DATA REQUEST: Gathering Typhoon H manufacturer data toward identifying possible component-based root cause for "Toilet Bowling" phenomenon...

[markvogt]

GREETINGS ALL Yuneec (H) Pilots !
Our small startup UAV (drone) engineering firm (based in Minneapolis, with satellite offices just west of Chicago) has nearly 20 Yuneec drones, some of them our beloved Q500's and G's, and most of them the wonderful H series...

CHALLENGE:
We too have been experiencing this "toilet bowling" on only some (not all ) of them, and under the same environmental conditions:

• never in warm weather; but
• when weather dips (well) below freezing (eg 20 F or -5 C or colder)
• even after repeated successful flights in very same locations.

UPSHOT:

• it's NOT about location, because same bird flys perfectly on other days/seasons;
• it's NOT about ALL the birds, because some (most) of our H's fly PERFECTLY, EVERYWHERE

THEORY:

• -it MAY be about SOFTWARE ONLY... but that would demand that ALL H's without the update would show this behavior... and they DON'T :-|

THEORY:

• it MAY be about COMPONENTS ONLY... so that only those H's with particular components (eg compass, GPS, flight controller, remote controller) from a particular VENDOR and particular BATCH would display these symptoms.
• the ONLY way to know this is for ALL of us to SHARE SERIAL NUMBERS & COMPONENT INFORMATION HERE, so that we're helping Yuneec

PROPOSED:
Our firm will post the following bird-specific information, hoping others with problems (and even without) will do the same:

• BIRD MODEL
• SERIAL NUMBER
• DATE OF PURCHASE
• FLIGHT CONTROLLER DETAILS
• GPS DETAILS
• COMPASS DETAILS
• REMOTE CONTROLLER DETAILS (ie, ST16 details)

I can't think of any better, surer approach to isolating the True Root Cause of this often-dangerous phenomenon.

WORKAROUND FOR WHEN IT HAPPENS:

1. GAIN altitude (note: at this time we're still NOT sure if it's the ALTITUDE which helps or the INCREASE IN INTERNAL BIRD (electronics) TEMPERATURE caused by the HEAT generated by quickly gaining altitude, we simply know it helps);
2. HOVER while
3. DISABLE GPS so you're on full manual then
4. 3. MANUALLY LAND (racing-drone-style, always fun fun fun with a $1200 drone ;-) )

WATCH for us to post details in the near future.

- Mark | NORTH AMERICAN ROBOTICS | [email protected]

 

[daved20319]

Sounds reasonable, but exactly what do you mean by details? I haven't had my H very long, is there a screen on the ST16 somewhere that has the info you're looking for, or does this mean opening the bird up and getting part numbers from the components?

I'll be looking forward to the results of your research, I've had some TB issues, and I've been flying in cold weather, at or below freezing. Had a good flight yesterday, but now you've got me concerned again, that was also the first time I've had it up in above freezing temps, although only just above freezing. Later.

Dave

 

[FlushVision]

Since I took delivery of my H480 at the start of June 2016 I have only ever once had to deal with a toilet bowl. Just a few minutes into the second flight of the day. Fairly warm weather; height around 20 ft. Kp=2 and no wind. Hand caught it on landing. I re-calibrated the compass and it flew just fine after that.

Let me hasten to say that I never fly my H480 in freezing conditions...always + a few deg above freezing at the very least. Not because I have any doubts about the H's ability to cope...more to do with myself being a softy and not liking the cold.

 

[AH-1G]

@markvogt
There have been many issues dealing with toilet bowl effects.
The best method is to look through each post regarding this issue, rather than waiting for a response, which could take hours or days.

Search results for query: toilet bowl

yuneecpilots.com

 

[Ty Pilot]

Mark, your scientific approach is commendable and your workaround for the TB scenario is proven effective. However, when you say:

• the ONLY way to know this is for ALL of us to SHARE SERIAL NUMBERS & COMPONENT INFORMATION HERE, so that we're helping Yuneec

. . . this is unlikely to happen due the work and shear numbers involved; not to mention the bit about helping Yuneec. The Typhoon H is effectively three years old now and while Yuneec is still producing them, many here would argue that Yuneec are not likely to revisit or rectify any component issues except to replace or repair individual units while under warranty. I never had this issue in over two years of operation but perhaps those who have experienced it and cured it will chime in.

