On April 19, 2006, at approximately 1200 mountain daylight time, a CubCrafters CC-18-180, N4678, was substantially damaged due to a ground loop during landing at Logan-Cache Airport, Logan, Utah. The airline transport pilot/flight instructor and the airline transport pilot receiving instruction were not injured. The flight instructor/owner was operating the airplane under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the cross-country instructional flight. No flight plan had been filed for the flight. The flight instructor said that he and this other pilot, his son, were flying back to their home in Oklahoma in this new airplane. He said that he was giving instruction to his son for a tail-wheel endorsement. He said that everything appeared normal during the landing. The flight instructor said that as the airplane slowed down he noticed some drifting left and right, and then the airplane suddenly ground looped to the right. The left main landing collapsed under the fuselage bending a longeron, and bending and wrinkling the left wing tip.