And not to forget all the others, who contributed such a tremendous amount of knowledge and ideas.
The last two days I was able to test a small Y4(T4) copter:
motor/motor: 21 cm
205 gr w/o battery
MutliWii1_7
ITG3205 cutout (direct wired)
BMA020
Here are my observations:
The rear of the copter yawed a lot in the direction of the lower rear motors rotation direction.
This could be solved by changing the motor mixer as follows:
Code: Select all
#ifdef Y4
motor[0] = rcCommand[THROTTLE] + axisPID[PITCH] * 6/5 - YAW_DIRECTION * axisPID[YAW]; //REAR_1 upper
motor[1] = rcCommand[THROTTLE] - axisPID[ROLL] - axisPID[PITCH]; //FRONT_R
motor[2] = rcCommand[THROTTLE] + axisPID[PITCH] + YAW_DIRECTION * axisPID[YAW]; //REAR_2 lower
motor[3] = rcCommand[THROTTLE] + axisPID[ROLL] - axisPID[PITCH]; //FRONT_L
#endif
The idea behind this is that the upper motors thrust is lowered, because there is the rotating propeller of the lower motor
in its airstream. The efficiency of the lower motor is higher.
I do not know if there are other explanations and solutions. But to increase the relative amount of thrust of the upper motor seems to work.
The copter performes reasonable well with the standard settings. Fine tuning of the PID settings has to be done.
Rolf