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FUEL SYSTEM QUESTION

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GLJSOJ1

Joined: 18 Aug 2007
Posts: 82
Location: Chesapeake, Virginia

Posted: Sat Apr 26, 2008 5:25 pm Post subject: FUEL SYSTEM QUESTION

Hi All



I am just finishing up my 601XL with a O-200 engine from a Cessna 150.  This engine does not have a mechanical fuel pump, so I have installed two electric fuel pumps, with separate electrical lines.  Here's my nagging problem.  If I lose the electrics in the plane I will have no fuel pressure.  How would some of you handle this possible problem?  When I have the engine overhauled in a few years I plan to put a mechanical pump on it, but till then?

_________________
601XL N676L FLYING PHASE I
CHESAPEAKE VA

purplemoon99(at)bellsouth
Guest

Posted: Sat Apr 26, 2008 5:49 pm Post subject: FUEL SYSTEM QUESTION

Back-up batt.,with it's own switch and  circuit..   Joe N101HD 601XL/RAM

---

Jeyoung65(at)aol.com
Guest

Posted: Sat Apr 26, 2008 5:50 pm Post subject: FUEL SYSTEM QUESTION

You could add another battery and allow the aircraft elect. system to only  charge the battery and have only the fuel pumps connected to this battery with a  special switch when you lost aircraft elect power.  This would be over  design!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  If you are worried about this  you may just installed a three way switch for each pump (ON to aircraft system)  (On to battery) and OFF.  Jerry of GA  DO NOT ARCHIVE

 In a message dated 4/26/2008 9:30:47 P.M. Eastern Daylight Time,  gljno10(at)HOTMAIL.COM writes:

   	  Quote: 	
		  -->    Zenith-List message posted by: "GLJSOJ1" <gljno10(at)hotmail.com>



Hi    All



I am just finishing up my 601XL with a O-200 engine from a Cessna    150.  This engine does not have a mechanical fuel pump, so I have    installed two electric fuel pumps, with separate electrical lines.     Here's my nagging problem.  If I lose the electrics in the plane I will    have no fuel pressure.  How would some of you handle this possible    problem?  When I have the engine overhauled in a few years I plan to put    a mechanical pump on it, but till then?



--------

601XL N676L     reserved

ALMOST DONE

CHESAPEAKE VA





Read this topic    online    here:



http://forums.matronics.com/viewtopic.php?p=179494#179494

	




Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.

  [quote][b]

gfmjr_20(at)HOTMAIL.COM
Guest

Posted: Sat Apr 26, 2008 5:52 pm Post subject: FUEL SYSTEM QUESTION

I'd insure one pump is feed directly from your battery(fused appropriately), while the other can run off of your electrical distribution buss. Typically loosing electrics implies loss of alternator. The battery will usually last about 1/2 hour with essentials. That should be enough to get you safey on the ground using the pump directly feeding off the battery.

  

 George May

 601XL 912s



 	  Quote: 	
		   Subject: FUEL SYSTEM QUESTION

 From: gljno10(at)HOTMAIL.COM

 Date: Sat, 26 Apr 2008 18:25:56 -0700

 To: zenith-list(at)matronics.com

 

 --> Zenith-List message posted by: "GLJSOJ1" <gljno10(at)hotmail.com>

 

 Hi All

 

 I am just finishing up my 601XL with a O-200 engine from a Cessna 150. This engine does not have a mechanical fuel pump, so I have installed two electric fuel pumps, with separate electrical lines. Here's my nagging problem. If I lose the electrics in the plane I will have no fuel pressure. How would some of you handle this possible problem? When I have the engine overhauled in a few years I plan to put a mechanical pump on it, but till then?

