On August 18, 2006, about 0730 mountain standard time, a Burkhart Grob Flugzeugbau G109 motorized glider , N39262, lost a propeller blade during the takeoff initial climb from Glendale Municipal (GEU), Glendale, Arizona. The pilot/owner operated the motorized glider as a personal flight under the provisions of 14 CFR Part 91. The glider sustained substantial damage. The pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed for the local area flight, and no flight plan had been filed. The flight was originating at the time. The glider landed at GEU without further incident at 33 degrees 31.62 minutes north latitude and 112 degrees 17.71 minutes west longitude. According to the pilot, shortly after takeoff a propeller blade separated from the propeller hub. He returned to the airport and landed without further incident. A Federal Aviation Administration (FAA) inspector examined the glider at GEU, and noted that the engine had pulled away from the firewall, which was damaged. The FAA inspector reported that he was not able to view the propeller assembly as it had been removed prior to his arrival. He asked the pilot/owner to allow him access to the propeller assembly. However, the pilot/owner did not produce the propeller for inspection. Repeated attempts to gather additional information about the glider and propeller assembly from the pilot by the National Transportation Safety Board investigator-in-charge went unheeded.