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EGT mal function

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michel.dierick(at)yahoo.c
Guest

Posted: Wed Jun 27, 2007 1:12 pm Post subject: EGT mal function

Hi everybody,

   

  I'm new to this list and I already have a question for my Kitfox Classic III.

   

  I just bought my Kitfox but have a problem with the EGT gauge.  I - well - my kitfox has the Rotax 582 engine.  The EGT indicates the temperature of 1 cylinder, not the second.  In flight, the reading of the first cylinder also stops, having no egt readings at all.

   

  As I looked in the engine compartment, I see that the EGT probes are well connected to the cylinder but both lines that are made of metal touch each other while between de engine and the instrument.



Do I have to put some tape around them to avoid contact ?

   

  How did you guys solve this problem.

   

  Greetz,

   

  Mchel Dierick "TheDailyFly" from Belgium where the weather isn't very "summer" today.



               Yahoo!7 Mail has just got even bigger and better with unlimited storage on all webmail accounts. Find out more. [quote][b]

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Wed Jun 27, 2007 2:13 pm Post subject: EGT mal function

On Jun 27, 2007, at 11:08 PM, michel dierick wrote:

 	  Quote: 	
		   I'm new to this list and I already have a question for my Kitfox 

 Classic III.


	


Hello Michel,

Well, I think we have a problem here  My name is also Michel and I 

am also from Belgium, although I have been living 30 years in Norway.I 

also have a Kitfox III which also had a 582 but now changed for a 

Jabiru 2200. Incidentally, I think the Kitfox Classic is the model IV 

and not III.



 	  Quote: 	
		   Do I have to put some tape around them to avoid contact ?


	


Well, since the EGTs are thermo-couplers and measure a variation in 

electrical resistance, it is certainly not good to have them shortcut. 

But I fail to understand why this would show one working correctly and 

the other showing nothing. Another thing is that the EGT probes have to 

be connected to the exhaust manifold (hence the name) and not the 

cylinders but I guess that's what you meant.



By the way, do you fly a Kitfox in Belgium? Under the experimental or 

the UL rule? The reason I ask is that I know there are no Kitfox 

registered in Belgium under the UL rule. You might be the first. I 

always wondered why. Norway that has half the population of Belgium has 

about six Kitfoxes in flying condition.



Greetings from Norway where the summer isn't much better either,



Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200

_________________
Kitfox 3 - Jabiru 2200

eskflyer

Joined: 24 May 2007
Posts: 44
Location: AK

Posted: Wed Jun 27, 2007 5:22 pm Post subject: Re: EGT mal function

Mine did the same thing . Changed the thermocouples and fixed the problem . It does not matter if the two wires are run touching together back to the instrument just make shure you have a good gromett through the firewall to keep them from rubbing and shorting out . Do you have the old style clamp-on, or the new thread in thermocouples? 



Good luck hope you get it fixed soon

_________________
FLY FUN FLY LOW FLY SLOW
John Perry
Kitfox 2 N718PD
582 cbox 2:62-1 IVO IFA
1220 Full Lotus

thesupe(at)hotmail.com
Guest

Posted: Wed Jun 27, 2007 9:05 pm Post subject: EGT mal function

The thermocouples probably connect to an "extention cord" to reach the 

instrument.   Eight connections there all togeather, any one or more of 

witch could be somewhat corroded.  Also you might try to switch the 

thermocouples around to determine if one half of the gauge is shot.  Jim 

Chuk,  Avid MK IV,  Chisholm MN

 	  Quote: 	
		  From: michel dierick <michel.dierick(at)yahoo.com.au>

Reply-To: kitfox-list(at)matronics.com

To: kitfox-list(at)matronics.com

Subject: EGT mal function

Date: Thu, 28 Jun 2007 07:08:28 +1000 (EST)



Hi everybody,



   I'm new to this list and I already have a question for my Kitfox Classic 

III.



   I just bought my Kitfox but have a problem with the EGT gauge.  I - well 

- my kitfox has the Rotax 582 engine.  The EGT indicates the temperature of 

1 cylinder, not the second.  In flight, the reading of the first cylinder 

also stops, having no egt readings at all.



   As I looked in the engine compartment, I see that the EGT probes are 

well connected to the cylinder but both lines that are made of metal touch 

each other while between de engine and the instrument.



Do I have to put some tape around them to avoid contact ?



   How did you guys solve this problem.



   Greetz,



   Mchel Dierick "TheDailyFly" from Belgium where the weather isn't very 

"summer" today.

---------------------------------

Yahoo!7 Mail has just got even bigger and better with unlimited storage on 

all webmail accounts. Find out more.


	


_________________________________________________________________

Make every IM count. Download Messenger and join the i’m Initiative now. 

