Before the flight, the pilot gave a safety briefing to his passenger, and explained to the passenger to keep his feet off of the rudder pedals and to stay clear of the cyclic during takeoff. After the briefing and startup, the pilot took off in the gyroplane with his passenger for a local flight. The grass runway was bumpy, so the pilot lifted the front wheel off the ground as soon as possible and rode the main wheels until speed was built up enough to lift off. As all the wheels came off the ground, the gyrocopter started to drift to the right off of the runway. The pilot tried to correct with cyclic but was unable to move the cyclic. The gyroplane continued to move to the right and touched down in a field nose first and bounced. The gyroplane hit a concrete obstacle and sustained substantial damage to the fuselage and main rotor. The pilot believed that the passenger’s left leg interfered with the movement of the cyclic which resulted in the right drift after takeoff. The pilot reported that there were no mechanical malfunctions or failures that would have precluded normal operations.