The pilot reported that he made a normal approach to land into a 10-15 knot wind. The flare for landing was initiated but the aircraft landed heavily, making first contact on the right mainwheel. The initial touchdown was some 8 metres beyond the boundary fence, 96 metres short of the strip end and 166 metres short of the marked threshold. The aircraft then bounced and touched down again on the strip 220 metres beyond the initial touchdown point. The pilot recalled that at this point he heard the landing gear warning horn sound and noticed that the right main gear safe indication light had gone out. The right wing then collapsed slowly and the aircraft slewed through 180 degrees as it came too rest on the wingtip about 550 metres from the first ground contact. There was some evidence that the approach was lower than usual and that windshear was present on the approach path. The right main undercarriage leg collapsed due to an overload failure of the bellcrank lugs.