Definition
Describes two components, typically propellers or turbine sections, mounted on the same axis or shaft line that rotate in opposite directions to each other.
Plain English
Two parts spinning around the same line, but in opposite directions — one clockwise, the other counterclockwise.
Context Anchor
Seen in powerplant and propeller discussions, especially when describing propeller systems or engine installations that turn opposite ways.
Derivation
From the Latin 'contra' meaning 'against' and 'rotare' meaning 'to turn.' Literally, 'turning against' — one part turns one way, the partnered part turns the opposite way.
Why Pilots Care
Cancels torque reaction and reduces left-turning tendencies, improving directional control especially during takeoff and climb.
Intuition Check
Contrarotating does not just mean “rotating.” It specifically means two parts are rotating opposite ways compared with each other.
Example Sentence 1
The engine drives a contrarotating propeller assembly, with the front and rear propellers spinning in opposite directions on the same shaft line.
Example Sentence 2
Contrarotating propellers on this installation eliminate most of the normal torque roll at full power.