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cliffh(at)outdrs.net
Guest

Posted: Thu Jun 28, 2007 5:57 am Post subject: EGT mal function

The thermocouples sometime burn out.

I have had to replace both of mine over the years.



Floran Higgins

Helena, Mt

Speedster

912ULS

---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Thu Jun 28, 2007 6:45 am Post subject: EGT mal function

So called "extension chords" of copper should never be  used.  By using a

copper wire extension you have just introduced resistances not to mention

four more couples to the circuit.  Wires should be of continuous alloys from

the  couple.



Noel



[quote] --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

thesupe(at)hotmail.com
Guest

Posted: Thu Jun 28, 2007 7:04 am Post subject: EGT mal function

I was refering to the extentions supplied with the gauges.   Most 

thermocouples I've seen are 4' long (to short to reach the gauge) and have  

male ends.  The connections on the gauge are also male.   Therefore, you 

need the extention to make the connection.  Thanks, Jim Chuk  Avid  MK IV



[quote]From: "Noel Loveys" <noelloveys(at)yahoo.ca>

Reply-To: kitfox-list(at)matronics.com

To: <kitfox-list(at)matronics.com>

Subject: RE: EGT mal function

Date: Thu, 28 Jun 2007 12:12:35 -0230






So called "extension chords" of copper should never be  used.  By using a

copper wire extension you have just introduced resistances not to mention

four more couples to the circuit.  Wires should be of continuous alloys 

from

the  couple.



Noel



 > --

michel.dierick(at)yahoo.c
Guest

Posted: Thu Jun 28, 2007 12:33 pm Post subject: EGT mal function

Well Michel, now you got me.

   

  And what do I do now ?  Do I respond in english, in het nederlands ou en français ? hahaha !   

   

  If you want to see my Kitfox, I put 2 pictures of my UL on the kitfox/photoshare.

   

  I'll put tape around to avoid shortcuts and check the connection. It has been put on the exhaust and not on the cylinders but it's  possible that they are not well placed. I'll check.

   

  I bought the Kitfox in France (Airfield Brienne-le-Chateau) and continue to have it registered in FR via DGAC Lille Lesquin. The procedure to fly with the Kitfox in Belgium is to ask the Belgian Authorities a 'Laissé passer de survol" so that you can enter Belgian Airspace. 

   

  Greetings from where we had wonderful cumulus today (good for glider pilots)

  Michel



Michel Verheughe  <michel(at)online.no> wrote:

  [quote]--> Kitfox-List message posted by: Michel Verheughe 



On Jun 27, 2007, at 11:08 PM, michel dierick wrote:

 	  Quote: 	
		   I'm new to this list and I already have a question for my Kitfox 

 Classic III.


	


Hello Michel,

Well, I think we have a problem here  My name is also Michel and I 

am also from Belgium, although I have been living 30 years in Norway.I 

also have a Kitfox III which also had a 582 but now changed for a 

Jabiru 2200. Incidentally, I think the Kitfox Classic is the model IV 

and not III.



 	  Quote: 	
		   Do I have to put some tape around them to avoid contact ?


	


Well, since the EGTs are thermo-couplers and measure a variation in 

electrical resistance, it is certainly not good to have them shortcut. 

But I fail to understand why this would show one working 	           Yahoo!7 Mail has just got even bigger and better with unlimited storage on all webmail accounts. Find out more. [quote][b]

lcfitt(at)sbcglobal.net
Guest

Posted: Thu Jun 28, 2007 1:43 pm Post subject: EGT mal function

Not quite true Noel.  As I understand it the temp difference between the 

sensor in the probe in the exhaust and the end of the braided end (cold 

junction) determines the EGT reading.  When we wired the Lancair there was 

insuffecient length to run to the gauge so we ensured that all the ends were 

in the same ralative location and pigtails are run from there to the gauge. 

This system is working fine.  Actually my Kitfox is wired the same way with 

copper from the cold junction to the gauge.



Lowell Fitt

Cameron Park, CA

Model IV-1200 R-912 UL Warp

1998 850 hrs.

---

Michel

Joined: 10 Jan 2006
Posts: 966
Location: Norway

Posted: Thu Jun 28, 2007 1:46 pm Post subject: EGT mal function

On Jun 28, 2007, at 10:29 PM, michel dierick wrote:

 	  Quote: 	
		   I'll put tape around to avoid shortcuts and check the connection.


	


You received some very good advices from the people on this list, 

Michel. Try them and maybe switch the two thermocouplers as advised 

first. Incidentally, it is a good way to check how they work. You'll 

always see one cooler than the other. To check if it is the gauge or 

the real temperature, you swap them and see how it works then. Good 

luck.



For the rest, I have sent you a direct email in French. We will not 

bother our English speaking friends and force them to use Babelfish! 





