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Backup AI replacement


Mark89114

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My standby AI, which I believe is an RC Allen instrument is extremely slow, tumbles around a lot during startup and generally doesn't like getting started, seems to have gotten worse with the cooler weather, meaning 40's, which isn't really cold, but that is another topic.  After spooled up, it works fine.  I had it overhauled about 1.5 years ago by Rudy's Aircraft instruments, lasted about 3 months, pulled it again and Rudy's blamed my low/incorrect vacuum pressure(which was nonsense) and then they claimed there were metal shavings in the inlet screen, which I find doubtful as no work has been done in the 4 years I have owned the airplane.  I am not interested in pulling it a 3rd time and going through the rigmarole of that.  

I want something new and looking at options and available now, not on some forecast release date, ala KI-300, AV-30, Dynon, etc.

Mid Continent Lifesaver - seems to be a good option, but it is $4K+  

Garmin G5 - I have a known ice airplane, which I guess is a sticking point, but I need this as a backup to the KI-256

Dynon D5 - any real world experience?

I like the digital instruments as they will also provide some backup to the traditional 6 pack.  

 

Any other thoughts?  I would like to start the transition away from vacuum pumps.  

Thanks,

Mark

 

 

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1 hour ago, MIm20c said:

Used lifesaver units sell for $500-700. The install would be very fast (cheap). They last a long time. 

not that I am that lazy, but I am....  where have you seen them at this price?  I debate about how to rationally upgrade.  

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Mine did about the same symptoms until it eventually couldn’t drive my Century AP in a straight line and I was stuck hand flying home from FL to TX.  It did turn out to be the Vacuum Pump which had shredded itself internally (hence metal frags on the screen) and was also leaking oil (minor).  Maxwell diagnosed and replaced from an East TX shop nearby. It wasn’t THAT expensive to fix.  Now that there are other excellent options are out there and more coming, I am planning for a non-vacuum fix in the future if either the ADI or vacuum pump act up again with all money going towards modern options.

Your options will likely be a decision tree of goals and interconnected systems.  The Dynon etc. will be a great economically positioned option in a stand alone requirement that isn’t connected to an incompatible AP.  My AP is fed from my ADI and has rules for compatible sources.  If you have a great long term AP today and can use an Aspen or similar to replace the AP signals, then that compatibility will give you a few options to consider.  If you need to drive a brand new AP upgrade and, for instance, if you want a GFC500, you need a Garmin G5.  If you are looking at the Bendix King as a future path, another set of options exist.  TruTrak...other options.

I’m dialing in my end goal, which is a replacement for my Century 21 AP to fly coupled approaches with altitude hold and GS capture.  That limits my options, but at least it narrows the field to something I can quickly validate or invalidate.  Since it’s been 7 years since Rudy’s fixed up my ADI and 3 years since my vacuum pump was replaced, I’m starting to get ready to have to do something on the gremlins timeline.  

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3 hours ago, Mark89114 said:

Any feedback on D10 versus Garmin G5?  

Thanks for the input.

 

It's going to depend on your final direction.   The D10A is the Back up instrument for the Dynon HDX System.   So it would be cost saved if you are wanting to end up in a Dynon solution.   Which then you bring into what else needs upgrading (engine monitor) and then how long till Dynon A/P (I am guessing 3 years)  Meanwhile the Dynon should be able to drive your A/P with some grey areas of what can connect to what.   If a Dynon is emulating a Garmin 430, is that the same as hooking up your A/P to an actual Garmin 430.

 

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The uVonics AV-20 https://uavionix.com/product/av-20s/ is a 2-1/4" flight timer with built in MEMS attitude indicator.   Agrees very consistently with the vacuum AI in my a/c.   The S model connects into the pitot-static system and an external air temperature probe to provide OAT and TAS (not super accurate in my experience).  It has an AOA sensor that is uncalibratable on a Mooney according to an e-mail I received from the developer (former Aerovonics).   I question whether it can be calibrated in any aircraft.

I like it as a timer.   Having a backup MEMS based AI is really comforting.   It has an internal 30 minute battery backup.

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+1 for having a back-up AI already...

Now...

The current list...  in no particular order...

Unless you are headed for an all Big G solution, or trying to stay with an all BK solution... (this makes additional sense)

  • Dynons are pretty good and getting better... have you seen their PFD lately? So a D1, D2, etc... makes a great BU for this in the future...
  • BK has their AI recently available but has shown some growing pains early on... no word from the company what caused the odd attitude indications yet, or if it has been solved... their AP interface isn’t quite available yet either... PearceBK is the MSer that reports their status...
  • RC Allen has a great history of making independent electric AIs
  • G5s make great instruments if you have gone GTN and other big G devices... lots of air data and other info can be ported to the displays... Sending AI info to the BK AP is going to be important if your G5 s going to be primary along the way...
  • uavionics makes an interesting clock/BU AI... but they added a sensorless AOAi that isn’t quite functional in many Mooneys... The company is in transition to new ownership recently...

All are worth a second look and a fair comparison...

I haven’t seen any reports of G5s not fitting in the panels... as they are going in a lot lately as primary AI and HSI combinations...

As space at the top of the panel gos.... the Moritz were sadly orphaned... and their unfindable sensor replacements are unfindable... Most owners are headed JPI or EI or Insight... or big G G500txi...

PP thoughts only, not an instrument guy...

Best regards,

-a-

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On 12/16/2019 at 10:55 AM, Mark89114 said:

not that I am that lazy, but I am....  where have you seen them at this price?  I debate about how to rationally upgrade.  

This was a good one. It sold for $295.00. 

https://www.ebay.com/itm/R-C-ALLEN-Electric-AI-Attitude-Gyro-RCA26BK-6-28V/223762507841?pageci=5d632bbe-e551-4349-983b-f6667b478e52

But I would strongly suggest you get at the least a solid state replacement gyro.  

Perhaps something like this?

https://www.ebay.com/itm/R-C-ALLEN-RCA2600-3-3-Digital-Electric-Attitude-Indicator/143478843440?hash=item2168016830:g:thkAAOSwC-5ds0XJ 

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16 hours ago, Jerry 5TJ said:

I got the RC Allen digital and battery backup to replace my old electric backup AI that had no battery. Per AC whatever I also moved it to the TC location with an Inclinometer. Then my JPI got the old AI spot.

No idea how it flies, but it sure looks pretty. Only headache was finding a place to secure the battery as it's not small, ended up ordering a longer harness for it.

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