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Smart Glide

Amadeus

Well Known Member
I have read that standalone G3X Touch Experimental can do Smart Glide with the latest software. Today I attempted to try it out and was 3,500' AGL with an airport less than five miles away. With no traffic in the area I pressed Direct To and held it two seconds and heard the voice alert say there was no airport in range and felt autopilot engage. This is where things went wrong.

Instead of putting the RV-12iS into Best Glide it nosed over into a steep dive while lowering the right wing and making a fast tight turn. The nose then began to rise and wings level before again going into a steep dive with right wing low and another fast and tight right complete turn (this can be seen on FlightAware N112DR).

I tapped the yellow "SmartGlide" strip at the bottom of the touch screen and stopped Smart Glide to hand fly the plane. The stick was heavy and the trim was in full nose down position (despite being told multiple times that autopilot does not change trim setting - but it does) so I corrected the trim setting and hand flew the plane.

After all this I positioned the aircraft one mile from the airport and was 2,000' AGL when I attempted another trial. Again received the voice alert that no airport in range and this time the airplane remained tracking the same direction and slowing to Best Glide and losing altitude. Once again I disconnected Smart Glide, corrected trim setting and hand flew the plane. I gave up the trials for the day and headed back to the airport.

What am I doing wrong? Smart Glide is such an ideal feature and I would love knowing that I could count on the G3X to reduce the immediate workload in an emergency.
 
Does your autopilot otherwise work fine? Have you tested your autopilot by changing speeds, introducing flaps, and changing pitch commands ?
Are you pulling the throttle back to idle prior to introducing smart glide? My airplane climbs instantly when the smart glide button is pressed to get to best glide speed.
 
Smart Glide Configuration

I have read that standalone G3X Touch Experimental can do Smart Glide with the latest software. Today I attempted to try it out and was 3,500' AGL with an airport less than five miles away. With no traffic in the area I pressed Direct To and held it two seconds and heard the voice alert say there was no airport in range and felt autopilot engage. This is where things went wrong.

Instead of putting the RV-12iS into Best Glide it nosed over into a steep dive while lowering the right wing and making a fast tight turn. The nose then began to rise and wings level before again going into a steep dive with right wing low and another fast and tight right complete turn (this can be seen on FlightAware N112DR).

I tapped the yellow "SmartGlide" strip at the bottom of the touch screen and stopped Smart Glide to hand fly the plane. The stick was heavy and the trim was in full nose down position (despite being told multiple times that autopilot does not change trim setting - but it does) so I corrected the trim setting and hand flew the plane.

After all this I positioned the aircraft one mile from the airport and was 2,000' AGL when I attempted another trial. Again received the voice alert that no airport in range and this time the airplane remained tracking the same direction and slowing to Best Glide and losing altitude. Once again I disconnected Smart Glide, corrected trim setting and hand flew the plane. I gave up the trials for the day and headed back to the airport.

What am I doing wrong? Smart Glide is such an ideal feature and I would love knowing that I could count on the G3X to reduce the immediate workload in an emergency.

It sounds like a few items may not be configured correctly. What value do you have entered for Vg?

It is probably best to review all of the associated configuration items, which we can easily do by reviewing a configuration file. With your SD card in the display, boot the system into configuration mode, and select CONFIG . Press the MENU button, and select the export option. Please email that to us at [email protected] and we can take a look at it for you.

If there was an SD card in the display during the flight, a flight data log would have been generated. If there was indeed a card in the display, please send us the datalog from that flight. It is a .CSV file, and the date and time of the flight will be included in the name.

Thanks,

Justin
 
Does your autopilot otherwise work fine? Have you tested your autopilot by changing speeds, introducing flaps, and changing pitch commands ?
Are you pulling the throttle back to idle prior to introducing smart glide? My airplane climbs instantly when the smart glide button is pressed to get to best glide speed.

Autopilot works perfectly and I did throttle back both times before activating Smart Glide. I was expecting to pitch up to reduce airspeed to best glide but instead a nose down attitude is what happened.

I have emailed the flight log and the config export to the G3Xpert so hopefully there is an easy solution. This appears to be such a wonderful feature.
 
Pat i will take b for $200

Sure sounds like the best glide speed and best glide rate of descent, or glide angle, is wrong. It sounds like it thinks the plane is a brick and is trying to fly it accordingly.
I thought the G3X displayed a line within which airports are in the gliding range. does this line show up normally?
 
Sure sounds like the best glide speed and best glide rate of descent, or glide angle, is wrong. It sounds like it thinks the plane is a brick and is trying to fly it accordingly.
I thought the G3X displayed a line within which airports are in the gliding range. does this line show up normally?

The glide distance ring did show an airport within glide range but upon activating the Smart Glide both times it immediately informed me there was not an airport within glide range.
 
R landing sites in Smart Glide

This could be operator error. There are times when I look at the glide ring I see Smart Glide locked onto an airport that's restricted when another airport (Probably easier to find in an emergency) is closer. At first I thought that the restricted one came into glide range earlier and Smart Glide did not change airports but that does not seem to be the case. Picture attached. Is there a way to fix this? I've also seen Smart Glide lock unto Sea Plane bases.
 

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This could be operator error. There are times when I look at the glide ring I see Smart Glide locked onto an airport that's restricted when another airport (Probably easier to find in an emergency) is closer. At first I thought that the restricted one came into glide range earlier and Smart Glide did not change airports but that does not seem to be the case.

This is normal in my experience. If the private airport was the only one in range when you activated Smart Glide, that's where it will take you. If you want to change destinations, use the Direct-To button.

I've also seen Smart Glide lock unto Sea Plane bases.

Sounds like you need to adjust the runway criteria on the Navigation config page.
 
User error ? Runway choices.

Recent cross country. Why would I choose a runway this far away ?
 

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Autopilot works perfectly and I did throttle back both times before activating Smart Glide. I was expecting to pitch up to reduce airspeed to best glide but instead a nose down attitude is what happened.

I have emailed the flight log and the config export to the G3Xpert so hopefully there is an easy solution. This appears to be such a wonderful feature.

Since the thread has been resurrected, I thought I'd ask... did you ever figure out what the issue was with your smart glide function?
 
Since the thread has been resurrected, I thought I'd ask... did you ever figure out what the issue was with your smart glide function?

Yes; user error. Smart Glide works correctly now.

Not sure why it was happening initially but Garmin (really smart and helpful people in the G3Xpert department - so happy to have such great avionics to fly) analyzed the flight log data and autopilot was being manually disconnected. I just make sure to keep hands off the stick and away from the A/P Disconnect button and Smart Glide takes over and performs wonderfully.

At no other time have I ever inadvertently manually disconnected autopilot but the data don't lie.
 
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