The pilot stated that the wind was blowing directly across the strip and he joined the circuit for a landing on runway 29. He reported that when the aircraft was on final approach it encountered a significant tailwind, and a missed approach was carried out, followed by a "tear-drop" style turn to align the aircraft on final for runway 11. The pilot stated that after touching down on the mainwheels, the nosewheel was lowered and he heard a bang before the nose of the aircraft contacted the runway. The aircraft slid along the runway before coming to rest just off the sealed surface. An inspection of the landing gear assembly revealed that the nosegear downlock linkage failed due to overload forces causing the nosegear to retract. The landing gear mechanism was also bent by overload forces. No evidence could be found to indicate that defects in the landing gear system existed prior to this landing. The nature of the failure of the nosegear is consistent with heavy nosewheel runway contact.