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H920 lost connection (fly-away)

DoomMeister

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How many batteries did you have installed for the flight?

Are they original OEM 6S 4000nAh batteries?

Are you using the A10 charger?

I’m asking because the voltage at startup was only 24.8V and should have been at 25.2V.
 
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How many batteries did you have installed for the flight?

Are they original OEM 6S 4000nAh batteries?

Are you using the A10 charger?

I’m asking because the voltage at startup was only 24.8V and should have been at 25.2V.

I have installed 3 batteries before the flight. It must be noted that I did not fly immediately after I turned on the drone. Before the flight, I tried to connect ST12 as fly operator, and ST24 as camera operator. This took quite some time and was not successful. In other words, drone was ON, with camera and gimble OF for quite some time (approx. 10 - 15 min). Could this drained batteries from full to 24.8V. Also, although I charged batteries fully before the flight, I did not check their voltage prior the flight with added voltmeter (as recommended in the manual).

All batteries are (2 of them came with drone, another 6 I bought) Yuneec YUNVC100 Power 6, 8C, 4000mAh, 6s/22.2v 89Wh.

I used A10 charge (the one which came with H920) to charge batteries as demonstrated on youtube.

The one thing that I do remember quite well, is that H920 battery, displayed on ST24, was shown to be full, when the fly away happened. Battery is one thing that I am paranoid about. For this reason, I look for battery indicator more frequently, than taking care of satellite number, or any other parameter..
 

DoomMeister

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Thanks @skorius.

The time spent trying to bind to the ST-12 could very well have amounted to the much voltage drop. So that mystery is solved there.

This is actually the first chance I’ve had to analyze telemetry from the H920. There are a few things that don’t show up in the program we use (Q500log2kml by one of our members @h-elsner) like status of circuitry such as IMU and GPS.

The error flags may be different also. We do not see any low battery alarms, yet the aircraft self landed after loss of connection. There may be options in the software that determine the aircraft’s actions under those circumstances.

We will continue to learn as we go forward.
 
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h-elsner

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Kurze Zusammenfassung: GPS manuell ausgeschaltet, vom Wind abgetrieben.
ScreenshotSchnellanalyse_1.png
There were some dropouts on the RC-connection but very short, 2-4sec. The drone was controllable all the time.
At 21:24:10 there was a short GPS loss for 2sec. Reason unknown.
At 21:24:16 the GPS was switched off by switch (9) on ST24. Speed increases without any stick input up to ~6m/s. The drone keeps this speed with some variations due to stick inputs until the end. So, I think it is wind speed and it fairly looks like that.
21:25:50 landing looks like a normal manual landing, motors switched off by arming button (Trottle=0 for more than 3sec). At this point the best what the pilot could do - and success.

Here are the minor dropouts (red pins means received telemetry data):
Diagramm_für_altitude_01.png

RC controls working, drone reacts as expected:
Throttle.png Pitch.png Roll.png yaw.png
The flight track:
KMLtrack.jpg

How the pilot moves towards the drone:
Pilot_moves.png

br HE

PS: Kopf hoch, weitermachen. Alleine der Sound vom H920 ist geil.
 

Steve Carr

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@skorius It would be beneficial if you did another test flight (w/o the camera). This time make sure both antennas on the ST24 are pointed straight up. Keep the rabbit/turtle rate slider in rabbit. Pay attention to voltage and sat count. Make sure you keep the GPS switch turned ON. Keep the top of the ST24 open to the sky so it can see the sats. It would help to compare the logs with a new flight.
 
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Kurze Zusammenfassung: GPS manuell ausgeschaltet, vom Wind abgetrieben.
View attachment 21003
There were some dropouts on the RC-connection but very short, 2-4sec. The drone was controllable all the time.
At 21:24:10 there was a short GPS loss for 2sec. Reason unknown.
At 21:24:16 the GPS was switched off by switch (9) on ST24. Speed increases without any stick input up to ~6m/s. The drone keeps this speed with some variations due to stick inputs until the end. So, I think it is wind speed and it fairly looks like that.
21:25:50 landing looks like a normal manual landing, motors switched off by arming button (Trottle=0 for more than 3sec). At this point the best what the pilot could do - and success.

Here are the minor dropouts (red pins means received telemetry data):
View attachment 20998

RC controls working, drone reacts as expected:
View attachment 21001 View attachment 20999 View attachment 21000 View attachment 21002
The flight track:
View attachment 21005

How the pilot moves towards the drone:
View attachment 21004

br HE

PS: Kopf hoch, weitermachen. Alleine der Sound vom H920 ist geil.
Dear HE,

thank you for this information! The terror cascaded from the point when I first lost GPS signal (first GPS lost, highest drone altitude). From the moment when I visually noticed drone flying to the side, I panicked and start running towards the drone, always looking up, and never to the ST24. Couple of times I tried to control drone with right ST24 controller (fly the drone backwards towards me), however I did not visually notice it to react. Then, while running, I tried to turn ON RTH, however, it is very likely that instead of S4, I turned S3 all the way down, which would be TURN GPS OFF, instead of RTH... What I do remember quite well, is that while running I was holding left ST24 controller down, which should have brought drone DOWN. It seems that it did work (drone from the highest point while flying was descending), but it did quite slow.
When drone descended into bushes (I did not see it anymore), I pressed rotor stopping button on ST24, which then stopped the rotors.

