On May 21, 2005, at 1149 eastern daylight time, a De Havilland DH-82-C, N82CQ, registered to a private owner, operating as a 14 CFR Part 91 personal flight, reported a partial loss of engine power on initial take off climb from Gum Creek Airport, Roopville, Georgia. The pilot initiated a forced landing, and the airplane collided with trees and wires, before coming to a stop near a private residence. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage. The private pilot reported no injuries. The passenger reported minor injuries. The flight originated from Gum Creek Airport on May 21, 2005, at 1148. The pilot stated he conducted an engine run up and the airplane experienced a magneto drop. A subsequent check of the magneto revealed no anomalies. The airplane departed from runway 24 and was about 50- feet above the ground when the engine experienced a partial loss of engine power and a reduction in rpm. The pilot observed trees off the departure end of the runway and made a 10-degree right turn to avoid a collision with the trees. The airplane collided with power lines, the nose of the airplane pitched down, and the airplane collided with the ground in a nose down attitude. Examination of the airplane revealed fuel was present in the fuel tank, fuel lines, carburetor, and gascolator. The fuel filter was inspected and free of debris. No anomalies were noted with the engine assembly. The right magneto was removed and turned by hand. Spark was present on all ignition towers. The left magneto was removed and turned by hand. No spark was present. The left magneto was transported to an authorized repair facility for further examination. The left magneto was turned with a bench grinder and intermittent spark was observed at all ignition towers. The magneto was disassembled and no anomalies were noted with the distributor cap, breaker points, internal gears, timing, upper and lower contacts, and the capacitor. The coil was removed and internal oil from the coil had leaked on the rotor and housing. The left magneto was returned to the registered owner on June 3, 2005.