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charles.long(at)gm.com
Guest

Posted: Tue Jun 19, 2007 9:41 am Post subject: Vaporlock issues - lessons learned

A friend of mine who also flies a Zodie Rocket had an issue on

takeoff the other day. His engine began to stumble right after liftoff on a

90 degree day. He immediately cut power and landed. Fortunately he had

plenty of runway. After assessing the situation, he found that he had

inadvertently turned on the electric fuel pump at the base of the wrong

tank. Two lessons to be learned here: ALWAYS USE THE ELECTRIC FUEL PUMP FOR

BACKUP ON TAKEOFF AND LANDING. SECONDLY, IF USING SEPARATE ELECTRIC PUMPS

FOR EACH TANK, CONFIRM YOU ARE USING THE RIGHT ONE. This incident was with

the Rotax 912s using auto fuel. It has been reported that auto fuel has a

higher vapor lock potential so the electric fuel pumps tend to be even more

critical for avoiding vapor lock issues. If the pump is at the base of the

tank, the problem is virtually eliminated since pressurized fuel won't

vapor lock.



      Before we bad mouth the 912s, I would argue that vapor lock is not an

engine-specific problem. I also had a vapor lock problem with my Jab

involving a restrictive fuel filter. The electric pump application

immediately corrected the vapor lock condition as reported below:

From:  Charles F. Long on 06/20/2005 11:40 AM



To:    Zenith-List Digest List <zenith-list-digest(at)matronics.com>

cc:    micheintz(at)gmail.com

Subject:    Fuel Filter Placement - Lessons Learned



      I experienced an engine stoppage during one of my first flights. It

occurred at altitude using cruise power with the Aux pump off. The engine

immediately restarted after turning the Aux pump on (windmilling propellor,

so engine starter was not required). I repeated the stoppage a second time

by shutting the pump off and confirmed that the Aux pump was required to

keep the engine running. My airplane configuration is as follows:



      601HDS built from Kit

      Jabiru 3300A purchased with FWD from ZAC

      Finger screens in the tank

      Dual Aux Facet pumps in wing root mounted close to the tank

      Selector valve on the floor just forward of the wing spar

      Single line feeding the Gascolator just aft of the firewall

      Jabiru Engine fuel pump in series with Aux pumps

      Bosch Metal Can auto fuel filter downstream of the Jab pump

      Fuel pressure sensor downstream of the Bosch filter

      Outside air temp - 80 F



      Jabiru recommends installing the fuel filter upstream rather than

downstream of their fuel pump. I did not follow this practice as I was

concerned about installing a filter on the suction side of the pump.



      The fuel system was designed to run at low pressures (<2 psi). The

Bosch filter may have caused a high enough pressure drop to induce Vapor

Lock. Fuel flow was tested before the first flight using the Aux pumps and

flow was confirmed to be over 20 gph. The test was repeated after this

incident and continued to be over 20 gph. The flow was never tested using

the Jabiru pump alone. The Jabiru pump was disassembled and showed no

indications of a problem or contamination.



      The Bosch filter was discarded and per the recommendations of those

on the Matronics list, a Flow Ezy stainless mesh filter (A S & S, p/n

05-28905) was installed upstream of the Jab pump. The Flow Ezy filter,

though rather expensive (close to $100), provides high flow/low pressure

drop. This appears to have cured the problem as I have had no additional

issues after 6 hours additional flight time. This includes several full

power climbs with Aux pumps off.



      Looking back on this, I should have used the high flow, stainless

filter from the get-go. Fortunately, the plane was designed with fuel pump

redundancy and the Aux pumps were used during Takeoff and Landing.



      I hesitate to air my dirty laundry here, but hopefully it will help

some other builders to avoid the same mistake. CFL

Clear Skies!

Chuck Long, CFI

Zodie Rocket

N601LE, 110 hr TT

crvsecretary

Joined: 18 Mar 2007
Posts: 38
Location: Naugatuck, CT

Posted: Tue Jun 19, 2007 11:59 am Post subject: Vaporlock issues - lessons learned

Gentlemen:

  

 Charles makes a number of very good points here...but I have a question or  two:

  

 - I'm looking to put a facet pump right at the base of each tank so the  whole run is pressurized fuel to reduce vapor lock.  Charles says to be  sure the correct pump is turned on....is there any danger to the facet pumps by  running one 'deadheaded' right into the fuel selector...that way both pumps can  be wired to ONE switch to eliminate pilot error.

