Toilet Bowl, fly away,

[Dick]

I just experienced my first TB and eventual Crash. I took off after 10 minutes of allowing the H to acquire a lock on Satellites. H was locked on 14 ans ST was locked on to 12. I started the motors and took it up 70 feet so I could record the view around my backyard. I hovered for around five minutes. Then the H began to circle in I guess it is called TB mode. I was flying in angle mode all the time. I lowered the landing gear and began my approach to land. The H response was jerky at best and when I held the left joy stick all the way down, it would not descend. I then toggled to Home and the H took off like a bat out of ****. I quickly toggled back to angle and again tried to land. The H began to TB again and this time got too close to the trees in the back yard.
Fortunately, I was able to get a ladder up the tree and rescue the poor bugger. The gimbal mount was damaged and broke two propellers. I have not done and further investigation on any other damage. I recovered the telemetry and plan to send it to Yuneec on Monday. Does anyone have any comments that will help me plead my case with Yuneec?

 

[NorWiscPilot]

I just experienced my first TB and eventual Crash. I took off after 10 minutes of allowing the H to acquire a lock on Satellites. H was locked on 14 ans ST was locked on to 12. I started the motors and took it up 70 feet so I could record the view around my backyard. I hovered for around five minutes. Then the H began to circle in I guess it is called TB mode. I was flying in angle mode all the time. I lowered the landing gear and began my approach to land. The H response was jerky at best and when I held the left joy stick all the way down, it would not descend. I then toggled to Home and the H took off like a bat out of ****. I quickly toggled back to angle and again tried to land. The H began to TB again and this time got too close to the trees in the back yard.
Fortunately, I was able to get a ladder up the tree and rescue the poor bugger. The gimbal mount was damaged and broke two propellers. I have not done and further investigation on any other damage. I recovered the telemetry and plan to send it to Yuneec on Monday. Does anyone have any comments that will help me plead my case with Yuneec?

Dick,

I saw your post in the other existing Toilet Bowl thread and replied there. After noticing you decided to create a new thread, I decided to copy my reply here as well. Hope it is of some help to you.

Jeff

--- My copied reply:

Dick,

Sorry to hear of your ordeal. Any chance you can describe what the flight or attitude of your H looked like when it was failing to fly correctly? Reason I ask is to continue my own research. I am suspecting we are seeing two different scenarios being termed "Toilet Bowl" and am trying to get some differentiation and your help is most appreciated.

Did it seem like your H was in a gentle circle around a point, or was it a more violent rotation, even pitching your H round and round (your camera, instead of at vertical, could have been angled 10, 20, 30 degrees or more).

Or, was the flight path more like a side to side, back and forth motion that eventually turns itself into an oval rather than a circle?

The latter is what I have been experiencing, intermittently, at about 4 feet. Lifting higher than 4 feet, or turning off GPS stopped this side to side to oval flight path. Also, i have been looking for TB videos. So far, all I have seen is more of the side to side path that eventually becomes an oval, rather than the violent circling some have described.

As for Yuneec, here are some recommendations as to being prepared:

1. Write down as much as you can remember, including: temperature, wind speed, cloud cover, time of day.
2. While telemetry can show voltages, switch settings, stick inputs, et al, if you can record what you remember, the better prepared you will be when you talk to customer support as well as having your email ready to send.
3. While you state you took off with 14 satellites on the H, do you recall how many had been acquired by the time you reached 100 feet>
4. Tell it like it happened. We all need to know what is causing these abnormal flights so... facts help. Saving face does not.

By the way, I expect others to chime in with respect to your satellite count. 14 is a bit low for me. I usually wait for 17, even 18 or more. Could be more of a personal preference, but 14 for me is just too low.

----

Now for some additional personal research questions:

Before you took off to 100 feet, did you do any pre-checks such as:

- hover between 4 and 10 feet, ensuring GPS and compass are able to hold consistent position.
- ensure battery voltage is sufficient for the expected duration of your flight.
- check response with some simple left to right, right to left, forward/backward maneuvers to ensure controls are responsive AND letting the sticks go to neutral stops your H and resumes stationary hover.

