Is there possible to build a quad plane (4+1 motor) without control surfaces?
autopilot may be able to control roll and pitch with brushless motors during the fixed-wing mode.
if it possible we don’t need aileron and elevator servos and surfaces. or we can have a backup.
I have already done some tests on small Depron planes with Airmode and low rpm running Betaflight. Basically it works as long as a thrust vector can be generated (the hover engines are far enough away from the centre of gravity). A control effect only from the torque unfortunately did not work and requires an additional inclination of the drives to achieve a sufficient control force e.g. for yaw. Or 2 propellers with differential thrust are used for the wing flight drive. I´ll try to implement a small vtol variant without servos in the near future with PX4 on small targets like Omnibus F4 Nano with 2S or PixRacer 3S. Even with the BLADE Inductrix Switch AIR not all but only the rear 2 drives are swivelled to get more yaw authority. A Quad Tailsitter without servos has a missing aileron effectiveness and doesn’t look nice either, because the drives have to be far enough away from the centre of gravity.
why we need to control yaw? flying wing drones turn with bank angle. textron x5-55 don’t use elevons but uses 4 thrust vectord motor not 4+1 motor.
During the tests I made the experience that without control surfaces only with thrust vector often flight attitudes are generated without airflow, which unfortunately can only be controlled with enough yaw effect. You´re right, a delta or flying wing with elevons is perfectly manoeuvrable without yaw control. Textron can swivel all engines separately so it is possible to create extreme yaw control in FW with differential thrust. Differential panning creates Aileron in FW and yaw in hover. As a tiltrotor I have also done it with PX4 but only with individual swivel of the front 2 drives (Convergence Vtol). At the moment there is still a small problem in PX4 V1.11 which prevents the rear drive from being switched off in FW mode. Full E-flite Convergence support
With a mixer in this style it should already work with PX4 cause no engine needs to be switched off and PX4 perfectly supports differential thrust in FW. So the mentioned Textron would need 4 esc and 4 individual swivelling servos that would cover all control axes without any moving surfaces.
I previously thought of a Vtol conversion without any servos or moving parts at all.