Any Unknown or Unlisted Aircraft Manufacturer
Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 75; Flight Crew Total 10500; Flight Crew Type 50
Human-Machine Interface
Ground Event / Encounter Ground Strike - Aircraft; Inflight Event / Encounter Loss Of Aircraft Control
Aircraft Aircraft Damaged
Aircraft; Human Factors
I made a normal three point landing in [a conventional landing gear equipped] Waco biplane.About half way through the rollout the right wing dropped; followed by a brief instability followed by a drift to the left I could not stop with full right rudder and right brake. The plane continued into the grass and onto a ramp area. As the plane slowed the turn left tightened and at about 15 MPH jerked left and spun around 180 degrees dragging the right wing tip. Inspection of the asphalt showed the final ground loop appeared to be the result of the wheel rim digging into the asphalt. The plane came to rest upright with the right shock strut appearing collapsed and the right tube support strut folded accordion style with about four to five folds. The gear leg was folded inward almost vertical. Not sure on performance of the right gear in this event. [It appeared it had been] damaged before but I have not been able to get much information on that.  An airport video showed the right wing drop and right rudder against the resulting left drift.
Following a normal three point landing the pilot of a Waco biplane was unable to arrest a ground loop; perhaps the result of some failure of the right landing gear structure; and significant damage to the gear was the result.