The strip direction at Riddell is 15/33. The intention was to fly circuits. There was a northerly wind blowing so takeoff was on the 330 degree strip. A storm was approaching from the south and during the circuit the pilot listened to the Essendon ATIS which indicated that the wind was going around to the south. On final approach the pilot noted that the windsock was indicating that the wind had swung around the southwest and was about 12 to 15 knots. He had flown a fairly tight circuit. Carburettor heat was selected on base when power was reduced and deselected on final approach. The pilot estimated that carburettor heat was probably only on for about 10 seconds. Approach to the 330 degree strip is over a gully. On short final the aircraft encountered some wind shear and began to sink below the glide path. The pilot pushed the throttle forward but there was no response from the engine. Further sink was encountered and it became obvious that the aircraft was going to touch down before the airfield boundary fence. The aircraft touched down heavily, ran into the fence and slowly went over onto its back. Post accident inspection of the engine did not reveal any mechanical reason for the lack of response to throttle application. Information from the Bureau of Meteorology showed that conditions were conducive to the formation of serious carburettor icing at any power setting. The pilot thought that because carby heat was only applied for about 10 seconds, carburettor ice was the only reasonable explanation for the loss of power.