An aerial vehicle including a main body having a leading edge. An inlet is recessed aft from the leading edge. Forward protrusions extend from the main body on opposite sides of the inlet. An outlet nozzle is proximate to an aft end. The inlet is in fluid communication with the outlet nozzle. Wings extend from the main body.

Disclosed is an aerial vehicle having a reduced noise signature. The aerial vehicle may be a vertical take-off and landing (VTOL) aerial vehicle. The aerial vehicle comprises an airframe and a plurality of rotors operatively coupled with one or more motors. The plurality of rotors may comprise a first, second, third, and fourth rotor. Each of the first, second, third, and fourth rotors may be arranged in a single plane and oriented to direct thrust downward relative to the airframe. In certain aspects, at least two of the plurality of rotors employ a different geometry to generate a targeted noise signature.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.

A vehicle, includes a main body. A fluid generator is coupled to the main body and produces a fluid stream. At least one fore conduit and at least one tail conduit are fluidly coupled to the generator. First and second fore ejectors are fluidly coupled to the fore conduit, coupled to the main body and respectively coupled to a starboard side and port side of the vehicle. The fore ejectors respectively comprise an outlet structure out of which fluid flows. At least one tail ejector is fluidly coupled to the tail conduit. The tail ejector comprises an outlet structure out of which fluid flows. A primary airfoil element is coupled to the tail portion. A surface of the primary airfoil element is located directly downstream of the first and second fore ejectors such that the fluid from the first and second fore ejectors flows over the such surface.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.

Falling drone warning apparatuses and methods are disclosed. The apparatus may be attached to a drone and may measure acceleration during the drone's operation in order to ascertain whether the drone is free falling. If the apparatus detects that the drone is free falling, the apparatus may activate an audible alarm to warn people on the ground of the potential danger and to afford them the opportunity to take action to avoid the drone's impact or minimize its effect.

Multiple propeller blades may be joined by tip connectors to form a closed propeller apparatus. The tip connectors may create continuous structure between adjacent tips of a first propeller and a second propeller. Use of the tip connectors may reduce vortices created near the tips of the propeller blades, which cause drag and slow the rotation of the propeller blades. The tip connectors may also reduce noise caused by rotation of propeller blades. Further, the tip connectors reduce or eliminate deflection of the propeller blades by creating a support structure to counteract forces that would otherwise cause deflection of the propeller blades, thereby improving propeller blade loading. In some embodiments, the tip connectors may be formed of a malleable material and/or include one or more joints that enable at least one of the propellers to modify a pitch of blades of the propeller.

A nosecone of an aircraft sensor probe may include a first portion defining a tip of the nosecone that is formed from a first material. The nosecone further includes a second portion aft of the first portion and formed from a second material. The second portion may define an internal volume. The second material may have a greater porosity than the first material. The nosecone may further include a third portion aft of the second portion. The third portion may be configured to arrange a microphone assembly relative to the internal volume. The nosecone may a component or subassembly or a sensor probe for the aircraft. For example, the sensor probe may include the nosecone and the microphone assembly. The nosecone may be configured to block the audio signals at the tip and reduce turbulent noise of the audio signals associated with non-parallel local flow angles of the airflow.

A drone-based audio system comprising a microphone mounted to a drone body for receiving environmental sound information. The drone-based audio system additionally comprising a processing unit configured to analyze the environmental sound information and calculate active noise cancellation information. The drone-based audio system further comprising a speaker mounted to the drone body for emitting the active noise cancellation information.

An aerial system having an obstacle detection and avoidance system is described herein. The obstacle detection and avoidance system includes a pair of ultra-wide angle lens cameras orientated coaxially along an optical axis. Each ultra-wide angle lens camera includes a field-of-view lens having a vertical angle of view greater than 180 degrees. The pair of ultra-wide angle lens cameras is orientated such that a portion of each corresponding camera field-of-view overlaps to define a viewable region of interest including overlapping vertical field angle.