The pilot and passenger were taking off for a pleasure flight in the local area. The aircraft had full fuel and was just below its Maximum Takeoff Weight (MTOW). After lift off, the pilot found that he was unable to climb out of ground effect and decided to land in a field of crops. During the subsequent landing, the aircraft flipped inverted. The pilot believes that a slight reduction in available power, coupled with calm wind conditions and the short runways at Netherthorpe, contributed to the accident.