An aircraft with the mechanics of bird flight was first envisioned by Leonardo da Vinci in 1485. Though scientists only recently have started experimenting with the bird’s flapping wings mechanism for the aircraft.
One of the most impressive of the new flock is a startup called Volerian that claims to be using a unique propulsion system which was never tested before. Volerian’s VTOL aircraft propulsion system has a series of flapping wings mounted in large ducts.
The wing motion is driven by a cam connected to three wings to keep the motor loading constant. Aircraft using a large array can simply change motor speed for control.
A second fixed “stator” wing is located downstream to further increase efficiency. The flapping action of the wing creates a stream of thrust producing vortices.
In case of power loss, the wings can be released to flutter against the airstream coming up through the bottom of the vents as the aircraft falls, acting a bit like a parachute.
Aeronautical company valerian has presented its newly-developed system at farnborough international airshow 2018. This rig was running at a slow speed but it demonstrated that these moving wings will be almost silent:
