Another thought.......

[biltno]

This for most of us is a hobby.
We do it for fun.
It may be a slightly expensive one at that. The more we read of problems, we should use it for education, not take the fun out of it.
Another way to look at it, spending the money
To fly should not impact your budget. If it does then fly cheaper aircraft or choose another hobby.
I learned so much from this forum and used to fly thinking constantly of something failing.
All we can do is educate ourself and share what we know but most of all enjoy it.

 

[rdonson]

@Steve Carr here's the Remote_00037.csv file you requested for analysis.

 

[rdonson]

@Steve Carr You've been teaching me a lot just looking at the files you've requested. Is there a guide anywhere on how to interpret the data in these files? For example, looking at the Remote_00037.csv file it shows data in 11 of the 24 columns (CH0-CH23) but what do the values in those columns mean? Is there a Yuneec service manual somewhere?

 

[rdonson]

Hello Ron,

How did the battery do? I sent mine into a tree this past summer and by the time my tree guy retrieved it, several hours later, the battery had swelled up enough that it was hard to remove. In my case, it was a bit warmer and it was sitting in, almost, direct sunlight until rescued.

Other than the battery being drained to 0 it seems to have held up well. I'm sure that didn't help the life of the battery but I was able to successfully charge it up to STORAGE level when I got it back.

 

[rdonson]

Make your own judgement. I am not advocating that you stop flying. Its your risk. Do what you may. I know that, for me, flying my H will not be the same now.

I understand your feelings. If you're like most people that feeling will subside some over time as you gain confidence in your skills and knowledge of the aircraft. Your awareness of the risks though should never go away. Its not unlike engaging in sports and being injured or for me when I was in the military and realized how fragile my existence on planet earth was.

 

[wings]

Thanks Ron: Bottom line for me is that I would never want to hurt someone with my H. I have good confidence in my flying ability's but can't control something that is out of my control.
When do you think you will be airborne again?

 

[rdonson]

I have no intention of ever harming anyone either. Whether its with a drone or car or anything else. If I did it would make me sick to my stomach.

I’m not sure on the timetable for flying again. Hopefully sometime in the next 7 days. I’ve got a lot to check out on this TH480 before I put it in the air and a few flights without the camera to ensure flight worthiness. I also have to fit that into other activities on my calendar.

I could fly my other TH480 but I want to get this one reliable again. This one has the better camera and yes, I know I can move that camera between both TH480.

BTW I’ve had a number of conversations with @Steve Carr about what happened and learning from him about his analysis of the telemetry files. The only conclusion we can come to is that a momentary glitch caused the flyaway. It could have been a result of a solar flare, software or a component glitch in the TH480. I know that this doesn’t sound conclusive and that’s because it isn’t. It’s the best answer we have based on the data available.

 

[wings]

Thanks for the reply Ron. Best of Luck with your H.

 

[WaterMainMan]

Hi Ron; A few years ago I was having a similar experience with a much less sophisticated aircraft, a Y3 multi. It range tested fine, everything seemed to work until we got in the air and then it just started 'Doing it's own thing'. I got real close to losing the aircraft when it happened the first time. I somehow got it to set down on a neighbor's roof. Time to play, Meet The Neighbors! On subsequent flights, I kept it tethered to the ground on a 30 foot Kevlar line. Kevlar was rated to 200# as I recall. It tried several more fly aways but the tether saved the day. This was a scratch built aircraft so I had to find the defective component by substitution. It turned out to be an ESC, oddly enough. Not what I would have suspected at all. I guess that's why it took me a few attempts to find it. Anyway, I thought that I might suggest tethering to you for an initial flight attempt. I would have had a real tough time sending that Y3 back into the air without some form of safety backup. I was glad I did.

Jim

 

[Steve Carr]

turned out to be an ESC

I can confirm your observation. It's happened a number of times on the Q500. As one motor looses power the FC tries to compensate by keeping the aircraft level. At that point it ignores any input from the sticks, tips in the direction of the bad motor and looses altitude until it hits the ground. On a hexacopter you would expect that not to happen since lowering power on the opposite motor circuit would level the aircraft and the other 4 motors should be able to maintain altitude. But....that's simply speculation on my part.

 

[rdonson]

Hi Ron; A few years ago I was having a similar experience with a much less sophisticated aircraft, a Y3 multi. It range tested fine, everything seemed to work until we got in the air and then it just started 'Doing it's own thing'. I got real close to losing the aircraft when it happened the first time. I somehow got it to set down on a neighbor's roof. Time to play, Meet The Neighbors! On subsequent flights, I kept it tethered to the ground on a 30 foot Kevlar line. Kevlar was rated to 200# as I recall. It tried several more fly aways but the tether saved the day. This was a scratch built aircraft so I had to find the defective component by substitution. It turned out to be an ESC, oddly enough. Not what I would have suspected at all. I guess that's why it took me a few attempts to find it. Anyway, I thought that I might suggest tethering to you for an initial flight attempt. I would have had a real tough time sending that Y3 back into the air without some form of safety backup. I was glad I did.

Jim

Thanks for the suggestion, Jim. I appreciate the approach you outlined and I'm glad that it was able to identify the bad ESC.

I'll have to defer to @Steve Carr but I think that a failing ESC might have been detectable in the various telemetry files that were analyzed. Perhaps not directly but maybe by anomalies in pitch or yaw or some other tracked metric.

