wafflejock
Well-Known Member
@WaltDiesel hey ran out of room in the private messages length so pasting a response here also can get some other folks two cents if anyone has tried this. For context Walt is planning to make a 5 motor copter and my feedback below on why this might be problematic. If anyone has tried this or other "non-standard" configurations I'm sure that input would be welcome.
While this could be done i wouldn't recommend it as a starting point would say stick with 4 to start since it is mechanically the simplest option that is basically balanced as is. With 4 motors two spin one way and two spin the opposite way, whenever a motor is spinning on a frame the frame is being pushed the opposite way (equal and opposite forces). With 4 motors if each pair is spinning opposite the other then the torque on the frame basically gets equalled out to 0 so there isn't any extra rotational force to try and stop the thing from yawing in a circle. If you add a 5th motor it will apply a torque in the yaw opposite of the direction the motor spins so it would need to have that torque counter acted by the pair of motors going the opposite direction so basically you'll have three motors working together but two working against those three that need to work harder if just flying forward. It isn't impossible but just adds complications and going either 4 or 6 will keep more evenly distributed load on all the motors.
Regarding tuning I did that with betaflight as well at first with my hexacopter since I know betaflight better but the tuning in iNav is still a thing that needs to be done. iNav has tuning parameters for when it's flying autonomously vs trying to hold position vs flying manually so I still have some work to do there but nice to know it can fly by using betaflight first.
While this could be done i wouldn't recommend it as a starting point would say stick with 4 to start since it is mechanically the simplest option that is basically balanced as is. With 4 motors two spin one way and two spin the opposite way, whenever a motor is spinning on a frame the frame is being pushed the opposite way (equal and opposite forces). With 4 motors if each pair is spinning opposite the other then the torque on the frame basically gets equalled out to 0 so there isn't any extra rotational force to try and stop the thing from yawing in a circle. If you add a 5th motor it will apply a torque in the yaw opposite of the direction the motor spins so it would need to have that torque counter acted by the pair of motors going the opposite direction so basically you'll have three motors working together but two working against those three that need to work harder if just flying forward. It isn't impossible but just adds complications and going either 4 or 6 will keep more evenly distributed load on all the motors.
Regarding tuning I did that with betaflight as well at first with my hexacopter since I know betaflight better but the tuning in iNav is still a thing that needs to be done. iNav has tuning parameters for when it's flying autonomously vs trying to hold position vs flying manually so I still have some work to do there but nice to know it can fly by using betaflight first.
