Fixed wing quad WITHOUT control surfaces - Help please!


Hi guys, I am new here and I have a problem which I see as being very simple yet I can’t get anyone to help,

I am developing a concept of electric VTOL aircraft with fixed wings, it is very similar to Airbus Vahana, with 2 staggered wings and 4 props per wing. I have two Pixhawk 2 in two experimental planes I am developing and I would like to adapt the SW to something more specific to my concept. Unfortunately, none of the VTOL options in Ardupilot/PX4 fit my concept.

I am using the copter firmware (Ardupilot build, mainly because of the Landing gear function) to fly the aircraft. My aircraft is controlled like a quad in vertical flight (I have 8 props for redundancy and have duplicated outputs to 4 groups of 2 props). I rotate my wings using a servo linked to the landing gear function (that way during landing the aircraft transition back to vertical automatically as the landing gear deploys). My aircraft transition from vertical to horizontal flight pretty well but once transitioned I want to control the aircraft with only thrust, I have NO control surfaces at all.

It works OK so far but there are 2 problems:

Problem #1, yaw and roll are inverted in horizontal flight compared with vertical flight, which makes it a little difficult to control by the pilot and I suspect difficult to stabilize by the autopilot too (as the autopilot does not “know” that yaw and roll are inverted).

Problem #2, I don’t believe the autopilot can control the aircraft in horizontal flight and RTL or follow a mission because the autopilot does not “know” that my props are now applying forward thrust (rather than upward thrust).

I noticed that there are a number of VTOL options in both Ardupilot and PX4 builds but none of them attempt to control the aircraft using only CCW and CW props in both vertical and horizontal flight.

Would anyone be able to help me create a new configuration that matches my airplane so that it can be flown safely with my PX4 in both vertical and horizontal configurations using only my props? (What is mean by safely is both in manual flight and in automatic flight, being as part of an automated mission or following the trigger of a failsafe).

I hope someone will be able to help,

Many thanks,


please send drawing of this concept .


yaw and roll are inverted in horizontal flight compared with vertical flight

I believe this was fixed in 1.9.0