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Redundancy

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Dennis.Kirby(at)kirtland.
Guest

Posted: Wed May 10, 2006 10:56 am Post subject: Redundancy

<< does anyone have a specific suggestion to routing the fuel lines from

both the mechanical pump and an electric fuel pump. I have read on this site

where many use their electric fuel pump taking off and then shut it off for

normal flight. I am about to re hose and add an electric fuel pump. 

Sucking air here in Ohio Ralph >>



Ralph -



The Rotax on my Kolb runs with two fuel pumps: A mechanical one, and a Facet

electric fuel pump.  I plumbed my fuel pumps in series.  No primer bulb.

The Facet is designed to allow unobstructed passage of fuel when it is

either off or failed.  That allows me to turn it on or off at my convenience

(such as during takeoff and landing).  Have had zero problems with this

setup since new.



Dennis Kirby

Mark-III, 912, 47 hrs

New Mexico

a58r(at)verizon.net
Guest

Posted: Wed May 10, 2006 11:01 am Post subject: Redundancy

The ultimate in redundancy is/was two seats!

regards,

Bob N.

http://www.angelfire.com/rpg/ronoy/



do not archive

Ralph Hoover

Joined: 09 Jan 2006
Posts: 206
Location: Central Ohio

Posted: Wed May 10, 2006 11:19 am Post subject: Re: Redundancy

and a Facet electric fuel pump. I plumbed my fuel pumps in series. No primer bulb. The Facet is designed to allow unobstructed passage of fuel when it is either off or failed. 



Dennis, Thank you. That is without a doubt what I will do. Now do you mount the electric pump close to the fuel tank (gulp..sparks), or is it mounted up along the frame of the cage so that you can see it?



Next, which model number pump is it and is it in the low (3 psi) range as previously described by others in order to not overcome the float bowles?



Thanks all for your assistance.



She'a gushin now ralph of Ohio

rlaird

Joined: 10 Jan 2006
Posts: 373
Location: Houston

Posted: Wed May 10, 2006 11:50 am Post subject: Redundancy

Dennis --



The Facet isn't fail-safe.  I had one where the internal check valve

got stuck.  When it was on and pumping, everything was fine.  But when

I turned it off, it created enough of a restriction that, under WOT,

it couldn't fill the bowl fast enough.  That was responsible for the

one and only engine-out I've ever had.  (I forgot to turn it on during

take-off, and the engine cut out at about 200 feet.  Luckily, I landed

straight ahead without incident.)



It took me quite a while to diagnose the problem, helped in large part

to a fuel flow meter I had.  Replacing the Facet fixed the problem, of

course.  And now I don't forget to turn it on!



  -- Robert



On 5/10/06, Kirby Dennis Contr MDA/AL <Dennis.Kirby(at)kirtland.af.mil> wrote:

 	  Quote: 	
		   



 << does anyone have a specific suggestion to routing the fuel lines from

 both the mechanical pump and an electric fuel pump. I have read on this site

 where many use their electric fuel pump taking off and then shut it off for

 normal flight. I am about to re hose and add an electric fuel pump.

 Sucking air here in Ohio Ralph >>



 Ralph -



 The Rotax on my Kolb runs with two fuel pumps: A mechanical one, and a Facet

 electric fuel pump.  I plumbed my fuel pumps in series.  No primer bulb.

 The Facet is designed to allow unobstructed passage of fuel when it is

 either off or failed.  That allows me to turn it on or off at my convenience

 (such as during takeoff and landing).  Have had zero problems with this

 setup since new.



