APM 2.8 - Lost Throttle Control

Hello All,
Thank you for taking the time to read this post. I appreciate any feedback (good or bad). If i’m posting in the wrong place or not following guidelines, let me know!

I have a relatively large/heavy copter that I’ve been engineering (designing in cad and 3D printing all the parts). I’ve been doing some small flight tests and testing as I go. I was able to get stable flight after tuning PIDs and adjusting some of my throttle responses, etc. That being said it has been flying good at low alts for the past couple of days. So, today I went out into a large field and started flying. It was flying good for a while and then started to yaw by itself (i was able to control it completely, so i just kept flying with it because the yaw was something i could probably trim out). While flying it literally just put the pedal to the metal and throttle was completely uncontrollable. I still had control over the roll/yaw/pitch, but the drone just wouldn’t come down for the life of me. After some time of just keeping the drone in the air, i decided to switch flight modes to land mode (3cm/s descent). At this point it just fell out of the sky. I flipped modes back as it was falling and was able to stabilize a little bit before crashing with minor damage.

I plan on trying to look at some of the flight data if possible and running some more test with props off, also checking fail safes, etc. The only thing i could think that it could be is that my minimum throttle was still enough for it to climb? Not sure exactly. First drone build.

Arducopter APM 2.8
920kv motors
11x4.5 props
9,000mah lipo 3s battery
standard pdb
flysky fs-ia6b 6 channel 2.4ghz radio/reciever
some basic fpv gear
gopro strapped on…
3d printed custom frame/arms, mounts, etc. Arms flex slightly on takeoff, but flight is stable. Was tweaking out oscillations and vibrations.

my throttle accel PIDs are set to the following

Throttle Accel (Accel to motor)
P = 0.4211
I = 0.8422
D = 0

Wondering if the integral is out of control and just causes it to keep thrusting upward?

I just did a bench test with no props and everything seemed perfect (granted the telemetry wasn’t detecting any movement)

You need to post the log file from the APM.

I downloaded the logs, and these are the only two from the timeframe of the crash. Not sure if they are helpful. I replayed the logs and it didn’t seem like they were the right flight logs.

2018-02-07 17-35-42.tlog (207.3 KB)
2018-02-07 17-52-36.tlog (532.8 KB)

Not the tlogs, the flight log (dataflash) from the FC.

Sorry if i’m being thick-headed. I opened mission planner, connected to my quad via USB-Com and went do “DataFlash Logs” downloaded all logs and then uploaded the two that were generated around the time of the crash. Is there something i’m missing?

You need the .bin or .log file. The tlog (telemetry log) is of limited value.

Okay, i found the .bin files. Unfortunately they’re not dated properly. I threw them in a zip folder and hosted them on a private server. here is the download link

My .bin files were too large to upload all at once.


You don’t have enough logging data enabled to determine much and no one is going to go thru 30 log files searching for a solution. Clear them all, set the log bitmask for 2046 and make another flight and post that log. What is the all up weight of the craft?

Okay, no problem. I’ll set the bitmask. I’m going to drop back and punt anyways. Going to default the apm and radio. Recalibrate ESCs and start from ground zero. New blades and gps should be here Monday, so hopefully i’ll know more this week. I’ve been flying without a gps up to this point.

Thank you for your time and support will post back once i have clean data.