Phantom 4 pro plus only wants to play lawn dart

[spaz_12]

So I bought this drone fairly cheap from a guy that I work with because it'd been wrecked. I like fixing stuff and thought a drone would be a good challenge. Even though I'd flown rc heli's years ago, I didn't and still don't want to keep it, basically wanted to make a small profit. That said, I don't want to sell a faulty drone and want to fly it at least a few times to make sure that I actually fixed it. And the obvious problems it had were 2 of the gimble arms/mounts, gimble yaw motor, top shell, and a new case for one of the batteries. All done and looks good as new and camera point in the correct position. Yay. But the **** thing has so far refused to do anything other than take off, hover for a few moments and then lose its freaking mind, roll over on its back and then play the lawn dart game.
But I'm pretty sure that my assumptions that if I can fly a completely unstable heli no problem, then surely flying a drone would be a walk in the park, might be slightly off the mark and that these things are a bit more complicated than I thought. But if we're being honest here, a quick search on YouTube on how to fly these as beginners doesn't yield the most informative results. Not a single one of them (that I watched) mentioned magnetic fields, which from reading this thread, Compass calibration issue in port is probably my issue, but I went to all the trouble of downloading a few programs and gathering the log files, and figure that I should probably ask the experts here to take a look at the files and tell me what ya'll think before I go assuming again and destroy the **** thing. Luckily, after 4 attempts of repeating the same thing over and over again, and only after damaging one of the landing struts, did I realize my insanity. Yay, I get to separate the two clam shells again, what fun! Not really.

Anyway, at this point , I have zero doubts that I did anything right as far as where the drone should be placed to correctly take off and then fly. Every single time was either from a concrete sidewalk, right next to one or even worse, a concrete pad covering what I believe is storm drainage. All of it within maybe a 20 foot perimeter and only the concrete pad being level and away from trees. Sorry, really did believe that these couldn't be hard to fly, or at least not so **** sensitive. Back in the days I only ever had to worry about the gyro...

Attached the .txt file and this is the MEGA link to the DAT file from the drone: 62.5 MB file on MEGA

Thank you in advance,
L Hall

 

[Starz]

From past experience with what you have, I have noticed that a crashed P4P that has been repaired most times will benefit from an IMU calibration. Was that done with what you worked on?

 

[spaz_12]

Thanks for the reply. Yes, I've done the IMU along with Vision and compass, which I now think didn't really need to be done according to the above referenced thread.

 

[Capt KO]

Any motor warnings in logs? Appears 1 or more are not holding speed after takeoff. Spin by hand to check for binding or check for an overheated motor after lawn darts game. Better yet, you can lock the drone down to the ground or table, run it up to speed and visually look for a motor failure. Can also check for overheated motor (by touch or temp guage) after turning off props. A bad motor is easily replaced with your previous experience.

 

[spaz_12]

Any motor warnings in logs? Appears 1 or more are not holding speed after takeoff. Spin by hand to check for binding or check for an overheated motor after lawn darts game. Better yet, you can lock the drone down to the ground or table, run it up to speed and visually look for a motor failure. Can also check for overheated motor (by touch or temp guage) after turning off props. A bad motor is easily replaced with your previous experience.

I didn't see any warnings in the logs. Just responses from the drone that I didn't command. Had it do auto takeoff and once stable and hovering I gave it small yaw commands, which it did two or three with no issues and then went crazy. Might have given it a bit of collective (?) throttle up (?), but only minor. Alsop, not only did I attempt to take off on or near concrete, but I also (props not running but powered up) picked it up once or twice and moved it to different locations when I noticed grass interfering with the cameras movement. Could have been a whole foot in altitude difference... Problem?


I pulled it apart and fixing the landing struts right now and looking it over very carefully for any other damage. When I get it put back together I'll strap it down to my electric scooter and give er the beans to see how the motors act. Should I go an entire minute? Should the controller give me a warning if there's no obvious issue? Either way I'll pull and post the logs tomorrow.

Thanks for the replies.

