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Aux fuel pump in 701.

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ggower_99(at)yahoo.com
Guest

Posted: Thu Feb 23, 2006 10:01 pm Post subject: Aux fuel pump in 701.

Jim and all...

   

  We have a 701 kit we built,..   It has the fuel system as the plans, the stock vented gas caps and the stock aluminum gascolator.  

  The only thing we added were a shut off  valve in each hose, from each tank, inside the lugage area where  the flaperon conectors covers are, easy reach by the pilot if need,  they are always opened.  

   

  What we note in this first 35 hours of flying the 701,  is that the right wing  uses the gasoline first,  the left tank is about 3/4 full when the right wing is near empty (1/4). in flights of more than 2 or 3 an hours (depending of the real flight time, off course).

   

  We tested in the hangar the flow of each tank independent and also both tanks at the same time, closing one valve and disconecting the hose just pass the main shut off valve...   

  Dont have the numbers now, but the diference was minimal.  we havent flew the plane that much time to see what happens when (if) the right tank gets empty,  

  I once shut the right tank valve for about 40 minutes over the dry lake (not chicken, just thinking safe   to use the left tank first and then both tanks,  when I landed both tanks where almost level. (used the calibrated level  tube)..

   

  Now,  given this,  a friend that is building another (701) kit here, got a 1 galon header tank from Kitfox, It is installed the same way the KF instructuins, in the back side of his seat , is plumbed betwen the tanks and the ZAC gascolator,  He also uses the shut off valves from the main tanks as we did.  

   

  This particular header tank  is vented with a T, and at the same level of the main tanks, so no overflow is spected...  I think this will help  keep both tanks level. 

  This 701 will ready to fly is a few weeks,  is almost finished.  So not field tested yet.

   

  As is impossible now to get the Kitfox header tank (bankrupt),  we are planning to make one similar made of aluminum for our plane...

   

  One extra from this header tank is that has an internal level switch that turns on a  LED in the instrument panel if  the level of the HT  is about 90% low...    If this happens the pilots has about 1 gallon left (10 minutes)  to look for a good place to glide...

   

  I dont know where we can look for a similar sender switch for our tank, because will be a good safety gadget.  If we can find the switch we will make our tank 2 galons to have 20 minutes to land... if needed.  hope never needed.

   

  What do you think?

   

  Saludos

  Gary Gower.



Jim Hoak <planejim(at)bellsouth.net> wrote:

  

George,



I have 601Hd fuel system plumbed as you described. I use auto gas 

exclusively. It has worked fine for 9 years (500.3 hours). I use the 

electric pump for T/O and landing (in case of a go around) in case the 

mechanical pump dies at the wrong time. The only question I have is the 

pressure you mentioned. My engine driven (Rotax 912UL) pump and the 

electric pump both put out around 5 Psi NOT 25 to 45 psi as you mentioned. 

My elec. pump is a Facet and I don't use a "check valve" in the system. I 

just checked my purchase records but the receipt doesn't mention the part 

number and the airplane is miles from home. I plumbed the electric pump in 

"parrallel" with the engine pump and it works fine.



Good luck.



Jim Hoak 601HD 500.3 hrs.

---

nyterminat(at)aol.com
Guest

Posted: Fri Feb 24, 2006 2:00 pm Post subject: Aux fuel pump in 701.

Gary,

 

I have the exact same situation, except that my left tank empties first. My gasolator is right behind the pilots seat in the bottom of the fuselage. I have only been able to fly 15 hrs so far but the left one definately empties first. I tried switching fuel caps and it made no difference. I wonder if the tank being closest to the gasolator makes a difference? Where is yours? I also put individual tank shut off valves at each door header. I shut off my left one to balance out the fuel. I also have an aux pump in series with the fuel line right after the gasolator. Seems to work well, used to initally bring fuel to carbs on 1st start up. I also use it for takeoff and landing.

