Compass replacement: vertical card?

[PeytonM]

I’ve gone thru a few of those plastic “wet compass” mounts. I just installed my last “virgin” one. (One that’s never been broken and glued, and I’ve broken a few!) New mounts, if you can get one, are over $100!  (Maybe >$150!)

I’m ready for a vertical card, I think. Suggestions please. I have a  24V 1989 J. I presume thery are model-specific. Thank you in advance. 

[0TreeLemur]

In previous Mooney, the DG precession required frequent adjustment.   The vertical card compass was great for that.  The '83 J that we recently bought has a PFD (Aspen) with a magnetic sensor.  I find that now I use the compass a lot less.   Our J has an itty-bitty SIRS compass that works just fine, and isn't as imposing as a vertical card compass.

My 2-cents: If you need a compass to keep your DG set, a vertical card compass is great.   If you have a magnetometer connected to a PFD, you don't need much of a compass.  In that case, the SIRS is more than sufficient.   At almost twice the cost of an Airpath compass, not cheap.  They are very good.

[GeeBee]

I love the SIRS unit. Standard equipment on Airbus. Real quality unit.

 

[EricJ]

3 hours ago, PeytonM said:

I’ve gone thru a few of those plastic “wet compass” mounts. I just installed my last “virgin” one. (One that’s never been broken and glued, and I’ve broken a few!) New mounts, if you can get one, are over $100!  (Maybe >$150!)

I’m ready for a vertical card, I think. Suggestions please. I have a  24V 1989 J. I presume thery are model-specific. Thank you in advance. 

I went through the exact same process;   got tired of others and myself breaking those flimsy plastic mounts and took the opportunity to put in a dry vertical-card compass.   It was easy to swing and has been awesome.

I got this one, and there's a 28V option:

https://www.aircraftspruce.com/catalog/inpages/vertcard_compass3.php

 

Edit:

This mount goes with it for the Mooney center post:

https://www.aircraftspruce.com/catalog/inpages/pacmovmn.php

[MikeOH]

2 hours ago, EricJ said:

I went through the exact same process;   got tired of others and myself breaking those flimsy plastic mounts and took the opportunity to put in a dry vertical-card compass.   It was easy to swing and has been awesome.

I got this one, and there's a 28V option:

https://www.aircraftspruce.com/catalog/inpages/vertcard_compass3.php

 

Edit:

This mount goes with it for the Mooney center post:

https://www.aircraftspruce.com/catalog/inpages/pacmovmn.php

That's the one that came with my plane.  No issues in over 5 years.

[hammdo]

Same here - works well…

-Don

[PeytonM]

I ordered it from Spruce!

[Red Leader]

I would love to upgrade my old Mooney compass but my DG is slaved to my currently installed unit. Is there a compatible new style that will give me the compass card display but keep my DG connected?

[PT20J]

7 hours ago, EricJ said:

I went through the exact same process;   got tired of others and myself breaking those flimsy plastic mounts and took the opportunity to put in a dry vertical-card compass.   It was easy to swing and has been awesome.

I got this one, and there's a 28V option:

https://www.aircraftspruce.com/catalog/inpages/vertcard_compass3.php

 

Edit:

This mount goes with it for the Mooney center post:

https://www.aircraftspruce.com/catalog/inpages/pacmovmn.php

That's the one that I have installed by a previous owner. When I swung the G3X, I swung this one also and was amazed at the accuracy. Most headings were dead on with the worst off by 4 deg. My only gripe is that I wish is was a bit smaller.

[ArtVandelay]

You can always install a panel mounted compass instead.

[Bolter]

5 hours ago, Red Leader said:

I would love to upgrade my old Mooney compass but my DG is slaved to my currently installed unit. Is there a compatible new style that will give me the compass card display but keep my DG connected?

In my Mooney experience with a mid-body, the factory (King) DG was slaved to a magnetometer in the pilot-side wing.  The whiskey compass was just an independent whiskey compass. 

