1) Modern surveillance vehicle
Found on
https://www.crosswordclues.com/clue/quadcopter
A quadcopter, also called a quadrotor helicopter, quadrotor, is a multirotor helicopter that is lifted and propelled by four rotors. Quadcopters are classified as rotorcraft, as opposed to fixed-wing aircraft, because their lift is generated by a set of rotors (vertically oriented propellers). Unlike most helicopters, quadcopters use 2 sets of ide...
Found on
http://en.wikipedia.org/wiki/Quadcopter
No exact match found.
