On September 2, 2011, at 0928 central daylight time, an experimental amateur-built Vicari model Waiex airplane, N100VY, was substantially damaged during a precautionary landing shortly after takeoff from Williamson County Regional Airport (KMWA), Marion, Illinois. The pilot was not injured. The airplane was registered to and operated by the private pilot under the provisions of 14 Code of Federal Regulations Part 91. Day visual meteorological conditions prevailed for the flight, which was operated without a flight plan. The local flight was originating at the time of the accident. The accident airplane was issued an airworthiness certificate on June 20, 2011, by a designated airworthiness representative, and had completed 5 hours of the required 40 hours of flight testing stipulated by its operating limitations. The pilot reported that there were no anomalies with the engine operation during a before-takeoff engine check or when he applied power for takeoff. He stated that shortly after liftoff he perceived that the engine was not producing maximum takeoff power and that the engine tachometer was indicating several hundred rpm lower than expected. Since there was insufficient runway remaining to land safely, he elected to land on the airport's crossing runway. The left wingtip collided with terrain as he maneuvered the airplane toward the crossing runway. The airplane subsequently came to rest in a grassy area alongside the intended runway. The pilot was able to taxi the airplane back to the ramp after the accident. A postaccident examination revealed substantial damage to the outboard section of the left main wing spar and the left wingtip closeout-rib. The engine, a Jabiru model 3300-A, serial number 33A-1806, had accumulated 8 hours since being manufactured on June 15, 2008. Mechanical continuity was confirmed from the cockpit engine controls to their respective engine components during a postaccident examination. Additionally, the accident engine demonstrated the ability to produce rated horsepower during a postaccident operational test run. At 0932, the airport's automated surface observing system reported the following weather conditions: wind 190 degrees at 6 knots; visibility 15 miles; sky clear; temperature 31 degrees Celsius; dew point 18 degrees Celsius; altimeter setting 30.05 inches of mercury. The carburetor icing probability chart included in Federal Aviation Administration Special Airworthiness Information Bulletin No. CE-09-35, Carburetor Icing Prevention, indicated that there was a potential for serious carburetor icing while operating at glide power. However, the postaccident investigation was unable to conclusively determine if carburetor icing had contributed to the partial loss of engine power.