(By the way, before lift off, I make sure I remember how to quickly turn off GPS in case the need arises!)

Since my first low level oval flight incident, I have incorporated those simple pre and post lift-off checks to make sure everything is working and low-level hover is possible. If I sense something not right, I am able to either gain altitude and regain stable flight, or turn off GPS to do the same. I only had to resort to "procedures" a couple times. Being prepared for them has definitely saved the day.

Looking forward to reading your kind replies, and also looking forward to the resolution you receive from Yuneec.

Good luck!

Jeff

 

[Dick]

Thanks Jeff for responding.


What I always do prior to take off is

1.0 Verify GPS is locked and I have at least 10 SAT

2.0 I start the motors and then slowly raise to 5 feet. I then check forward and backward controls movement, then side to side. And hover for a few minutes.

3.0 Then I fly to my designated flight path I choose for that period.

Today it was finally 50 deg F wind was variable around 2 mph. full sun.

I took the H up to around 70 feet, although I remember looking down at my ST and seeing an altitude of 112 feet. Thought that was strange.

I hovered at that altitude and turned on the recorder to record a 360 view above my house and backyard.

After that was done I was going to go up a little higher and take some more video. At that time the H began to slowly move side to side. I thought it was trying to correct for wind. Then it began to do an oval move. I was concerned, since I had read several post of others who experienced the same issue.

So to be safe I decided to bring her home. The rest is what I posted.


You mentioned turning of GPS. I’m not sure how that is done. I looked at my ST-16 and have not seen that option. Not to say it’s not there, the manual has a lot to be desired.

 

[NorWiscPilot]

Thanks Jeff for responding.


What I always do prior to take off is

1.0 Verify GPS is locked and I have at least 10 SAT

2.0 I start the motors and then slowly raise to 5 feet. I then check forward and backward controls movement, then side to side. And hover for a few minutes.

3.0 Then I fly to my designated flight path I choose for that period.

Today it was finally 50 deg F wind was variable around 2 mph. full sun.

I took the H up to around 70 feet, although I remember looking down at my ST and seeing an altitude of 112 feet. Thought that was strange.

I hovered at that altitude and turned on the recorder to record a 360 view above my house and backyard.

After that was done I was going to go up a little higher and take some more video. At that time the H began to slowly move side to side. I thought it was trying to correct for wind. Then it began to do an oval move. I was concerned, since I had read several post of others who experienced the same issue.

So to be safe I decided to bring her home. The rest is what I posted.


You mentioned turning of GPS. I’m not sure how that is done. I looked at my ST-16 and have not seen that option. Not to say it’s not there, the manual has a lot to be desired.

Dick,

Thank you for the additional detail. Good to know the exact description of the unwanted flight path. Me thinks we needs a new name rather than Toilet Bowl! TB seems to convey too violent a flight, twirling down the drain. Your flight, and I suspect a lot of others, do not twirl and spin.

As for turning off GPS, look at the right side of your ST16, specifically the "settings and calibration" icon. When your H is connected, pressing this should show you the toggle for GPS along with calibrations and Return Home flight altitude. If you do not see it, your ST16 likely is overdue for a software update.

Jeff

 

[Dick]

Thanks Jeff
I will look at that in the morning.
Regards:
Dick

 

[Dick]

Well just got off the phone with Yuneec USA. Told me I should have done a compass calibration prior to take off. Apparently when you fly in different locations that are more than 10 miles apart, it is recommended. That was a new one for me?? Since the gimbal was broken, they recommended that I send it in to a repair center since it is under warranty. They will update the firmware and re-calibrate the gimbal and do a complete check of the drone and controller. My current firmware is as follows: ST-16 V03.01.B27, XMTR: V00.24, Rcvr: V01.10. Typhoon-H Gimbal V1.25, AutoPilot: V1.3, Camera: V3.2.26 (A), Real Sense: V1.1. I hope the current updates will not cause and more issues.

