Vertical take off and landing unmanned aerial vehicle (UAV) comprising a multi-propeller propulsion system (“the system”), an outer protective cage surrounding the system, an autonomous power source, a sensing system, and a control system. The sensing system has an orientation sensor and a displacement sensor. The system has at least two propellers spaced apart in a non-coaxial manner. The control system controls the flight or hovering of the UAV. The control system reverses thrust on at least one propeller distal from a point of contact with an obstacle while controlling a motor of a proximal propeller from the contact point to generate lift, the thrust of the distal and proximal propellers being controlled to exert lift on the UAV to counteract gravitational force thereon and apply a moment of rotation about said point of contact to stabilize the position of the UAV or to counteract torque resulting from inertia.

The disclosure generally relates to aircraft vehicles, specifically vertical takeoff and landing (VTOL) aircraft that include propellers. A propeller is coupled to a boom and the boom includes a boom control effector. The boom control effector is configured to direct the airflow behind or below the propeller. The boom control effector can be configured to control the yaw movement of the aircraft and mitigate noise from the propeller. A boom control effector can be a single effector or a split effector. The split effector may operate in conjunction with a boom that operates as a resonator to reduce noise produced by the propeller.

The disclosure generally relates to aircraft vehicles, specifically vertical takeoff and landing (VTOL) aircraft that include propellers. A propeller is coupled to a boom and the boom includes a boom control effector. The boom control effector is configured to direct the airflow behind or below the propeller. The boom control effector can be configured to control the yaw movement of the aircraft and mitigate noise from the propeller. A boom control effector can be a single effector or a split effector. The split effector may operate in conjunction with a boom that operates as a resonator to reduce noise produced by the propeller.

An unducted thrust producing system has a rotating element with an axis of rotation and a stationary element. The rotating element includes a plurality of blades, each having a blade root proximal to the axis, a blade tip remote from the axis, and a blade span measured between the blade root and the blade tip. The rotating element has a load distribution such that at any location between the blade root and 30% span the value of ΔRCu in the air stream is greater than or equal to 60% of the peak ΔRCu in the air stream.

An unducted thrust producing system has a rotating element with an axis of rotation and a stationary element. The rotating element includes a plurality of blades, each having a blade root proximal to the axis, a blade tip remote from the axis, and a blade span measured between the blade root and the blade tip. The rotating element has a load distribution such that at any location between the blade root and 30% span the value of ΔRCu in the air stream is greater than or equal to 60% of the peak ΔRCu in the air stream.

A multi-rotor aircraft includes a fuselage, a propulsion engine coupled to the fuselage that generates thrust to propel the aircraft along a first vector during forward flight, and rotors coupled to the fuselage, each rotor comprising blades, each rotor coupled to a motor, and each motor configured to supply power to and draw power from the coupled rotor. The aircraft includes a flight control system configured to control the motors coupled to the rotors in a power managed regime in which a net electrical power, consisting of a sum of the power being supplied to or drawn from each rotor by its motor, is maintained within a range determined by a feedback control system of the flight control system. The flight control system can also be leveraged to adjust rotor control inputs to modify at least one of thrust, roll, pitch, or yaw of the multi-rotor aircraft.

An active flow control system for generating yaw control moments for an aircraft during hover flight. The system includes right and left yaw effectors disposed proximate the right and left wingtips of the wing. A pressurized air system includes a pressurized air source and a plurality of injectors operably associated with the right and left yaw effectors. Based upon which of the injectors is injecting pressurized air, the right and left yaw effectors generate no yaw control moment, generate a yaw right control moment or generate a yaw left control moment.

An active flow control system for generating yaw control moments for an aircraft during hover flight. The system includes right and left yaw effectors disposed proximate the right and left wingtips of the wing. A pressurized air system includes a pressurized air source and a plurality of injectors operably associated with the right and left yaw effectors. Based upon which of the injectors is injecting pressurized air, the right and left yaw effectors generate no yaw control moment, generate a yaw right control moment or generate a yaw left control moment.

An airfoil segment for inclusion in an aircraft wing is provided. The multi-element slotted airfoil segment has at least one propeller operatively located in a slot communicating therethrough for improved low speed performance and control. Upstream propeller flow field effects generated allow the front portion of the airfoil segment to be structurally efficient thicker airfoils with higher lift-to-drag laminar airfoils or higher maximum lift coefficient designs. The downstream propeller flow field acting on the aft portion of the airfoil segment increases lift and allows flaps on the aft portion to provide control forces/moments at static or low flight speeds for short or vertical take-off.

An airfoil segment for inclusion in an aircraft wing is provided. The multi-element slotted airfoil segment has at least one propeller operatively located in a slot communicating therethrough for improved low speed performance and control. Upstream propeller flow field effects generated allow the front portion of the airfoil segment to be structurally efficient thicker airfoils with higher lift-to-drag laminar airfoils or higher maximum lift coefficient designs. The downstream propeller flow field acting on the aft portion of the airfoil segment increases lift and allows flaps on the aft portion to provide control forces/moments at static or low flight speeds for short or vertical take-off.