 Dennis Kirby

 Mark-III, 912, 47 hrs

 New Mexico

_________________
~~~~~~~~~~~~~~~~~~~
Robert Laird
formerly: MkIIIc w/ 912ULS & Gyrobee
current: Autogyro Cavalon w/ 914ULS
Houston, TX area
http://www.Texas-Flyer.com

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed May 10, 2006 12:15 pm Post subject: Redundancy

And now I don't forget to turn it on!

|

|  -- Robert

Seems like that would be a good case for doing a full power runup 

prior to takeoff with the electric pump shut down.



Would have to hold WOT long enough until you were satisfied the engine 

driven pump was going to pump enough fuel to keep the engine happy.



My experience with 2 and 4 stroke Rotax engines indicates the both 

shut down right now if they get a "little" starved for fuel.



I have been using a Facet and engine driven pump set up since 1987, on 

my Firestar.  Seems to be working well.



Primer bulbs were always a source of fuel delivery problems in the old 

days.  Maybe they have improved them since then.  That's the first 

thing not to be installed on my airplane.



I have had several ignition related engine failures with the Cuyuna 

ULII02 and the point ignition 447.  Lost the plug cap off a spark plug 

on inverted engine, had an NGK BR8EV lose an electrode, and had plug 

fouling twice.  All four times put me in the forced landing mode and 

on the ground.  Dual ignition would have prevented the forced landings 

until I could get to a suitable area to land and see what my problem 

was.



Once I tried a JC Whitney "el cheapo" Facet look alike pump on the FS. 

Was on one of my flights up to the Flight Farm in Monterey, NY.  The 

electric pump went belly up during the trip.  While in the process of 

cutting toilet paper and approximately 100 feet, the Mikuni engine 

driven pump bit the dust.  Very lucky to be in a position to push the 

nose over and land in a nice hay field.  Come to find out, the rebuild 

kit I purchased from LEAF was a no name aftermarket kit.  The diaphram 

with its little flapper valves lasted about 30 minutes.  I built the 

pump at the Flight Farm.  I pulled the old Mikuni diaphram out of the 

trash can and reinstalled it.  On my return home I contacted LEAF to 

let them know of my disappointment in their inferior parts.  They gave 

me my money back, but did not seem too concerned about the problem. 

No telling how many of us UL nuts out there were flying around with 

these things.  heehee



1500 and black as night outside.  So dark the security light is 

burning bright.  Really erie feeling to know it is still the middle of 

the afternoon, look up from the computer and see a totally black 

window.  So far the major thunderstorms are just north of my location.



Hunkered down at hauck's holler, alabama,



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

rlaird

Joined: 10 Jan 2006
Posts: 373
Location: Houston

Posted: Wed May 10, 2006 12:54 pm Post subject: Redundancy

On 5/10/06, John Hauck <jhauck(at)elmore.rr.com> wrote:

 	  Quote: 	
		   



  And now I don't forget to turn it on!

 |

 |  -- Robert



 Seems like that would be a good case for doing a full power runup

 prior to takeoff with the electric pump shut down.



 Would have to hold WOT long enough until you were satisfied the engine

 driven pump was going to pump enough fuel to keep the engine happy.


	


I've yet to find any brakes that would hold a 912 or 912S for a WOT

full power runup for that long, but maybe, with a large amount of

money, they can be found.  (Probably put me on my nose!     Prior

to this event, I had detected a much lower fuel flow rate than nominal

when at a high cruise speed.  That was my first clue.



  -- Robert

_________________
~~~~~~~~~~~~~~~~~~~
Robert Laird
formerly: MkIIIc w/ 912ULS & Gyrobee
current: Autogyro Cavalon w/ 914ULS
Houston, TX area
http://www.Texas-Flyer.com

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Wed May 10, 2006 1:04 pm Post subject: Redundancy

| I've yet to find any brakes that would hold a 912 or 912S for a WOT

| full power runup for that long, but maybe, with a large amount of

| money, they can be found.  (Probably put me on my nose!     Prior

| to this event, I had detected a much lower fuel flow rate than 

nominal

| when at a high cruise speed.  That was my first clue.

|

|  -- Robert

The brakes are out there.  MATCO makes a good set with 3/4" axles 

w/tapered roller bearings (that are adjustable like real wheels), and 

enough braking power to hold the 912uls.  However, main gear located 

in the stock position will put you on your nose.



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Dave Bigelow

Joined: 29 Jan 2006
Posts: 103
Location: Kamuela, Hawaii

Posted: Thu May 11, 2006 1:27 am Post subject: Re: Redundancy

Dennis,



The electric pump redundancy is a good idea.  If you look at the specs for the Mikuni engine pumps that come with the two stroke Rotax engines, you'll see that they are rated to lift fuel no more than about 36 inches.  Measure the distance to the mid point of your fuel tanks and you'll see that it is pretty close to that.



I've believed for some time that some of the mysterious engine seizures that seem to happen for no known reason are partial fuel starvation caused by the pulse pump not putting out enough fuel.  The classic failure is a full power take off and climb, followed by a seizure when the power is pulled back.



The electric pump should be plumbed in parallel rather than in series.  Both the mechanical and electric pumps have a built in check valve, so you don't need to add check valves unless you want more redundancy.  If you plumb the pumps in series, the fuel pressure will be too high (unless you install a regulator), and either pump failing can block the single fuel path to the engine.  There was a good article in "Ultralight Flying" several years ago by Arnold Anderson (Fight Safety Notebook) on the subject.



I don't see any reason to turn the electric pump off in flight unless you don't have battery charging, and want to save electricity.

_________________
Dave Bigelow
Kamuela, Hawaii
FS2, HKS 700E

esteuber(at)rochester.rr.
Guest

Posted: Thu May 11, 2006 2:41 am Post subject: redundancy

You guys are making my head hurt from all this complication , I'm with =

BB on the simplistic side of the issue....The reason I got into =

ultralights was the shear joy of uncomplicated flight....also .... I =

tend to be a bit cheap so buying 2 of everything is not an option =

anyway...