  

  - there was a prolific lister here some time ago that was  exceptionally knowledgeable on vapor lock issues.  He suggested eliminating  the fuel selector completely and running a check valve at the outlet of each  pump.  That way BOTH pumps could supply fuel during takeoff and landing and  ONE pump can run during cruise.  When one pump is running, the check  valve(s) will eliminate crossfeeding from one tank to another.  In  addition, by using a 2-gang rotary switch wired Left-Right-Left+Right there is  no way the plane can suffer from NO pumps on due to pilot error.  My only  problem with this setup is that the one fuel pump switch presents a single point  of failure.......

  

 Any thoughts??

  

 Thanks

  

 Tracy Smith

 N458XL (reserved)

 Do Not Archive 

  

  

  

 In a message dated 6/19/2007 12:42:37 PM Eastern Standard Time,  charles.long(at)gm.com writes:

  	  Quote: 	
		  -->    Zenith-List message posted by: charles.long(at)gm.com

         A friend of mine who also flies a Zodie Rocket had an issue    on

takeoff the other day. His engine began to stumble right after liftoff    on a

90 degree day. He immediately cut power and landed. Fortunately he    had

plenty of runway. After assessing the situation, he found that he    had

inadvertently turned on the electric fuel pump at the base of the    wrong

tank. Two lessons to be learned here: ALWAYS USE THE ELECTRIC FUEL    PUMP FOR

BACKUP ON TAKEOFF AND LANDING. SECONDLY, IF USING SEPARATE    ELECTRIC PUMPS

FOR EACH TANK, CONFIRM YOU ARE USING THE RIGHT ONE. This    incident was with

the Rotax 912s using auto fuel. It has been reported that    auto fuel has a

higher vapor lock potential so the electric fuel pumps tend    to be even more

critical for avoiding vapor lock issues. If the pump is at    the base of the

tank, the problem is virtually eliminated since pressurized    fuel won't

vapor lock.



      Before we bad mouth the    912s, I would argue that vapor lock is not an

engine-specific problem. I    also had a vapor lock problem with my Jab

involving a restrictive fuel    filter. The electric pump application

immediately corrected the vapor lock    condition as reported below:

From:  Charles F. Long on    06/20/2005 11:40 AM



To:    Zenith-List Digest List    <zenith-list-digest(at)matronics.com>

cc:       micheintz(at)gmail.com

Subject:    Fuel Filter Placement - Lessons    Learned



      I experienced an engine stoppage during    one of my first flights. It

occurred at altitude using cruise power with    the Aux pump off. The engine

immediately restarted after turning the Aux    pump on (windmilling propellor,

so engine starter was not required). I    repeated the stoppage a second time

by shutting the pump off and confirmed    that the Aux pump was required to

keep the engine running. My airplane    configuration is as follows:



      601HDS built from    Kit

      Jabiru 3300A purchased with FWD from ZAC

         Finger screens in the tank

      Dual Aux    Facet pumps in wing root mounted close to the tank

         Selector valve on the floor just forward of the wing spar

         Single line feeding the Gascolator just aft of the firewall

         Jabiru Engine fuel pump in series with Aux pumps

         Bosch Metal Can auto fuel filter downstream of the Jab    pump

      Fuel pressure sensor downstream of the Bosch    filter

      Outside air temp - 80 F



         Jabiru recommends installing the fuel filter upstream rather    than

downstream of their fuel pump. I did not follow this practice as I    was

concerned about installing a filter on the suction side of the    pump.



      The fuel system was designed to run at low    pressures (<2 psi). The

Bosch filter may have caused a high enough    pressure drop to induce Vapor

Lock. Fuel flow was tested before the first    flight using the Aux pumps and

flow was confirmed to be over 20 gph. The    test was repeated after this

incident and continued to be over 20 gph. The    flow was never tested using

the Jabiru pump alone. The Jabiru pump was    disassembled and showed no

indications of a problem or    contamination.



