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Wandering Compass

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jim-bean(at)att.net
Guest

Posted: Tue Aug 15, 2006 3:34 pm Post subject: Wandering Compass

all,

I am experiencing large swings in the compass of my RV-8. It is a panel mount, 

not vertical, from Vans. There is nothing really near it that carries 

substantial current, just a G meter and the VOR indicator head. A Garmin 430 is 

about 8 inches away. I have all of my fuses/breakers on the side panels so the 

main panel has little on it with current flow. Could the rollover hoop be 

magnitized? If it is, why doesn't the compass show a constant error rather than 

swinging? Or could the (Chinese) compass just be junk?

Confused

Jim Bean

N99JA 37 hours.

n223rv(at)wolflakeairport
Guest

Posted: Tue Aug 15, 2006 5:37 pm Post subject: Wandering Compass

I have never seen a panel mounted compass that works in an RV.  Mine

would never swing east, no matter what....

The only one I have ever seen work is above panel mount.

-Mike



--

sportav8r(at)gmail.com
Guest

Posted: Tue Aug 15, 2006 7:01 pm Post subject: Wandering Compass

My whiskey compass would swing crazily in response to control stick movements on the ground.. the pax stick was magnetized and too near the compass.  A switch to aluminum tube for the right stick corrected this.  I have no clue why Van supplies steel for this part when aluminum seems plenty robust for the task and is lighter and nonmagnetic.  I plan to replace the pilot's stick with aluminum one day, if I can locate proper OD tubing - haven't bothered to look for it yet.  Look after the ounces and the pounds take care of themselves... 



-Stormy



On 8/15/06, jim-bean(at)att.net (jim-bean(at)att.net) <jim-bean(at)att.net (jim-bean(at)att.net)> wrote: [quote]--> RV-List message posted by: jim-bean(at)att.net (jim-bean(at)att.net) 



all,

I am experiencing large swings in the compass of my RV-8. It is a panel mount,

not vertical, from Vans. There is nothing really near it that carries

substantial current, just a G meter and the VOR indicator head. A Garmin 430 is 

about 8 inches away. I have all of my fuses/breakers on the side panels so the

main panel has little on it with current flow. Could the rollover hoop be

magnitized? If it is, why doesn't the compass show a constant error rather than 



[b]

FLYaDIVE(at)aol.com
Guest

Posted: Tue Aug 15, 2006 11:57 pm Post subject: Wandering Compass

In a message dated 8/15/06 7:38:08 PM Eastern Daylight Time, jim-bean(at)att.net 

writes:



 	  Quote: 	
		   all,

  I am experiencing large swings in the compass of my RV-8. It is a panel 

 mount, not vertical, from Vans. There is nothing really near it that 

carries 
	


 	  Quote: 	
		    substantial current, just a G meter and the VOR indicator head. A Garmin 

430 
	


 	  Quote: 	
		   is about 8 inches away. I have all of my fuses/breakers on the side panels 

so 
	


 	  Quote: 	
		   the main panel has little on it with current flow. Could the rollover hoop 

be 
	


 	  Quote: 	
		    magnitized? If it is, why doesn't the compass show a constant error rather 

 than swinging? Or could the (Chinese) compass just be junk?

  Confused

  Jim Bean

  N99JA 37 hours.

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


Jim:



The Chinese invented the compass, except way back then it was a South seeking 

instead of North.  Maybe it is trying to revert back to its ancestry?



A simple check for electromagnetic fields can be done by starting the engine, 

then shut off the Master and ALL circuits.  Then one item at a time turn it 

on observe the compass and then turn it off.



Did the compass ever work correctly in the installation?



Does the "swings" maintain a constant error?



Have you ever adjusted the "Swing" of the compass?



Get a Good Boy Scout Compass and work it around the panel while going through 

the power ON / Off steps.  It will POINT to the problem area.



Barry

"Chop'd Liver"



"Show them the first time, correct them the second time, kick them the third 

time." 

Yamashiada

Doug Gray

Joined: 10 Jan 2006
Posts: 112
Location: Sydney, Australia

Posted: Wed Aug 16, 2006 12:48 am Post subject: Wandering Compass

Jim,



See if you can get hold of 'growler' I think they are commonly used for

demagnetising starter armatures (SnapOn tools?).  Plug it into the mains

and wave it over all the steel parts.  This will make a huge difference

to the compass performance.



