On February 22, 1996, at 1030 central standard time, a Beech P35, N178DP, registered to and operated by a private owner, was substantially damaged during takeoff near Brownwood, Texas. The commercial pilot sustained serious injuries. The aircraft was being operated as a personal flight under Title 14 CFR Part 91. Visual meteorological conditions prevailed for the local flight for which a flight plan was not filed. The airplane was departing runway 17 at Brownwood Airport. The pilot reported that the aircraft lifted off "but would not climb or accelerate." He also reported that he believed "a landing gear collapsed at or about rotation and that the propeller contacted the runway. I spent too much time trying to find the problem and ran out of runway." The airplane came to rest in an upright position less than 1/4 mile from the end of the runway. The airplane sustained damage to the wings, engine mount, firewall, propeller, and tail. A witness to the accident reported that the airplane was about 10 to 15 feet high when he noticed the right landing gear door was partially down. On scene inspection by the FAA inspector revealed that there were 35 propeller strikes on the runway and several imprints corresponding to the landing gear doors and belly of the airplane on the runway. Inspection of the cockpit area of the airplane revealed that the landing gear handle was in the "up" position. The pilot's operating manual provided by the manufacturer stated that the gear should be retracted after a positive rate of climb has been established.