The Helicopter Balloon
This weird and comic forerunner to the helicopter was tested out in 1921 and was thought to be the first free flight since Paul Cornu's flight in 1907. The flying machine was designed by former Peugeot engineer Etienne Oehmichen. The twin rotor helicopter had a 5000 cubic foot balloon on top. The balloon increased stability and Oehmichen had plans to fit a bigger and more powerful engine. This flight lasted 90 seconds and the helicopter raised 25 feet off the ground.