It might be a good idea to remove the compass (and any other

magnetically sensitive items)  before degaussing the steel.



Doug Gray



On Tue, 2006-08-15 at 23:32 +0000, jim-bean(at)att.net wrote:

 	  Quote: 	
		   

 

 all,

 I am experiencing large swings in the compass of my RV-8. It is a panel mount, 

 not vertical, from Vans. There is nothing really near it that carries 

 substantial current, just a G meter and the VOR indicator head. A Garmin 430 is 

 about 8 inches away. I have all of my fuses/breakers on the side panels so the 

 main panel has little on it with current flow. Could the rollover hoop be 

 magnitized? If it is, why doesn't the compass show a constant error rather than 

 swinging? Or could the (Chinese) compass just be junk?

 Confused

 Jim Bean

 N99JA 37 hours.

krhooper(at)gmail.com
Guest

Posted: Wed Aug 16, 2006 4:33 am Post subject: Wandering Compass

An easy way to check for magnetized items is to use a non magnetized steel sewing needle suspended by a thread near all steel parts. If you need to remove a magnetic field, a Weller pistol type soldering gun will do the trick. Just pull the trigger and hold it near the object. It is best to make sure the needle is demagnetized before starting and after it touches any magnetic item. 

  

 Randy Hooper

  

 

 

 On 8/16/06, Doug Gray <dgra1233(at)bigpond.net.au (dgra1233(at)bigpond.net.au)> wrote: [quote]--> RV-List message posted by: Doug Gray <dgra1233(at)bigpond.net.au  (dgra1233(at)bigpond.net.au)>



Jim,



See if you can get hold of 'growler' I think they are commonly used for

demagnetising starter armatures (SnapOn tools?).  Plug it into the mains

and wave it over all the steel parts.  This will make a huge difference 

to the compass performance.



It might be a good idea to remove the compass (and any other

magnetically sensitive items)  before degaussing the steel.



Doug Gray



On Tue, 2006-08-15 at 23:32 +0000,  jim-bean(at)att.net (jim-bean(at)att.net) wrote:

 	  Quote: 	
		   --> RV-List message posted by: jim-bean(at)att.net (jim-bean(at)att.net)



 all,

 I am experiencing large swings in the compass of my RV-8. It is a panel mount, 

 not vertical, from Vans. There is nothing really near it that carries

 substantial current, just a G meter and the VOR indicator head. A Garmin 430 is

 about 8 inches away. I have all of my fuses/breakers on the side panels so the 

 main panel has little on it with current flow. Could the rollover hoop be

 magnitized? If it is, why doesn't the compass show a constant error rather than

 swinging? Or could the (Chinese) compass just be junk? 


	


[b]

sportav8r(at)gmail.com
Guest

Posted: Wed Aug 16, 2006 4:54 am Post subject: Wandering Compass

My compass gave me fits at frirst, due to magnetism in the pax side joystick.  Replacing that piece with aluminum tube cured the compass' tendency to follow the joystick left and right.  Not sure why the joysticks aren't aluminum anyhow; seems amply strong for the task and certainly lighter and nonmagnetic.  What sort of control forces was Van engineering for when he did that, I wonder? 



-Stormy



On 8/16/06, FLYaDIVE(at)aol.com (FLYaDIVE(at)aol.com) <FLYaDIVE(at)aol.com (FLYaDIVE(at)aol.com)> wrote: [quote]--> RV-List message posted by: FLYaDIVE(at)aol.com (FLYaDIVE(at)aol.com) 



In a message dated 8/15/06 7:38:08 PM Eastern Daylight Time, jim-bean(at)att.net (jim-bean(at)att.net)

writes:



 	  Quote: 	
		   all,

  I am experiencing large swings in the compass of my RV-8. It is a panel 

 mount, not vertical, from Vans. There is nothing really near it that

carries
	


 	  Quote: 	
		    substantial current, just a G meter and the VOR indicator head. A Garmin

430
	


 	  Quote: 	
		   is about 8 inches away. I have all of my fuses/breakers on the side panels 

so
	


 	  Quote: 	
		   the main panel has little on it with current flow. Could the rollover hoop

be
	


 	  Quote: 	
		    magnitized? If it is, why doesn't the compass show a constant error rather

 than swinging? Or could the (Chinese) compass just be junk? 

  Confused

  Jim Bean

  N99JA 37 hours.