      The Bosch filter was discarded and    per the recommendations of those

on the Matronics list, a Flow Ezy    stainless mesh filter (A S & S, p/n

05-28905) was installed upstream of    the Jab pump. The Flow Ezy filter,

though rather expensive (close to $100),    provides high flow/low pressure

drop. This appears to have cured the    problem as I have had no additional

issues after 6 hours additional flight    time. This includes several full

power climbs with Aux pumps    off.



      Looking back on this, I should have used the    high flow, stainless

filter from the get-go. Fortunately, the plane was    designed with fuel pump

redundancy and the Aux pumps were used during    Takeoff and Landing.



      I hesitate to air my dirty    laundry here, but hopefully it will help

some other builders to avoid the    same mistake. CFL

Clear Skies!

Chuck Long, CFI

Zodie    Rocket

N601LE, 110 hr TT

	


 

  



See what's free at AOL.com. 

  [quote][b]

_________________
Zenith 601XL N458XL (reserved)
Naugatuck, CT
Tail Complete; working on wings

Gig Giacona

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

Posted: Tue Jun 19, 2007 12:05 pm Post subject: Re: Vaporlock issues - lessons learned

This has been discussed and I will say the same thing I said then.



Get a glass of water and two drinking straws. Put both straws in your mouth. Put one straw in the water and the other outside the glass.



Now suck.



The outcome is exactly what will happen if one fuel tank is empty. 



[quote="crvsecretary"]Gentlemen:

  

 Charles makes a number of very good points here...but I have a question or  two:

  

 - I'm looking to put a facet pump right at the base of each tank so the  whole run is pressurized fuel to reduce vapor lock.  Charles says to be  sure the correct pump is turned on....is there any danger to the facet pumps by  running one 'deadheaded' right into the fuel selector...that way both pumps can  be wired to ONE switch to eliminate pilot error.

  

  - there was a prolific lister here some time ago that was  exceptionally knowledgeable on vapor lock issues.  He suggested eliminating  the fuel selector completely and running a check valve at the outlet of each  pump.  That way BOTH pumps could supply fuel during takeoff and landing and  ONE pump can run during cruise.  When one pump is running, the check  valve(s) will eliminate crossfeeding from one tank to another.  In  addition, by using a 2-gang rotary switch wired Left-Right-Left+Right there is  no way the plane can suffer from NO pumps on due to pilot error.  My only  problem with this setup is that the one fuel pump switch presents a single point  of failure.......

  

 Any thoughts??

  

 Thanks

  

 Tracy Smith

 N458XL (reserved)

 Do Not Archive 

  

  

  

 In a message dated 6/19/2007 12:42:37 PM Eastern Standard Time,  charles.long(at)gm.com writes:

  	  Quote: 	
		  -->    Zenith-List message posted by: charles.long(at)gm.com

  ï¿½      A friend of mine who also flies a Zodie Rocket had an issue    on

takeoff the other day. His engine began to stumble right after liftoff    on a

90 degree day. He immediately cut power and landed. Fortunately he    had

plenty of runway. After assessing the situation, he found that he    had

inadvertently turned on the electric fuel pump at the base of the    wrong

tank. Two lessons to be learned here: ALWAYS USE THE ELECTRIC FUEL    PUMP FOR

BACKUP ON TAKEOFF AND LANDING. SECONDLY, IF USING SEPARATE    ELECTRIC PUMPS

FOR EACH TANK, CONFIRM YOU ARE USING THE RIGHT ONE. This    incident was with

the Rotax 912s using auto fuel. It has been reported that    auto fuel has a

higher vapor lock potential so the electric fuel pumps tend    to be even more

critical for avoiding vapor lock issues. If the pump is at    the base of the

tank, the problem is virtually eliminated since pressurized    fuel won't

vapor lock.