 

 --------

 601XL N676L reserved

 ALMOST DONE

 CHESAPEAKE VA

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=179494#179494

 

 

 

 > ========================> 

 

 


	


Express yourself wherever you are. Mobilize!  [quote][b]

Terry Phillips

Joined: 11 Jan 2006
Posts: 346
Location: Corvallis, MT

Posted: Sat Apr 26, 2008 8:04 pm Post subject: FUEL SYSTEM QUESTION

I would suggest that you adopt the philosophy advocated by Electric Bob of 

the Aeroelectric Connection. IIRC, Bob's basic premise is that you should 

wire your airplane so that the failure of the alternator will not result in 

a life threatening situation. Consider his schematic Z-xx.



http://www.aeroelectric.com/Reference_Docs/Misc_PDF/Zxx.pdf



Notice that there is an endurance bus. The endurance bus should only power 

electrical loads that are necessary for survival. In Z-xx, the endurance 

bus powers the GPS, transponder, NAV/COM, turn coordinator, intercom, and 

the fuel boost pumps. During normal operation, the endurance bus is powered 

by the alternator through a diode. In the event of an alternator failure, 

the pilot manually throws a switch to power the endurance bus from the 

battery. The diode blocks the power from flowing backwards to the main 

power bus.



The idea is that you size your battery to provide however many minutes you 

believe you will need to land in the event of an alternator failure. Let's 

say the total load on the endurance bus is 15 amps. If you install, e.g., 

an Odyssey 925 battery, the advertised capacity is 50 minutes with a 25 amp 

load. Since your endurance bus only draws 15 amps, you should be able to 

fly for ~83 minutes while you look for a place to land. Hopefully, with 

your GPS you would not have too much trouble flying to a suitable airport 

in 83 minutes. If you decide that you don't need your NAV/COM or turn 

coordinator while you are en route to the airport, you could switch those 

off until you get close to the airport and, thereby, increase your endurance.



Finally, you say your are doing, the two fuel boost pumps on separate 

circuits and fuses so that a short in one pump's power circuit would not 

disable the other pump.



I'm a long way from doing that wiring myself, but Electric Bob's approach 

makes good sense to me. My Jabiru engine has a mechanical pump, but I am 

still putting a boost pump (and gascolator) in each wing.



Terry

At 06:25 PM 4/26/2008 -0700, you wrote:

 	  Quote: 	
		  Hi All



I am just finishing up my 601XL with a O-200 engine from a Cessna 

150.  This engine does not have a mechanical fuel pump, so I have 

installed two electric fuel pumps, with separate electrical lines.  Here's 

my nagging problem.  If I lose the electrics in the plane I will have no 

fuel pressure.  How would some of you handle this possible problem?  When 

I have the engine overhauled in a few years I plan to put a mechanical 

pump on it, but till then?


	




Terry Phillips

ttp44~at~rkymtn.net

Corvallis MT

601XL/Jab 3300 s .. l .. o .. o .. w build kit - Tail, flaps, & ailerons 

are done; working on the wings

http://www.mykitlog.com/N47TP/

_________________
Terry Phillips
Corvallis, MT
ttp44<at>rkymtn.net
Zenith 601XL/Jab 3300 slow build kit - Tail feathers done; working on the wings.

kmccune

Joined: 22 Sep 2007
Posts: 577
Location: Wisconsin, USA

Posted: Sun Apr 27, 2008 3:48 am Post subject: Re: FUEL SYSTEM QUESTION

Don't forget to give yourself a way to know that the alternator has quit, otherwise the battery may not be of any use. Voltmeter, idiot light ect...

_________________
â€œAlways do what you are afraid to do.â€
R.W. Emerson (1803-1882)

"Real freedom is the sustained act of being an individual." WW - 2009

"Life is a good deal...it's worth it" Feb 1969
Dorothy McCune

m.l.marcotte(at)sympatico
Guest

Posted: Sun Apr 27, 2008 6:30 am Post subject: FUEL SYSTEM QUESTION

I would install a small alternator like this one

http://www.aircraftspruce.com/catalog/eppages/sdaltreg.php (only 4 pounds)

where the vacuum pump normally goes and connect it to a completely separate

electrical system for the second fuel pump and for a few critical electrical

flight instruments that would replace the normally vacuum-driven

instruments. I would install the minimum size battery that this alternator

will accept.  You might want to add a tie-breaker that could connect your

two electrical systems together in case one of your alternators fails in

flight but keep in mind that the new alternator provides only 8 amps. This

is also a very nice back-up system for glass panels and with this

installation you would never need to install the mechanical pump.



