On June 9, 2017, about 0830 central daylight time, an amateur built Angel Hawk II airplane, N335JT, collided with terrain during a forced landing near the Homer Municipal Airport (5F4), Homer, Louisiana. The pilot/airplane builder was seriously injured, and the airplane was substantially damaged. The airplane was registered to a private individual and was being operated by the pilot as a 14 Code of Federal Regulations Part 91 personal flight. Visual flight rules conditions existed near the accident site at the time of the accident, and a flight plan had not been filed for the local flight. The airplane departed 5F4 just before the accident.The pilot reported that he had been having trouble with increased cylinder head temps on the engine, a VW Type 1. During one flight, the engine popped and quit when he was on downwind and he landed the airplane back on the runway. He couldn't get the engine to restart. He replaced some ignition system components and adjusted the valves which were too tight. He was then able to start the engine and it ran fine during run-up tests. The plan for the accident flight was takeoff and circle above the runway to make sure the engine was running ok. Just after takeoff, the engine began sputtering. He made a left 180° turn to return to the runway and during the turn, the engine lost all power. He stated that the airplane stalled when he was in the turn and he did not have enough time to recover before contacting the ground. The engine was originally a Volkswagen 1.6L Type 1, which had been converted by the pilot to a variation of the Volkswagen 1.9L Type 4. The fuel mixture adjustment was pre-set at the carburetor and not adjustable in the cockpit. The ignition system included a single battery, ignition coil, centrifugal advance distributor, points, condenser and one spark plug per cylinder. The lubrication system had an added external sump attached beneath the oil drain with steel braided hose connecting to a "spin-on" type oil filter mounted on the firewall. The engine had about 47 hours of operating time since new. A postaccident examination of the engine was conducted by a Federal Aviation Administration airworthiness inspector. The examination revealed there was melted plastic material inside the distributor rotor and the distributor drive shaft. The inspector reported that the condition of the spark plugs was indicative of a lean fuel mixture/high temperature operation. The engine timing could not be determined.