      Before we bad mouth the    912s, I would argue that vapor lock is not an

engine-specific problem. I    also had a vapor lock problem with my Jab

involving a restrictive fuel    filter. The electric pump application

immediately corrected the vapor lock    condition as reported below:

From:  Charles F. Long on    06/20/2005 11:40 AM



To:    Zenith-List Digest List    <zenith>

cc:       micheintz(at)gmail.com

Subject:    Fuel Filter Placement - Lessons    Learned



      I experienced an engine stoppage during    one of my first flights. It

occurred at altitude using cruise power with    the Aux pump off. The engine

immediately restarted after turning the Aux    pump on (windmilling propellor,

so engine starter was not required). I    repeated the stoppage a second time

by shutting the pump off and confirmed    that the Aux pump was required to

keep the engine running. My airplane    configuration is as follows:



      601HDS built from    Kit

      Jabiru 3300A purchased with FWD from ZAC

ï¿½        Finger screens in the tank

      Dual Aux    Facet pumps in wing root mounted close to the tank

         Selector valve on the floor just forward of the wing spar

         Single line feeding the Gascolator just aft of the firewall

ï¿½        Jabiru Engine fuel pump in series with Aux pumps

         Bosch Metal Can auto fuel filter downstream of the Jab    pump

      Fuel pressure sensor downstream of the Bosch    filter

      Outside air temp - 80 F



  ï¿½      Jabiru recommends installing the fuel filter upstream rather    than

downstream of their fuel pump. I did not follow this practice as I    was

concerned about installing a filter on the suction side of the    pump.



      The fuel system was designed to run at low    pressures (<2 psi). The

Bosch filter may have caused a high enough    pressure drop to induce Vapor

Lock. Fuel flow was tested before the first    flight using the Aux pumps and

flow was confirmed to be over 20 gph. The    test was repeated after this

incident and continued to be over 20 gph. The    flow was never tested using

the Jabiru pump alone. The Jabiru pump was    disassembled and showed no

indications of a problem or    contamination.



      The Bosch filter was discarded and    per the recommendations of those

on the Matronics list, a Flow Ezy    stainless mesh filter (A S & S, p/n

05-28905) was installed upstream of    the Jab pump. The Flow Ezy filter,

though rather expensive (close to $100),    provides high flow/low pressure

drop. This appears to have cured the    problem as I have had no additional

issues after 6 hours additional flight    time. This includes several full

power climbs with Aux pumps    off.



      Looking back on this, I should have used the    high flow, stainless

filter from the get-go. Fortunately, the plane was    designed with fuel pump

redundancy and the Aux pumps were used during    Takeoff and Landing.



      I hesitate to air my dirty    laundry here, but hopefully it will help

some other builders to avoid the    same mistake. CFL

Clear Skies!

Chuck Long, CFI

Zodie    Rocket

N601LE, 110 hr TT

	


 

  



See what's free at AOL.com. 

   	  Quote: 	
		  [b]

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

dredmoody(at)cox.net
Guest

Posted: Tue Jun 19, 2007 1:37 pm Post subject: Vaporlock issues - lessons learned

I agree with Gig that you want a "Right - Left - Off" valve arrangement ,not a "Right - Left - Both" type of arrangement. If both tanks are connected to the fuel system at the same time and one is empty or very low, that low tank constitutes a problem that the full one does not compensate for.



Now as for having both pumps run whenever the (single) switch is "on", I don't think it would be a problem in the operation of fuel delivery but it may not be good for the pump that is pushing against a closed valve. You could check that out with the manufacturer of the pump. If the pump is not run dry, it may not harm it to run against the closed valve.



Dred



---- Crvsecretary(at)aol.com wrote: 

 	  Quote: 	
		    

 Gentlemen:

  

 Charles makes a number of very good points here...but I have a question or  

 two:

  

 - I'm looking to put a facet pump right at the base of each tank so the  

 whole run is pressurized fuel to reduce vapor lock.  Charles says to be  sure the 

 correct pump is turned on....is there any danger to the facet pumps by  

 running one 'deadheaded' right into the fuel selector...that way both pumps can  be 

 wired to ONE switch to eliminate pilot error.

  

  - there was a prolific lister here some time ago that was  exceptionally 

 knowledgeable on vapor lock issues.  He suggested eliminating  the fuel selector 

 completely and running a check valve at the outlet of each  pump.  That way 

 BOTH pumps could supply fuel during takeoff and landing and  ONE pump can run 

 during cruise.  When one pump is running, the check  valve(s) will eliminate 

 crossfeeding from one tank to another.  In  addition, by using a 2-gang rotary 

 switch wired Left-Right-Left+Right there is  no way the plane can suffer from NO 

 pumps on due to pilot error.  My only  problem with this setup is that the 

 one fuel pump switch presents a single point  of failure.......

  

 Any thoughts??