---

steerr(at)bellsouth.net
Guest

Posted: Sun Apr 27, 2008 8:06 am Post subject: FUEL SYSTEM QUESTION

What George suggests can be done indirectly, with the endurance buss 

normally fed through a diode bridge that derives it's feed from the 

output side of the battery contactor, but with an switch-controlled 

alternate feed directly from the battery (i.e., the input side of the 

battery contactor).  One fuel pump is then fed from the endurance buss.  

See Figure Z1 of the Aeroeletric Connection publication, which uses a 

fuselink for protecting the wire.



Bill

601HD Stratus N109BS



george may wrote:

 	  Quote: 	
		   I'd insure one pump is feed directly from your battery(fused 

 appropriately), while the other can run off of your electrical 

 distribution buss. Typically loosing electrics implies loss of 

 alternator. The battery will usually last about 1/2 hour with 

 essentials. That should be enough to get you safey on the ground using 

 the pump directly feeding off the battery.

  

 George May

 601XL 912s

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Sun Apr 27, 2008 10:49 am Post subject: Re: FUEL SYSTEM QUESTION

Since I'm going to be flying a Corvair that not only has two electrical fuel pumps but also needs electrics to power the ignition system I've looked at this issue quite a bit.



The Aeroelectric manual has a pretty simple 2 battery design that charges both batteries but separates them electrically.



It isn't an over design at all. The manual's out at the airport so I can't go over the details but it really isn't that big a deal.

 	  Jeyoung65(at)aol.com wrote: 	
		  You could add another battery and allow the aircraft elect. system to only  charge the battery and have only the fuel pumps connected to this battery with a  special switch when you lost aircraft elect power.  This would be over  design!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!  If you are worried about this  you may just installed a three way switch for each pump (ON to aircraft system)  (On to battery) and OFF.  Jerry of GA  DO NOT ARCHIVE

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

rtdin

Joined: 16 Mar 2008
Posts: 46
Location: Florida panhandle

Posted: Sun Apr 27, 2008 11:25 am Post subject: FUEL SYSTEM QUESTION

Your O-200 has no fuel pump mounted now, but I know that it has a pad to install one. You are planning to install one eventually. My humble recommendation is to invest $300 (or less) and put one on now. Avoid the extra batteries & switches.

 Bob

 Do not archive

**************

Need a new ride? Check out the largest site for U.S. used car listings at AOL Autos.

      (http://autos.aol.com/used?NCID=aolcmp00300000002851)  [quote][b]

floyd wilkes

Joined: 11 Jun 2007
Posts: 39
Location: spring branch, tx

Posted: Sun Apr 27, 2008 3:13 pm Post subject: Re: FUEL SYSTEM QUESTION

Adding a fuel pump may not be so easy.

My O-200 also came off of a C-150.  I overhauled the engine and wanted to add a fuel pump.

The cam installed would not support a fuel pump.  It took a different cam/gear part number.  The only one I could find was approx $1300!

That was just the cam.  Then I would have needed the pump at another $400.  A total of $1700.



Thinking long and hard-not really.  I chose go with two $35 electric pumps.



Bottom line, you need to check the cam part number to see if it will support the fuel pump.



Floyd

_________________
Floyd Wilkes

dougsnash

Joined: 14 Apr 2008
Posts: 282

Posted: Mon Apr 28, 2008 6:55 am Post subject: FUEL SYSTEM QUESTION

How about an old style Wobble Pump like what was used

on aerobatic aircraft?  It's a small hand pump that

would likely only need a couple of strokes every

thirty seconds or so to keep the float bowls full. 

It's a non-electric alternative.  This eliminates the

added complexity of an essential buss.



I think they are available for Aircraft Spruce but

don't have a specific link for them.



Doug MacDonald

CH-701 Scatch Builder

NW Ontario, Canada



(Also have AcrosportII plans)



Do Not Archive



 	  Quote: 	
		   george may wrote:

 > I'd insure one pump is feed directly from your

 battery(fused 

 > appropriately), while the other can run off of

 your electrical 

 > distribution buss. Typically loosing electrics

 implies loss of 

 > alternator. The battery will usually last about

 1/2 hour with 

 > essentials. That should be enough to get you safey

 on the ground using 

 > the pump directly feeding off the battery.

 >  

 > George May

 > 601XL 912s


	


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