Greetings from Norway where we also have perfect glider weather. (due 

to prevailing winds, whatever weather is over Belgium, it will be over 

Norway 24 hours later! )



Michel Verheughe

Norway

Kitfox 3 - Jabiru 2200



do not archive

_________________
Kitfox 3 - Jabiru 2200

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Thu Jun 28, 2007 7:42 pm Post subject: EGT mal function

Let me see if I have this right you are saying that  you can connect copper to the alloys of a thermocouple with out creating a  thermo couple within the connection.  To maintain a linear calibration the  wires should have alloy continuity right from the hot junction to the cold  junction to the gauge itself. 



What is true is the small EGT gauges  we use may not be sensitive enough to display the difference and lets face it  none of us are flying in -60C so the use of a cold junction is or questionable  value.  However no one, other than the man upstairs, will know for sure  what the introduction of another four cold junctions will do for the linearity  and accuracy of the system as a whole.



Ref:    Aircraft  Instruments, Second Edition, ISBN 0-582-01898-6, E.J.H. Pallett

Ch. 11,  Pg.291

External Circuit and Resistance

The external circuit of a  thermoelectric indicating system consists of a thermocouple and it's leads, and  leads form the junction box at the engine bulkhead to the indicator  terminals.  From this point of view, it might therefore be considered as a  simple and straight forward electrical instrument system.  However, whereas  the latter may be connected up by means of the appropriate copper leads or cable  normally used in aircraft, it is not acceptable to do so in a thermoelectric  system.

This may be explained by taking the case of a copper/constantan  thermocouple which is to be connected to a cylinder-head temperature  indicator.  If a length of normal twin-core cable is connected to the  thermocouple terminal box, the one copper lead will be joined to it's  thermocouple partner, but the other one will be joined to the constantan  lead.  It is thus apparent that the joining of two dissimilar metals  introduces another effective hot junction which will respond to temperature  changes at the junction box, and in unbalancing the temperature/e.m.f. will  cause the indicator readings to be in error.  Similarly, all terminal  connections which may be necessary for routing the leads through the aircraft  and connections at the indicator itself will create additional hot junctions and  so aggravate indicator errors.

In order to eliminate those hot junctions, it  is the practice to use leads made of the same materials as the thermocouple  itself, such leads being known as extension leads.  It is sometimes the  practice also to use thermocouple materials having similar thermoelectric  characteristics in combination; for example, a chromel/alumel thermocouple may  be joined to it's indicator by copper/constantan leads, known as compensating  leads.  These leads not only compensate for parasitic effects but also  reduce the cost as chromel/alumel is expensive.



There is more going into  consistency of resistance to the system but I think you get the  idea. As anyone who has read my posts will know there  will probably be enough typos in here to qualify me into the non-typist pool...  I apologize for typo errors that may occur as I transposed this myself.

 

Long and short is it may work, after a fashion, with speaker or  telephone copper wire extensions wired in, but it is in no way right or  proper.

 

[img]cid:304383103(at)29062007-0D0E[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 Archive this one

 

 

 



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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Thu Jun 28, 2007 7:47 pm Post subject: EGT mal function

You can also test the output of the thermocouples  at relatively low temperatures by putting the tips of the probes in boiling  water ( just below 212 F for most people) or in the flame of a butane lighter  which should be above 500F... just make sure you test both probes at the same  time. and get the same readings.



 

[img]cid:606524403(at)29062007-0D15[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 

 

 

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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

thesupe(at)hotmail.com
Guest

Posted: Thu Jun 28, 2007 8:40 pm Post subject: EGT mal function

I believe that in the directions that come with the gauge, there is a number 

(resistance?) you should be able to read on an electrical meter between the 

black and white wire on the thermocouple if it is working correctly.  I just 

looked at an instruction sheet for a Westach gauge.  They call the 

"extention cord" I refered to a patch cable.  This is what they say:  Patch 

cable may be shortened or lengthened up to 20 feet without affecting 

accurity of unit.  Useing 20-22 gauge stranded wire is recommended.  Thanks, 

  Jim Chuk  Avid MK IV

[quote]From: "Noel Loveys" <noelloveys(at)yahoo.ca>

Reply-To: kitfox-list(at)matronics.com

To: <kitfox-list(at)matronics.com>

Subject: RE: EGT mal function

Date: Fri, 29 Jun 2007 01:15:00 -0230



You can also test the output of the thermocouples at relatively low

temperatures by putting the tips of the probes in boiling water ( just 

below

212 F for most people) or in the flame of a butane lighter which should be

above 500F... just make sure you test both probes at the same time. and get

the same readings.

