The development of a Variable Diameter Tiltrotor (VDTR) demonstrator has been identified by the PSU aerospace engineering department and the Boeing supported Rotorcraft Center of Excellence (RCOE) at PSU, as a necessary requirement for future research and educational activities relating to VDTR technologies.  The demonstrator is intended to serve as a test apparatus and educational resource for the aerospace department and the RCOE.  Two design groups consisting of aerospace and mechanical engineering undergraduate students worked interdependently to complete the VDTR demonstrator.  The demonstrator used a simplified version of a jackscrew, bevel-gear actuator design being developed by the Sikorsky Aircraft Corporation to extend telescoping blades on a single rotor.  To ensure the safe operation of the demonstrator, the rotor will operate at a reduced speed and will be encased within a transparent safety cage.  The aerospace group was tasked with developing the blade extension mechanism, including all necessary gearing and drive components.  The mechanical group was responsible for the rotor drive mechanism (including controls) and the ballistic safety shield.  The mechanical group also worked to develop a design for the rotor-tilting mechanism.  This mechanism was developed such that the rotor has coordinated tilting and blade extension capabilities.