On May 15, 2008, about 1415 central daylight time, a single-engine Stinson 108-3 high-wing airplane, N6805M, and a single-engine Piper PA-28-161 low-wing airplane, N8295X, collided at the Northwest Regional Airport (52F) in Roanoke, Texas. The Stinson was on the takeoff roll and the Piper was in the landing flare when the collision occurred. The commercial pilot, the sole occupant, of the Stinson and the certified flight instructor (CFI) and student pilot in the Piper were not injured. The Stinson was owned and operated by the pilot. The Piper was owned by RTJE Bach Enterprises LLC., of Waukesha, Wisconsin, and operated by US Aviation Group of Denton, Texas. Visual meteorological conditions prevailed and flight plans were not filed for the 14 Code of Federal Regulations Part 91 flights. The Stinson was being operated as a personal flight and the Piper as an instructional flight. Photographs provided to the NTSB investigator-in-charge (IIC) revealed that the left wing of the Piper and the upper fuselage of the Stinson sustained structural damage. According to the pilot of the Stinson, after looking for approaching traffic he announcing his intentions, via the airport's common traffic advisory frequency (CTAF), to depart runway 35. He then taxied onto runway 35 and began his takeoff roll. As the airplane approached takeoff speed the pilot heard a "loud noise" and the airplane stopped moving. Not knowing what had happened, the pilot elected to exit the airplane. Once out of the airplane the pilot observed the Piper resting on top of his Stinson. The CFI, who was providing instruction in the Piper, reported that he and his student had completed four touch-and-go maneuvers and were performing the fifth when the accident occurred. While abeam the runway numbers, on the downwind leg of the traffic pattern for runway 35, the instructor reduced the engine power to idle and asked the student to perform a simulated engine out procedure. While on final approach the instructor added engine power to correct for the student's low approach. Once over the runway the student flared for landing. During the flare the instructor heard a "thud" and observed that the airplane was not flying and was not on the ground. It was then that he realized they had landed on top of the Stinson. The instructor reported that the student pilot had transmitted position reports for the downwind, base, and final legs of the traffic pattern. The instructor further reported, "At no time during the flight did I see the other aircraft." Runway 35 was a 3,500-foot by 40-foot asphalt runway. The runway's threshold was displaced 320-feet due to trees, that were approximately 50-feet tall, located south and along the approach path. The pilot of each airplane reported that the trees contributing to the accident. According to 14 CFR 91.113, Right-of-way rules: Except water operations, "Aircraft, while on final approach to land or while landing, have the right-of-way over other aircraft in flight or operating on the surface, except that they shall not take advantage of this rule to force an aircraft off the runway surface which has already landed and is attempting to make way for an aircraft on final approach."