electric attitude indicator question

[DKirkpatrick]

Mornin' — making some panel changes and avionics upgrades to an older Cessna 172D. Want to put in an electric AI in this 14VDC airplane.

1. So, do I need to find a 14V indicator? Or can a newer indicator from a 28VDC be configured to work?
2. should I buy a new battery for the installation while the panel's out for work? They're pricey...
3. Anyone have one they have flown behind and really works well, reliable, etc? Mid-Continent units look pretty rock solid.

Don't want to put in a new G5, etc., by the way.
Coaching appreciated.
dan

 

[flyingron]

You do know that electric attitude indicators are very pricey? By the time you get done, you probably have a good chunk of the G5 money (or a uAvionix version).

Most electric AIs I've seen are NOT dual voltage. If you have a 14V plane you either get a 14V attitude indicator or get a 14->28V converter. I still have one of those stuck to my firewall when I had the 28V beechcraft engine instruments in my 14V Navion. Again, that will add about $200 to the price just for the converter. Needs about 1.5A for most.

Midcontiennt makes a flexible voltage AI, but as I said, it's close to $3000.

 

[Lndwarrior]

Electric AI use very little power. I wouldn't upgrade the battery for that reason alone, if that is what you were questioning. Check the Amp draw for the model you are considering.

 

[Bell206]

do I need to find a 14V indicator? Or can a newer indicator from a 28VDC be configured to work?

It depends on the indicator. Some are 10v-32v and some require selecting the system voltage. If possible you don't want to get into converting voltages.

should I buy a new battery for the installation while the panel's out for work? They're pricey...

I take it your replacing a vacuum AI? If so, depends on what reference you'll use to install the electric AI and battery requirements. If using the FAA policy statement guidance there is a provision to use the aircraft battery provided you can determine its charge state prior to takeoff and have the AI supplied direct off the battery bus. If using a different reference you have to follow it.

Anyone have one they have flown behind and really works well, reliable, etc? Mid-Continent units look pretty rock solid.

I've installed several RC Allen 2600 series AI with no reports of problems. There's also the used route especially for the Mid-Con AI units as they get replaced with digital displays/PFDs. You can save some big bucks on a good, used Mid-Con provided you have someone with experience to handle this for you when calling shops, etc.

 

[bradg33]

(1) If you're flying the plane IFR, I wouldn't want to fly behind an electric AI that doesn't have it's own independent battery backup. Tied directly to the main AC battery wouldn't do it for me, I want the instrument to have its own dedicated battery.

(2) The RC Allen units are expensive. Probably, all in, more than a G5 or AV-30C, if you get a battery backup for it. Install might be a little easier (no pitot/static), but it's also got less functionality.

 

[DKirkpatrick]

thanks for the intel. Yes, planning on the battery backup for the unit... how long do these last before they need to be changed?
Not planning on getting totally away from the vacuum, just need to replace the AI and found some good looking Mid Con equipment, with battery, with a not-very-long warranty for 600 to 1000. that price for a good IFR electric ai is looking pretty attractive.
appreciate the help with this. I don't read up on electric attitude indicators for fun... and this real world info is really helpful.
dan

 

[bradg33]

thanks for the intel. Yes, planning on the battery backup for the unit... how long do these last before they need to be changed?
Not planning on getting totally away from the vacuum, just need to replace the AI and found some good looking Mid Con equipment, with battery, with a not-very-long warranty for 600 to 1000. that price for a good IFR electric ai is looking pretty attractive.
appreciate the help with this. I don't read up on electric attitude indicators for fun... and this real world info is really helpful.
dan

I hear what you're saying, but IMHO, the attitude indicator isn't a place to save money in an IFR airplane. $1k for a used mid-continent one, or $3k for a G5 or AV30C (installed)? The latter is well-worth the extra money, in my opinion.