The pilot was competing in the Hinkler Bi-Centennial Air Race. Earlier in the day the aircraft had made a forced landing near Roma due to a propeller oil seal failure. Following repairs by the owner/pilot the aircraft departed Roma for Charleville. At approximately 1740 hours the pilot made a PAN call and advised he was shutting the engine down due to another propeller oil seal failure. During the subsequent forced landing the pilot had to swing the aircraft left to avoid a tree. The aircraft hit an anthill, causing the landing gear to collapse. The pilot received facial lacerations. Investigation revealed that the moulded leather propeller seal had failed in the area of the moulding. It could not be determined if the second propeller seal failure was associated with the change of the seal following the first propeller seal failure. This accident was not the subject of an on-scene investigation.