                   Ed in Western NY

        do not archive

Richard Pike

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

Posted: Thu May 11, 2006 4:24 am Post subject: Redundancy

I disagree that the pressure would be too high. I have a fuel pressure 

gauge on the panel, my pumps are in series, and I learned that with both 

pumps working, the fuel pressure pickup located between the Mikuni and 

carbs, the pressure is 3 1/2 pounds.



I relocated the pickup for the pressure gauge, so that it now only 

monitors the Facet electric pump. Still shows 3 1/2 pounds. Left the 

pressure pickup at that location. I test the Mikuni during taxi out and 

run up by turning the electric pump off, (fuel pressure gauge falls to 

zero) engine still runs ok, Mikuni must be working, and drawing fuel 

through the Facet.



Then I turn the electric pump back on for the rest of the flight. Should 

the Mikuni fail in flight, as long as the pressure is showing 3 pounds 

or better, I know I will get fuel, because I see no way for the Mikuni 

to block the fuel that the electric pump is pushing into the inlet side.



Don't know about the article in Ultralight Flying, but I know what 

works. It might get blocked up tomorrow, but it's worked fine since '98.



Richard Pike

MKIII N420P (420ldPoops)

Dave Bigelow wrote:

 	  Quote: 	
		   



 Dennis,



 The electric pump redundancy is a good idea.  If you look at the specs for the Mikuni engine pumps that come with the two stroke Rotax engines, you'll see that they are rated to lift fuel no more than about 36 inches.  Measure the distance to the mid point of your fuel tanks and you'll see that it is pretty close to that.



 I've believed for some time that some of the mysterious engine seizures that seem to happen for no known reason are partial fuel starvation caused by the pulse pump not putting out enough fuel.  The classic failure is a full power take off and climb, followed by a seizure when the power is pulled back.



 The electric pump should be plumbed in parallel rather than in series.  Both the mechanical and electric pumps have a built in check valve, so you don't need to add check valves unless you want more redundancy.  If you plumb the pumps in series, the fuel pressure will be too high (unless you install a regulator), and either pump failing can block the single fuel path to the engine.  There was a good article in "Ultralight Flying" several years ago by Arnold Anderson (Fight Safety Notebook) on the subject.



 I don't see any reason to turn the electric pump off in flight unless you don't have battery charging, and want to save electricity.



 --------

 Dave Bigelow

 Kamuela, Hawaii

 FS2, Rotax 503 DCDI





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=33990#33990

_________________
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0

Forgiving is tough, being forgiven is wonderful, and God's grace really is amazing.

NeilsenRM(at)comcast.net
Guest

Posted: Thu May 11, 2006 8:07 am Post subject: Redundancy

I have two electric fuel pumps plumed into my fuel system in series. I would 

prefer one of my fuel pumps to be some thing other than electric but my 

reduction drive sits were the mechanical fuel would be. I use a Facet as one 

of my pumps. I would never want to depend on a Facet pump because I have 

experienced a few failures with them.



I use the following procedure that tests both pumps before each flight. I 

prime my carbs by turning on only the Facet pump which is the first in 

series and is my backup or boost pump. I can physically see the flow rate as 

I have a short piece of transparent fuel line just before the carbs. then I 

turn it off. I then start the engine using only the primary pump and 

continue thru warm-up and run up. Just before take off I switch on the Facet 

pump. After takeoff I turn the Facet pump off.



I don't like to run both pumps all the time because I feel that I might be 

wearing out both pumps and want to have at least one fairly unused pump 

there for back up if my primary pump fails. This is also the same procedure 

I was trained to use and described in the Piper Owners Manual. There must 

have been reason Piper Aircraft suggested turning off the boost pump at 

altitude so I follow the same guideline with my Kolb.



Rick Neilsen

Redrive VW powered MKIIIc

---

slyck(at)frontiernet.net
Guest

Posted: Thu May 11, 2006 8:48 am Post subject: Redundancy

Easy to tell when the Facet is ready.  -Turn on the ignition and wait 

until the

tone changes and its ready to hit start.

For the person who wanted the low pressure number:  40105

AC Spruce has them in stock

-BB



On 11, May 2006, at 12:00 PM, Richard & Martha Neilsen wrote:



[quote] 

 <NeilsenRM(at)comcast.net>



 I have two electric fuel pumps plumed into my fuel system in series. I 

 would

 prefer one of my fuel pumps to be some thing other than electric but my

 reduction drive sits were the mechanical fuel would be. I use a Facet 

 as one

 of my pumps. I would never want to depend on a Facet pump because I 

 have

 experienced a few failures with them.



