Incident Description
According to the pilot of the tailwheel-equipped airplane, the takeoff was attempted from a grassy, wet, and down sloping surface. The pilot stated that prior to the takeoff, he walked the intended takeoff area and found no obstacles that would have prevented a safe takeoff.
During the takeoff roll, the pilot kept the airplane's tailwheel off the ground while rolling down the slope. As the airplane progressed, the main landing gear wheels rolled over a patch of mud, which created a pivot point and caused the airplane to nose over.
Damage
The airplane sustained substantial damage to the vertical stabilizer, rudder, and wing struts.
Pilot Report
The pilot reported that there were no mechanical malfunctions or anomalies with any part of the airplane prior to the takeoff roll that would have precluded normal flight operations.