I have quite big octocopter with flat frame cinenestar type with 16" propellers and t-motor u7 420kv motors. It has 120 cm frame size. I would like to change the propellers in it to 18" to have longer flight time. I can use longer booms but the copter will be too big for my car so I am wondering about using the same booms but 4 motors up and 4 motors down like in the picture in attachment. Is that setting is as efficient like flat octo or I will lost same flight time like on coax setup ?? What kind of mixer I should use for such setting ? I am using Mikrokopter FC but I think that will be similar in APM or Pixhawk.
There was a research paper floating around on the net that showed with a ~10% overlap, there was a ~5% increase in efficiency. Don't hold me to those numbers. It was something like that. Unfortunately I don't have the link anymore.
Luc Maximilien said:
The overlapping will cause no problems but I doubt it will increase efficiency .
You can change by software the motor direction if you have black MK Esc or last version MK Esc, if you have the red MK Esc it is not possible and you have to switch two motor cables that arrives to Esc to change the rotation direction.
What is your AUW, payload and Flight Time ?
Tested 7 years ago at the beginning of multirotor adventure, as I wrote : The overlapping will cause no problems but I doubt it will increase efficiency .
When I will have same free time I will do the test ...