The pilot of the Aeronca 7AC stated that he intended to fly to another airport, and have an annual inspection completed on his airplane. During the engine run-up for departure, the pilot observed that the right magneto "failed." The pilot taxied the airplane back to the ramp, and a mechanic serviced the right magneto. The pilot then performed another engine run-up, which was satisfactory, and the airplane departed on runway 17. About 50 feet above ground level, the engine lost partial power. The pilot attempted a left turn back toward the airport, as there were trees in front of him. During the turn, the airplane stalled, impacted terrain, and sustained damaged to the left wing, forward fuselage, and landing gear. The airplane was manufactured in 1946, and its most recent annual inspection was completed about 14 months prior to the accident. The airplane had accumulated 7 hours of operation since that inspection. The pilot reported a total flight experience of 2,055 hours; of which, 104 hours were in the accident airplane. The pilot had not flown during the 90-day period preceding the accident. Examination of the wreckage by a Federal Aviation Administration inspector revealed an inoperative left magneto.