The aircraft was operating from a grass field at Aghadoe and the Pilot, with his son as passenger, lined up for take-off in an easterly direction. As the aircraft accelerated the Pilot felt a loss of power. He immediately abandoned the take-off but ran out of runway and impacted a ditch which contained an embedded concrete pillar, at the far end of the field. The Pilot and his son exited the aircraft unaided. The Pilot sustained an injury to his left wrist. His son was uninjured. There was no fire.