At Rotation, His Rotor Speed Was Marginal, And The Rotor Blades Began To Flap Before Contacting The Gyroplane’s Tail Analysis: The pilot of the gyroplane began the takeoff roll and attempted to build rotor rpm. He reported that at rotation, his rotor speed was marginal, and the rotor blades began to flap before contacting the gyroplane’s tail. The pilot then lost control of the gyroplane, and it impacted the runway and rolled onto its side. The fuselage and tail of the gyroplane were substantially damaged during the accident sequence. The pilot reported that there were no preaccident mechanical malfunctions or failures with the gyroplane that would have precluded normal operation.