Bamboo-copter

This helicopter-like top originated in Jin dynasty China around 320 AD,[1] and was the object of early experiments by English engineer George Cayley, the inventor of modern aeronautics.

"[2] The Jin dynasty Daoist philosopher Ge Hong's (c. 317) book Baopuzi (抱樸子 "Master Who Embraces Simplicity") mentioned a flying vehicle in what Joseph Needham calls "truly an astonishing passage".

[3] Some have made flying cars [feiche 飛車] with wood from the inner part of the jujube tree, using ox-leather (straps) fastened to returning blades so as to set the machine in motion [huan jian yi yin chiji 環劍以引其機].

[3]Needham concludes that Ge Hong was describing helicopter tops because "'returning (or revolving) blades' can hardly mean anything else, especially in close association with a belt or strap"; and suggests that "snakes", "dragons", and "oxen" refer to shapes of man-lifting kites.

[4] Other scholars interpret this Baopuzi passage mythologically instead of literally, based on its context's mentioning fantastic flights through chengqiao (乘蹻 "riding on tiptoe/stilts") and xian (仙 "immortal; adept") techniques.

The Russian polymath Mikhail Lomonosov developed a spring-driven coaxial rotor in 1743, and the French naturalist Christian de Launoy created a bow drill device with contra-rotating feather propellers.