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Two "Tip Overs"... Why?

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I'm new to flying the Typhoon H, but I am well-read on the operation of this sUAS and I have quite a bit of experience with other systems.

I've had two "Tip-Overs" on landing out of about 10 landings. Fortunately, I've only lost one prop so far. Both times I noticed my aircraft responding with flight patterns that did not match what I was commanding, and it was drifting around. I've done gimbal and accelerometer cals at home prior to flying. I have been flying in the same park, open area, my phone on airplane mode or off completely and 15m away from the aircraft, and I have done calibrations before EVERY takeoff so far. Aircraft indicates successful compass cal each time. Normally I'm seeing 20 sats on the aircraft, 16 sats on the ST16.

Let's back up a little. I have two batteries, one is a Power 4 Yuneec 5400mah (OEM), and I've got a Gifi 8050mah. I have not had any issues with drifting or landing using the Yuneec battery. Both times I have had tip-over landings after noticing the aircraft drifting it has been with the GiFi battery. Both times I noticed the aircraft not responding correctly or holding position, the battery indicator on the ST16 was reporting at around 14.8v-14.9v after around 10-12 minutes of flight. Almost identical scenarios. I'm trying my best to look at and notice what was going on, and I feel like it was really the exact same situation both times.

Could there be some sort of RF interference issue while using the GiFi battery when it discharges and/or heats up during flight?

Is there some sort of weight difference and/or CG issue between the OEM and GiFi battery?

I welcome your assistance.
 

WTFDproject

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@scott96D,
I'm not sure without more details, but I suspect your TH may be one of those subject to the "Toilet Bowl" effect. I am not very familiar with it, but several of the members are. Those members are not on-line at the moment. If they also see the possibility, I am sure they will want a screen shot of your Firmware versions screen (Hold down the center button under the ST16 screen, then upload the file). They may also want a copy of your flight logs for review. (See Attachment 53 (Typhoon H Flight Log Retrieval) in the document attached to "Way To Fix Drones project" as needed.
There are other possibilities, of course. Other possibilities include loose controller pots or minor corrosion on those pots. The discussions will eventually center in on the real issue for resolution.
You may be able to find some preliminary information by doing a search for "Toilet Bowl" and related terms. This search will get you started: "Search results for query: Toilet Bowl".
 

Steve Carr

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My first suggestion is to fly again for a few min and then bring it down to land. If it drifts and doesn't respond correctly, then go up to 50' and hover. See if it's stable high and unstable low.
Remove the camera before testing. And only do the compass cal once in a grassy area.
 
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FlushVision

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There should be no difference in the performance using either the Power 4 or the Giffi battery. I have a giffi and I have no issues with it. Albeit that I haven't flown now for a couple of months due to our 'lock-down' rules. Your problem lies somewhere other than your batteries. A good practice is to 'stir' your sticks before each flight and regularly use contact cleaner spray. That may make an impact on your issues. However, as mentioned above, it'd be nice to see some telemetry.
 
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I had a similar issue noticed a couple of times my H plus kept rocking forward a few inches during a few landings,my problem turned out to be human error .I unconsciously kept my thumb on the right stick now and then when i was landing, trying to land and move forward at the same time, ooops my bad !!
 

NorWiscPilot

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I'm new to flying the Typhoon H, but I am well-read on the operation of this sUAS and I have quite a bit of experience with other systems.

I've had two "Tip-Overs" on landing out of about 10 landings. Fortunately, I've only lost one prop so far. Both times I noticed my aircraft responding with flight patterns that did not match what I was commanding, and it was drifting around. I've done gimbal and accelerometer cals at home prior to flying. I have been flying in the same park, open area, my phone on airplane mode or off completely and 15m away from the aircraft, and I have done calibrations before EVERY takeoff so far. Aircraft indicates successful compass cal each time. Normally I'm seeing 20 sats on the aircraft, 16 sats on the ST16.

Let's back up a little. I have two batteries, one is a Power 4 Yuneec 5400mah (OEM), and I've got a Gifi 8050mah. I have not had any issues with drifting or landing using the Yuneec battery. Both times I have had tip-over landings after noticing the aircraft drifting it has been with the GiFi battery. Both times I noticed the aircraft not responding correctly or holding position, the battery indicator on the ST16 was reporting at around 14.8v-14.9v after around 10-12 minutes of flight. Almost identical scenarios. I'm trying my best to look at and notice what was going on, and I feel like it was really the exact same situation both times.

Could there be some sort of RF interference issue while using the GiFi battery when it discharges and/or heats up during flight?

Is there some sort of weight difference and/or CG issue between the OEM and GiFi battery?

I welcome your assistance.

Scott,

First things first... it will be very difficult to nail down a cause if the variables are always changing with every flight. What I mean is, stop doing calibrations before every flight! They are not necessary. You will find discussions about calibrations and when to do them in many, many threads, so I will not repeat everything here.

The basics:
  • Compass: Calibrate after firmware update, a change in flying locations if by a significant difference (search for threads), or... something seems amiss.
    • Reason to abstain: every time one does a calibration, the chances of a BAD calibration exist! Get a good one, stick with it. In your case, if you observe proper flight characteristics, and landings after a "successful" compass calibration, trust it and leave it alone.
  • Accelerometer: Even less frequent than compass - calibrate after firmware update. If things are going haywire, then consider another calibration. Otherwise, leave alone.
Try a few more flights without touching calibrations, and see what happens. You may indeed have issues with your particular GiFI batteries, but unlikely, as others have already stated. Nothing is off the table as yet.

