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Permalink Reply by Rich Astley on April 20, 2022 at 8:25pm

I double checked with the ferry pilot and he stated that the indicated altitude matched his EFB.

I'm wondering if the Enigma uses another sensor or way of getting altitude data?

I cant fly right now as I'm ironing out a few other quirks - and the weather is bad.

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Permalink Reply by Bob Simmons on April 20, 2022 at 8:54pm

I'm no MGL expert, but the Enigma can use two different types of port connections, depending on the type of AOA probe you have installed. They are single port (relative) systems or dual port (differential) systems. I imagine the indications you're seeing are due to the unique attributes involved with your particular installation. You can consult the installation manual (https://support.michiganavionics.com/portal/en/kb/articles/enigma-a...) and the user manual (https://support.michiganavionics.com/portal/en/kb/articles/enigma-a...). If you can't get your answers from there, I'd suggest asking questions on the MGL User Forum (https://mglavionics.co.za/phpBB3/index.php). Sorry I can't help more.

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Permalink Reply by Rich Astley on April 20, 2022 at 9:10pm

Thanks for your reply Bob.

I've been through the manuals but cant seem to make any headway.  I appreciate the link to the MGL forum.

I think I'm missing something here.  The AOA ports are not connected.  I have a pitot and static tube/port under the left week.

I'm wondering if the EFIS can get the altitude date from somewhere else.

This is all fairly new to me.

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Permalink Reply by Bob Simmons on April 20, 2022 at 10:26pm

Technically you can get altitude data from ambient air inside the cockpit for unpressurized, VFR aircraft that don't fly high, and some people actually do that. It would take some exploration and investigation to determine if that's what was done in your plane.

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Permalink Reply by Rich Astley on April 20, 2022 at 10:54pm

I've put a post on the MGL forum.  Hopefully someone over there will be able to shed some light on how the Enigma derives its altitude.

I guess I could hook it up to a 12V battery and drive up mountain to see what happens.

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Permalink Reply by Jerry Latimer on April 21, 2022 at 4:24pm

The airspeed indicator is also attached to the static port.  So when you apply vacuum to the static port the pressure differential between static and pitot increases.  This should show an increase in indicated airspeed.

I have a MGL MX1 but the same applies to my AV30 and my old analog steam gauges.

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Permalink Reply by Rich Astley on April 21, 2022 at 8:52pm

Thanks Jerry,

I tested this this morning.  I sucked on the static port of an analogue ASI and it showed speed.
I hooked up the EFIS to an external battery and drove to elevation.  It worded and was within 30-40 feet of the gps altitude on Foreflight.

Did some high speed taxi tests and the airspeed was working.  It read higher than ground speed on foreflight but that was to be expected with a pretty strong headwind.

Things are starting to come together :)

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