Method of assemblying and operating an autorotating payload delivery device

A method of assembling an air drop device configured to be deployed from an aircraft and travel along a flight path to a predetermined landing destination, the method comprising:

• providing a payload configured to be delivered from the aircraft to the predetermined landing destination;
• attaching a tail-kit assembly to a first end of the payload thereby defining the air drop device, the tail-kit assembly comprising
• a rotor blade assembly comprising
• a plurality of rotor blades having a vertical central axis of rotation proximate the first end of the payload, and
• a plurality of pitch link control servomotors that are configured to input a collective pitch control and a cyclic pitch control to each of the plurality of rotor blades via a swashplate,
• wherein the plurality of rotor blades are configured to passively rotate about the vertical central axis of rotation under power only generated by an airstream parallel to the vertical central axis of rotation impinging upon the plurality of rotor blades, and
• a flight control portion controlling the plurality of pitch link control servomotors to input the collective pitch control and the cyclic pitch control to the plurality of rotor blades of the rotor blade assembly;
• and
• controlling, by the flight control portion, the air drop device along the flight path to the predetermined landing destination by
• navigating the air drop device via the cyclic pitch control, under control of the flight control portion, by controlling a rotor assembly to rotate a leading-edge of each blade of the plurality of rotor blades of the rotor assembly to a 90-degree negative leading-edge angle relative to a plane of rotation of the rotor assembly and parallel to the vertical central axis of rotation and the airstream, thereby enabling the air drop device to travel at a maximum vertical descent speed along a portion of the flight path, and
• producing a vertical thrust force via the collective pitch control of the rotor blade assembly during an end portion of the flight path, wherein the vertical thrust force is produced by rotational energy from the passively rotating plurality of rotor blades;
• and
• removing the tail-kit assembly from the first end of the payload after the payload is delivered to the predetermined landing destination.