1) Helicopter component
Found on
https://www.crosswordclues.com/clue/coaxial-rotors
Coaxial rotors or corotors are a pair of helicopter rotors mounted one above the other on concentric shafts, with the same axis of rotation, but turning in opposite directions (contra-rotation). This configuration is a feature of helicopters produced by the Russian Kamov helicopter design bureau. == History == In 1859, the British Patent Office aw...
Found on
http://en.wikipedia.org/wiki/Coaxial_rotors
No exact match found.
