On April 26, 1994, about 1542 eastern standard time, a Cessna 170A, N9530A, registered to Dennis W. Woodard, operating as a 14 CFR Part 91 paradrop flight, experienced a partial loss of power on initial climb from Bushnell Airport, Bushnell, Florida. The pilot made a forced landing straight ahead to an open field maneuvering around some cows and trees. The pilot stated he flared a little high, landed hard, and the right main landing gear separated. The airplane was substantially damaged. The commercial pilot received minor injuries and the three passengers were not injured. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated about 2 minutes before the accident. The pilot stated on climb at about 50 feet agl, the airplane started to vibrate, and the engine ran rough. He thought he had blown a cylinder, and he made a forced landing straight ahead to avoid colliding with a tree line at the end of an open field. Examination of the engine by the FAA and the registered owner revealed the engine exhaust valve on the No. 3 cylinder was loose.