Engineering thumb|A first ever spring-driven coaxial rotor The idea of a coaxial rotor originated from Mikhail Lomonosov. In July 1754, he developed a model of a small helicopter with a coaxial rotor and demonstrated it to the Russian Academy of Sciences.
engineering thumb|a first ever spring-driven coaxial rotor the idea of a coaxial rotor originated from mikhail lomonosov in july 1754 he developed a model of a small helicopter with a coaxial rotor and demonstrated it to the russian academy of sciences