Compass position

[danny_galaga]

Thinking of using a panel mount compass in my instrument panel. The design is not set in stone yet but there will be limited room in the centre due to allowing space for an iPad. Is there much issue with the compass being off to one side? My thought is no because the difference in degrees between magnetic north and one side of the plane or the other is minuscule .  Am I on the right track?

 

i will of course have to bear in mind anything magnetic in front of th compass but that’s a given in any case.

 

 

[Yenn]

It doesn't much matter where you put it, so long as you can set it correctly. The other point to watch is that you have to be able to see it.

 

Possibly seeing it isn't so important nowadays as we tend to use electronic gizmos to show our ground track. I can't remember when I last set a gyro to match the compass.

 

 

[pmccarthy]

With no bug on the gyro, I set it so North is my heading. Works for me.

 

 

[Peter Anson]

Don't forget that the ipad you are going to place near the compass also has a magnetic field.  I just checked my own ipad near a compass and it deflected the needle by up to 60 degrees.  Makes me feel justified in being too lazy to build a decent mount for it on the panel.

 

Peter

 

 

[danny_galaga]

Hadn’t thought of that! How close was the iPad when it started to deflect? Maybe I’ll have to go with the compass mounted on top instead. Panel was just because it would look neater. But if it’s not going to work properly it would be useless anyway!

 

 

[peter]

what is the legal requirement for a compass? I never use a magnetic compass anymore. they are prone to a multitude of errors and in my incredibly simple layout I have garmin GPS, ipad GPS, iphone GPS and I'm flying VFR so I can just look out the windscreen. My iphone  and garmin etrex both have magnetic compass built in. That provides about 5 layers of redundancy with out a fitted/dedicated compass. Aren't we about simple flying?

 

Peter

 

 

[Peter Anson]

I tried two things.  My ipad has a folding lid cover which incorporates a couple of magnets in the lid.  In the right position it can really muck up a compass readings (180 degrees error) so I also tried it without the cover attached. The ipad itself parked about 100mm from the compass will deflect the needle by 10 degrees - obviously enough to get you lost.  Have to admit that I rarely use my compass, only as a check and backup to the GPS bearing shown on my phone.

 

Another Peter

 

 

[danny_galaga]

what is the legal requirement for a compass? I never use a magnetic compass anymore. they are prone to a multitude of errors and in my incredibly simple layout I have garmin GPS, ipad GPS, iphone GPS and I'm flying VFR so I can just look out the windscreen. My iphone  and garmin etrex both have magnetic compass built in. That provides about 5 layers of redundancy with out a fitted/dedicated compass. Aren't we about simple flying?Peter

Well yes, I want simple flying. Can’t get much simpler than a compass . There is going to be quite a bit of flying where I can just keep the iPad stowed away. Would still be nice to know the general direction I’m headed  

 

 

[peter]

Actually a magnetic compass is not that simple, you need to accurately swing the compass , which needs to be done with the engine running at various speeds and on a range of headings. Where you position it can be critical. Hence the development of gyroscopic heading devices. An accurate magnetic compass is expensive. A compass provides heading but not track. A 100 dollar Garmin etrex will give accurate track, can be mounted easily, (just needs to “see” the sky). It needs no ongoing adjustment.

 

Cheers Peter

 

 

[danny_galaga]

Just checked out the etrex. That’s a pretty cheap ‘piece of mind’ device  will probably keep one of those stashed away since it can go 25 hours on two AA batteries  

 

But I will still mount a compass  

 

 

[peter]

Go for it! At least with the etrex around you can monitor the lack of accuracy of your magnetic compass!

 

My etrex is 16 years old and has guided me safely through white outs in Antarctica and heavy fog in the Arctic, places where magnetic variation can be as much as 80degrees, as well as all my flying here in Oz so I'm pretty biased.

 

Have you swung a compass before?

 

Cheers Peter

 

PS congrats on the build and keep us updated 

 

PPS don't believe the 25 hours, depends on screen settings and ambient temp, spare batteries are pretty cheap

 

PPPs having a GPS continuously tracking where you came from is also pretty comforting when dodging showers which is why I like to have the phone GPS as well!

 

 

[spacesailor]

Hi Peter.

 

Which model of etrex is yours. A quick check of ebay shows different models.

 

spacesailor

 

 

[peter]

The yellow one is the original and still works perfectly but I wanted to go hi tech with a colour screen hence the new one. The new one also has built in magnetic compass,

 

cheers Peter