So, more and more this fly away accident appears to be my antenna arranging and panic error.
Thank you for all your efforts in trying to explain what happened!
 
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@skorius It would be beneficial if you did another test flight (w/o the camera). This time make sure both antennas on the ST24 are pointed straight up. Keep the rabbit/turtle rate slider in rabbit. Pay attention to voltage and sat count. Make sure you keep the GPS switch turned ON. Keep the top of the ST24 open to the sky so it can see the sats. It would help to compare the logs with a new flight.
Right, Steve. Will do that!
 
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One remark: The stick movements of all sticks are limited to 54%. That means your gight slider was set to turtle mode. This may explain the reluctant reaction from the drone.

Gruß HE
HE, correct. I moved rate knob towards turtle mode. However, before "fly away" drone was both climbing and descending reasonably fast. That is, much faster than when it was descending while "flying away". In the coming days, I will try to find empty field to make more flights.

Thanks!
 
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Dear all,

Today I was able to fly H920 once again. I did 2 flights: 1) 3 batteries no camera; 2) 3 batteries with camera. The procedure was as follows:

1. I started ST24, waited for it to boot. At the same time I took H920 out of car, fixed the arms and found the flat place for it.
2. Turned H920 on (without camera), however, noticed that ST24 screen went black, and did not respond to touching.
3. Turned H920 off.
4. Restarted ST24, waited for it to boot, then immediately started H920.
5. Did binding procedure. Everything went smooth.
6. Waited until satellite number for both ST24 and H920 did not increase anymore.
7. Flipped antenna 90 degrees to ST24 screen.

All went fine.

After battery indicator droped by two possitions, I restated everything with camera on.

Attached is the FlightLog.

Sincerely,

Simonas
 

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Steve Carr

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It appears to be a routine flights. The signal strength does appear to drop off at a distance but that may normal.
What is the structure you were flying near?
 
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It appears to be a routine flights. The signal strength does appear to drop off at a distance but that may normal.
What is the structure you were flying near?
Steve, good question... When I went there, first I thought it was some kind watering system (from the distance it looked like that). However, now when I looked from Google Earth, it seems more **** frightening... I spent there some 30 to 40 min. Several people passed me on their way for a walk. No one said anything whether it is allowed to play there with drone or not...

I found an app (DFS Deutsche Flugsicherung GmbH), thus next time, will be more careful.

Also, will drive there just to check, what is that structure.
 
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Ohh, that thing I have overlooked. Good point.
This is a VHF Omnidirectional Radio Range (VOR): VOR/DME LEG (115,85MHz, CH105y). Too low frequency to disturb 2.4GHz.
View attachment 21075

br HE
To your knowledge, was I committing a crime flying around there? Could I return there for future flights? The place is actually very nice. The space is open with no obstacles (appart that VOR).
 
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To your knowledge, was I committing a crime flying around there? Could I return there for future flights? The place is actually very nice. The space is open with no obstacles (appart that VOR).
You are in Germany? Your question indicates you should immediatley read into existing drone laws and keep your hands far far away from the 920. Hint: read into weight classes for drones.
 
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You are in Germany? Your question indicates you should immediatley read into existing drone laws and keep your hands far far away from the 920. Hint: read into weight classes for drones.
Yes, I am working in Germany (Leipzig). I have red DFS Drone Check points (see attachment). As of now, I never fly anywhere else but in the wide wide open fields, with neither people, nor property to be damaged around. I intend to use drone for air quality research (at institute that I am working in). But to do that, I must first to know how to at least lift drone from the ground. Also, I will be getting license, so I do not want to go to exam without even trying to fly the drone. So no, I do not think I will keep my hands far far away from the 920. Thanks for the hint though, I am aware of it. With that being said, all flights that we do for research (e.g. tethered balloons) are agreed with appropriate local authorities. Future H920 flights will not be an exception. However, just for now, its learning stage by practice...
 

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Yes, I am working in Germany (Leipzig). I have red DFS Drone Check points (see attachment). As of now, I never fly anywhere else but in the wide wide open fields, with neither people, nor property to be damaged around. I intend to use drone for air quality research (at institute that I am working in). But to do that, I must first to know how to at least lift drone from the ground. Also, I will be getting license, so I do not want to go to exam without even trying to fly the drone. So no, I do not think I will keep my hands far far away from the 920. Thanks for the hint though, I am aware of it. With that being said, all flights that we do for research (e.g. tethered balloons) are agreed with appropriate local authorities. Future H920 flights will not be an exception. However, just for now, its learning stage by practice...
To close this debate from my side: The 920 with camera is more than 5Kg which by law you need the drone pilot license (more than 2kg) to fly and a flight permission by state authorities (more than 5kg) for your specific model plus an insurance for your drone. Violation of airspace rules with a multicopter is up to 5 years in prison and/or a 50000 Euro fee. Of course you can decide if you are going to continue "practicing" with a 920 in an area with several airports around of which you need to keep 1,5 km distance and have restricted airspace around them. But you are aware of those rules for sure.
The 920 here is sold by pro shops with the added remark : "We only sell this drone with an onside introduction". Go figure.
 

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