  

 Thanks

  

 Tracy Smith

 N458XL (reserved)

 Do Not Archive 

  

  

  

 In a message dated 6/19/2007 12:42:37 PM Eastern Standard Time,  

 charles.long(at)gm.com writes:

 

 

 

 

 A friend of mine who also flies a Zodie Rocket had an issue  on

 takeoff the other day. His engine began to stumble right after liftoff  on a

 90 degree day. He immediately cut power and landed. Fortunately he  had

 plenty of runway. After assessing the situation, he found that he  had

 inadvertently turned on the electric fuel pump at the base of the  wrong

 tank. Two lessons to be learned here: ALWAYS USE THE ELECTRIC FUEL  PUMP FOR

 BACKUP ON TAKEOFF AND LANDING. SECONDLY, IF USING SEPARATE  ELECTRIC PUMPS

 FOR EACH TANK, CONFIRM YOU ARE USING THE RIGHT ONE. This  incident was with

 the Rotax 912s using auto fuel. It has been reported that  auto fuel has a

 higher vapor lock potential so the electric fuel pumps tend  to be even more

 critical for avoiding vapor lock issues. If the pump is at  the base of the

 tank, the problem is virtually eliminated since pressurized  fuel won't

 vapor lock.

 

 Before we bad mouth the  912s, I would argue that vapor lock is not an

 engine-specific problem. I  also had a vapor lock problem with my Jab

 involving a restrictive fuel  filter. The electric pump application

 immediately corrected the vapor lock  condition as reported below:

 

 

 From:  Charles F. Long on  06/20/2005 11:40 AM

 

 To:    Zenith-List Digest List  <zenith-list-digest(at)matronics.com>

 cc:     micheintz(at)gmail.com

 Subject:    Fuel Filter Placement - Lessons  Learned

 

 I experienced an engine stoppage during  one of my first flights. It

 occurred at altitude using cruise power with  the Aux pump off. The engine

 immediately restarted after turning the Aux  pump on (windmilling propellor,

 so engine starter was not required). I  repeated the stoppage a second time

 by shutting the pump off and confirmed  that the Aux pump was required to

 keep the engine running. My airplane  configuration is as follows:

 

 601HDS built from  Kit

 Jabiru 3300A purchased with FWD from ZAC

 Finger screens in the tank

 Dual Aux  Facet pumps in wing root mounted close to the tank

 Selector valve on the floor just forward of the wing spar

 Single line feeding the Gascolator just aft of the firewall

 Jabiru Engine fuel pump in series with Aux pumps

 Bosch Metal Can auto fuel filter downstream of the Jab  pump

 Fuel pressure sensor downstream of the Bosch  filter

 Outside air temp - 80 F

 

 Jabiru recommends installing the fuel filter upstream rather  than

 downstream of their fuel pump. I did not follow this practice as I  was

 concerned about installing a filter on the suction side of the  pump.

 

 The fuel system was designed to run at low  pressures (<2 psi). The

 Bosch filter may have caused a high enough  pressure drop to induce Vapor

 Lock. Fuel flow was tested before the first  flight using the Aux pumps and

 flow was confirmed to be over 20 gph. The  test was repeated after this

 incident and continued to be over 20 gph. The  flow was never tested using

 the Jabiru pump alone. The Jabiru pump was  disassembled and showed no

 indications of a problem or  contamination.

 

 The Bosch filter was discarded and  per the recommendations of those

 on the Matronics list, a Flow Ezy  stainless mesh filter (A S & S, p/n

 05-28905) was installed upstream of  the Jab pump. The Flow Ezy filter,

 though rather expensive (close to $100),  provides high flow/low pressure

 drop. This appears to have cured the  problem as I have had no additional

 issues after 6 hours additional flight  time. This includes several full

 power climbs with Aux pumps  off.

 

 Looking back on this, I should have used the  high flow, stainless

 filter from the get-go. Fortunately, the plane was  designed with fuel pump

 redundancy and the Aux pumps were used during  Takeoff and Landing.

 

 I hesitate to air my dirty  laundry here, but hopefully it will help

 some other builders to avoid the  same mistake. CFL

 

 

 Clear Skies!

