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601XL fuel sender

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oaksnspokes(at)earthlink.
Guest

Posted: Mon Jul 23, 2007 8:52 am Post subject: 601XL fuel sender

All,



I am looking for some input on the subject of fuel senders.  I recently

finished a 601XL and about 20 hours into its life the left fuel tank is

reading zero, regardless of the amount of fuel in the tank.  I switched

the sender wires at the Dynon and can read the right tank on both

"gauges".  I traced the left wire all the way back to where it exits the

fuselage and that all looks good.  Before I start drilling out rivets in

the sender cover, I thought I would throw this out to this group and see

if anyone has any helpful ideas.   



I was not overly impressed with the senders when I put them in.  They

were the factory provided units, I think they are VDOs.  If I end up

replacing the sender, I would like to "upgrade" if possible (I have the

2x15 gal. tanks).  I have seen senders of a similar design in the

Aircraft Spruce catalog for about $12.  These had what looked like a

rectangular solid float, rather than the hollow cylindrical float that I

have now.



Two questions:



1> Does anyone have any useful insights that could help

   with my current (apparent) sender problem?

2> Does anyone have any recommendations for a superior sender,

   if it comes to that?



Thanks.



Alan Smith

Zodiac 601XL - N601FW

Olympia, WA

zenith601xl(at)gmail.com
Guest

Posted: Mon Jul 23, 2007 9:18 am Post subject: 601XL fuel sender

Even if they work properly, due to the dihedral in the wing; if the sender is outboard the gauge will read empty while still about half full, and full until half empty if the sender is inboard.  There is no easy way to avoid this.  I too don't like the VW units supplied with the kit and am considering not cutting holes to install any senders. Visually checking each tank before each flight and measuring running time with a clock.  Basic but effective.  Fuel flow and level indications on a glass panel will be a back up. 



Dennis Shoup



On 7/23/07, oaksnspokes <oaksnspokes(at)earthlink.net (oaksnspokes(at)earthlink.net)> wrote:[quote] --> Zenith-List message posted by: "oaksnspokes" <oaksnspokes(at)earthlink.net (oaksnspokes(at)earthlink.net)>

All,



I am looking for some input on the subject of fuel senders.  I recently 

finished a 601XL and about 20 hours into its life the left fuel tank is

reading zero, regardless of the amount of fuel in the tank.  I switched

the sender wires at the Dynon and can read the right tank on both

 "gauges".  I traced the left wire all the way back to where it exits the

fuselage and that all looks good.  Before I start drilling out rivets in

the sender cover, I thought I would throw this out to this group and see 

if anyone has any helpful ideas.



I was not overly impressed with the senders when I put them in.  They

were the factory provided units, I think they are VDOs.  If I end up

replacing the sender, I would like to "upgrade" if possible (I have the 

2x15 gal. tanks).  I have seen senders of a similar design in the

Aircraft Spruce catalog for about $12.  These had what looked like a

rectangular solid float, rather than the hollow cylindrical float that I

 have now.



Two questions:



1> Does anyone have any useful insights that could help

   with my current (apparent) sender problem?

2> Does anyone have any recommendations for a superior sender,

   if it comes to that?  [quote][b]

Gig Giacona

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

Posted: Mon Jul 23, 2007 10:27 am Post subject: Re: 601XL fuel sender

Doesn't FAR Sec. 91.205 (B) 9 require a fuel guage for each tank? The way a read it it does.



Sec. 91.205



Powered civil aircraft with standard category U.S. airworthiness certificates: Instrument and equipment requirements.



(a) General. Except as provided in paragraphs (c)(3) and (e) of this section, no person may operate a powered civil aircraft with a standard category U.S. airworthiness certificate in any operation described in paragraphs (b) through (f) of this section unless that aircraft contains the

instruments and equipment specified in those paragraphs (or FAA-approved equivalents) for that type of operation, and those instruments and items of equipment are in operable condition.

(b) Visual-flight rules (day). For VFR flight during the day, the following instruments and equipment are required:

...

(9) Fuel gauge indicating the quantity of fuel in each tank.

...

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

tonyplane(at)bellsouth.ne
Guest

Posted: Mon Jul 23, 2007 11:45 am Post subject: 601XL fuel sender

Alan,

  

 For what it is worth.

 If I recall, the resistance of the VDO gauge is 30  to 70 ohms.  You could check you wiring to see if there is any resistance  (I believe the 30 ohms was either empty or full and 70 ohms also either empty of  full, with in-between neither full nor empty). 

  

 You could have a stuck float if you installed it  too close to the side of the tank.  I have one of my four tanks (an aux  tank) that when empty, the float does make slight contact the side of the  tank.  Fortunately, when fuel is installed, the tank "bulge", relieves this  problem.  If the float is stuck, use the 'ol thump the tank when  full).

