On June 4, 2003, about 1300 eastern daylight time, a homebuilt Avro-504K, N4929, was substantially damaged during a forced landing, following a loss of engine power after takeoff from Old Rhinebeck Aerodrome (NY94), Rhinebeck, New York. The certificated commercial pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the local personal flight conducted under 14 CFR Part 91. The pilot reported that during the initial climb from the north runway, about 50 feet agl, the engine began to slowly lose power. The pilot attempted to fly a traffic pattern back to the runway, but on a crosswind leg, the engine lost all power. He then performed a forced landing to a parking lot. During the landing, the left wing and engine struck the ground. The pilot further stated that the airplane was powered by a Le Rhone Type J, nine-cylinder rotary engine. The engine was manufactured about 1914. An initial examination of the wreckage by a Federal Aviation Administration (FAA) inspector did not reveal pre-impact mechanical malfunctions. However, the inspector was unable to rotate the propeller due to cylinder impact damage. He recovered a fuel sample of the 100LL/Mogas combination from the wreckage. The fuel was clear and absent of visible contamination. The inspector added that two mixture controls were used to control rpm, but there was no placarded data for the position of the controls.