Before a diagnosis of "toilet bowl" is thrown in here, it might be advisable to knock off a few more items from the checklist:
  • Let the aircraft sit for at least 15 minutes prior to first flight of the day, ensuring GPS almanac can refresh.
  • Make sure environmental inference is not affecting flight.
    • Does the drifting, tip-overs, et al occur in the same general vicinity as to where you are flying?
    • Is the area void of trees possibly blocking GPS?
    • Are you away from power lines (above AND underground)?
    • Away from buildings, especially metal? (or similar objects)
  • Ensure unwanted stick input is not being applied. Assuming mode 2:
    • Right stick is not being deflected
    • left stick (throttle) is being held down until motors idle
    • left/right deflection is not being applied to throttle stick (unwittingly)
  • Speaking of sticks, ensure a good stir has been performed before each flying session, maybe each flight. Hardware monitor and cleaning is discussed in many other threads.
  • Prepare to abort!
    • When you are attempting a landing, are you prepared to abort?
    • Have you ever successfully attempted an abort?
    • If, upon landing, you notice the motors are not going to idle, and in fact, you may notice the pitch starts fluctuating. To abort, give full throttle to get back airborne. (Takes quick thinking and hands, hence the "always expect an abort" credo.)
    • If able to get airborne, should only need 10 to 20 feet of altitude. Stay steady, and try again.
Give the above some thought and try some test flights. To eliminate your batteries, stay away from the GiFi for awhile and just fly your OEM batteries. Chances are, if your aircraft is having issues, it will eventually show up with any battery. The key is to eliminate as many variables as possible.

For background, I had similar issues with my original Typhoon H. I actually experienced what I called "oscillating flight" whereby when close to the ground, the aircraft "sometimes" would initiate what appeared to be a circular movement, but soon transformed to a back and forth, more oval flight pattern. My first instinct was to land as soon as possible. Wrong! Tip-over, of course. Glad snow was soft. After than, I learned to abort, gain some altitude, and try again.

What really solved it, in my opinion, was proper compass re-calibration (once) and allowing GPS to refresh, after layoffs.

Even now, with another craft, I will encounter unwanted attempts for the H480 to destroy a few propellers. Aborts work! Also, realizing they seem to happen in one general area near my long gravel driveway, I anticipate and avoid. By the way, underground power lines are on the other side of the driveway. I think I found a spot where interference may concentrate enough to affect the electronics.

Hope the above may lend assistance, at least in the troubleshooting phase of your personal research. Please let us know how you are progressing.

Good luck!

Jeff
 
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h-elsner

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I have had inspected a lot of flight logs in the past. What I have observed very often ist the higher probability for occurance of compass calibration errors when the voltage is low.
This is in the first step not explainable because the power supply of the sensors is stabilized by the step-down-converter to 5V and later to 3.3V, means there is a good seperation to the battery voltage.
On the other hand, lower voltage means higher current to get the same result to hold the drone in the air. Magnetic fields depends only on current, not on voltage. This may do the trick.

If the voltage drop of the Gifi batteries is more intensive this may have an influence on the compass.

We have to look on the flight logs regarding compass errors during landing, voltage curve and possible other reasons like unwanted stick inputs (stick calibration, dusty potis, etc.).

br HE
 
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On the other hand, lower voltage means higher current to get the same result to hold the drone in the air. Magnetic fields depends only on current, not on voltage.

If aircraft is drifting on custom battery and after switching to Yuneec battery all is good, you got the answer.

I'm doing little research on custom battery packs and it's simple, in H series GPS (compass) module is too close to the battery, it's not a rule and it depends on single pack but you can get more drifting when using custom battery, compass calibration warning or even GPS lost warning.
One guy put his GPS/compass module above the motors level, using custom build "chimney" or "tower", GPS fix within 30 seconds he said no problems with custom packs.

image;s=261x203
 
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My first suggestion is to fly again for a few min and then bring it down to land. If it drifts and doesn't respond correctly, then go up to 50' and hover. See if it's stable high and unstable low.
Remove the camera before testing. And only do the compass cal once in a grassy area.

Removing the Cam is a Super Idea
 
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All very good advice, and much appreciated. I'll give it some more test flights and REMOVE the gimbal completely. Will update soon, thanks again!
 
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So Scott, have you learned any more about your problem? Concerning the tip-over at landing, I've completely given up on the throttle-down + red button technique. Now I fly to within about 2 feet above the ground, hovering over my landing pad and tap the red button a few times to lower the aircraft gradually. When it is about to touch the ground, hold the red button down. Works flawlessly and so easy!
Concerning the toilet-bowl effect, I purchase a refurbished airframe that exhibited toilet-bowl on about half of my flights. One time it was very severe and dangerous. I sent the TH back to the vendor who replaced the flight controller. Works perfectly now. This should be your last choice if nothing else suggested in this thread doesn't help. Stay healthy.
 

PatR

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If aircraft is drifting on custom battery and after switching to Yuneec battery all is good, you got the answer.

I'm doing little research on custom battery packs and it's simple, in H series GPS (compass) module is too close to the battery, it's not a rule and it depends on single pack but you can get more drifting when using custom battery, compass calibration warning or even GPS lost warning.
One guy put his GPS/compass module above the motors level, using custom build "chimney" or "tower", GPS fix within 30 seconds he said no problems with custom packs.

image;s=261x203

Been telling people this for several years but few listen. Maintaining a sleek aircraft appearance is more important than stability for many.

Doing it right requires several inches of elevation.
 

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