This is 3D printed coaxial dualcopter made from common multirotor parts.
This is how it flies: https://youtu.be/lt3TfAiue1Q
* Thrust and yaw control is
...Show more provided by 2 counter rotating propellers
* Upper motor is 2205 2300KV with 5x4.5x3 propeller rotation in CW direction
* Lower motor is 2205 2600KV with 4x4.5x3 propellers rotating CCW
* Flight controller runs INAV 2.0
* Control surfaces are rotated 45 degrees from long axis to fit servos
* flight controller is also 45 degrees rotated
* control surfaces installed with tape hinges
* any 9g servos will do
* runs on 4S battery that has to be on the top of dualcopter
* structure is provided by 2 14mm carbon pipes
* use hot glue and zip ties to secure all the parts on the carbon tubes
* each STL file has to be printed once
Required parts:
* 1 2205 2300KV brushless motor
* 1 2205 2600KV brushless motor (2300 also will do but will have less yaw authority)
* 1 5x54.5x3 propeller
* 1 4x4.5x3 propeller
* 2 14mm carbon pipes (12mm internal diameter), each around 270mm long
* 2 2g servos
* 3m bolts to secure the motors
* good adhesive tape to make control surface hinges
* some pushrods
* hot glue
* flight controller compatible with INAV
* radio receiver
# INAV mixer
```
mmix reset
mmix 0 1.000 0.000 0.000 -1.000
mmix 1 1.000 0.000 0.000 1.000
smix reset
smix 0 0 0 50 0
smix 1 0 1 -50 0
smix 2 1 0 50 0
smix 3 1 1 50 0
```
PIDs (you will have to retune depending on thrust and servo throw, they are way from perfect)
```
set mc_p_pitch = 140
set mc_i_pitch = 50
set mc_d_pitch = 10
set mc_p_roll = 140
set mc_i_roll = 50
set mc_d_roll = 10
set mc_p_yaw = 50
set mc_i_yaw = 20
set mc_d_yaw = 0
```
This is highly experimental device! During take off, do not ramp up the throttle. You have to yank it to 75% and then settle low. Control surfaces needs airflow to maintain stability
**EDIT 2018-10-04**
Updated STL files to slightly move center of gravity up improve in the air handling
