Hey Everyone:

I have a heavy home built quadcopter and am having some issues getting it properly tuned. I've tried to give as much detail as possible. Hopefully this will help! Thank you so much for your help, input, and suggestions!

ISSUES

  1. Slow Yaw after takeoff
    The copter slowly yaws counter clockwise for at least a minute. Eventually it looks like stops. I've checked the mounts, and they appear to be level and rotated straight  (I checked what I could with a level). I've also moved all ESC and power cables as far away as I could. I've done the manual compass calibration dance and set my declination. I'm not sure what PID to get this to lock in.
  2. Jumpy Alt Hold
    When I engage the Alt Hold, the copter appears to be very jumpy. It will surge up and then down, sometimes even landing! I've checked my raw z-accel and it looks to be within range. (See below) I've also set my THR_MID to my average throttle (700), which I know is high, but this is a heavy copter. See spec below. Maybe I need to try larger props?

QUADCOPTER SPECIFICATIONS

  • Homemade Aluminum Frame
  • Heavy! Approximately 5lbs (2.27kg) fully loaded (Battery, Camera, FPV hardware)
  • 4x eRC BL450S Motors (950KV)
  • 10 x 4.5 Propellers (I also have 11 x 4.7 I can try)
  • Turnigy Plush 30A ESCs

I've tuned it using the great tuning guide on this forum. I wish this was available for all the PID's! It flys great in stabilize mode (other then the initial yawing). Also, V2.8.1 was much better for me using ALT HOLD. I'm sure once I get this tuned up, it will be better then ever.

GRAPHS & PIDs

Raw Accel (XYZ)

3691022984?profile=original

Mag Field vs Throttle

3691023231?profile=original

Raw Mag vs Throttle

3691023001?profile=original

Throttle IN (CH3) vs Throttle Out

3691023138?profile=original

Throttle Vs Heading

3691023262?profile=original

Raw Pressure vs Abs Scaled Pressure

3691023279?profile=original

VCC Power

3691023248?profile=original

PIDs

3691023305?profile=original

Quadcopter Test Flight.log

Quadcopter Test Flight.tlog

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Replies

  • I just added a screen shot of my PIDs at the bottom.

  • T3
    Your zAccel looks marginal. You need to work on your vibration. I would try larger props, 70% to hover does not leave you much room. Your Vcc looks messed up as well. Are you using 3DR power module?
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