 

[NorWiscPilot]

Well just got off the phone with Yuneec USA. Told me I should have done a compass calibration prior to take off. Apparently when you fly in different locations that are more than 10 miles apart, it is recommended. That was a new one for me?? Since the gimbal was broken, they recommended that I send it in to a repair center since it is under warranty. They will update the firmware and re-calibrate the gimbal and do a complete check of the drone and controller. My current firmware is as follows: ST-16 V03.01.B27, XMTR: V00.24, Rcvr: V01.10. Typhoon-H Gimbal V1.25, AutoPilot: V1.3, Camera: V3.2.26 (A), Real Sense: V1.1. I hope the current updates will not cause and more issues.

The 10 mile suggestion is a new one for me too. Greater distances, as in 100+ miles, is what I recall as to advice.

Maybe Yuneec is tightening this recommendation as a possible solution. Would make sense, other than when some of us have been flying off the same launch point for months.

I am still thinking there is an issue with the GPS/Compass collaboration, either maintaining memory, interference, or a combination. I am tending to conclude this way due to the intermittency of our experiences. If it were a solid issue, we and Yuneec would have a greater chance to nail down the causes and thus better solutions.

Hopefully the teamwork will result in a final remedy, either hardware, software/firmware, or procedures (or a combination).

Jeff

 

[FlushVision]

Thanks Jeff for responding.


What I always do prior to take off is

1.0 Verify GPS is locked and I have at least 10 SAT

<snip>...

10 satellites is way too low. IMHO you need to raise your minimum satellites lock to 14 or 15 at least. For example, I won't take off until I have at least 15 locked...preferably 16.

Where you take off from can impact on the number of satellites your H sees too. There is a thing called the mask. If your take off place is next to a hill, trees, building, or any other large object, then that object will 'mask' the satellites and may prevent you from locking onto enough satellites. Sometimes just moving the aircraft a few feet can make the difference between seeing enough satellites and not. Note that, generally, the higher you fly the less mask is encountered.

 

[Dick]

The 10 mile suggestion is a new one for me too. Greater distances, as in 100+ miles, is what I recall as to advice.

Maybe Yuneec is tightening this recommendation as a possible solution. Would make sense, other than when some of us have been flying off the same launch point for months.

I am still thinking there is an issue with the GPS/Compass collaboration, either maintaining memory, interference, or a combination. I am tending to conclude this way due to the intermittency of our experiences. If it were a solid issue, we and Yuneec would have a greater chance to nail down the causes and thus better solutions.

Hopefully the teamwork will result in a final remedy, either hardware, software/firmware, or procedures (or a combination).

Jeff

Jeff:

thanks, I was not overly impressed with the Tech support person I spoke with. She seemed not at all concerned about my issue. I had to push to get her to at least look at the telemetry log. Then I got an email opening the case and two minutes later another email closing the case as being resolved!!

What resolution? Will keep you updated.

Dick

 

[PatR]

There is soooo much missing from all these toilet bowl threads. Why is it nobody posts precisely how they set up an H prior to the flight? How many received a compass error warning during the flight? What color was flashing at the back of the H?

 

[Rayray]

10 satellites is way too low. IMHO you need to raise your minimum satellites lock to 14 or 15 at least. For example, I won't take off until I have at least 15 locked...preferably 16.

This is so true...time after time on here I see folks taking of with less than 15 GPS Sats on the TH. The bird, not the ST16. ST16 is OK with 10 or more.

Pat, I also notice much info is missing. I'm dubious of the "10 mile" business.

 

[NorWiscPilot]

There is soooo much missing from all these toilet bowl threads. Why is it nobody posts precisely how they set up an H prior to the flight? How many received a compass error warning during the flight? What color was flashing at the back of the H?

PatR,

Agree completely. Exactly why I asked Dick for more information... Dick actually responded with answers a few replies above.