 I use the following procedure that tests both pumps before each 

 flight. I

 prime my carbs by turning on only the Facet pump which is the first in

 series and is my backup or boost pump. I can physically see the flow 

 rate as

 I have a short piece of transparent fuel line just before the carbs. 

 then I

 turn it off. I then start the engine using only the primary pump and

 continue thru warm-up and run up. Just before take off I switch on the 

 Facet

 pump. After takeoff I turn the Facet pump off.



 I don't like to run both pumps all the time because I feel that I 

 might be

 wearing out both pumps and want to have at least one fairly unused pump

 there for back up if my primary pump fails. This is also the same 

 procedure

 I was trained to use and described in the Piper Owners Manual. There 

 must

 have been reason Piper Aircraft suggested turning off the boost pump at

 altitude so I follow the same guideline with my Kolb.



 Rick Neilsen

 Redrive VW powered MKIIIc

 ---

Dennis.Kirby(at)kirtland.
Guest

Posted: Thu May 11, 2006 12:15 pm Post subject: Redundancy

<< do you mount the electric pump close to the fuel tank (gulp..sparks), or

is it mounted up along the frame of the cage so that you can see it? ralph

of Ohio >>



Ralph - Using a pair of aluminum brackets spanning between two of the cage

members on the fuselage side, I fashioned a method to attach the Facet level

with the bottom of the fuel tanks and angled at 45 degrees (per fuel pump

installation instructions).  Part of my preflight is to peer behind the seat

to inspect the pump, mostly for security of hose connections.  Easy to see

and service (if needed).



<< Next, which model number pump is it and is it in the low (3 psi) range as

previously described by others in order to not overcome the float bowles? >>



 	  Quote: 	
		  From the ACSpruce catalog, I purchased the Facet model 40105, 2.5 to 4.5 psi

max, 12v, solid state pump.  As it is solid state (not an electric motor),
	


there is no worry about sparks.



The Rotax manuals warn that pressures above 5.8 psi may lead to "override of

float valves," but there is some protection in the float bowl overflow

feature.  The overflow can handle pressures up to perhaps 7 or 8 psi before

the floats become overwhelmed with too much incoming fuel.  I have never yet

seen the carb bowls overflow on my Bings from the Facet pump being left on

(while the engine is running).



You are wise to follow the "keep it simple" advice from the List members

that offer it, with regard to fuel systems.



Dennis Kirby

Mark-III, 912ul, in

Cedar Crest, NM

John Hauck

Joined: 09 Jan 2006
Posts: 4639
Location: Titus, Alabama (hauck's holler)

Posted: Thu May 11, 2006 1:31 pm Post subject: Redundancy

| The Rotax manuals warn that pressures above 5.8 psi may lead to 

"override of

| float valves," but there is some protection in the float bowl 

overflow

| feature.  The overflow can handle pressures up to perhaps 7 or 8 psi 

before

| the floats become overwhelmed with too much incoming fuel.  |

| Dennis Kirby

| Mark-III, 912ul, in

| Cedar Crest, NM

Dennis:



That outlet on the float bowl chamber of the 912 carb is not an 

overflow as I thought when I initially installed the 912 on my mkIII 

in 1994.  That is one of the static air sources that works with the 

other static air source in the lip of the carb inlet.  These two 

static sources and the position of the throttle plate tell the piston 

in the carb where it should be positioned.  That is why it is 

important for them to all read the same static pressure.



The low pressure Facet and the engine driven pump will not produce 

enough pressure to override the floats and needles.



This is covered in the Rotax 912 School presented by Eric Tucker. 

After three classes over the last six years I think I have that part 

down correctly.  hehehe



john h

mkIII

_________________
John Hauck
MKIII/912ULS
hauck's holler
Titus, Alabama

Dennis.Kirby(at)kirtland.
Guest

Posted: Mon May 15, 2006 7:59 am Post subject: Redundancy

<< I start the engine using only the primary pump and continue thru warm-up

and run up. Just before take off I switch on the Facet pump. After takeoff I

turn the Facet pump off. Rick Neilsen >>



This is how I used to do it.  Thought I was saving wear and tear on the

Facet fuel pump.  But after reading Richard Pike's enlightening post

regarding the expected operating life of the Facet fuel pump (gazillion

hours), and after hearing Rick Neilsen's account of experiencing failures in

Facet pumps in the past, I think I will change my procedures.



 	  Quote: 	
		  From now on, I'm just gonna leave the Facet pump turned "on" for the

duration of my flying.  On the 912, running both pumps in series (electric
	


one first, followed by the mechanical pump) does not overpressure the carbs.

Although I do not have a fuel pressure sensor, my carbs have never

experienced overpressure (with both pumps operating) sufficient to cause

fuel to overflow from the float bowls, as long as the engine is running.

Maybe the Mikuni pressure-pulse pump (on the two-stroke Rotax engines)

provides different results ... I do not know.



Dennis Kirby

Mark-III, 912ul

Getting ready to depart for Monument Valley on Thursday

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