 

[PatR]

I strongly discourage people against disassembling their systems to obtain serial numbers unless the company requesting that information publicly states they will repair any of the systems damaged by disassembly and assembly.

There are too many people barely qualified to use eating utensils and to encourage them to take a stab at using tools on small electrical assemblies is tantamount to disaster.

 

[AH-1G]

See this, start with post #44

TOILET BOWLING !

the only thing i would say is when you are landing don't come straight down , the prop wash of your drone creates a turbulence that has been posted before on many drone sites . Yikes! In my opinion that is very wrong. Coming straight down creates equal pressure all around from the props...

yuneecpilots.com

 

[DCH]

My experience with troubleshooting TB (Toilet Bowl) led me to believe it is an issue with the Main Flight Control board. The outside temperature did not matter, it always appeared at the same time, about 5 minutes into the flight, -every flight, suggesting it was related to internal component temperature. In the end I discovered that replacing the Main Board was the only thing that cured the symptom, and it is gone for good. Without schematics for the aircraft it is impossible to trace it down to the individual component, but since a new main board from a new parted-out H can be purchased for about $25 bucks, it is the quickest and cheapest way to solve TB once and for all.

I suspect Yuneec fixed this issue with later model H480 FCs, since TB seems to have stopped being an issue with later H480s.

The best and only workaround for TB when it happens is to turn GPS off ASAP. TB will instantly cease. For this reason my first suspect was the GPS board so I swapped it out first, only to find out it was NOT the cause.

Here is the post with my TB findings:
FrankenPhoon is ALIVE! No more Toilet Bowl

 

[Steve Carr]

We too have been experiencing this "toilet bowling" on only some (not all ) of them, and under the same environmental conditions:

• never in warm weather; but
• when weather dips (well) below freezing (eg 20 F or -5 C or colder)
• even after repeated successful flights in very same locations.

Obviously this topic has been around a long time. I have not found a specific cause but it is always cured first by changing the GPS module and if that fails, then changing the flight controller. I think I still have a couple of FC's that were causing this issue.

The sure test to verify a bad component is to install it in a known working bird. I always do this kind of testing with no camera installed.

At least one of the FC's that failed was from last summer when flying in very hot conditions in bright sunlight. Generally heat is the enemy, not cold. The location of the FC lends itself to overheating. One of the firmware updates added a heating cycle for very cold conditions.

 

[markvogt]

@markvogt
There have been many issues dealing with toilet bowl effects.
The best method is to look through each post regarding this issue, rather than waiting for a response, which could take hours or days.

Search results for query: toilet bowl

yuneecpilots.com

Hi AH,
I'm ok with waiting to see if people do at least post their S/N's.
Even I am quick to acknowledge it's a pain to open up the Typhoon H series to get at the components - you literally have to tear it apart :-|
But maybe the S/N's will be "parse-able" into codes about the components or we'll see some other patterns.

Cheers,

-MV

 

[AH-1G]

Hi AH,
I'm ok with waiting to see if people do at least post their S/N's.
Even I am quick to acknowledge it's a pain to open up the Typhoon H series to get at the components - you literally have to tear it apart :-|
But maybe the S/N's will be "parse-able" into codes about the components or we'll see some other patterns.

Cheers,

-MV

I understand that, I just recently replaced all six engines. 4 hours!?

 

[markvogt]

My experience with troubleshooting TB (Toilet Bowl) led me to believe it is an issue with the Main Flight Control board. The outside temperature did not matter, it always appeared at the same time, about 5 minutes into the flight, -every flight, suggesting it was related to internal component temperature. In the end I discovered that replacing the Main Board was the only thing that cured the symptom, and it is gone for good. Without schematics for the aircraft it is impossible to trace it down to the individual component, but since a new main board from a new parted-out H can be purchased for about $25 bucks, it is the quickest and cheapest way to solve TB once and for all.

I suspect Yuneec fixed this issue with later model H480 FCs, since TB seems to have stopped being an issue with later H480s.

The best and only workaround for TB when it happens is to turn GPS off ASAP. TB will instantly cease. For this reason my first suspect was the GPS board so I swapped it out first, only to find out it was NOT the cause.