 Chuck Long, CFI

 Zodie  Rocket

 N601LE, 110 hr TT

 

 

 

 

 

 

 

 

 

 ************************************** See what's free at http://www.aol.com.

purplemoon99(at)bellsouth
Guest

Posted: Tue Jun 19, 2007 4:04 pm Post subject: Vaporlock issues - lessons learned

Dred, here's my set up ,2 facet pumps set up after the gasolater with a on 

and off fuel slector on each wing tank going to the gasolater 2 swiches on 

the dash 1for each pump ,I flip them both on for take and landings,and use 

only 1 for cruise I alt from time to time on the 1 for cruise. any in put? 

Joe N101HD 601XL

---

bryanmmartin

Joined: 10 Jan 2006
Posts: 1018

Posted: Tue Jun 19, 2007 4:34 pm Post subject: Vaporlock issues - lessons learned

You also want to be able to turn off the fuel flow in case of emergency. You don't want to be trying to get out of the cabin after a crash landing while the pumps are filling the cabin with fuel through ruptured fuel lines.



  	  Quote: 	
		  --> Zenith-List message posted by: <dredmoody(at)cox.net (dredmoody(at)cox.net)>

I agree with Gig that you want a "Right - Left - Off" valve arrangement ,not a "Right - Left - Both" type of arrangement. If both tanks are connected to the fuel system at the same time and one is empty or very low, that low tank constitutes a problem that the full one does not compensate for.

	






 -- 

Bryan Martin

N61BM, CH 601 XL,

RAM Subaru, Stratus redrive.

do not archive.

 



 [quote][b]

_________________
--
Bryan Martin
N61BM, CH 601 XL, Stratus Subaru.
do not archive.

JAPhillipsGA(at)aol.com
Guest

Posted: Tue Jun 19, 2007 4:39 pm Post subject: Vaporlock issues - lessons learned

Joe, do you have a header tank ? I didn't see the need for fuel pumps from the wing tanks without a header tank on a standard XL. Do you have some special issues ?  I have only one elec fuel pump between gasalator to mech fuel pump on my XL and it seems to do fine. I have an in line filter between pumps. This is with a 3300 Jab. Maybe I missed something, Best regards, Bill of Georgia

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

 See what's free at http://www.aol.com.  [quote][b]

daveaustin2(at)primus.ca
Guest

Posted: Tue Jun 19, 2007 5:03 pm Post subject: Vaporlock issues - lessons learned

When a facet fuel pump is directly feeding the float bowls it is pushing 

against closed float valves for a large part of the time.

No prob.

Dave Austin  601HDS - 912, Spitfire Mk VIII

purplemoon99(at)bellsouth
Guest

Posted: Tue Jun 19, 2007 5:32 pm Post subject: Vaporlock issues - lessons learned

Bryan, I have 2 dash switches,and a wing fuel valve  for each wing, so I can shut everything off,if thing's go south.  Joe  N101HD

 [quote]   ---

purplemoon99(at)bellsouth
Guest

Posted: Tue Jun 19, 2007 6:05 pm Post subject: Vaporlock issues - lessons learned

Bill,I don't have a mech. pump ,so I have 2 for my  Ram 130 Subaru.I had thought about add another pump on a seperate small batt,  switch independnt from the other 2  I n case of elect failure  . Joe N101HD  

  	  Quote: 	
		       ----- Original Message

   From:    JAPhillipsGA(at)aol.com (JAPhillipsGA(at)aol.com) 

   To: zenith-list(at)matronics.com (zenith-list(at)matronics.com) 

   Sent: Tuesday, June 19, 2007 8:38  PM

   Subject: Re: Vaporlock    issues - lessons learned

Joe, do you have a header tank ? I didn't see    the need for fuel pumps from the wing tanks without a header tank on a    standard XL. Do you have some special issues ?  I have only one elec fuel    pump between gasalator to mech fuel pump on my XL and it seems to do fine. I    have an in line filter between pumps. This is with a 3300 Jab. Maybe I missed    something, Best regards, Bill of    Georgia

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

See what's    free at http://www.aol.com.  	  Quote: 	

href="http://www.matronics.com/Navigator?Zenith-List">http://www.matronhref="http://forums.matronics.com">http://forums.matronics.com

    [quote][b]

p.mulwitz(at)worldnet.att
Guest

Posted: Wed Jun 20, 2007 1:14 am Post subject: Vaporlock issues - lessons learned

Hi Tracy,



My favorite old instructor had a lesson he repeated many times to me: 

"If it ain't broke, don't fix it."