 

[spaz_12]

Had to go down to Marine base in Riverside yesterday to help my kid pack his stuff so didn't get a chance to fly drone but will do so shortly. Could have jjust waited to post after flight but my mind goes a mile a minute and I forget some things that I want to ask. So, while I'm thinking about it, anyone have any thoughts on aftermarket props? More specifically, MasterAirscrew? I bought a set of the "stealth" ones and I'm really not impressed at all. They have casting burrs all over them, even on leading and trailing edges and the ones that spin clockwise to mount had casting flaws on the inside that prevented them from going in, turning and then rising back up to lock in place. They would come up a bit and being the first time flying these I didn't want to break the plastic locking tabs and so I thought the force I was using to test if they were seated correctly was sufficient. Apparently not and twice before flight I gave it a good bit of throttle and then backed off, both times causing enough breaking force to have the props part ways with the motors. Of course when they came back down neither of them landed in the soft grass, but instead on the concrete sidewalk which scratched the heck out of them. Basically ruined them aesthetically since they're black and the scratches are very noticeable. Parting ways with the motor would cause a bit more concern I suppose and so until about twenty minutes or so ago I used that as the threshold to consider them ruined. But for some reason I stuck them on the motors, was thinking of tracking blades like we did for helicopters and so was looking at their sideways profile and noticed that the two white (clockwise lock) props were sitting closer to the motors. Sure enough, casting mark burrs were causing them to not come back up and sit correctly in the fully seated position. Good thing that they don't cost near as much as set of heli blades. For a company that touts its blades being used by military, I question someones decision on that.

Anyway, off to go test the drone in the high schools grass field right down the street.

 

[BudWalker]

So I bought this drone fairly cheap from a guy that I work with because it'd been wrecked. I like fixing stuff and thought a drone would be a good challenge. Even though I'd flown rc heli's years ago, I didn't and still don't want to keep it, basically wanted to make a small profit. That said, I don't want to sell a faulty drone and want to fly it at least a few times to make sure that I actually fixed it. And the obvious problems it had were 2 of the gimble arms/mounts, gimble yaw motor, top shell, and a new case for one of the batteries. All done and looks good as new and camera point in the correct position. Yay. But the **** thing has so far refused to do anything other than take off, hover for a few moments and then lose its freaking mind, roll over on its back and then play the lawn dart game.
But I'm pretty sure that my assumptions that if I can fly a completely unstable heli no problem, then surely flying a drone would be a walk in the park, might be slightly off the mark and that these things are a bit more complicated than I thought. But if we're being honest here, a quick search on YouTube on how to fly these as beginners doesn't yield the most informative results. Not a single one of them (that I watched) mentioned magnetic fields, which from reading this thread, Compass calibration issue in port is probably my issue, but I went to all the trouble of downloading a few programs and gathering the log files, and figure that I should probably ask the experts here to take a look at the files and tell me what ya'll think before I go assuming again and destroy the **** thing. Luckily, after 4 attempts of repeating the same thing over and over again, and only after damaging one of the landing struts, did I realize my insanity. Yay, I get to separate the two clam shells again, what fun! Not really.

Anyway, at this point , I have zero doubts that I did anything right as far as where the drone should be placed to correctly take off and then fly. Every single time was either from a concrete sidewalk, right next to one or even worse, a concrete pad covering what I believe is storm drainage. All of it within maybe a 20 foot perimeter and only the concrete pad being level and away from trees. Sorry, really did believe that these couldn't be hard to fly, or at least not so **** sensitive. Back in the days I only ever had to worry about the gyro...

Attached the .txt file and this is the MEGA link to the DAT file from the drone: 62.5 MB file on MEGA

Thank you in advance,
L Hall

It would appear that the right front motor has a problem. Compared to the other motors the current is generally higher and very erratic. Here the red plot shows the right front motor current.

Looking at the last second or two of accelerometer data the impact with the ground occurs at 92.418 secs. Immediately before that the right front was commanded to 100%.

Also, the P4 started tumbling; rolling CW, yawing CCW, and pitching down/forward. All consistent with right front reduced propulsion.

I'm guessing the right front motor is the culprit.

There were no indications of a compass problem.