Here is the post with my TB findings:
FrankenPhoon is ALIVE! No more Toilet Bowl

Hi DCH,
Another great post from other members - thanks !
Clearly your experiences (behavior at higher-than-freezing temps) are significantly different than our own; but they absolutely enable us to rule out freezing-related temps being a root cause.
The mention about replacing the Flight Controller - I agree - seems to be the most cost-effective and time-effective solution to the problem..

AT OTHERS WHO HAVE EXPERIENCED "TOILET BOWL SYNDROME"

• DID you replace the Flight Controller as well ?
• WHAT was YOUR experience (did it resolve your issue)?

Let's see if we can gather enough responses to support a definitive trend !

Cheers,
-Mark

 

[markvogt]

Sounds reasonable, but exactly what do you mean by details? I haven't had my H very long, is there a screen on the ST16 somewhere that has the info you're looking for, or does this mean opening the bird up and getting part numbers from the components?

I'll be looking forward to the results of your research, I've had some TB issues, and I've been flying in cold weather, at or below freezing. Had a good flight yesterday, but now you've got me concerned again, that was also the first time I've had it up in above freezing temps, although only just above freezing. Later.

Dave

Hi Dave,
Sadly, I'm talking about the actual numeric information on the actual physical electronic components...
(read "disassemble your H" :-( ...)

THAT SAID, we're all in the same boat:

• the H's which displayed this behavior are now (typically) 2-3 YEARS old (from their actual DateOfManufacture);
• it appears (only appears) that whatever was the TrueRootCause for this behavior has been RESOLVED in actual CURRENT H's; but
• those of us who bought "new" H's which in fact turned out to be OLD STOCK still have this problem :-(

We're ALSO in the same boat about this:

• the most LIKELY TrueRootCause is a bad set of Flight Controllers;
• these are now 2-3 YEARS old;
• by the time each of with H's that displayed this behavior knew it, our H's were OUT OF WARRANTY; so that
• the BEST FIX is also the MOST EXPENSIVE FIX: a new (truly "new stock") Flight Controller from Yuneec, which appears to be $80-$249 (I'm still researching this); or
• take a chance on a parted-out used H, which MAY be CHEAPER, but also MAY actually have another OLD STOCK Flight Controller, so you COULD still have the problem; AND
• no matter which Flight Controller you get, it's still OPEN HEART SURGERY to replace these components in an H :-(

I'm STILL curious to at least see if there is a traceable pattern amongst even SERIAL NUMBERS, which should be on the outside of the H's.

Q: ARE you ok with starting there?

I'll post my H's Serial Number here shortly...

-Mark

 

[Sureshot]

In past experience with home built & modified quads & hex's, the one sure way to get the TB effect is to have the compass is not aimed the same direction as the FC.
Another cause can be nearby magnetic interference during calibration or in flight near a steel structure.
The GPS knows the current location and the desired location, but it relies on the compass to know which way the plane is aimed.
If the compass is off, the GPS will tell the FC that the new location is wrong, and the FC will end up circling the new location.

 

[FlushVision]

Hi DCH,
Another great post from other members - thanks !
Clearly your experiences (behavior at higher-than-freezing temps) are significantly different than our own; but they absolutely enable us to rule out freezing-related temps being a root cause.
The mention about replacing the Flight Controller - I agree - seems to be the most cost-effective and time-effective solution to the problem..

AT OTHERS WHO HAVE EXPERIENCED "TOILET BOWL SYNDROME"

• DID you replace the Flight Controller as well ?
• WHAT was YOUR experience (did it resolve your issue)?

Let's see if we can gather enough responses to support a definitive trend !

Cheers,
-Mark

As I mentioned previously. my one and only time I had TB on my now nearly 3 year old H, I rectified the issue by simply landing (hand catch) doing a power cycle and re calibrating the compass. Flew great after that.

 

[John Dube]

As I mentioned previously. my one and only time I had TB on my now nearly 3 year old H, I rectified the issue by simply landing (hand catch) doing a power cycle and re calibrating the compass. Flew great after that.

Agree with FlushVision. Have three H's (one H and two H Pros). ON the rare occasions I did have a TB (2017), re-calibration of the Compass resolved it. For newer or lesser experienced pilots, remember to calibrate away from metal (min 25'), cars, buildings, concrete as it has rebar in it, and remove your smart watch, phones and other electronics from your pockets.

Happy and Safe Flying!

 

[Steve Carr]

This is a flight controller that, without question, caused TB after a few minutes of flight. It was replaced after the GPS replacement failed to solve the problem.