Maybe what we need is an incident form. "Before posting, fill out this form with as much information as possible, concerning the incident to which you are about to describe".

Jeff

 

[Dick]

Hi Pat:
When the moment happens there is soooo much Adrenalin flowing it is hard to keep things straight. I agree these are things that should be noted.
Now that this has happened to me I will be more observant. As far as some of your questions go , I did not do a compass calibration prior to flight. I did not know that it was a recommendation. I got no compass or GPS error. In fact I looked specifically at the number of SAT and that number was at a high of 20 and a low of 14. I tis hard to see the color of the rear light in bright sunlight. Hopefully I won't have to experience this again. After discussing with Jeff( earlier post reply) this may not have been a TB issue.
Thanks for you input

 

[Dick]

This is so true...time after time on here I see folks taking of with less than 15 GPS Sats on the TH. The bird, not the ST16. ST16 is OK with 10 or more.

Pat, I also notice much info is missing. I'm dubious of the "10 mile" business.

Ray I think the Tech Support person wrote me off as another owner that has no idea of how to operate his equipment. Instead, I wish she had been a lot more inquisitive about what happened. It would be nice if someone explained the relationship between the compass and the GPS and how they interact. Perhaps then we could all be educated and know what to watch out for.

 

[Ty Pilot]

Dick, sorry for your loss and I hope you get your issue resolved in a timely manner. I think you have asked a really good question about the compass/GPS relationship needing to be discussed in a little more detail as well as the satellite numbers being nailed down.There is a sticky title at the top of the "Typhoon H discussion" board with a PDF checklist that suggests having 12 satellites. That thread was posted just 4 months ago it seems? I have read for some time in threads like this that sixteen is what one should see on the craft.


I would also like to ask the more tech-savvy and in-the-know types if it is possible that the magnetic deviation that occurs in some areas is a cause for concern? The Agonic line that runs thru Florida (for example) is just about 10 miles from me and has a deviation of about six degrees, is that a problem?

Pat

 

[Rayray]

There is a sticky title at the top of the "Typhoon H discussion" board with a PDF checklist that suggests having 12 satellites. That thread was posted just 4 months ago it seems? I have read for some time in threads like this that sixteen is what one should see on the craft.

TY, THANK YOU for pointing out that mistake in the Check List PDF. (In the H Help Sticky Thread)

Some sorry devil was not taking care of business when he did that...(SSD be me)

Hopefully it is corrected, I'm not good at editing PDFs.
Thanks again, TY.

 

[PatR]

I wasn't leaning on you specifically. I do UAV incident investigations professionally. Most of the incident descriptions I see in forums would be instantly kicked back for more detail, starting with set up and pre-flight actions. They can be critically important. How and when we do, or don't do, something can have a grand impact on what the aircraft does.

 

[Ty Pilot]

TY, THANK YOU for pointing out that mistake in the Check List PDF. (In the H Help Sticky Thread)

Some sorry devil was not taking care of business when he did that...(SSD be me)

Hopefully it is corrected, I'm not good at editing PDFs.
Thanks again, TY.

You're welcome. I really appreciate this forum and all of its contributors, staff and users for putting all of this info out here.

Pat

 

[bigrich007]

all calibration done before flight
Second GPS replaced by Yuneec
this is a design flaw
three crash of this type.

 

[PatR]

Were you flying right next to a car for every one? I saw two things in your video that suggested problems would soon become apparent. The first was the density of the housing. How many of those homes might have WiFi routers? That neighborhood is frequency saturated. Flying right next to a car, with the H between you and the car, set the stage for signal bounce. There's a very small time delay in that bounce, meaning the H is seeing the same or similar signal twice, milliseconds apart. That confuses control logic. I found this out when shooting a steel hulled ship where control was dicey with the H between me and the ship. Changing my position to where radio signal would not reflect back directly at the H restored control.

This would not be a design defect but simply a function of signal reflectivity. People put antennas high up in clear air for a reason.