On this day, 89 years ago, on June 26, 1936 (May 8, 1936 in the lunar calendar), the world's first normally steerable helicopter was successfully tested for the first time in Germany. On June 26, 1936, after making various improvements to early helicopters, Fokker of Germany publicly demonstrated its own FW-61 helicopter. A year later, the aircraft set many world records. This is a large twin-rotor horizontal helicopter with a fuselage similar to a fixed-wing aircraft but no fixed wings. Its two rotors are supported to the upper right and upper left by two sets of thick metal frames, and the two rotors are horizontally mounted on the top of the bracket. The plane shape of the blade is tapered and connected to the hub with flapping hinges and shimmy hinges. An automatic tilt device is used to tilt the rotor rotation plane for longitudinal control, and yaw control is achieved by tilting the two rotors in different directions. The total pitch of the rotor blades is fixed, and the rotor pull is changed by changing the rotor speed. Use rudder and horizontal tail fins to increase stability. The FW61 rotor hub is equipped with a periodic pitch varying device that can change the blade pitch during rotor rotation. There is also a control stick with variable pitch to change the tilt of the rotor surface for flight direction control. The FW61 relies on this set of periodic pitch changing devices and joysticks to ensure its maneuver flight. The rotor diameter of the aircraft is 7 meters. The power unit is a piston engine with a power of 140 horsepower. This is the world's first helicopter with normal maneuverability. The aircraft has a speed of 100 to 120 kilometers per hour, a range of 200 kilometers, and a take-off weight of 953 kilograms. In 1938, a young German girl Hannareich piloted a twin-rotor helicopter for a perfect flight performance at the Berlin Stadium. This helicopter is regarded by the helicopter industry as the world's first helicopter to successfully test flight. Comment: This is a pioneering work of mankind. When a disaster breaks out, it can save many people! Comment: Great progress in human material civilization. When will it be as convenient to take a helicopter as taking a taxi?