On March 31, 1996, at 1347 hours Pacific standard time, a homebuilt experimental Lampert Revolution M500 helicopter, N750GL, collided with the ground and rolled over during landing at San Carlos, California. The aircraft was owned, built, and operated by the pilot. Visual meteorological conditions prevailed at the time and no flight plan was filed. The helicopter sustained substantial damage. The non-rotorcraft rated private pilot, the sole occupant, sustained minor injuries. The flight originated at Half Moon Bay, California, on the day of the accident at 1315 as a personal cross-country flight to San Carlos. According to FAA airman records, the pilot does not hold a rotorcraft category rating. FAA inspectors examined the pilot's logbook and reported that he received a solo endorsement in helicopters about 1 1/2 years ago. The pilot reported that he flew from San Carlos to Half Moon Bay earlier in the day and was returning to the San Carlos airport. About 1 mile west of the airport the pilot began to smell something burning and said he "sensed something was wrong." Shortly thereafter, he heard a "slap" sound as the helicopter transitioned through 50 feet and 50 knots about 1/4 mile from the runway. The pilot stated that he "didn't do anything [with the controls] but keep it headed for an open area between the taxiway and the runway." The pilot said he did not flare or touch the collective and the helicopter hit hard in the open area and rolled on its left side. An FAA airworthiness inspector examined the helicopter and found the engine to transmission drive belt fragmented, with rubber transfer throughout the engine compartment. Rubber transfer on the pulleys showed a forward movement pattern of the belt off the pulley. The inspector reported that the pulley is designed without a flange or other means to keep the belt aligned.