G5 Garmin in lieu of gyros.

[Echo]

Oh wait, are you serious?

[Echo]

EMP.  That is going to be the issue.

[Echo]

I am a "specialist" for a title at work.  (doesn't mean s$&#)  Don't tell anyone...

[Denis Mexted]

So the AHRS is not a modern fancy and affordable IRS ?

The AH would still remain upright, wouldn't it ?

[T. Peterson]

1 hour ago, Denis Mexted said:

So the AHRS is not a modern fancy and affordable IRS ?

The AH would still remain upright, wouldn't it ?

I have the same question. …..and another similar one. Is the attitude display dependent on GPS working??? When flying west over New Mexico it is not uncommon to lose GPS signal. If the AI requires gps, that’s a disaster in the making. Surely I am missing something in translation.

[RobertGary1]

34 minutes ago, T. Peterson said:

I have the same question. …..and another similar one. Is the attitude display dependent on GPS working??? When flying west over New Mexico it is not uncommon to lose GPS signal. If the AI requires gps, that’s a disaster in the making. Surely I am missing something in translation.

It’s a bit of a logic stretch. AHRS units do require some reference to motion to avoid slewing. They take an airspeed input and if that’s not available they should take gps. That was the 275 dual failure. When airpseed wasn’t available it sometimes didn’t calculate gps correctly and went red X. That’s why gps feed is mandatory for an attitude indicator display in the Garmin approval. 
There is a better tech explanation but that’s probably good enough. 

[rbp]

An AHRD is a solid-state IRU 

 

https://en.m.wikipedia.org/wiki/Vibrating_structure_gyroscope#MEMS_gyroscopes

[EricJ]

Any IRU/IMU/IRS/IMS/AHRS will drift if it doesn't get reference info once in a while.   Gyros do that, too, they just do it in a way that we don't realize it's happening (except DG precession, which gets annoying).

I did some update work on my stratux recently and tried the AI display on my EFB from the cheapie $15 AHRS that the stratux has, which also has a cheapie $20 gps attached.    The AI from the stratux was very solid, I'd be fine keeping that as a backup if needed.   It'd be an interesting experiment to disable the GPS and see how much it drifts, but the way the case is made there's not an easy way to disconnect it on the fly.   Maybe the software would just red-x it if the gps went away, I don't know.

The GPS system has seemed far more reliable than the typical vacuum pump, so I don't think it's unreasonable to rely on AHRS systems that need GPS for drift correction.

[T. Peterson]

17 hours ago, rbp said:

An AHRD is a solid-state IRU 

 

https://en.m.wikipedia.org/wiki/Vibrating_structure_gyroscope#MEMS_gyroscopes

Interesting and informative. In all the big words I didn’t see anything about a gps connection, unless one of those big words was code for gps connection! 
Some folks have used the word “drift”, but to me that indicates a navigation error not gyroscope precession of the AI. I still feel a bit confused, but I am of Swedish descent, so go easy on me!

[McMooney]

So i got a chance to play with the g5's before installation.  I was completely impressed that out of the box without external connections except for the battery, it functions as a fully capable AI.   playing with it while walking around surveying, it didn't seem to drift any.

 

pretty sure a mechanical AI after being jostled and turned upside down a few dozen times,  would've broken.

 

[rbp]

check out the G3X installation manual, chapter 10, which has all the info on the GSU 25 ADAHRS

 https://static.garmincdn.com/pumac/190-01115-01_0K.pdf

[Denis Mexted]

My electrical man dropped by yesterday afternoon and canned the idea of putting it on the avionics shelf behind the back cabin bulkhead. Too close to the battery. He's talking in the wing.

Anyone got a pic's of a wing installation?

[ArtVandelay]

My electrical man dropped by yesterday afternoon and canned the idea of putting it on the avionics shelf behind the back cabin bulkhead. Too close to the battery. He's talking in the wing.
Anyone got a pic's of a wing installation?

Are we talking a shelf for magnetometer or just remote avionics boxes?

[EricJ]

2 hours ago, Denis Mexted said:

My electrical man dropped by yesterday afternoon and canned the idea of putting it on the avionics shelf behind the back cabin bulkhead. Too close to the battery. He's talking in the wing.

Anyone got a pic's of a wing installation?

Most of them seem to wind up in the wing.    I'm not sure why the battery would be an issue.

[EricJ]

3 hours ago, McMooney said:

So i got a chance to play with the g5's before installation.  I was completely impressed that out of the box without external connections except for the battery, it functions as a fully capable AI.   playing with it while walking around surveying, it didn't seem to drift any.

 

pretty sure a mechanical AI after being jostled and turned upside down a few dozen times,  would've broken.

 

The G5 has a pretty good GPS receiver built into it, so even if you lose your GPS navigator, it has a chance to work on its own.   This also allows it to be installed without an external GPS source.   There's a connector on the back for an external passive GPS antenna, but it also has an internal antenna.   Mine will acquire satellites on its own without an external antenna.

