QUAD+ VTOL with rotating back motor, storage hatches and separate yaw servo

Dear all,

I am very new to the PX4. So my apologies if i say something stupid or obvious.

I am currently making a F35 VTOL plane that has a QUAD-PLUS setup for vertical flight. (See youtube for the first hover tests, https://www.youtube.com/watch?v=VRuxMWr-To8) However i do not have a separate puller/pusher prop. Instead the back motor rotates. So in addition to its throttle i would also need a pwm pulse that slowly rotates the back motor according to the transition progress (airspeed preferably or just time based). Although the first 30 or so degrees need to rotate immediately to direct the thrust for forward speeding up.

Creating a forward speed is not done by increasing thrust on the back motor and lowering on the front to create a forward pitch like a quadcopter but is done by the back motor rotating backwards to create forward thrust and a little backwards to create a backward thrust.

When the transition is completed the other 3 props need to stop rotating because the hatches close to cover these up. I prefer that these hatches are also controlled by the transitioning to make sure that they are always open before the props start rotating and close when not rotating.

Additionally the yaw in hover mode is not controlled like a normal quad. A separate servo does the yaw. So the yaw control on the 4 quad motors needs to be disabled and a separate yaw signal needs to be available. Please note that the yaw servo remains the same for hover and forward flight.

Basically i am trying to imitate the same VTOL behavior as the actual F35. With a KK2 we are already close. But it is just not good enough.

I am trying to learn the code base (it will take a while though), I have already played with it for several days however I would really appreciate some advice.

Where to start? Can this be done without to much modification of the code base? Would the functionality that i describe be interesting to add to the master branch or is this something that is to exotic?

I guess that i will need to make my own mixer for the yaw. The VTOL tiltrotor is the closest to what i need but not quite. But how to add the extra transition functionality (motor rotating servo signal / hatches servo signal)?



You can configure a tiltrotor setup.
This is supported by default

@fly3rbug Very cool
@sanderux I’m impressed that the tiltrotor vehicle type is so flexible

@sanderux indeed impressive.
I have just not figured out on how to use it then.

How would i be able to add this control logic that the hatches have to open before the motors engage?