Abstract: One example includes a passive rotor pitch control system. The system includes a counterweights that are each associated with one of a respective plurality of rotors and can be arranged to have a center of mass configured to provide a pitch torque about a pitch axis associated with the respective one of the rotors in response to rotation of the rotors about a rotation axis. The system also includes a spring forcer comprising a pitch rod and a spring configured to provide a spring force on the pitch rod. The system further includes a pitch change assembly coupled to the counterweights and the pitch rod. The pitch change assembly can be configured to rotate a pitch of each of the rotors from a first pitch state to a second pitch state in response to a sum of pitch torques associated with the counterweights being greater than the spring force.

Abstract: One example includes a passive rotor pitch control system. The system includes a counterweights that are each associated with one of a respective plurality of rotors and can be arranged to have a center of mass configured to provide a pitch torque about a pitch axis associated with the respective one of the rotors in response to rotation of the rotors about a rotation axis. The system also includes a spring forcer comprising a pitch rod and a spring configured to provide a spring force on the pitch rod. The system further includes a pitch change assembly coupled to the counterweights and the pitch rod. The pitch change assembly can be configured to rotate a pitch of each of the rotors from a first pitch state to a second pitch state in response to a sum of pitch torques associated with the counterweights being greater than the spring force.

Abstract: An air data system and method for a ducted fan air-vehicle is described. The air data system includes a plurality of air pressure sensors placed around a lip of an air duct of the ducted fan air-vehicle. The air data system calculates the speed and direction of airflow surrounding the ducted fan air-vehicle based on pressure data measured across the lip of the air duct. Additionally, the air data system may estimate forces generated by airflow surrounding the air-vehicle.

Abstract: An air data system and method for a ducted fan air-vehicle is described. The air data system includes a plurality of air pressure sensors placed around a lip of an air duct of the ducted fan air-vehicle. The air data system calculates the speed and direction of airflow surrounding the ducted fan air-vehicle based on pressure data measured across the lip of the air duct. Additionally, the air data system may estimate forces generated by airflow surrounding the air-vehicle.