86 years old lost aircraft 🤯🤯🤯

This is a 86 years old lost aircraft that seemed to defy Isaac Newton's third law of motion. It had no engine or propulsion system, but it was able to fly by flapping its wings like a bird. It was developed by the Soviet Union in the late 1930s, and it was a truly groundbreaking aircraft for its time. Unfortunately, it disappeared during World War II, and the secret of its unique wing design was lost.