  

 Tony Graziano

 601XL/Jab3300A; N493TG; 265 hrs.

  

             601XL fuel  sender        From:              oaksnspokes (oaksnspokes(at)earthlink.net ([email]oaksnspokes(at)earthlink.net?subject=Re:%20601XL%20fuel%20sender&replyto=001b01c7cd49$9c0c0a90$6501a8c0(at)OaksNSpokes[/email]))        Date:              [b]Mon Jul 23 - 9:52        AM[/b] [quote] 	  Quote: 	
		  All,



I am looking for some input on the subject of fuel senders.  I recently

finished a 601XL and about 20 hours into its life the left fuel tank is

reading zero, regardless of the amount of fuel in the tank.  I switched

the sender wires at the Dynon and can read the right tank on both

"gauges".  I traced the left wire all the way back to where it exits the

fuselage and that all looks good.  Before I start drilling out rivets in

the sender cover, I thought I would throw this out to this group and see

if anyone has any helpful ideas.   



I was not overly impressed with the senders when I put them in.  They

were the factory provided units, I think they are VDOs.  If I end up

replacing the sender, I would like to "upgrade" if possible (I have the

2x15 gal. tanks).  I have seen senders of a similar design in the

Aircraft Spruce catalog for about $12.  These had what looked like a

rectangular solid float, rather than the hollow cylindrical float that I

have now.



Two questions:



1> Does anyone have any useful insights that could help

   with my current (apparent) sender problem?

2> Does anyone have any recommendations for a superior sender,

   if it comes to that?



Thanks.



Alan Smith

Zodiac 601XL - N601FW

Olympia, WA 	
[b]

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Mon Jul 23, 2007 12:23 pm Post subject: Re: 601XL fuel sender

How does the ground wire look? Are you grounding to the hull or using a seperate groundwire?



If you're using a groundwire, is the ground actually complete the circuit to the gauge is a gasket or ProSeal causing a break in the connection?

ashontz

Joined: 27 Dec 2006
Posts: 723

Posted: Mon Jul 23, 2007 12:29 pm Post subject: Re: 601XL fuel sender

This is a good point. I wonder if two floats (one outboard and one inboard in each tank) wired (in parallel I believe) would give a more accurate reading.



do not archive



[quote="zenith601xl(at)gmail.com"]Even if they work properly, due to the dihedral in the wing; if the sender is outboard the gauge will read empty while still about half full, and full until half empty if the sender is inboard.  There is no easy way to avoid this.  I too don't like the VW units supplied with the kit and am considering not cutting holes to install any senders. Visually checking each tank before each flight and measuring running time with a clock.  Basic but effective.  Fuel flow and level indications on a glass panel will be a back up. 



Dennis Shoup



On 7/23/07, oaksnspokes <oaksnspokes> wrote:[quote] --> Zenith-List message posted by: "oaksnspokes" <oaksnspokes>

All,



I am looking for some input on the subject of fuel senders.  I recently 

finished a 601XL and about 20 hours into its life the left fuel tank is

reading zero, regardless of the amount of fuel in the tank.  I switched

the sender wires at the Dynon and can read the right tank on both

 "gauges".  I traced the left wire all the way back to where it exits the

fuselage and that all looks good.  Before I start drilling out rivets in

the sender cover, I thought I would throw this out to this group and see 

if anyone has any helpful ideas.



I was not overly impressed with the senders when I put them in.  They

were the factory provided units, I think they are VDOs.  If I end up

replacing the sender, I would like to "upgrade" if possible (I have the 

2x15 gal. tanks).  I have seen senders of a similar design in the

Aircraft Spruce catalog for about $12.  These had what looked like a

rectangular solid float, rather than the hollow cylindrical float that I

 have now.



Two questions:



1> Does anyone have any useful insights that could help

   with my current (apparent) sender problem?

2> Does anyone have any recommendations for a superior sender,

   if it comes to that?   	  Quote: 	
		  [b]

s.c.richards(at)homecall.
Guest

Posted: Mon Jul 23, 2007 1:02 pm Post subject: 601XL fuel sender

---

Gig Giacona

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

Posted: Mon Jul 23, 2007 1:52 pm Post subject: Re: 601XL fuel sender

 	  s.c.richards(at)homecall. wrote: 	
		  --- 	




S.C., We can't see your message in the forum. E-mail Matt.



