AN RV3 PLT LOSES CTL OF HIS ACFT ON LNDG RESULTING IN A GND LOOP; GEAR COLLAPSE; AND PROP STRIKE. NO INJURIES.

Narrative

DURING A LNDG AT AN 1800 FT PVT GRASS STRIP; MY RV3 BEGAN TO YAW TO THE R NEAR THE END OF THE ROLLOUT. FULL L RUDDER WAS APPLIED THEN HARD L BRAKE. THE ACFT CONTINUED TO YAW TO THE R AND A GND LOOP BEGAN. WHEN THE ACFT WAS AT THE R EDGE OF THE MOWED AREA OF THE GRASS STRIP AND ALMOST POINTED 90 DEGS TO THE R; THE L GEAR LEG MOUNT TORE FROM THE ENG MOUNT AND COLLAPSED UNDER THE FUSELAGE. THIS RESULTED IN THE PROP AND THE L WINGTIP STRIKING THE GND. NO INJURIES OR PROPERTY DAMAGE OTHER THAN TO THE ACFT OCCURRED. AT THE TIME; WINDS WERE CALM AND THE GRASS SURFACE WAS CUT AND DRY. THE GND LOOP OCCURRED DURING THAT PORTION OF THE ROLLOUT WHERE THE RUDDER WAS NOT EFFECTIVE DUE TO LOW SPD AND TAILWHEEL STEERING AND DIFFERENTIAL BRAKING WERE NOT ENOUGH TO MAINTAIN DIRECTIONAL CTL ON THE GRASS SURFACE ONCE THE YAW BEGAN. A SHORT APPLICATION OF PWR MIGHT HAVE INCREASED RUDDER EFFECTIVENESS AND AVOIDED THE GND LOOP. SINCE I HAVE NEVER NEEDED TO USE THAT CORRECTIVE ACTION IN THE PAST; IT DID NOT OCCUR TO ME TO USE IT AT THE CRITICAL MOMENT.