New to Multirotors and have some performance questions about my tricopter

[Magnus357]

I'm relatively new to multirotors, having only a Traxxas QR4 before.

I went in feet first and bought the Batbone tricopter kit.

It's equipped as follows:

Turnigy Park300 motors
GemFan 8x45 props (CCW only)
Turnigy Plush 18A ESCs
Turnigy XGD-10HM Digital Micro Servo 2.2kg / 10g / 0.12
KK2.0

Here's a terrible picture of it:


I got it up an running the other day after taking my time to make sure everything was right.

- I've setup my KK2.0 trims so every is zeroed
- The channel move in the direction indicated on the KK2.0 (I assume when it says right/left/up/down that is the direction the TX stick is supposed to move)
- Calibrated the KK2.0 on a level surface
- Set the PI values to what was recommended on a tricopter video on YouTube

Now for the issues I'm having:

1. The tail servo assembly doesn't want to center. When my TX stick goes back to center the tail assembly wont get back to center automatically. I can move then stick a bit then release again and it seems to center. The servo I bought has equal or better specifications to the one recommended by Flitetest. Do I just need a higher quality servo or do I potentially need a stronger one? The tail assembly doesn't seem to be binding and the servo will move through the entire range of motion.

2. Once I get the tricopter into a hover it wants to yaw the the right slowly. It requires a constant left rudder input, about 25%, to keep the unit stable. I can't really tell if the yawing gets worse as throttle increases or not. Is this a KK2.0 calibration thing or do I need to be playing with the PI settings?

3. Motor temp on my tail motor seems high. After a few minutes of flight, I can touch the motor, but I can't leave my finger on it very long. It seems to be getting warmer than the two front motors. The ESCs for all motors seem about the same temp. I imagine that the tail motor has to work a little harder than the front. I don't have an IR temp gun, but supposed I had a way to measure the temp, what should I be looking at as a max temp?

I'm nervous about the motor temp as the first tail motor I had failed on the first flight. I got luck and was only about 5 feet off the ground over grass. The unit flipped backwards, but landed up right. When that motor failed, the body was so hot it burned me the instant I touched it. The failure mode had to do with the position of the motor leads. When in a certain position, the coil was shorting. That motor was a total loss.

I appreciate any guidance the more experienced folks here can provide.

 

[colorex]

1. The tail servo assembly doesn't want to center. When my TX stick goes back to center the tail assembly wont get back to center automatically. I can move then stick a bit then release again and it seems to center. The servo I bought has equal or better specifications to the one recommended by Flitetest. Do I just need a higher quality servo or do I potentially need a stronger one? The tail assembly doesn't seem to be binding and the servo will move through the entire range of motion.

Is this on the ground? Or in flight? The tricopter yaw servo acts a bit unpredictable when active.

2. Once I get the tricopter into a hover it wants to yaw the the right slowly. It requires a constant left rudder input, about 25%, to keep the unit stable. I can't really tell if the yawing gets worse as throttle increases or not. Is this a KK2.0 calibration thing or do I need to be playing with the PI settings?

Increse yaw p-gain by 10 at a time and see if this helps? Otherwise you might have to make the motor tilt a bit on a centered servo.

3. Motor temp on my tail motor seems high. After a few minutes of flight, I can touch the motor, but I can't leave my finger on it very long. It seems to be getting warmer than the two front motors. The ESCs for all motors seem about the same temp. I imagine that the tail motor has to work a little harder than the front. I don't have an IR temp gun, but supposed I had a way to measure the temp, what should I be looking at as a max temp?

Where is you battery located? try moving it forward. If you're using a 2200mAh batt, it should stick out about half inch from the front of the frame to balance the copter.

 

[Magnus357]

Is this on the ground? Or in flight? The tricopter yaw servo acts a bit unpredictable when active.

It's on the ground and in flight. When controlling the unit, you naturally correct for it, but it can create a bit of oscillation. I tested the servo without the KK2.0 board, i.e. connected directly to the RX, and it had the same performance.

Increse yaw p-gain by 10 at a time and see if this helps? Otherwise you might have to make the motor tilt a bit on a centered servo.

I'll play with that tonight.

Where is you battery located? try moving it forward. If you're using a 2200mAh batt, it should stick out about half inch from the front of the frame to balance the copter.

Ah, I bet I have my battery much too far back. I'm using a 2200, and it was fully under the tri and maybe even a little back.

 

[IBeHoey]

In regards to the yaw issue you're having, looking at your picture, it appears that you're using all standard pitched props. To help compensate for the torque of the motors, you should change the prop of one of the front motors to have it spin in the opposite direction of the other, clockwise, and use a right-handed/reverse pitched prop.