The pilot was attempting to takeoff from a county road. The airplane had full fuel, four persons aboard, and the road sloped upward in the direction of takeoff. The air temperature was approximately 93 degrees. The airplane started sinking and drifting to the left while the pilot was flying in ground effect. The airplane drifted off of the road and nosed-over in a ditch. The estimated density altitude at the time of the accident was 4,800' msl.