How to implement a hexacopter coaxial model?

Hello everyone!
I’m a beginner at PX4 field and I would like if you know guys how to develop a hexacopter coaxial model and simulate it with Gazebo. I’ve reading the developement guide for a few weeks but I’m still a little bit stucked.
I started by creating that kind of airframe in ROMFS/px4fmu_common/init.d. And now i have some questions…:

  • Since my coaxial hexacopter hasn’t got any servo, it is needed to create a mixer?
  • Once defined the airframe, the only thing I need is to create the respective model files in Tools/sitl_gazebo/models?

Thank you all for your answers and nice to meet you!!

Did you manage to figure it out? Because I’m trying to do something quite similar?