On June 29, 2003, at 1824 central daylight time, a Bowers Fly Baby, N1878, collided with terrain during a forced landing following a reported loss of engine power shortly after takeoff from a private airstrip in Altus, Arkansas. The airplane was substantially damaged. Thecommercial pilot received serious injuries. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The pilot reported he performed a preflight inspection of the airplane prior to takeoff. The preflight included checking the fuel capacity (13 gallons), the oil capacity (3 3/4 quarts), and draining the fuel sump. The pilot stated he then hand propped the engine and it started and idled "smoothly." The pilot also stated the engine ran normally during the engine run-up, takeoff run, and initial climb. He stated that upon reaching an altitude of 150 feet, the engine lost power. He stated, "It then surged and began to run again. It did this three times then quit. I reached for the primer to see if I could pump enough fuel to stay airborne. The engine surged again when I used the primer then quit again." The pilot stated the airplane was descending and he was able to fly between two trees toward an open pasture. He stated it then looked like he was going to contact a large oak tree so he made a turn to the left, during which the left wing contacted the ground. He stated the fuselage broke in half during the impact and the fuel tank ruptured. He turned off the fuel valve and magnetos then exited the airplane. The pilot stated, "Also there was no indication of any internal malfunction, shaking or backfiring of the engine. The engine shut down very smoothly but at a very inappropriate time." Inspection of the airplane by an inspector from the Federal Aviation Administration Little Rock, Arkansas, Flight Standards District Office, failed to reveal any failure/malfunction of the engine. The inspector reported the fuel tank was ruptured.