Accident Description
The pilot was departing to the south from the midpoint of a private dirt strip. The airplane accelerated normally during the takeoff roll. Just after the pilot raised the tail of the airplane, he realized that a control lock was caught on the control stick. The pilot could not pull the stick back. He stated that he 'throttled back too late.' The propeller struck the ground, and the airplane performed a somersault, coming to rest on its back.
Wreckage Examination
Examination of the wreckage revealed that a secondary ground control lock, which had been installed by the pilot and owner of the airplane, was hooked onto the control stick. This prevented any movement of the ailerons or elevator. No other anomalies with the airplane were found.
Pilot Account
The pilot reported that the airplane's acceleration was normal until the tail came up. At that point, the control lock interfered with the control stick, making it impossible to raise the nose. His attempt to reduce power was too late to prevent the propeller from contacting the ground.