I recently upgraded to the APM2.0 for my aerial video platform (F550 clone from Hobbyking). I followed all instructions and brushed up on my PID tuning skills, but on my maiden flight the helicopter had some seriously strange characteristics. First of all...here's my setup:
APM 2.0 with v2.6 firmware
F550 clone with integrated PDB
6x Turnigy Plush 30A ESC
6x NTM 2830 750kV motors
Turnigy 4s 5000 mAh
Gemfan 10x4.5 props
Dx7 Tx & AR7000
AeroXcraft landing gear/camera mount
Pretty standard setup really. Now - as for the strange characteristics: on take off the copter had odd drift, very unstable yaw, very unpredictable throttle response, and it was generally un-flyable! I've gone through some PID tuning troubleshooting with the help of some folks on this site, but still no headway. After reaching a point of complete frustration I decided to revert to my last known flyable settings with my old HK KK2.0 board and HK Orange 6 ch Rx. Thinking I'd at least be able to get off the ground and have some fun until the new 2.7 firmware releases this week. WELL, I had the same problems but even more exaggerated! Terrible throttle response, weird pitch and roll issues (poor stabilization with verified settings from several days ago), and yaw was all out of whack. I've re-calibrated the ESC's both manually and automatically, checked prop rotation, board orientation and firmware, etc etc etc. I'm really flustered and don't know what else to do! Any help is greatly appreciated!
do you have video of it flying?
just trying to think of the most likely things that could have happened since you last had the HK board on there - if youve suffered a few bumps with the ground your props may be off balance and causing vibrations. other than that perhaps the motors are slightly misaligned?
No bumps with the ground since the last successful flight & i'm not sure how the motors could be misaligned b/c the frame will not really allow that. The really frustrating (but also comforting) part is that I disconnected the APM 2 and reverted to the HK board which is giving me the same issues. I feel confident that it's not the board, but would a bad motor bearing or poorly balanced props/motor cause this much interference?
I will try to get video of my flight issues tonight.
Video of flight issues....the racing throttle is not me increasing it. I have no idea what is going on!
Hi will, I'm sorry to pound this issue again, but your hexa seems to be achieving a too high rotation before taking off, wich usually is a symptom of propellers mounted wrong way. Make sure all your propellers have the lettering (with size and pitch 10x4.7 or so), facing upwards. Also make sure the pushers are turning clockwise and the regulars turning counter clockwise. Don't be offended or consider this as a noob issue, because it's not :) often experienced flyers make mystakes due to confidance, I believe most of us have 1 or 2 issues wich cause embarassment, but no one is here to judge, only to help.
That is definitely a rookie move that I didn't even think of! Sometimes it's something so obvious like that...
So to refresh my memory - clockwise rotating props are 1047R and counter clockwise are 1047? Motor layout and rotation seems to be okay, but I will check all that and get back to you.
okay so I checked and double checked the rotation and prop orientation. everything is good. What is strange is that when I bring up the motors to just where they start to spin the perpendicular left motor seems to start to race...when I yaw right it seems like only the front left motor starts to spin faster and when I jay left all the motors start to spin and the hex starts to shake violently. I have checked and double checked firmware setup and I am in Hex "x" mode...ARGH! :)
That is indeed strange, I mention the motor sound because I have a 1800gr hexa with the same approx specs than yours (xaircraft diy hexa frame vs your dji) and sunnysky 2212 980kv motors with 3s battery and mine lifts with a less rpm noise (using 10x4.7 props), but that can also be the motors that emit less noise. Have you tryied to reconfigure everything ? And I mean not only uploading firmware but, before doing that, going into cli mode, do erase and after, reset, and then, unplug the board, and reupload, and recalibrate radio. I'm suggesting this because I had a somehow identical problem wich I believe it to be corrupt eprom values and it solved re doing everything again. Another test you could make, would be connecting each esc to the RX ch3 (throttle usually) and test them to see if they respond correctly, because since you mention to be having those problems also on the other board, we might incline to rx issue, also, how are you powering the APM ? If you'r using BEC from the ESC, you should connect only the motor 1 servo cable with 3 wires and the other ESCs should only connect the white (signal wire) to the top row pin. If you're using a separate uBEC, you should set it as far away from the RX as possible, since switching uBECs can cause interference. I've seen some posts where people say it's ok to connect all the ESC BEC cables, however, from personal experience, I've seen what brown outs are :) and how they were gone after connecting only 1 cable.
Have you confirmed your radio is in ACRO mode and no mixes are active ? (do not use HELI mode)
Just confirmed everything is okay on the radio. No mixes and Tx is in ACRO mode...everything is definitely in the last known good configuration. I feel confident that the boards are okay because it seems like they're both acting up the same way (HK board is more exaggerated). Is it possible that a bad motor or non balanced props could be causing this problem? The motors are pretty cheap and they may not be suited for the payload that I'm carrying. NTM 2830 750kV. Or maybe a bad ESC? Is there a way to troubleshoot these possibilities? I have noticed that ESC #2 got really warm when I powered up my APM 2 board...maybe it is fried? Obviously i'm just spit balling, but it's really confusing what's going on!
how much weight are you carrying, whats the total flying weight? how much throttle does it need to hover?
a bad esc or a bad connection somewhere might be able to destabilize it this way, how about testing each motor and esc seperately to make sure they run at about the same speed?
Full battery 4s with 5000 mAh it hovers right at 1/2 stick...no more than 3/4 stick when battery gets down to 13.8 (ish) V. I always land before the voltage drops below 13.4. I'm not positive on total weight all up, but I'm guessing somewhere in the 4-4.5 lb range. I will try to weigh tonight. The motors are pretty warm after a 6 or 7 min flight, but not too hot to touch. ESC's are never too warm.
Also, have you checked if the ESCs have a brake feature and if some of them have it on ? That could also make strange behaviours since when they slow down some will loose rpm faster than the others.