noun

• 1A hub with a number of radiating aerofoils that is rotated in an approximately horizontal plane to provide the lift for a helicopter or other rotary wing aircraft.

  ‘The aircraft featured two large rotors located in nacelles on the ends of its wings linked to an air-cooled Daimler Benz 600 engine in the fuselage.’

  More example sentences

  • ‘The aircraft would have launched standing upright like a rocket, but instead of using a blast of fire to take off the pilot would have simply adjusted the thrust and pitch of the rotors as with a helicopter.’
  • ‘The sound of the helicopter's rumbling rotors became louder, as it flew by directly overhead us, and began hovering over the red smoke.’
  • ‘I could hear the thwapping of helicopter rotors, the grinding of tank treads, the sound of RPG's and bazookas.’
  • ‘The shot was from a news helicopter and Cecil could hear the thudding of the helicopter rotors in the background as the reporter began to speak.’
  • ‘The helicopters' rotors started turning, first slowly, then faster and faster, making a loud chopping noise as they cut the air.’
  • ‘He walked up to Blaine just as the helicopter rotors disengaged.’
  • ‘He barely dodged a humongous hammer that flew past him and destroyed the main rotor on one of the remaining helicopters.’
  • ‘They were pretty useless when confronted with the high-pitched whine of the rotor's gears directly above our heads.’
  • ‘They heard the engine revving and the quickening beat of the rotors.’
  • ‘With a soft hum of power the large rotors started up and the officers were off, soaring up to investigate the powerless upper levels of the massive city.’
  • ‘He fired up the engine and the rotors began to whirl.’
  • ‘As the rotors slowed, a side hatch opened and the Security Chief climbed out, followed by Director Bakan and their respective aides.’
  • ‘He raised his suntanned right arm to his face and shielded his eyes from the swirling clouds of dirt and dust kicked up by the Dauphin's rotors.’
  • ‘The rotors started to spin up and they hurriedly jumped to the roof a few feet below, ducking to avoid the backwash from the spinning propellers as the copter lifted off the heliport and headed into the night skyline.’
  • ‘You'll hear your rotor speeding up and slowing down, and the roar of missiles as they fly by you.’
  • ‘He opened the door and leapt out while the rotors were still spinning and brushed off his clothes.’
  • ‘Will gave a light two fingered salute to those staying, as the rotors whirred and the chopper left.’
  • ‘The helicopter rises up over the ridge line, the noise of the rotors scattering the targets below.’
  • ‘Then the sound of rotors is heard, and they look up, only to see the two Serpent helicopters hovering above them.’

• 2The rotating assembly in a turbine.

  ‘Should they malfunction or prove insufficient to slow the rotor in high winds, a large disk brake mounted on the generator shaft can smoothly bring the turbine to a halt.’

  More example sentences

  • ‘The higher-wattage plants, with their large-diameter, low-rotation-per-minute rotors, are designed to capture energy from low wind speeds.’
  • ‘Take away the 2.2 birds killed by the rotors, and the balance for wind energy, + 1707.8 birds per turbine a year, is not bad.’
  • ‘The rotor turns an attached generator, creating electricity with a simple elegance, carving energy from the sky.’
  • ‘A fearless reaper, it pivots on its tower to face the wind, propellerlike rotor already scything around, faster and faster.’
  • ‘Wind plant rotors have either two or three blades.’
  • ‘Standing at the base of one of the towers, there's only a gentle whoosh as the rotors sweep around.’
  • ‘The wind generated by the rotors while sitting on the ground is tremendous.’
  • ‘‘The bigger the rotor, the more wind you can collect,’ Sagrillo explained.’
  • ‘To achieve this same increase using a larger rotor is usually a more expensive choice than placing a smaller rotor on a higher tower where it will receive stronger winds.’
  • ‘She had to return to Southampton and have the turbine rotors completely redesigned and rebuilt.’

  1. 2.1The armature of an electric motor.
  2. 2.2The rotating part of the distributor of an internal combustion engine which successively makes and breaks electrical contacts so that each spark plug fires in turn.
     ‘Motorists who failed to immobilise their cars, by taking away the rotor arm from the distributor, were liable to find their tyres deflated by the police.’
     More example sentences

     • ‘I immediately changed the oil, plugs, distributor cap, rotor arm, and a friendly independent specialist fixed the exhaust.’
     • ‘After 20 minutes he decided the problem was with the rotor arm, and fashioned some wire underneath it to solve the problem.’
     • ‘It might have been tougher for Godfrey had the Cooper S of his competitors not lost nearly 10 minutes right at the start of the Radnor stage with a broken rotor arm.’
     • ‘While Freestone had a good run on his first experience of the stage, they had a nightmare when a broken rotor arm cost them over two minutes.’
     • ‘The heavy impact damaged the rotor arm and though he carried on, Andrew was handicapped by a misfiring engine and could only struggle home sixth.’
     • ‘For example, if D hires a car to P and then removes the rotor arm from it rendering it inoperable, he may be guilty of criminal damage.’
     • ‘This time we had lost the rotor arm as well and Phil had to sprint back 100 yards to find it.’
     • ‘Unlike a piston engine, where reciprocating parts move up and down, the twin rotors in the Mazda just spin around.’
     • ‘Rear rotors are vented on the GT and solid on the V - 6.’
  3. 2.3The rotating container in a centrifuge.
     ‘One junior intelligence analyst thought that although they weren't at all like modern American centrifuge rotors, they might be usable in what are known as a Zippe centrifuge.’
     More example sentences

     • ‘The Department of Energy rejected the claim that the country was importing aluminum tubes to produce centrifuge rotors for enriching uranium.’
  4. 2.4The rotary winder of a clockwork watch.

• 3Meteorology
  A large eddy in which the air circulates about a horizontal axis, especially in the lee of a mountain.

  More example sentences

  • ‘a rotor cloud’