Noel Loveys, RPP, AME intern

Campbellton, Newfoundland,

Canada

Kitfox Mod III-A, 582, B box, Ivo IFA

Aerocet 1100s

  <mailto:noelloveys(at)yahoo.ca> noelloveys(at)yahoo.ca



 > --

pwmac(at)sisna.com
Guest

Posted: Thu Jun 28, 2007 9:13 pm Post subject: EGT mal function

The aeroelectric list has beat this subject to death. Small error,  just keep the junctions in the same place. Lots of planes flying with copper wire extensions. No need to be theoretically correct for EGT.



 Test it at low temps and see a big error. Test it at 1400 degrees and the error is lost.

 Paul

 =======================

 At 09:39 PM 6/28/2007, you wrote:



 [quote]Let me see if I have this right you are saying that you can connect copper to the alloys of a thermocouple with out creating a thermo couple within the connection.  To maintain a linear calibration the wires should have alloy continuity right from the hot junction to the cold junction to the gauge itself. 



 What is true is the small EGT gauges we use may not be sensitive enough to display the difference and lets face it none of us are flying in -60C so the use of a cold junction is or questionable value.  However no one, other than the man upstairs, will know for sure what the introduction of another four cold junctions will do for the linearity and accuracy of the system as a whole.



 Ref:    Aircraft Instruments, Second Edition, ISBN 0-582-01898-6, E.J.H. Pallett

 Ch. 11, Pg.291

 External Circuit and Resistance

 The external circuit of a thermoelectric indicating system consists of a thermocouple and it's leads, and leads form the junction box at the engine bulkhead to the indicator terminals.  From this point of view, it might therefore be considered as a simple and straight forward electrical instrument system.  However, whereas the latter may be connected up by means of the appropriate copper leads or cable normally used in aircraft, it is not acceptable to do so in a thermoelectric system.

 This may be explained by taking the case of a copper/constantan thermocouple which is to be connected to a cylinder-head temperature indicator.  If a length of normal twin-core cable is connected to the thermocouple terminal box, the one copper lead will be joined to it's thermocouple partner, but the other one will be joined to the constantan lead.  It is thus apparent that the joining of two dissimilar metals introduces another effective hot junction which will respond to temperature changes at the junction box, and in unbalancing the temperature/e.m.f. will cause the indicator readings to be in error.  Similarly, all terminal connections which may be necessary for routing the leads through the aircraft and connections at the indicator itself will create additional hot junctions and so aggravate indicator errors.

 In order to eliminate those hot junctions, it is the practice to use leads made of the same materials as the thermocouple itself, such leads being known as extension leads.  It is sometimes the practice also to use thermocouple materials having similar thermoelectric characteristics in combination; for example, a chromel/alumel thermocouple may be joined to it's indicator by copper/constantan leads, known as compensating leads.  These leads not only compensate for parasitic effects but also reduce the cost as chromel/alumel is expensive.



 There is more going into consistency of resistance to the system but I think you get the idea.

 As anyone who has read my posts will know there will probably be enough typos in here to qualify me into the non-typist pool... I apologize for typo errors that may occur as I transposed this myself.



 



 Long and short is it may work, after a fashion, with speaker or telephone copper wire extensions wired in, but it is in no way right or proper.



 

 [img]cid:7.1.0.9.0.20070628230350.01e48f20(at)sisna.com.1[/img]  



 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)



 Archive this one



 

 



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Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Fri Jun 29, 2007 8:41 am Post subject: EGT mal function

Let's see... Westach, eh.(just practicing 2  days from Canada day)  Isn't that the company that manufactured the great  tachometers that everyone has been having problems with??  The harness with  my EGTs (Westach) were long enough to require some shortening.  It could  have been a problem if I had a pusher style plane.  The units are of such  high calibre that a quarter turn of one of the probes corrected a 40 degree  mismatch in EGT readings. 



Never the less if you want to avoid  problems, do it right.  If that means getting the correct wire  (chromel/alumel)  to connect the instrument so be it.



There is a  strong point to be made that even a poor EGT is preferable to none.  Let's  face it we are only looking for temperature trends at this level.  When an  uncalibrated, uncompensated instrument featuring several additional hot  junctions of unknown value and a harness resistance of un known value reads 950F  are you really willing to accept that until you check your plugs and verify that  in fact it's probably closed to 1100F.



I stand by my experience and training in this particular  topic.



 

[img]cid:679392916(at)29062007-0D5F[/img]  

 Noel Loveys, RPP, AME intern

 Campbellton, Newfoundland, 

 Canada

 Kitfox Mod III-A, 582, B box, Ivo IFA

 Aerocet 1100s

 noelloveys(at)yahoo.ca (noelloveys(at)yahoo.ca)

 

 

 



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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

lcfitt(at)sbcglobal.net
Guest

Posted: Fri Jun 29, 2007 12:25 pm Post subject: EGT mal function

Nope!



Lowell

---

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