On February 8, 2011, about 1450 central standard time, a Cessna 210N, N92MP, sustained minor damage during a gear-up landing at the Columbia Regional Airport (COU), near Columbia, Missouri. The private pilot was not injured. The airplane was registered to and operated by the Missouri State Highway Patrol. Visual meteorological conditions prevailed, and a flight plan was not on file for the 14 Code of Federal Regulations Part 91 public use flight. The flight departed about 1440, from the Jefferson City Memorial Airport (JEF), near Jefferson City, Missouri, and was destined for COU. The pilot indicated that about ten miles south of COU, he made an initial position call to the air traffic control tower. The tower advised that there was another Cessna airplane with a similar call sign that was approaching COU from the west. The tower directed the other Cessna airplane to report a two-mile left base. The tower advised the pilot that he was second to land following the Cessna airplane approaching from the west and to report a two-mile straight in final. The pilot did not have the other Cessna airplane in sight and he maneuvered his airplane to the left to give the other Cessna airplane room to set up for its final approach. The pilot located the other Cessna airplane on final when the other pilot made his radio report. The tower made an advisory radio call when the incident airplane was approximately two miles out, to the other Cessna airplane that had landed and was taxing, to yield to another aircraft that was also taxing. The pilot looked for both taxing airplanes to have situational awareness. The pilot said that he was maneuvering the airplane to touchdown and noticed that the airplane was settling lower to the ground than normal. He realized that he did not lower the landing gear and he increased the power to full-throttle when he heard the sound of the airplane’s fuselage rubbing the ground. The airplane became airborne and the pilot lowered the landing gear and subsequently landed on the landing gear. The pilot reported that he did not use the landing checklist and that the landing gear warning horn did not sound during the landing. An airframe and powerplant mechanic reported that the incident airplane’s landing gear warning horn was tested March 16, 2011 during the airplane’s ferry flight from COU to JEF. The horn was tested five times with activation of the horn with indicated manifold pressure gauge readings from 9.5 inches to 14 inches of mercury. Retarding the throttle at a slower speed resulted in a lower manifold pressure reading. Retarding the throttle at a faster speed resulted in a higher manifold pressure reading. According to the mechanic, the throttle cable had some play which may have contributed to the wide range of readings. The landing gear functioned as normal.