On September 2, 2007, at 0930 eastern daylight time, a Piper PA-28-181, N465MA, was substantially damaged during a midair collision with an unknown airplane, at Spruce Creek Airport (7FL6), Daytona Beach, Florida. The certificated private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local flight. The personal flight was conducted under 14 Code of Federal Regulations Part 91. According to the pilot, he entered the traffic pattern on a 45-degree entry to the downwind leg of the traffic pattern. He transmitted his intentions on the Unicom frequency for the airport and announced when he was on the downwind, base, and final, traffic pattern legs. When he was at 100 feet on short final to runway 23, he noticed a "yellow airplane," which looked to him like a "Piper J-3," or "American Legend Cub," enter the active runway prior to his landing. He "yelled in the radio," that he was "going around" and initiated a go-around, over flying the airplane on the active runway. The unknown airplane on the runway began its take off roll as he was flying above it. The unknown airplane began to climb out and the two airplanes came together. The pilot of the PA-28-181 then landed "straight ahead" on the runway. The unknown airplane continued on its flight and at the time of this writing has not been located. Examination of the PA-28-181 by a Federal Aviation Administration (FAA) inspector, revealed that the point of impact occurred on the right wing leading edge and that the airplane was substantially damaged. The PA-28-181 was a single-engine, four-place low wing airplane. According to FAA and maintenance records it was manufactured in 2001. The airplane's most recent annual inspection was completed on October 5, 2006 and at that time had accumulated 400 total hours of operation. According to FAA and pilot records, the pilot of the PA-28-181 held a private pilot certificate with ratings for airplane single-engine land, and instrument airplane. His most recent FAA third-class medical was issued on December 1, 2006. He reported 1000 hours of total flight experience. A weather observation taken about 23 minutes after the accident at Daytona Beach International Airport (DAB), Daytona Beach, Florida, located about 6 nautical miles north of the accident site, recorded the winds as 250 degrees at 5 knots, visibility 10 miles, sky clear, temperature 29 degrees Celsius, dew point 23 degrees Celsius, and an altimeter setting of 30.09 inches of mercury.