This is only the third real attempt to get a stable hover from my multirotor. Everything appears to be balanced — fore-aft CG, props, etc. — yaw seems stable, but I still require manual trim input on the Tx of about 20% right roll and 5% up pitch for it to behave as well as it does in the video. As an aside, I have Ch 6 set to adjust the 'I' value for Rate Pitch/Roll. I'd love for it to be rock steady but I'm not sure know how to get there.
Video is here: http://youtu.be/MKuDWPVwAaM and log file is here.
The other thing that concerns me is are two of the motors. After this video I checked them and motors 3 and 4 were too hot to hold tightly while the others two were barely above room temperature.
For safety, the skids are covered in foam pipe insulation and a prop protector stick was added to each arm and I'm wearing ear muffs (the sticks are from 2 carbon fiber arrows -- $3.50 each at Walmart =).
Props: APC 12x4.5
Motors: NTM Prop Drive 28-30S 800KV
ESCs: Turnigy PLush 40A
Battery: Turnigy 40C 5A 4S
Flight controller: APM 2.6 w/uBlox GPS
Receiver: FrSky D8R-II PLUS (modified antennas)
Transmitter: ER9X with FrSky ACCST 8CH module
Weight as shown: 2.4kg
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Thanks, hadn't considered that. I'll give it a shot tomorrow.
About 20% right roll and 5% up pitch. Power isn't an issue, I don't think the throttle ever got above 40%. The overheating is only on 2 motors -- the other two are more or less at room temp. The bearings on the hot motors are also louder than the others -- bit of clattering sound. I expected better from motors with less than 15 minutes run time on them.
Yeah, I really should be doing this outdoors where there's more room to maneuver but it's been raining here.
Thanks! It's been a rewarding build and it's not done yet. =)
Still no love. At least not with the CW motors. Re re re re re-calibrated everything. Again. Also re-balanced the props, correcting for some minor hub imbalance, and I disassembled the two hot motors, lubricated their bearings, and balanced their cans. The CW motors are still too hot to touch after 5 minutes while the CCW motors are cool. Bizarre.
It is more stable now, maybe adding 1% or 2% right roll and about 5% of up pitch.
At one point during the last test I lost throttle response even though I was still getting 15.1 volts from the battery.
Looking at the log file is interesting. The graph shows that motors 1 & 2 -- the CCW motors -- very nearly mirror each other in output power, while motors 3 & 4 -- the CW motors -- show they are drawing nearly twice the power!
I've done everything I can think of, from re-calibrating absolutely everything to balancing the motors bells to lubricating the bears to re-balancing the props.
The copter still requires trim at the Tx and the CW motors are still overheating.