At Huffman Prairie, lighter winds made takeoffs harder, and they had to use a longer starting rail than the 60-foot (18 m) rail used at Kitty Hawk. The first flights in 1904 revealed problems with longitudinal stability, solved by adding ballast and lengthening the supports for the elevator. During the spring and summer they suffered many hard landings, often damaging the aircraft and causing minor injuries. On August 13, making an unassisted takeoff, Wilbur finally exceeded their best Kitty Hawk effort with a flight of 1,300 feet (400 m). Then they decided to use a weight-powered catapult to make takeoffs easier and tried it for the first time on September 7.