 

Bob Spudis

N701ZX  CH701/912S

 

--

tshank(at)core.com
Guest

Posted: Fri Feb 24, 2006 6:36 pm Post subject: Aux fuel pump in 701.

This situation might be caused by the differential pressure on the 

vents. The propeller is sending s spinning column of air back toward the 

wings, if the vent from the two tanks are not connected a different 

pressure can be present in each tank causing one to empty before the 

other. I plan on being able to feed form both tanks on my 601 so I 

connected the vents.



Tim Shankland



nyterminat(at)aol.com wrote:



[quote]



 Gary,

 

I have the exact same situation, except that my left tank empties first. My gasolator is right behind the pilots seat in the bottom of the fuselage. I have only been able to fly 15 hrs so far but the left one definately empties first. I tried switching fuel caps and it made no difference. I wonder if the tank being closest to the gasolator makes a difference? Where is yours? I also put individual tank shut off valves at each door header. I shut off my left one to balance out the fuel. I also have an aux pump in series with the fuel line right after the gasolator. Seems to work well, used to initally bring fuel to carbs on 1st start up. I also use it for takeoff and landing.

 

Bob Spudis

N701ZX  CH701/912S

 

--

craig(at)craigandjean.com
Guest

Posted: Fri Feb 24, 2006 8:07 pm Post subject: Aux fuel pump in 701.

Wouldn't connecting the two vents create a single point of failure?



-- Craig

ggower_99(at)yahoo.com
Guest

Posted: Fri Feb 24, 2006 8:52 pm Post subject: Aux fuel pump in 701.

Hi Bob,

   

  No,  the gascolator is as the plans, in the "floor" behind the left (pilot)  seat...  and in my case the right tank is the one to empty first,  We even opened the wing root skins to see if the hose curves were tighter in the left wing and no,  the curves were wide (normal) in  both sides.   

   

  I recieved an off list mail from Ron,  He has a good theory:   that probably I (we) are flying in cruise with one wing lower than the other, and the gasoline migrates to the other tank...    Yes could be...  But has to be the rigging...  Because Larry (my brother) also flys the plane and same results,  is dificult to have the same type of flying,   well,  we had the same Instructor 

   

   I thought about installing a pair of check valves...(one in each tank),  but two more things to go wrong.  I am a "preacher" for simplicity and safety in aviation, so wont do it.., only and just in case is the only safe solution. 

   

  Our only concern is:  Can "air or vapor type lock" (sp?)  happen if the right tank empties first complete and air goes inside the gascolator and the gasoline pump?...  

   I will appreciate your advise,  Frank...

  The electric fuel gauges could be so erratic...   

   

  This is why I have the idea of installing a 1 or 2  gallons "header tank" behind the seat back (just in case has to be exactly in the middle of both seats!!!    and use the same gascolator.

   

  Saludos

   

  Gary Gower

  Flying from Chapala, Mexico

  701  912S 

nyterminat(at)aol.com wrote:  



Gary,



I have the exact same situation, except that my left tank empties first. My gasolator is right behind the pilots seat in the bottom of the fuselage. I have only been able to fly 15 hrs so far but the left one definately empties first. I tried switching fuel caps and it made no difference. I wonder if the tank being closest to the gasolator makes a difference? Where is yours? I also put individual tank shut off valves at each door header. I shut off my left one to balance out the fuel. I also have an aux pump in series with the fuel line right after the gasolator. Seems to work well, used to initally bring fuel to carbs on 1st start up. I also use it for takeoff and landing.



Bob Spudis

N701ZX CH701/912S



--

jeffrey_davidson(at)earth
Guest

Posted: Fri Feb 24, 2006 9:03 pm Post subject: Aux fuel pump in 701.

Wouldn't connecting the two vents create a single point of failure?