DO NOT ARCHIVE

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

tonyplane(at)bellsouth.ne
Guest

Posted: Mon Jul 23, 2007 7:07 pm Post subject: 601XL fuel sender

I just checked the specs for the P/N 226 002 VDO  sender and:

 The resistance is 10 ohms when the tank is empty  (float at bottom) and 180 ohms when full (float at top).  If you get a  reading of about 10 or slightly more ohms then I would suspect the float is  stuck.  

 Tony Graziano

  

   

  

  	  Quote: 	
		                      Subject:                  Re: 601XL fuel sender            From:                  T. Graziano (tonyplane(at)bellsouth.net ([email]tonyplane(at)bellsouth.net?subject=Re:%20601XL%20fuel%20sender&replyto=002701c7cd61(at)pavilion[/email]))            Date:                  [b]Mon Jul 23 - 12:45        PM[/b]    	  Quote: 	
		   	  Quote: 	
		  Alan,



For what it is worth.

If I recall, the resistance of the VDO gauge is 30 to 70 ohms.  You 

could check you wiring to see if there is any resistance (I believe the 

30 ohms was either empty or full and 70 ohms also either empty of full, 

with in-between neither full nor empty). 



You could have a stuck float if you installed it too close to the side 

of the tank.  I have one of my four tanks (an aux tank) that when empty, 

the float does make slight contact the side of the tank.  Fortunately, 

when fuel is installed, the tank "bulge", relieves this problem.  If the 

float is stuck, use the 'ol thump the tank when full).



Tony Graziano

601XL/Jab3300A; N493TG; 265 hrs.



      601XL fuel sender 

      From:      oaksnspokes (oaksnspokes(at)earthlink.net ([email]oaksnspokes(at)earthlink.net?subject=Re:%20601XL%20fuel%20sender&replyto=002701c7cd61(at)pavilion[/email])) 

      Date:      Mon Jul 23 - 9:52 AM 



All,



I am looking for some input on the subject of fuel senders.  I recently

finished a 601XL and about 20 hours into its life the left fuel tank is

reading zero, regardless of the amount of fuel in the tank.  I switched

the sender wires at the Dynon and can read the right tank on both

"gauges".  I traced the left wire all the way back to where it exits the

fuselage and that all looks good.  Before I start drilling out rivets in

the sender cover, I thought I would throw this out to this group and see

if anyone has any helpful ideas.   



I was not overly impressed with the senders when I put them in.  They

were the factory provided units, I think they are VDOs.  If I end up

replacing the sender, I would like to "upgrade" if possible (I have the

2x15 gal. tanks).  I have seen senders of a similar design in the

Aircraft Spruce catalog for about $12.  These had what looked like a

rectangular solid float, rather than the hollow cylindrical float that I

have now.



Two questions:



1> Does anyone have any useful insights that could help

   with my current (apparent) sender problem?

2> Does anyone have any recommendations for a superior sender,

   if it comes to that?



Thanks.



Alan Smith

Zodiac 601XL - N601FW

Olympia, WA

	
	
	
   [quote][b]

AlanSmith

Joined: 24 Jul 2007
Posts: 2

Posted: Tue Jul 24, 2007 11:52 am Post subject: Re: 601XL fuel sender

I’ll check the resistance on the sender wire, that’s a good tip.  I would like to avoid drilling out my sender access covers, and messing up our new paint, but expect it to come to that eventually. 



The failure must be something other than a physically stuck float, because it failed when we had about 6 gallons in the tank.  I suppose the float could be sitting on the bottom of the tank, with a hole in it...  I have attempted to look into the tank with a mirror, but have not been able to get the right angle and the right light. 



When the sender was working, it worked well.  We were getting reasonable readings in ½ gallon increments.  The float hits the top of travel at about 13 gallons, so it can’t see 14 and 15.  When the gauge reads 0 gallons, we still have about 2/3 of a gallon, but that’s close enough to zero for me.  



Thanks for all the input.

_________________
Alan Smith
Zodiac 601 N601FW
oaksnspokes@earthlink.net

MaxNr(at)aol.com
Guest

Posted: Tue Jul 24, 2007 1:52 pm Post subject: 601XL fuel sender

A Capacitance fuel sending unit eliminates problems with one end of the tank higher than the other. Calibration is done with a screwdriver. Any water in the fuel will cause a false high reading. Its true that you don't need ANY fuel gauge in an air plane registered other than Standard. In fact, certified aircraft are allowed operation with fuel gauges inop if they have and comply with a Minimum Equipment List. (MEL.) Compliance routinely means a logbook entry & topping off or measuring with a dip stick. The Dynon line can use either resistance or capacitance fuel senders.