I don't understand why there should be a problem with the fuel system 

as designed by Chris Heintz.  Fuel is gravity fed from both tanks to 

the fuel selector valve.  Gravity works to get it to the 

gascolator.  Then it is pumped by one electric and one mechanical 

pump to the engine.  This is a completely round wheel.



The lister who moved on the RV project sounded like he knew what he 

was talking about, but he was an engineer.  You know how some 

engineers can go down the garden path with eccentric ideas and never 

find their way back.  Perhaps the notion of putting a fuel pump on 

each wing is a good one if  you are using cheap auto fuel that is not 

suited to high altitude use in airplanes.  If you plan to use avgas, 

as I do, I think the fuel system should work fine as originally designed.



Paul

XL fuselage

At 12:54 PM 6/19/2007, you wrote:

 	  Quote: 	
		    - there was a prolific lister here some time ago that was 

 exceptionally knowledgeable on vapor lock issues.  He suggested 

 eliminating the fuel selector completely and running a check valve 

 at the outlet of each pump.  That way BOTH pumps could supply fuel 

 during takeoff and landing and ONE pump can run during 

 cruise.  When one pump is running, the check valve(s) will 

 eliminate crossfeeding from one tank to another.  In addition, by 

 using a 2-gang rotary switch wired Left-Right-Left+Right there is 

 no way the plane can suffer from NO pumps on due to pilot 

 error.  My only problem with this setup is that the one fuel pump 

 switch presents a single point of failure.......



Any thoughts??

601zv(at)ritternet.com
Guest

Posted: Wed Jun 20, 2007 4:35 am Post subject: Vaporlock issues - lessons learned

My 601XL plans have the fuel running uphill to the selector valve, with the 

valve located above the tops of all 4 tanks. I am in the process of 

extending the valve linkage to place the valve body on the cockpit floor to 

eliminate the uphill run.



---

Jeyoung65(at)aol.com
Guest

Posted: Wed Jun 20, 2007 6:32 am Post subject: Vaporlock issues - lessons learned

Hi Joe, What part of the country do you live in?  Jerry -  GA



See what's free at AOL.com. 

  [quote][b]

crvsecretary

Joined: 18 Mar 2007
Posts: 38
Location: Naugatuck, CT

Posted: Wed Jun 20, 2007 7:15 am Post subject: Vaporlock issues - lessons learned

Hi Dave:

  

 The best part of this list is having good advise from different  perspectives - and you are exactly right with your reply.  Thank you for  your insight.

  

 Tracy Smith

 N458XL (reserved)

 Do Not Archive

  

  

  

 In a message dated 6/19/2007 8:04:53 PM Eastern Standard Time,  daveaustin2(at)primus.ca writes:

  	  Quote: 	
		  -->    Zenith-List message posted by: "Dave Austin"    <daveaustin2(at)primus.ca>



When a facet fuel pump is directly    feeding the float bowls it is pushing 

against closed float valves for a    large part of the time.

No prob.

Dave Austin  601HDS - 912,    Spitfire Mk VIII 



	


 

  



See what's free at AOL.com. 

  [quote][b]

_________________
Zenith 601XL N458XL (reserved)
Naugatuck, CT
Tail Complete; working on wings

MaxNr(at)aol.com
Guest

Posted: Wed Jun 20, 2007 9:43 am Post subject: Vaporlock issues - lessons learned

I have learned a great deal from this thread and enjoyed it very much. I would like to add an opinion if I may. I saw the word "check valve" mentioned and my antennae went up. I consider check valves as necessary evils. In my previous life before retirement, many of my fuel system malfunctions in turbine A/C were traced to bad check valves and they took as long as 2 days of trouble shooting to clear. I am sold on red "LOW FUEL PRESS" warning lights. I would like add one to my project if possible. That light saved the day once on downwind to base when it gave me enough warning to go into cross feed and keep number 2 eng running. Had 1 hour fuel on board at the time. Bad check valve. Other times, when it comes on at runup, you just taxi back and get it fixed and avoid the drama.

