudden failures reported with these filters.  Each production run is many times different and cheaper than the last, so one that someone bought years ago is not even close to the same filter you buy now, even though it looks the same.  The metal threads has been changed to the cheapest, garbage metal available and can strip making the end come loose, suddenly pouring fuel everywhere.  The glass can also break without warning, suddenly pouring fuel everywhere.  The screen in this filter is not fine enough to adequately protect the carburetor.  Rest assured that any general use Chinese filter you buy today will have the cheapest materials that can be found, even if it causes the filters to fail quickly, the Chinese will take saving 10 cents over making a good product any day. The Chinese factory does not care if the filter fails the week after you install it.  The filter you should use is this high quality 10 micron air filter.  It has several stages of filtering internally, and a large stainless filter mesh that will stop the smallest debris, yet not become clogged or stopped by water.  This filter is cleanable, so you only buy it once.  This is huge added safety, and will pay for itself over the years.  



http://www.aircraftspruce.com/catalog/appages/micron10.php



78.00 dollars for this filter is a bargain given the huge increase in safety and performance, and considering that it is the last filter you will ever have to buy.



Mike

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"NO FEAR" - If you have no fear you did not go as fast as you could have !!!

Kolb MK-III Xtra, 912-S

gotime242

Joined: 09 Jul 2010
Posts: 52
Location: West Palm Beach, FL

Posted: Sat Jul 17, 2010 1:03 pm Post subject: Re: Critique my Fuel System.

Jetpilot - Thanks for the words, you make a very good case to get that micron 10 fuel filter. Like you said: its only a little bit expensive ONCE. 



You mentioned that you also have a facet pump that you transfer fuel with, are both the fuel pumps you use model #40105? The ones with 2.5-4.5psi max?

JetPilot

Joined: 10 Jan 2006
Posts: 1246

Posted: Sat Jul 17, 2010 1:22 pm Post subject: Re: Critique my Fuel System.

Yes, I bought several of the Facet fuel Pumps rated for my 912-S, and also for the Rotax 503 / 447 and used them.  I forget the exact model number, but I looked up the pressure ratings of the two models that CPS carries and bought the ones of the correct pressure for each engine.   I also have 4 of the 10 micro fuel filters in 4 planes now,  2 flying and 2 under construction / repair.  2 on Rotax 912 - S and 2 of them on 2 stroke 447  engines.   



The only difference I have in my installation from your diagram is that my 10 Micron fuel filter is after the pulse pump and right before the carburetor.  Its seem like a minor difference, and I would feel safe flying either way.  On my Kolb with the 912-S, I have the 10 micron pump before the engine driven pump, just because I did not want to mount a fuel filter on top of the hot engine, so like I say, I am happy with either placement depending on physical layout.  With these filters, I check my carb bowls once in a while just to make sure the floats are not starting to come apart, the carb bowls are always clean enough to drink wine out of, never a drop of water nor even a spec of debris 



Mike

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Richard Pike

Joined: 09 Jan 2006
Posts: 1671
Location: Blountville, Tennessee

Posted: Sun Jul 18, 2010 12:42 pm Post subject: Re: Critique my Fuel System.

You are smart to keep as much junk as possible from ever getting into your fuel system, before it gets to the pump or the filters. As Barney used to say "NIP IT IN THE BUD!" 



For the pickup in the bottom of your fuel tanks, go to Advance or AutoZone and get a big strainer type fuel filter that is designed to go in your car's gas tank just ahead of the in-tank fuel pump.  Here is one for a 2000 Honda Accord, it is not expensive, and it is typical of what you want - a lot of surface area so that no matter how much mung you manage to get in the gas tank, you don't overwhelm the strainer's surface area.



The opening in the strainer for your fuel pickup line to fit in is about the diameter of the end of your little finger, get creative with some brass fittings & solder something to the end of your pickup tube to make it the proper size, and clamp the filter to it. 



You want it to be mounted above the bottom of the tank by about an inch minimum, so that if you get water in the tank, your pickup is not immersed in it. which means that you will need to run a second line to the bottom of your tank to sump it. OK, do that, soft 1/4" aluminum fuel line from Aircraft Spruce is cheap. Run it to the lowest point in the tank when the aircraft is sitting level, and when you want to sump the tank, open the sump drain, blow into the tank's air vent line, & if there is any water, you will force it out. 



PS: Don't forget to close the sump, you just started a siphon...



Richard Pike

MKIII N420P (420ldPoops)

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Dennis.Kirby(at)kirtland.
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Posted: Mon Jul 19, 2010 9:54 am Post subject: Critique my Fuel System.

"Richard Pike" wrote: << … so that no matter how much mung you manage to get in the gas tank …>>  

   

There’s that word again: mung.  

Very descriptive, yet I’ve never seen it in any dictionary or technical manual.  

   

Wonderful word – I learned it here on the Kolb List!  

   

Do not archive.  

      [quote][b]

Thom Riddle

Joined: 10 Jan 2006
Posts: 1597
Location: Buffalo, NY, USA (9G0)

Posted: Tue Jul 20, 2010 2:38 am Post subject: Re: Critique my Fuel System.

Dennis,



Mung has more than one meaning, see:



http://en.wikipedia.org/wiki/Mung



I assume Richard was using it in the "disgusting substance" sense. 



do not archive

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