Please help with flight issues

[JosephCook]

I am hoping someone can please help me with an issue I'm having. I have flown the DJI Phantom for about 2 years and then I upgraded to a custom built Hexacopter recently. I finally seem to have all the kinks worked out but it is giving me other issues now. I shot a video today, while not taking it to high for safety reasons. I cut all the semi-smooth stuff at the beginning and put the bad stuff at the end all together so you could see what it was doing. It was flying smooth and steady on GPS and Atti mode and at random times, the hexa would act like it was going in to convulsions or like small seizures. Possible gains not set high enough? Too high? Interference? Everything is balanced. Any ideas? Also, how hot should the motors and ESC's get.

Everything is brand new, iPower iBM2814Q 750KV motors, ipeaka iq 40a opto hv brushless esc with simonk firmware, DJI Naza-m V2, Hitec Optima 9 channel receiver, Hitec Aurora 9 radio

Password for both videos is: flight

From Hexa camera -
http://vimeo.com/m/101187323

From phone view - another day -
http://vimeo.com/m/101868413

 

[simondorr]

Hi, came across your thread and I seem to be having similar issues with a self build Hex. Had four really difficult flights yesterday resulting in a minor crash and damage to one of the skids. All gains were at 100%, I had planned to gradually increase them rather than go too high and have to reduce them. This did not work as the Hex kept on getting into a state of oscillation resulting in a rapid return to earth, luckily as they were the first flights I kept the altitude to no more than 10 feet.

Changed the gains to those recommended by dji for the F550 (as it was the closest), running initially on a 3S battery and took the air again today. I had a successful 6 min flight with a 3S 2200mah with a really gentle and controlled landing and only a minute hint of oscillation which I was planning to slowly eliminate by adjusting the gains. Decided to run on a 4S and initially everything was the same, very smooth and again only a slight hint of oscillation then she started oscillating which got worse ending in a roll of death and just dropped out of the sky. Just before I could hear an alarm from the Hex, not sure what this was. I did have a low battery alarm fitted but I checked the battery afterwards and it still had 78%. The link for the video is below, the stats are as follows:
Tarot Iron Man 680 Frame
Naza-M V2 4.02 firmware
T-Motor 35 Amp SimonK 600MHz ESCs
13 x 4 CF Props
AX-2810Q 750KV Motors from Hobbyking
Zippy 4S 2200mah 40C Battery
Basic Gain: Pitch 170, Roll 170, Yaw 150, Vertical 140
Attitude Gain: Pitch 170, Roll 170
Amazingly not a huge amount of damage done. Video link: http://youtu.be/AG4LEwpgcns

Have posted this into a number of threads in the hopes that someone will enlighten me, if I get anything I'll let you know.