On May 23, 1997, at 1538 hours Pacific daylight standard time, a Crosby Gee Bee Sportster, N11044, lost engine power and attempted a forced landing in an open farm field 2.5 miles from the Watsonville, California, airport. The aircraft sustained substantial damage and the commercial instrument rated pilot/owner, the sole occupant, received minor injuries. The flight originated from the Sacramento, California, airport at 1330, and no flight plan was filed. Visual meteorological conditions existed for the personal flight. The pilot stated that he arrived at the Watsonville airport along with numerous other aircraft and made one pass down the runway, but was unable to land due to a slower landing aircraft. He stated that he went around and re-entered the downwind for landing. ". . .My engine slowed to idle and I attempted an off airport landing. At about 50 [feet] agl the engine seized and rolled the aircraft to the right." The right wing made contacted the ground and the aircraft cartwheeled. In an interview with an Federal Aviation Administration (FAA) inspector from the San Jose, California, Flight Standards District Office, the pilot stated that the he climbed to approximately 1,000 feet agl on a tight downwind for the airport. The tower controller asked if he could widen his downwind to allow a Bonanza to land ahead of him. The pilot stated that he complied with the request and checked his airspeed which had dropped to 95 knots. He attempted to add power, but the engine went to idle. The pilot reported that he knew he was in trouble and had to land immediately. He reported that he "felt a jolt and saw something depart the engine" and hit the right wing. He thought it was a cylinder; however, postcrash investigation revealed that the object that had departed the airplane was the propeller. At the same instant that he saw the object depart the aircraft, the right wing dipped down and contacted the ground. The aircraft bounced once, contacted the ground again in a right wing low attitude, and flipped over onto its back. The engine was torn from the aircraft on impact and came to rest under the right wing of the airplane. The FAA inspector found that the belly of the fuselage was covered with oil and that no oil was found in the engine. The reason for the loss of oil was not determined due to the separation of the engine from the airframe. The FAA inspector also reported that the crankshaft did not break during the in-flight separation of the propeller.