On July 16, 2010, about 0800 Pacific daylight time, a light sport aircraft experimental weight-shift-control TopDog Ultralights Top Dog 582 (trike), N82047, was substantially damaged during takeoff near Eagle Point, Oregon. The pilot received serious injuries and the pilot rated passenger received minor injuries. The owner operated the personal flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the local flight, which was originating at the time of the accident. No flight plan had been filed. According to the passenger, he and the pilot were co-owners of the trike. Shortly after takeoff from a grass strip, the trike drifted to the left of the grass strip and into tall bushes. The trike came to rest in a creek, adjacent to the runway. The right wing was substantially damaged during the accident sequence. In a written statement submitted by the pilot, after takeoff the trike turned sharply to the left, impacted bushes, and then terrain. During recovery of the trike, it was discovered that the left wingtip had separated from the trike and was located away from the main wreckage. The separation was not associated with impact damage. According to a Federal Aviation Administration inspector with extensive experience in weight-shift aircraft, the wingtip will separate because it is not installed correctly or because it came loose. He stated that after the wingtip separates, lift is lost from that side of the trike, and the trike experiences control difficulties thereafter. The actual reason for the wingtip separation was not determined.