 

[PatR]

I can confirm your observation. It's happened a number of times on the Q500. As one motor looses power the FC tries to compensate by keeping the aircraft level. At that point it ignores any input from the sticks, tips in the direction of the bad motor and looses altitude until it hits the ground. On a hexacopter you would expect that not to happen since lowering power on the opposite motor circuit would level the aircraft and the other 4 motors should be able to maintain altitude. But....that's simply speculation on my part.

Steve, I can understand why people would believe that principle to be true as Yuneec was the first to advertise the motor redundancy feature with the the Typhoon H hex. Unfortunately, a well designed flat hex, octo, or coaxial tri-copter or X-8 doesn't work that way, and those systems were the ones that established how a motor out condition was dealt with. They maintain stability due to having a significant amount of "headroom" built into the power system while their flight controllers are "smart" enough to sense the imbalance and send higher power commands and control compensation to the remaining motors. That headroom translates to having more power necessary, usually by a factor of two or three, than what is necessary to carry the design payload capacity. Any decent flight controller will sense thrust imbalance and compensate with ESC commands that will maintain a "balanced" aircraft, IF it has the excess power available from the remaining motors. Properly designed a well designed and set up system will be able to continue the mission and return to base normally with a motor out. That all comes together better with coaxial arrangements that flat designs but done right both are effective. The Typhoon H cannot do that.

Only Yuneec uses the alternating thrust method of changing motor direction to keep the aircraft controllable. The reason they do it that way is because the system was designed around the minimum power necessary to keep it in the air so as there is no excess available power they had to design a very complex method of maintaining minimal stability that would allow the aircraft to remain controllable enough to get back on the ground safely. I'm still astounded the Yuneec method manages to work at all, but it does.

 

[Steve Carr]

I'm actually referring to the different reactions to a motor circuit failure between a quad and a hex. It is unlikely an ESC failure on this hex would result in a flyaway.

 

[PatR]

Completely agree.

 

[Steve Carr]

For those who might have an interest in the telemetry of Ron's flight I am posting a snippet of that flight at the time the GPS stopped responding.

 

[PatR]

Steve,

What if those are not errors in telemetry, but indicators of system defects generating impossible data reported to the tel file? A garbage in, garbage out type thing?

 

[Steve Carr]

Right. I agree the numbers reflect what is being read and recorded. Since the roll, pitch and yaw are from the x,y,z gyros and compass they may be correct. It's interesting that the speed is calculated from x,y,z accelerometers on the same board but they appear to be incorrect.

 

[hlorenzl]

I think I've had 2 flyaways and one was for sure.

Today was the for sure flyaway. I was in a spot where I've flown a dozen times without incident. I was within 100 ft of the TH480 and it was about 50' up. I had the rate control slider in Turtle position. All of a sudden I got a GPS message on the ST-16 and it took off like a bat out of Hades, it was unresponsive to controls and no time to turn GPS off before it lodged itself about 50' up in a pine tree.

There were no GPS issues when I launched. ST-16 and TH480 had more than enough satellites and things looked good.

Now I've got to find a tree service to retrieve the TH480. There's no way I'm going up that tree.

This sux.

I guess in the future I will take a screenshot of the ST-16 to prove I had enough satellites prior to launch.

I have no idea why the GPS error happened or why the TH480 simply took off like that.

I remember a video wherein the user was trying out the speed of the H without GPS. After his trial, he turned back on his GPS while the H was still up in the air. The result was that the H recognized that its position was far from the GPS location where it should have been, so it tried to move to that point where the GPS data tells it should have been.

In connection to this, I am thinking that maybe the reason behind the failure of your GPS might have been hardware-triggered. There are many more factors but I thought it would be the GPS antenna that must have caused your flyaway. Either it became faulty (such as a problem with its connection to the mobo), or an internal interference might have caused it to do so (such as battery-induced interference that might have gone through the shielding, or the shielding between the antenna and the battery might have been the problem).. or maybe vibrations caused by the motors of the aircraft might have fatigued some connections relating to GPS causing it to loose contact and make errors on its readings...

Anyway, how is your drone now?

 

[rdonson]

My drone is looking good. Only a single broken prop after making its way down from 50' up a pine tree. The gentleman who discovered it said he was able to reach up and take it from a low branch. It never hit the ground. Quite likely the 35 mph gusts overnight were what aided its return toward the ground. It was amazing it didn't suffer more damage. I've still got to run a number of calibrations and tests before I put it in the air again. Without the camera for the first few test flights.

My understanding is the GPS module in the Typhoon H actually includes a GPS, a compass (magnetometer) and a barometric pressure sensor. It is quite likely that the GPS module glitched. @Steve Carr has always seen that as a possibility.

There is information available online that there are actually 3 versions of the Yuneec GPS module. Only Yuneec at their factory has the ability to "flash" the firmware in that module. If I were to replace the GPS module in my TH480 that experienced the flyaway I would look to see what version is in my TH480 and search for a version 3 module to replace it.

It is amazing to see all the computational things going on in a drone to achieve flight. Its a flying computer. If you'd like a taste of some of that just go to YouTube and search on IMU. It may alter your perspective on what goes on in these drones and the IMU is just a part of it. Just the matrix math is enough to take me back to college as an engineer (when the earth's crust was cooling) and cringe at doing that again.

Anyway, I'm reminded of Arthur C. Clarke's third law:

Any sufficiently advanced technology is indistinguishable from magic.

 

[Eagle's Eye Video]

When you run without the camera, you will not have certain visual tools, such as the green arrow. Unless you are very comfortable in flying the H on sticks alone, I would not recommend trying to fly GPS off, w/o a camera.