Tip gap control systems with active blade tips

A rotorcraft having a vertical takeoff and landing flight mode and a forward flight mode, the rotorcraft comprising:

• a fuselage;
• a flight control computer comprising:
• a tip gap monitoring system including one or more sensors;
• and
• a blade length control module configured to generate a blade tip actuator command in response to the rotorcraft converting between the vertical takeoff and landing flight mode and the forward flight mode;
• and
• a proprotor system coupled to the fuselage and in data communication with the flight control computer, the proprotor system comprising:
• a duct;
• a plurality of proprotor blades surrounded by the duct, each of the proprotor blades including an active blade tip movable into a plurality of positions including a retracted position and an extended position;
• and
• one or more actuators coupled to the active blade tips;
• wherein, the tip gap monitoring system is configured to monitor a tip gap between the proprotor blades and the duct;
• and
• wherein, the one or more actuators are configured to move the active blade tips between the retracted position and the extended position based on the blade tip actuator command, thereby controlling the tip gap between the proprotor blades and the duct.

A method for controlling a tip gap for a ducted aircraft having a vertical takeoff and landing flight mode and a forward flight mode, the method comprising:

• monitoring a tip gap between a duct and a plurality of proprotor blades using one or more sensors;
• generating a blade tip actuator command in response to the ducted aircraft converting between the vertical takeoff and landing flight mode and the forward flight mode;
• transmitting the blade tip actuator command to a proprotor system including the duct and the proprotor blades, the proprotor blades including active blade tips;
• and
• moving at least one of the active blade tips between a retracted position and an extended position in response to the blade tip actuator command, thereby controlling the tip gap between the proprotor blades and the duct.