On July 30, 2000, approximately 0930 Pacific daylight time, an experimental Jonas Falcon XP airplane, N90345, was substantially damaged in a forced landing following a loss of engine power on the crosswind leg of the airport traffic pattern at Pendleton, Oregon. The private pilot-in-command, who was the airplane's sole occupant, was not injured in the accident. The pilot reported that visual meteorological conditions existed and that no flight plan had been filed for the 14 CFR 91 local personal flight out of Pendleton. The pilot reported that after taking off on runway 25 and turning left to clear the runway, he felt a slight vibration and noticed a lack of thrust. He stated that the engine RPM was "full at 6300" but that the plane was slowing. He reported that he then leveled out to regain speed, but that this was not effective. The pilot reported that he then turned left to land immediately on a parallel taxiway, and that he landed level but short of the taxiway. In a telephone conversation with the NTSB investigator-in-charge (IIC) on April 9, 2001, the pilot stated that this landing was in grass adjacent to the taxiway, and that the landing roll was uneventful until the aircraft's main gear entered a "rabbit hole" in the grass. The pilot reported that the aircraft's right axle then sheared, and that the aircraft did a "flip flop" from the right wingtip to the left wing and stopped. The pilot stated that he suspected a gearbox failure as the reason for full engine RPM with no associated thrust. The aircraft received its experimental-category airworthiness certificate on July 15, 2000, about 2 weeks before the accident. The pilot reported that the aircraft's 74-horsepower (HP) Rotax 618 engine was manufactured in 1998 and had 13 hours total time, with 6.4 hours since its last inspection. The pilot reported that he took off with 9 gallons of 93-octane automotive fuel aboard on the accident flight (he stated that the aircraft's fuel capacity is 15 gallons.) Investigators did not determine the reason for the loss of power.