Abstract: An aircraft can include a stacked propeller to generate lift during assent and descent. The stacked propeller includes a first propeller and a second propeller that co-rotate about an axis of rotation. In one embodiment, the blades are coupled to a rotor mast that contains an internal cavity. In one mode of operation, the first propeller and/or the second propeller can be stored in the internal cavity in order to reduce drag during flight. The aircraft can include one or more stacked propellers, such as a port propeller and a starboard propeller, which rotate in opposite directions during one or more modes of flight.

Abstract: A vertical landing and take-off aircraft VTOL transitions from a vertical takeoff state to a cruise state where the vertical takeoff state uses propellers to generate lift and the cruise state uses wings to generate lift. The aircraft has an M-wing configuration with propellers located on the wingtip nacelles, wing booms, and tail boom. The wing boom and/or the tail boom can include boom control effectors. Hinged control surfaces on the wings, tail boom, and tail tilt during takeoff and landing to yaw the vehicle. The boom control effectors, cruise propellers, stacked propellers, and control surfaces can have different positions during different modes of operation in order to control aircraft movement and mitigate noise generated by the aircraft.

Abstract: An aircraft can include a stacked propeller to generate lift during assent and descent. The stacked propeller includes a first propeller and a second propeller that co-rotate about an axis of rotation. In one embodiment, the blades are coupled to a rotor mast that contains an internal cavity. In one mode of operation, the first propeller and/or the second propeller can be stored in the internal cavity in order to reduce drag during flight. The aircraft can include one or more stacked propellers, such as a port propeller and a starboard propeller, which rotate in opposite directions during one or more modes of flight.

Abstract: An aircraft with a forward swept wing is configured to transition between vertical flight and forward flight. The aircraft includes propellers attached laterally along the wing. The propellers may be stacked propellers with two or more co-rotating rotors. The aircraft also includes booms attached along the wing and at each free end of the wing. The booms can include boom control effectors configured to direct airflow below a propeller. The aircraft includes one or more cruise propellers, configured to operate during forward flight to generate lift. The aircraft can also include control surfaces on the wings and tail that may tilt during takeoff and landing to yaw the vehicle.

Abstract: One embodiment of a microphone housing having at its base a cylindrical solid section (4) containing circuit boards (3) and on which is mounted transducer (2) and acoustically permeable basket (1). The basket is made of rigid, conductive foam providing electrical shielding, mechanical protection and wind and pop screening, without appreciably altering the acoustical characteristics of the transducer. Another embodiment is also described and shown.

Abstract: One embodiment of a microphone housing having at its base a cylindrical solid section (4) containing circuit boards (3) and on which is mounted transducer (2) and acoustically permeable basket (1). The basket is made of rigid, conductive foam providing electrical shielding, mechanical protection and wind and pop screening, without appreciably altering the acoustical characteristics of the transducer. Another embodiment is also described and shown.