On June 22, 2006, about 1900 mountain daylight time, an un-registered un-certificated experimental amateur-built Challenger II airplane sustained substantial damage when it encountered soft terrain during an off-airport landing following a loss of control in the initial climb after takeoff from Emmett Municipal Airport, Emmett, Idaho. The un-certificated pilot and the passenger, who was the airplane's owner, were not injured. Visual meteorological conditions prevailed and no flight plan was filed for the 14 CFR Part 91 personal local flight. The pilot reported that he had about 500 hours flight time in ultralights including time in a Challenger I, but he had not previously flown a Challenger II. Before the flight, he reviewed the Challenger II owner's manual and found that it recommended use of full flapperons for takeoff. Therefore, he set full flapperons. After takeoff, as the airplane over flew the end of the runway, it "stopped" climbing. The pilot attempted to raise the flaperrons, but could not reach the crank handle, which was located above and behind his head. He was "able to keep nose level at full throttle" and executed an off-airport landing in a hay field. During the ground roll in the soft terrain, the nose landing gear collapsed.