Background
The pilot intended to wash the airplane but lacked the Cessna-issued gust lock designed to fit into the hole in the control yoke. As a substitute, he inserted a machine bolt into that hole to keep the flight controls steady during washing.
Preflight and Takeoff
During the subsequent preflight inspection and pretakeoff checks, the pilot did not observe that the flight controls had restricted movement. The airplane then began a takeoff roll.
Incident Sequence
As the airplane became airborne, the presence of the bolt was discovered. The pilot responded by retarding the throttle, initiating a rejected takeoff. The airplane contacted the runway in a nose-low attitude and began to porpoise while decelerating.
Damage
The porpoising motion resulted in bending of the firewall and fuselage.