The pilot taxied out for take off on strip 36. Run up and pretakeoff checks were normal. Full power was applied for take off and the aircraft accelerated. However, by two thirds to three quarters of the 1000 metre length the aircraft was not airborne. The pilot applied back pressure on the control column and lifted off. The airspeed then decreased so the pilot lowered the nose. The left wing dropped and the aircraft descended, striking the ground nose down and overturning. The pilot had inadvertently taken off in strong gusty downwind conditions. Significant Factors The following factors were considered relevant to the development of the accident: 1. The pilot did not pay adequate attention to ascertaining the direction of the wind. 2. The pilot attempted a take off in strong downwind conditions.