This article aims at helping beginner pilots to mechanically setup a CP head.

Parts:
Linkage A / B / C – as shown in the figure
Linkage D – Linkage between CCPM servos and swashplate
Pitch Slider – slider between swashplate and hub
Timing pin – The pin that keep the pitch slider sync with hub
Mixer PS – Mixer arm at the pitch slider
Mixer BG – Mixer arm at the Main Blade Grip
Assumptions:
  1. Swash mix at 60% for Elevator, Aileron, Pitch
  2. Hitec HS65MG servos travel as reference. Servos with similar travel limit (E-Sky, Towerpro) should be working fine with the steps. Other servos with different travel limits may have the need to adjust the swash mix first.
Aim:
Setup the rotor mechanically so that 0 ° pitch appears at pitch curve 50%

Step:
Caution – Setting pitch need to move the throttle stick up and down and the rotor may start if it is not locked.



  1. Turn on Radio. Connect the battery, and make sure you locked the throttle or disconnected the motor.
  2. Set the pitch curve to 50% output. You may set it to 50% flat horizontal line, or move the throttle stick to the 50% output point.
  3. Install the servo horn. Try to make all the horns as close to horizontal as possible. (You may leave the horn screws at the moment. Secure them later when the battery is disconnected.)
  4. Adjust the Trim, Sub Trim, or Servo midpoint at the Transmitter so that all 3 servo horns are in horizontal position.
  5. Do NOT connect linkage D. Adjust Linkage C, so that the slider could have at least 5mm movement for both up and down side. (i.e. Linkage C is controlling where the pitch slider stay at 0deg pitch.)
  6. Move the swash up and down so that Mixer PS stay horizontally. This is what the length of Linkages D should be. Adjust Linkage D so that the swash keep the swash at that level. Note that the 3 linkages should keep the swash horizontal as well. If the Swash is tilted, you need to have cyclic input while hovering.
  7. Install Linkage D. Now, the 50% pitch slider position is set.
  8. Keep the blade grip at 0°pitch by a blade holder or DIY card board. (Refer to another article: How do we measure pitch)
  9. Linkage A & B are in pairs. Adjust them so that Mixer-BG becomes horizontal. Make sure both pairs are in same length. (Better measured by a caliper)
  10. Done. Set the pitch curve according to your style and keep the blades in track by adjusting Linkage A / B.
Reference:
~ 500g AUW, 4° pitch will give you around 2800 rpm for 255 wood blade at hovering.