The idea is that both tanks still have their own vents, the vents are just

now connected.  If one vent becomes clogged, that tank would still be vented

through the interconnection to the other tank's vent.  This was recommended

to me if the fuel selector had the "Both" position by ZAC, assuming a two

wing tank - no header configuration.  This was for a 601 too.



Jeff Davidson

tshank(at)core.com
Guest

Posted: Sat Feb 25, 2006 10:41 am Post subject: Aux fuel pump in 701.

No, because if have two vents one in each wing, on the bottom recessed, 

similar to a Grumman Cheetah.



Tim



Craig Payne wrote:



 	  Quote: 	
		  



Wouldn't connecting the two vents create a single point of failure?



-- Craig

nyterminat(at)aol.com
Guest

Posted: Sat Feb 25, 2006 3:29 pm Post subject: Aux fuel pump in 701.

Gary,

 

This is my concern too. Has anyone ran a tank dry on purpose to see what happens? I like the idea of a header tank behind the seatback but I have installed a load of goodies back there. May consider something in the future though. Does the header tank get a separate vent or does it use the wing tanks as a vent?

 

Bob Spudis

N701ZX/912S



  Our only concern is:  Can "air or vapor type lock" (sp?)  happen if the right 

tank empties first complete and air goes inside the gascolator and the gasoline 

pump?...  

   I will appreciate your advise,  Frank...

  The electric fuel gauges could be so erratic...   

   

  This is why I have the idea of installing a 1 or 2  gallons "header tank" 

behind the seat back (just in case has to be exactly in the middle of both 

seats!!!    and use the same gascolator.

   

  Saludos

   

  Gary Gower

  Flying from Chapala, Mexico

  701  912S

nyterminat(at)aol.com
Guest

Posted: Sat Feb 25, 2006 3:33 pm Post subject: Aux fuel pump in 701.

Tim 

 

I suppose that is possible. We were not offered any way of venting the tanks on the 701 other thann the fuel caps.

 

Bob Spudis

N701ZX    do not archive 

 

--

ggower_99(at)yahoo.com
Guest

Posted: Sat Feb 25, 2006 7:24 pm Post subject: Aux fuel pump in 701.

The header tank (in the Kitfox and in my friends 701 instalation) has its own vent tube, but goes up to the same level of the wing tank vents,  so no overflow will be there.   Mean while we will fly the first hour in the left tank,  once we get to level flight with both.   Also be sure to have both on before beguining the landing.

   

  Saludos

  Gary Gower. 



nyterminat(at)aol.com wrote:

  



Gary,



This is my concern too. Has anyone ran a tank dry on purpose to see what happens? I like the idea of a header tank behind the seatback but I have installed a load of goodies back there. May consider something in the future though. Does the header tank get a separate vent or does it use the wing tanks as a vent?



Bob Spudis

N701ZX/912S



Our only concern is: Can "air or vapor type lock" (sp?) happen if the right 

tank empties first complete and air goes inside the gascolator and the gasoline 

pump?... 

I will appreciate your advise, Frank...

The electric fuel gauges could be so erratic... 



This is why I have the idea of installing a 1 or 2 gallons "header tank" 

behind the seat back (just in case has to be exactly in the middle of both 

seats!!!  and use the same gascolator.



Saludos



Gary Gower

Flying from Chapala, Mexico

701 912S 

		

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leogates(at)allvantage.co
Guest

Posted: Sun Feb 26, 2006 11:05 am Post subject: Aux fuel pump in 701.

All,



I ordered my HDS LE tanks right after ZAC offered them (5-6) years ago.  

I asked them to weld in a 1/4" overflow/vent line in each tank 

terminating about 1/8" from the top and just outboard of the fuel cap.  

They did so at no charge.



Leo Gates

N601Z

nyterminat(at)aol.com wrote:



 	  Quote: 	
		  



Tim 

 

I suppose that is possible. We were not offered any way of venting the tanks on the 701 other thann the fuel caps.

 

Bob Spudis

N701ZX    do not archive

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