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


Jim:



The Chinese invented the compass, except way back then it was a South seeking

instead of North.  Maybe it is trying to revert back to its ancestry? 



A simple check for electromagnetic fields can be done by starting the engine,

then shut off the Master and ALL circuits.  Then one item at a time turn it

on observe the compass and then turn it off.



Did the compass ever work correctly in the installation? 



Does the "swings" maintain a constant error?



Have you ever adjusted the "Swing" of the compass?



Get a Good Boy Scout Compass and work it around the panel while going through

the power ON / Off steps.  It will POINT to the problem area.  [quote][b]

khorton01(at)rogers.com
Guest

Posted: Wed Aug 16, 2006 6:04 am Post subject: Wandering Compass

It might be acceptable to replace the passenger stick with an  

aluminum one, but I would be hesitant to do this for the pilot's  

stick.  An aluminum pilot's stick might be OK for normal flight  

conditions, but there have been cases on RVs, and other aircraft,  

where something jams the controls.  In this case, the pilot may need  

to exert a very high force on the stick to overcome the jam.  If the  

stick bends or breaks before the jam is overcome, then this leads to  

an accident.



Kevin Horton

On 16-Aug-06, at 7:53 AM, Bill Boyd wrote:



 	  Quote: 	
		   My compass gave me fits at frirst, due to magnetism in the pax side  

 joystick.  Replacing that piece with aluminum tube cured the  

 compass' tendency to follow the joystick left and right.  Not sure  

 why the joysticks aren't aluminum anyhow; seems amply strong for  

 the task and certainly lighter and nonmagnetic.  What sort of  

 control forces was Van engineering for when he did that, I wonder?

finn.lassen(at)verizon.ne
Guest

Posted: Wed Aug 16, 2006 8:19 am Post subject: Wandering Compass

My guess it's more a point of ease of fabrication. I mean the weldment 

at the bottom.

Now you have too go and make it complicated, splitting the thing into 

two: steel weldment at the bottom and alu stick at the top 



Finn



Bill Boyd wrote:



 	  Quote: 	
		   My compass gave me fits at frirst, due to magnetism in the pax side 

 joystick.  Replacing that piece with aluminum tube cured the compass' 

 tendency to follow the joystick left and right.  Not sure why the 

 joysticks aren't aluminum anyhow; seems amply strong for the task and 

 certainly lighter and nonmagnetic.  What sort of control forces was 

 Van engineering for when he did that, I wonder?



 -Stormy

sportav8r(at)gmail.com
Guest

Posted: Wed Aug 16, 2006 9:19 am Post subject: Wandering Compass

Good thought, Kevin.  My guess is something else in the "drive train" like a bellcrank would give way first, but that's purest speculation on my part. I have no desire to test the elevator or aileron linkages to failure just to see what gives first.  The hardest force I've ever held on the controls in flight was the time my trim control deck left me stuck with inop elevator trim in the landing config and I was in takeoff and cruise mode.  Fought that for 20 minutes with about 15 lbs?? of forward stick force before I gave up and returned to land and fix it at home rather that press on to the destination.  There are no standard flight maneuvers I can think of that call for anywhere near that force in an RV.  My arms were like jell-o when I landed, from isotonic muscle fatigue.  Since I was using a stgeel joystick, I suppose that proves nothing to the present point  



-Stormy



On 8/16/06, Kevin Horton <khorton01(at)rogers.com (khorton01(at)rogers.com)> wrote:[quote] --> RV-List message posted by: Kevin Horton <khorton01(at)rogers.com (khorton01(at)rogers.com)>



It might be acceptable to replace the passenger stick with an

aluminum one, but I would be hesitant to do this for the pilot's 

stick.  An aluminum pilot's stick might be OK for normal flight

conditions, but there have been cases on RVs, and other aircraft,

where something jams the controls.  In this case, the pilot may need

to exert a very high force on the stick to overcome the jam.  If the 

stick bends or breaks before the jam is overcome, then this leads to

an accident.



Kevin Horton

On 16-Aug-06, at 7:53 AM, Bill Boyd wrote:



[quote] My compass gave me fits at frirst, due to magnetism in the pax side 

 joystick.  Replacing that piece with aluminum tube cured the

 compass' tendency to follow the joystick left and right.  Not sure

 why the joysticks aren't aluminum anyhow; seems amply strong for

   	  Quote: 	
		  [b]

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