Following is a transcript of the video. This helicopter has dual-crossing rotors for increased precision The K-MAX uses a unique double rotor system where the two rotors cross each other.

Report reveals new details into New York helicopter crash that killed six - A lack of video or data recording could make the ...

But thanks to a doctoral thesis he found, it’s also possible to control a traditional single-rotor helicopter by substituting flexible rotor hinges and precise motor speed control for the ...