On April 14, 2003, at 1512 eastern daylight time, a homebuilt Minimax 1500R, N20569, was substantially damaged during a forced landing at Trenton-Robbinsville Airport, Robbinsville, New Jersey. The certificated private pilot received minor injuries. Visual meteorological conditions prevailed for the personal flight. No flight plan had been filed for the local flight that was conducted under 14 CFR Part 91. According to the pilot, the accident flight was the first flight of the airplane. He had previously accomplished high speed taxis, with the airplane momentarily becoming airborne in what he described as "crow hopping." The pilot reported that after initial takeoff, he stayed in the traffic pattern for one landing and then climbed to 2,500 feet, and departed the traffic pattern. He accomplished airwork, and checked the low speed flight characteristics of the airplane. The pilot then returned to the traffic pattern at Robbinsville, for takeoff and landing practice. The first two approaches terminated in go-arounds. On the third approach, in the flare, the airplane ballooned, and he added power for another go-around. During the climb, the pilot realized the engine was not developing full power. The engine never quit; however, it was not developing sufficient power to maintain altitude. The pilot was unable to restore full power, and felt that a turn back to the airport would not be successful. He initiated a slight turn to the right to avoid a tree, but the left wing contacted it. The outboard 1/3 of the left wing separated from the airplane. The airplane struck the ground and came to rest inverted. An inspector from the Federal Aviation Administration (FAA) stated: "...The fuel system was reconstructed as best we could using the aircraft fuel pump, lines, and filters. No issues were noted. The ignition was examined, spark occurred at engine rotation. Spark plugs were in new condition and clean. The engine rotated freely. Examination of the pistons did not reveal indication of detonation...." In a telephone interview, the FAA inspector reported that although some contamination was found in the fuel filter, it was insufficient to block the flow of fuel to the engine. The airplane was equipped with a non-certificated two cylinder, two stroke engine. The owners manual stated the engine was suject to sudden stoppage, and had not received any individual safety or durability testing.