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Typhoon H Crash - suddenly lost control - GPS false to true

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Hello,
Can anyone help out to analyze what went wrong with my Typhoon H when it crashed today.
I was flying it without GPS mode as I usually do (have had some problem with GPS mode earlier).
After a couple of minutes it suddenly started to wobble and shake. It went straight down by itself and crashed against the roof of a building.
When I looked in the Telemetry file, the only strange thing I could find was that the GPS_used parameter changed from FALSE to TRUE a couple of times and also just when it went down. Anyone knows why this is and why it changed even if I did not change anything in regards to the GPS setting.

I attached the Telemetry file if someone can take a look and give me some advice. I hope this could be a warranty issue.

//Lars
 

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Steve Carr

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Hello,
Can anyone help out to analyze what went wrong with my Typhoon H when it crashed today.
I was flying it without GPS mode as I usually do (have had some problem with GPS mode earlier).
After a couple of minutes it suddenly started to wobble and shake. It went straight down by itself and crashed against the roof of a building.
When I looked in the Telemetry file, the only strange thing I could find was that the GPS_used parameter changed from FALSE to TRUE a couple of times and also just when it went down. Anyone knows why this is and why it changed even if I did not change anything in regards to the GPS setting.
I attached the Telemetry file if someone can take a look and give me some advice. I hope this could be a warranty issue.
//Lars
I can take a look later today but I need the telemetry file and remote file from flight 00074. Please just add a .txt to the end of each file name to upload them.
 
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...and here is the Remote file also.
Thanks for your help!

I realize also that the Error flag indicated that the battery went down to 14,3V (but I never got this warning on the display). Right after that the GPS_used went from FALSE to TRUE and GPS_status turned to 1 from 0.

//Lars
 

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Lars,
I apologize, as I can not find my Telemetry cheat sheet.
I see where the battery voltage increased (page 74 of your file) from 14.2 to 15.0 right about the time your GPS went from False to true.
Can you upload the raw Telemetry file please.
Just change the extension from .CSV to .TXT do nothing else to the file. Upload it here then we can put it into programs to better look at things.

Bob

Opps Steve beat me to it.
 
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Bob,
I added both the raw files for Telemetry as well as the Remote file. Hope they can be read.

//Lars
 

Steve Carr

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It's often difficult to determine what causes a problem with a flight unless there is a very obvious fault of some type. I see no faults in the telemetry. The GPS status doesn't change until after the H touches down so I see no issue with it.

I can only speculate on the cause. The flight is only about 8 min but there are a lot of maneuvers and fairly fast flying. Over 9000' is traveled in that short time and there is one landing mid flight and another launch all on the same battery. The first low battery warning actually came on twice, the second near the end of the flight while the speed of the aircraft is increasing and the pitch is 34 degrees. That final maneuver would consume significant power but the battery is so low at that point that it cannot supply enough amperage to sustain that airspeed. When the battery reaches 14.2 volts and the pitch is 38 degrees the motors essentially shut down.

I would conclude the flight ended because the aircraft was too far from the landing zone with insufficient battery power to make it back. If you had gone to a slow descent with slow airspeed to an alternate landing location the H would have likely landed intact.

I would submit your telemetry to Yuneec. They may come up with a different conclusion.
 
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Thanks Steve!
I will check with Yuneec, to see what they have to say.
Strange is that I did not get any battery warnings.
//Lars
 
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Steve Carr

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Thanks Steve!
I will check with Yuneec, to see what they have to say.
Strange is that I did not get any battery warnings.
//Lars
I don't know how long the warning in the telemetry has to be before it triggers the alarm on the ST16. It's possible it wasn't quite long enough. I have developed a habit of being close to home when the battery is 14.8 volts. The voltage can go down quickly after that.
 
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Thanks Steve,
I lost my sheet I had that explained the various flight modes.
I was surprised when I see where the aircraft went into GPS on mode, at the same time the battery shows an increase in voltage by almost a whole volt. The one and only time I forced my H into a low battery "Auto Land" it pretty much came straight down and landed, no drifting or noticeable flight to a different location.
 

Steve Carr

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Thanks Steve,
I lost my sheet I had that explained the various flight modes.
I was surprised when I see where the aircraft went into GPS on mode, at the same time the battery shows an increase in voltage by almost a whole volt. The one and only time I forced my H into a low battery "Auto Land" it pretty much came straight down and landed, no drifting or noticeable flight to a different location.
The GPS went to True at the same time the flight mode went to 12 which is motor shut down after a crash. Since the motors are off at that point the voltage will rebound.
 
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Because each cell is not monitored separately, all it takes is one cell to dip to 3v (or close to it) and that's enough to cause a crash. A hard throttle can do that if one cell is weaker than the rest. If you look inside the battery bay, the designers definitely thought about smart monitoring but didn't follow through. It wouldn't have increased the cost of the battery one dime.
 

Steve Carr

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Because each cell is not monitored separately, all it takes is one cell to dip to 3v (or close to it) and that's enough to cause a crash. A hard throttle can do that if one cell is weaker than the rest. If you look inside the battery bay, the designers definitely thought about smart monitoring but didn't follow through. It wouldn't have increased the cost of the battery one dime.
Excellent point. I suspect that would be exactly what happened here. I don't think a smart battery can take the place of careful monitoring of voltage while flying. Once the voltage drops below 15 it's time to fly less aggressively and move the aircraft closer to a landing area.
 
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Excellent point. I suspect that would be exactly what happened here. I don't think a smart battery can take the place of careful monitoring of voltage while flying. Once the voltage drops below 15 it's time to fly less aggressively and move the aircraft closer to a landing area.
Oh yes, I agree. On my DIY all have Frsky battery sensors that link direct to the receiver and sends to the radio in realtime.

On those that don't monitor cell voltage, one should measure the cell voltage immediately after landing on occasion to see how the cells are doing. I had a MS 10A battery 4 cell go bad recently; over .5v variance from the others. Wow. A crash waiting to happen.

I really like my H, but IMO is lacking in some areas. If only Yuneec would make some refinements based on user feedback......call it the H2.....whatever....it would go along way to boost sales I think. OTOH, maybe Yuneec is content with their marketing strategy and is moving away from consumer priced drones. Not saying they are, just wondering why they don't announce any planned improvements. Obviously you don't announce improvements while you have shelves full of unsold product, but I can think of one specific hardware that IMO definitely needs replacing; the GPS/compass.

bloviating /off
 

Steve Carr

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one specific hardware that IMO definitely needs replacing; the GPS/compass.
Agree with that. I see lots of issues related to the GPS module that don't necessarily relate to loss of position or faulty position. It's hard to tell if it's related to GPS, compasss or the FC programming.
 

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