Upgraded Design To Provide 650 -b. Internal, 750-Lb. External Payload Increases MD Helicopters has introduced the MD 564, a new light-single-engine helicopter derived from the long-running MD 500 series and aimed at operators that need more lift, endurance and hot-and-high capability without moving into a larger aircraft class. The company said the MD 564 combines a six-blade main rotor, a four-blade tail rotor, and a Rolls-Royce 250-C47E/3 engine with dual-channel FADEC. MD is positioning the helicopter as a higher-performance evolution of the 500-series platform rather than an all-new design.