 Bob

 Pace, FL      XL/Lyc

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

 See what's free at http://www.aol.com.  [quote][b]

planes_by_ken(at)bellsout
Guest

Posted: Wed Jun 20, 2007 11:15 am Post subject: Vaporlock issues - lessons learned

Hi all,



On the piper warrior the fuel selector is about level with the bottom of 

the tanks.  There is enough head pressure to drain the gascolator, but 

not for high power settings..  On Trauma-hawks the selector is at base 

of the panel probably above the fuel level.  Both run the fuel through 

the gascolator and then to the pump.  My ideal design would be to have a 

pump at each wing tank and one more after the fuel selector.  It would 

have dual electrical systems as I don't want to spend $1300 to put a 

fuel pump on my 0-200.  With a few switches and diodes it could be 

reasonably seamless operation.  A switch mounted to the throttle control 

like for gear warning that turns on the emergency pump at 90% power for 

takeoff.  Two microswitchs mounted to turn on left or right pumps as 

selected by the tank selector.  The third pump, after the gascolator 

would use an emergency pump switch.   The traditional Facett 

intermittent pumps are not constant displacement, so running with no 

flow is not a problem.  I do not know about the smaller new pumps.  And 

in an emergency?  You did turn off the fuel selector before hitting the 

trees at the end  of the clothing optional beach didn't you?  Also on 

certified aircraft that are not gravity feed a "both" position on the 

fuel valve is prohibited.  An empty take will cause the pump to suck air.

Ken Lilja

p.mulwitz(at)worldnet.att
Guest

Posted: Wed Jun 20, 2007 11:27 am Post subject: Vaporlock issues - lessons learned

Hi Robin,



I am currently installing the fuel components in the cockpit, and it 

appears I have the same small uphill run to the selector switch you mentioned.



I wonder if water will accumulate in the fuel line where the line 

turns up to the switch.  Perhaps any water will be forced out of that 

point by the fuel flow and wind up in the gascolator.  If it isn't 

forced out, i.e. if the water says in the fuel line while the fuel 

flows past, then it isn't a problem either.



With the official design, the gascolator is indeed at the lowest 

point in the fuel system.  It might be appropriate to consider small 

intermediate low points in the fuel line the same way as we consider 

water in the fuel tank below the fuel port in the tank.  Of course 

there is a drain valve in the tank, so maybe this is a bad comparison.



I guess I am not convinced one way or the other about moving the 

selector switch.  Of course, it would be easier to install it 

according to the plans since that is the approach the kit includes parts for.



Paul

XL fuselage

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At 05:31 AM 6/20/2007, you wrote:

 	  Quote: 	
		  My 601XL plans have the fuel running uphill to the selector valve, 

with the valve located above the tops of all 4 tanks. I am in the 

process of extending the valve linkage to place the valve body on 

the cockpit floor to eliminate the uphill run.

601zv(at)ritternet.com
Guest

Posted: Wed Jun 20, 2007 1:25 pm Post subject: Vaporlock issues - lessons learned

All I know is the Andair parts to do the extension cost more than the valve!



---

dfmoeller

Joined: 19 Jun 2006
Posts: 60
Location: Austin, TX

Posted: Wed Jun 20, 2007 2:56 pm Post subject: Re: Vaporlock issues - lessons learned

I am really hoping someone can explain how the fuel would flow uphill to the valve without relying on the system being primed first.  This is something I've been wondering about.



Doug

p.mulwitz(at)worldnet.att
Guest

Posted: Wed Jun 20, 2007 3:29 pm Post subject: Vaporlock issues - lessons learned

At 03:56 PM 6/20/2007, you wrote:

 	  Quote: 	
		  I am really hoping someone can explain how the fuel would flow 

uphill to the valve without relying on the system being primed 

first.  This is something I've been wondering about.



Doug


	




Perhaps the same way a syphon hose is used to get gas from an auto 

gas tank - by having the fuel pump suck on the line . . .



I am not sure the head of fuel in the tank is lower than the fuel 

switch.  The discussion recently pointed out that there is an uphill 

bend in the fuel line to get to the tank valve mounted near the 

instrument panel.  Considering the wing dihedral it is easy to 

suspect the fuel will actually be above the valve.



It is the intermediate low point in the fuel line that interests 

me.  I wonder if water will accumulate at that point and also whether 

it even matters.



Paul

XL fuselage

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