So it's possible that yours was using gps without your knowledge.   There is a way on the maintenance/configuration pages to see how many satellites it's tracking.

[Fly Boomer]

3 minutes ago, EricJ said:

The G5 has a pretty good GPS receiver built into it, so even if you lose your GPS navigator, it has a chance to work on its own.   This also allows it to be installed without an external GPS source.   There's a connector on the back for an external passive GPS antenna, but it also has an internal antenna.   Mine will acquire satellites on its own without an external antenna.

Redundant GPS receivers is good, but what about when there is just no usable GPS signal.  I have not experienced it yet, but lots of people have experienced drop outs.  Especially in remote areas.  Theory is that military is jamming for some reason.

[Denis Mexted]

Are we talking a shelf for magnetometer or just remote avionics boxes?

The magnetometer. 

I imagine a shelf would have to be built. Any pics or is there a pre-fabbed one I can purchase?

I'm not sure why the battery would be an issue.

I didn't go into it, but just the concept of mutual inductance and magnetic fields makes my head spin. 

 

[ArtVandelay]

Are we talking a shelf for magnetometer or just remote avionics boxes?
The magnetometer. 
I imagine a shelf would have to be built. Any pics or is there a pre-fabbed one I can purchase?
I'm not sure why the battery would be an issue.
I didn't go into it, but just the concept of mutual inductance and magnetic fields makes my head spin. 
 

I don’t think it would be hard to fabricate it, this is in the tail, back about 2 feet or so from the battery.

[hammdo]

That is how mine is installed…

-Don

[EricJ]

2 hours ago, Fly Boomer said:

Redundant GPS receivers is good, but what about when there is just no usable GPS signal.  I have not experienced it yet, but lots of people have experienced drop outs.  Especially in remote areas.  Theory is that military is jamming for some reason.

The receiver in my stratux will do GPS or GLONASS, so unless they're both down I'm covered.   If they're both down there'll probably be other things to worry about, too. 

[Andy95W]

1 hour ago, Denis Mexted said:

Are we talking a shelf for magnetometer or just remote avionics boxes?

The magnetometer. 

I imagine a shelf would have to be built. Any pics or is there a pre-fabbed one I can purchase?

I'm not sure why the battery would be an issue.

I didn't go into it, but just the concept of mutual inductance and magnetic fields makes my head spin. 

 

This is how I mounted mine, in the right wing.  I fabricated the mount and went to a lot of trouble to get it perfectly aligned and level.  I probably didn’t need to be so careful, one person on this board simply mounted his to the bottom skin of the wing and drilled 4 holes to mount it.  I’m not sure if I agree with that exactly, but it would have saved me about 6 hours of work.

[Ragsf15e]

3 hours ago, EricJ said:

The G5 has a pretty good GPS receiver built into it, so even if you lose your GPS navigator, it has a chance to work on its own.   This also allows it to be installed without an external GPS source.   There's a connector on the back for an external passive GPS antenna, but it also has an internal antenna.   Mine will acquire satellites on its own without an external antenna.

So it's possible that yours was using gps without your knowledge.   There is a way on the maintenance/configuration pages to see how many satellites it's tracking.

Yes, mine works fine without an antenna as well.  There is a selection in the configuration menu that turns the internal gps on/off.  Mine is connected to my 430w and doesn’t have an external antenna, so it’s supposed to be off, however…

the g5 will accept the best gps solution it has available.

I want to say @PT20J asked garmin about this, but I thought they can also use pitot input to help them stay aligned if gps goes out?

[PT20J]

22 hours ago, Ragsf15e said:

Yes, mine works fine without an antenna as well.  There is a selection in the configuration menu that turns the internal gps on/off.  Mine is connected to my 430w and doesn’t have an external antenna, so it’s supposed to be off, however…

the g5 will accept the best gps solution it has available.

I want to say @PT20J asked garmin about this, but I thought they can also use pitot input to help them stay aligned if gps goes out?

I did ask Garmin, but I never got an answer. I believe that when the G5 is configured as a standby for the G3X you cannot configure the G5 internal or external antenna. But, the G3X has a non-WAAS GPS, so that gives me a backup. 

[201Mooniac]

I had asked Garmin when I had the G5 as a backup to my G500TXi.  Since there was really little interface, unlike the G3X, the TXi probably didn't matter.  I was told I could enable the GPS in the G5 while it was also connected to the GTN and that the G5 would use the best GPS fix it got, whether internal or external.  I tested it several times and the G5 was solid on either.  To see how it would work in a GPS denied area, I disabled the G5 internal GPS from the settings menu and then turned off the GTN in flight.  The pitot static input kept the G5 aligned for the 20 mins on flying that I did.  No extreme maneuvers though, just basic turns to navigate my route and fly the pattern.

[Denis Mexted]

Andy95W.

Rippa. Thanks for those pics. Just what I was looking for.