On September 15, 2022, about 1442 mountain daylight time, an experimental CGS Hawk, N5148G, was substantially damaged when it was involved in an accident near Lander, Wyoming. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he was on a cross-country flight that originated on August 28, 2022, with the final destination being Isabell Field Airport (4A9), Fort Payne, Alabama. On the day of the accident, he departed Hunt Field Airport (KLND), Lander, Wyoming, and was enroute to the Kimball Municipal Airport (IBM), Kimball, Nebraska. About 40 minutes after departure and about 9,500 ft mean sea level (msl), the empennage section started to violently shake up and down. The pilot decided to execute an off-airport landing; he decreased the throttle setting and started a glide. The pilot stated that the airplane was stable during the glide without any excessive vibration and that he was able to smoothly control the airplane. Shortly after touchdown, the airplane bounced and landed hard on sloped and uneven terrain. Subsequently, the airplane nosed over and sustained substantial damage to the tail assembly. Law enforcement officials reported that the pilot received assistance from a local resident who discovered the airplane and the pilot in a field. The local resident helped the pilot move the airplane from the field onto a flatbed truck. The local resident reported that during the recovery process, the pilot admitted to using zip ties to keep sections of the airplane intact. In addition, the pilot expressed his disinterest in keeping the airplane and he sent a digital copy of the airplane’s title to him via text message. An FAA inspector was able to take pictures of the airplane disassembled on a flatbed truck, but he was not able to conduct an examination of the engine or airframe. The pilot stated that he purchased the airplane about a month before the accident. He added that the installed engine was a pre-owned car engine, which had accumulated about 59,000 miles before being installed on the airplane about 7 years before the accident. He believed that the installed engine and frame were too heavy for the airframe. According to the pilot, this was the first time in the last 90 days, which amounted to about 204 flight hours, that the empennage section had a violent shake during flight. The pilot reported that his visa would expire about two weeks after the accident, and that he would be returning to his home country. Despite repeated attempts to reach the pilot after the initial interview, the NTSB IIC did not receive a response. In addition, despite numerous phone calls, the local resident did not respond to a request to examine the wreckage.