Mikrokopter Coaxial experts

[ebawho]

Hey guys, so I just got my x8 build put together and it flies fairly decently now with the default mk settings, but I noticed shorter than expected flight times. I looked at the current draw for the motors and they seem all over the place. The only pattern I see is that all the ccw spinning motors have a higher current draw. Wouldn't that make everything yaw ccw? Does anyone else flying mk coax set ups have any insight into this?




Here are the numbers




Avg. max
Motor 1 5.7 10
Motor 2 5.8 10.7
Motor 3 9.0 13.4
Motor 4 11.1 14.0
Motor 5 11.2 16.6
Motor 6 11.6 16.6
Motor 7 6.9 10.1
Motor 8 7.9 11.3




And here they are arranged as they are on the copter, I'm using the x8 setup from the mk wiki: Mikrokopter.de/ucwiki/mkm




Top motors on top




5.7......9.0
11.2....6.9




11.1.....5.8
7.9.......11.6

 

[smartaerials]

Fligh times will be reduced, its in the nature of coaxial setups due to energy los caused by to top props air flux on the botom ones.To obtimize performance you have two options:
a)Prop combination:Botom props may have biger pitch or larger surface in order to reduce flux efect.
b)Decreasing the % in the top rotors on the MIXER Table if using the same props.In my case I found optimum performance in 54 top motors and 64 on the botom ones.Anyways,the real guide is AMP consumption wich should be fairly similar in all motors.
Heres my MK Dodeka, 14minute flight with 2x6000 4s batts.
https://www.youtube.com/watch?v=StGuBfcKQ1M

 

[FerdinandK]

Your motors are not sufficiently leveled, you have to improve that. If you power consumption of CW & CCW is almost the same (on top and bottom) your motors are sufficiently leveled.

best regards
Ferdinand

 

[multirotorxy8]

Ferdinand, any tips on leveling the motors on an x8, I do it by eye comparing it to a t-square as I don't have right angles to press the square against on the motors once they are on the booms.

Your motors are not sufficiently leveled, you have to improve that. If you power consumption of CW & CCW is almost the same (on top and bottom) your motors are sufficiently leveled.

best regards
Ferdinand