[Pinecone]

I have never heard of a slaved DG slaving to the mag compass.

[Red Leader]

17 hours ago, Bolter said:

In my Mooney experience with a mid-body, the factory (King) DG was slaved to a magnetometer in the pilot-side wing.  The whiskey compass was just an independent whiskey compass. 

Is that how it works? I must've misunderstood what I was told. That's excellent news - I can upgrade my compass!

[Bolter]

6 minutes ago, Red Leader said:

Is that how it works? I must've misunderstood what I was told. That's excellent news - I can upgrade my compass!

One check is to remove the whiskey compass from the steel bar, and you should only see a single 2-wire connector, and that is for the light.  

 

[PeytonM]

Airplane is in Annual, and I just installed the Precision Vertical Card Compass.  (89 J) I have not swung it yet, but it is off by some 30°. Yikes.

I see in their compensation information that “steel framed aircraft- Mooney, Bellanca, etc.” can present compensation problems. Have you had to do anything more than swing it to get it to work? Have you had to resort to their “balancing balls?!”

[1980Mooney]

11 minutes ago, PeytonM said:

Airplane is in Annual, and I just installed the Precision Vertical Card Compass.  (89 J) I have not swung it yet, but it is off by some 30°. Yikes.

I see in their compensation information that “steel framed aircraft- Mooney, Bellanca, etc.” can present compensation problems. Have you had to do anything more than swing it to get it to work? Have you had to resort to their “balancing balls?!”

It needs vibration to work.  They should have given you a brass flat blade for adjusting.  

I don't need the balancing balls.

[T. Peterson]

19 minutes ago, PeytonM said:

Airplane is in Annual, and I just installed the Precision Vertical Card Compass.  (89 J) I have not swung it yet, but it is off by some 30°. Yikes.

I see in their compensation information that “steel framed aircraft- Mooney, Bellanca, etc.” can present compensation problems. Have you had to do anything more than swing it to get it to work? Have you had to resort to their “balancing balls?!”

This is why I don’t work on my own airplane! There is no such thing as an easy project. If I worked on my plane it would probably look like the set from the television series Sanford and Son and be just as airworthy!

[EricJ]

1 hour ago, PeytonM said:

Airplane is in Annual, and I just installed the Precision Vertical Card Compass.  (89 J) I have not swung it yet, but it is off by some 30°. Yikes.

I see in their compensation information that “steel framed aircraft- Mooney, Bellanca, etc.” can present compensation problems. Have you had to do anything more than swing it to get it to work? Have you had to resort to their “balancing balls?!”

Get it away from the airplane (and other things) to see whether the compass is off or there is something in the vicinity of the airplane that is influencing it.    It should be swung mounted with the engine running and all the radios on, so those are the conditions that really matter.

The center post on a J is stainless, so it is unlikely that the rest of the cage is magnetized enough to disturb the compass that much.

Mine took very, very little adjustment to swing.   It was nearly spot-on right out of the box.

[1980Mooney]

21 minutes ago, 1980Mooney said:

It needs vibration to work.  They should have given you a brass flat blade for adjusting.  

I don't need the balancing balls.

I assume you purchased the Mooney specific approximately 45° angle mount that attaches to the center bar. It was likely sent preassembled. Although you can’t see it there is a foam cushion (slightly narrower than a postage stamp) between the center bracket and the bracket attached to the front of the compass. It allows some vibration, but not too much vibration, to shake the compass. 
 

Over time, and faster in warm climates, that cushion will compress losing all dampening. With too much vibration, the compass will start to precess. The fix is to replace the cushion which only costs a couple dollars.  Over 20+ years, I’ve replaced the cushion twice on my vertical card compass.  Luckily for me just went over to the little shop where it is assembled- near the 1940 Hobby Airport Terminal building. 
 

 

[Z W]

Thanks for posting this.  My old whisky compass on the windshield post has started swinging 30 degrees off at most times.  I had been wondering how that simple device could fail.  A new cushion would be an easy fix to try.