The present disclosure relates to a vertical takeoff and landing (VTOL) aircraft (100) and a propulsion system (600) thereof. The propulsion system (600) comprises a primary rotor (108) configured to couple to an airframe (102) and oriented to generate a vertical thrust relative to the airframe (102), a drivetrain (626) operably coupled to an engine (602) and configured to mechanically drive the primary rotor (108), and a plurality of tiltable secondary rotor assemblies (114) configured to be disposed about the primary rotor (108). The primary rotor (108) comprises a plurality of collective-only variable-pitch blades. Each of the plurality of tiltable secondary rotor assemblies (114) may have a secondary rotor (116) and an electric motor (608) to drive the secondary rotor (116). An electric generator (606) operably coupled to the engine (602) or to the drivetrain (626) may be configured generate electric power for each electric motor (608) of the plurality of tiltable secondary rotor assemblies (114). Each of the plurality of tiltable secondary rotor assemblies (114) is configured to tilt between a vertical configuration (200b) and a horizontal configuration (200a) as a function of a phase of flight of the VTOL aircraft (100).

An improved aircraft design to harness advantages of vertical or short-takeoff and landings (V/STOL) and efficient horizontal flight. Configuration improves aircraft flight stability and efficiency in flight profiles: (1.) vertical flight; (2.) transition to and from horizontal flight and; (3.) horizontal flight on wings. The aircraft is capable of stable flight at any airspeed from hover to its maximum designed speed. It has the possibility of a controlled emergency landing using autorotation or, wings or, a combination of the two. Aircraft design includes: multiple thrust sources and, wings free to rotate on a spanwise axis. Wing rotation is independent—not coupled—with either the fuselage or, the thrust sources. Wing configurations include single, tandem or, multiple sets. Wings are coupled each other such that rotation induced in one wing affects rotation in all wings. Thrust sources are directed vertically during hover and some degree forward of vertical for horizontal flight. Thrust sources for vertical and horizontal flight can be the same rotors, such as in tilt-rotor configurations; or, divided between vertical flight rotors and horizontal flight rotors, such is in lift and cruise (a.k.a. lift and thrust) configurations.

There is provided a composite air vehicle system including: a first air vehicle capable of independent aerodynamic flight; a second air vehicle capable of independent aerodynamic flight; and at least one connector element configured for reversibly interconnecting the first air vehicle and the second air vehicle in tandem arrangement to provide a composite air vehicle capable of aerodynamic flight. The composite air vehicle system is configured for enabling at least in-flight separation of composite air vehicle into the first air vehicle and second air vehicle, and for enabling each one of the first air vehicle and said second air vehicle to operate independently of one another.

There is provided a composite air vehicle system including: a first air vehicle capable of independent aerodynamic flight; a second air vehicle capable of independent aerodynamic flight; and at least one connector element configured for reversibly interconnecting the first air vehicle and the second air vehicle in tandem arrangement to provide a composite air vehicle capable of aerodynamic flight. The composite air vehicle system is configured for enabling at least in-flight separation of composite air vehicle into the first air vehicle and second air vehicle, and for enabling each one of the first air vehicle and said second air vehicle to operate independently of one another.

A multirotor aircraft that includes a chassis, three or more vertical rotors, one or more free wings and one or more fixed horizontal rotor. The free wing is attached to the chassis by an axial connection so that the angle of the free wing is changed relative to the chassis according the flow of air over the free wing. The fixed horizontal rotor enables the multirotor aircraft to lower and climb while flying forward at a stable horizontal pitch of the chassis.

Methods, apparatus, systems and a vertical take-off and landing (VTOL) vehicle are provided. The VTOL vehicle includes: a fuselage having longitudinally a front section, a central section and a rear section; a first lifting surface comprising two wings respectively secured to opposite sides of the rear section of the fuselage; a second lifting surface comprising two wings respectively secured to opposite sides of the front section of the fuselage; where each wing comprises at least one engine module, each of the engine modules being pivotally coupled to the wing and each engine module being independently controlled for transitioning between a vertical mode of flight and a horizontal mode of flight.

Methods, apparatus, systems and a vertical take-off and landing (VTOL) vehicle are provided. The VTOL vehicle includes: a fuselage having longitudinally a front section, a central section and a rear section; a first lifting surface comprising two wings respectively secured to opposite sides of the rear section of the fuselage; a second lifting surface comprising two wings respectively secured to opposite sides of the front section of the fuselage; where each wing comprises at least one engine module, each of the engine modules being pivotally coupled to the wing and each engine module being independently controlled for transitioning between a vertical mode of flight and a horizontal mode of flight.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings zin a staggerwing configuration with first and second swept pylons extending therebetween. A distributed thrust array is attached to the airframe. The thrust array includes a first plurality of propulsion assemblies coupled to the first wing and a second plurality of propulsion assemblies coupled to the second wing. A flight control system is coupled to the airframe and is configured to independently control each of the propulsion assemblies. The first plurality of propulsion assemblies is longitudinally offset relative to the second plurality of propulsion assemblies such that rotors of the first plurality of propulsion assemblies rotate in a different plane than rotors of the second plurality of propulsion assemblies.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings zin a staggerwing configuration with first and second swept pylons extending therebetween. A distributed thrust array is attached to the airframe. The thrust array includes a first plurality of propulsion assemblies coupled to the first wing and a second plurality of propulsion assemblies coupled to the second wing. A flight control system is coupled to the airframe and is configured to independently control each of the propulsion assemblies. The first plurality of propulsion assemblies is longitudinally offset relative to the second plurality of propulsion assemblies such that rotors of the first plurality of propulsion assemblies rotate in a different plane than rotors of the second plurality of propulsion assemblies.

An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or maybe otherwise configured.