 Do not archive

 Bob  XL/Lyc

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

 Get a sneak peek of the all-new AOL at http://discover.aol.com/memed/aolcom30tour  [quote][b]

s.c.richards(at)homecall.
Guest

Posted: Wed Jul 25, 2007 1:24 am Post subject: 601XL fuel sender

Alan

             If you did read my previous reply it was incorrect I had the 

sence wrong.

 I fitted DATCON gauges with universal senders to Rays The resistances were 

33 ohms Full 240 Ohms Empty. You can compair with your working side.

   So if the wire to sender is open circuit to ground you may have lost the 

tank ground. I assume you fitted one as the tanks are insulated with cork 

and should be grounded to airframe to prevent static differences. 

Also if you are relying on this to ground the sender is the sender grounded 

to the tank and not insulated by the gaskets The universal sender I fitted 

was designed to be grounded by a staple through the gasket to the tank which 

I thought would be unreliable so I fitted a ground wire.

Clive Richards

RAYS 601HD G CBDG 140 Hrs



---

Gig Giacona

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

Posted: Wed Jul 25, 2007 5:36 am Post subject: Re: 601XL fuel sender

Is there a Capacitance sender that could be installed into the top location of the 601XL tank?



I've got to reopen the wings of mine because I changing the type of fuel line installed and now I think the the Capacitance might be a better way to go.



Anyone thought out the pros and cons of the options?

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

s.c.richards(at)homecall.
Guest

Posted: Wed Jul 25, 2007 9:15 am Post subject: 601XL fuel sender

Gig

              We have a capacitance type fitted in the side of the header 

tank which works ok after we fitted a 12.5 volt regulator to supply it. It 

will not see the top 2 inches. I fitted Datcon resistive type in the end of 

the wing tanks with difficulty as we did not want to open the wings & the 

capacitor type would not fit in this location. (Thought we did not need 

gauges as we had header tank but found out they were mandatory in UK).Will 

indicate from about the first 5 to 40 litres. the indication is reasonably 

steady when you are flying straight & level. A fellow builder on the 

airfield fitted capacitance type in his HDS wing tanks & says he only gets a 

reliable reading on the ground, I assume he fitted the bendable type in the 

top and the fuel sloshes up & down the measuring section.  Note you can only 

bend a short length at the top not the working part. The straight type may 

be ok but due to slope of tank you are limited to ammount you can measure. 

Both types are in Aircraft Spruce catalogue.

Clive Richards

Ray Lasnier 601 HD G CBDG

---

craig(at)craigandjean.com
Guest

Posted: Wed Jul 25, 2007 9:25 am Post subject: 601XL fuel sender

The downside to capacitive probes is that they give different readings for

different fuel composition. So avgas will differ significantly from mogas.

And given the funky things that happen with the blends of mogas you could

even get changes in calibration between fill-ups. IMHO I would only use a

capacitive probe if I was going to use avgas exclusively.



Mechanically the capacitive probes are (literally) flexible in their

installation. The actual sensor is just a hollow tube with an electrically

isolated wire inside. The two form the "plates" of the capacitor. If your

gauge or probe can be calibrated then you can cut and bend a probe to fit

your tank.



Here is one source: http://centroidproducts.com/



-- Craig

AlanSmith

Joined: 24 Jul 2007
Posts: 2

Posted: Thu Jul 26, 2007 1:08 pm Post subject: Re: 601XL fuel sender

I have not gotten a chance to put a VOM on the wire yet, but I did fill the take to about 13 gal. and fly for an hour or so.  Somewhere along the way my wife noticed that the gauge started reading something believable (12.5).  After I while it dropped to 4, than up to 8, then 5.... 



It can't simply be getting stuck, because there is no reason for it to have ever hit zero.  It can't have a hole in the float, because it never would gave risen up from zero.  



It must be some kind of failure in the sender, or faulty wiring on my part.

The up-side of these senders is that they fit.  No need for any dome covers on the wings.



Thanks for the input.



Alan

_________________
Alan Smith
Zodiac 601 N601FW
oaksnspokes@earthlink.net

Gig Giacona

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

Posted: Fri Jul 27, 2007 11:39 am Post subject: Re: 601XL fuel sender

I missed it. What kind of sender are you using?

 	  AlanSmith wrote: 	
		  I have not gotten a chance to put a VOM on the wire yet, but I did fill the take to about 13 gal. and fly for an hour or so.  Somewhere along the way my wife noticed that the gauge started reading something believable (12.5).  After I while it dropped to 4, than up to 8, then 5.... 



It can't simply be getting stuck, because there is no reason for it to have ever hit zero.  It can't have a hole in the float, because it never would gave risen up from zero.  



It must be some kind of failure in the sender, or faulty wiring on my part.

The up-side of these senders is that they fit.  No need for any dome covers on the wings.



Thanks for the input.



Alan

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

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