Normal helicopters work at a fixed rate of rotor revolutions per minute.

The rotor in the distributor was a slip-on thing made of bakelite.

Simply summon an eight-rotor air module that resembles a supersized consumer drone.

In order to lighten the load, the rotor had been taken out.

Bell and Karem are both working on designs based on tilt-rotor aircraft.

You fire up the four-rotor copter and fly your camera into position.

AgustaWestland says it plans on having the tilt rotor certified in 2016.

All I really need is the total mass and the rotor size.

The Marines' K-MAX is a pilotless version of a popular twin-rotor helicopter.

Something about the thwop of the rotor blades must have lulled her.

The rotor's motion is smoothed by ceramic ball bearings instead of oil.

And then the welcoming thrum of helicopter rotor blades filled the air.

A piece of the helicopter's rotor blade was sticking through his breastplate.

Even the clumsy rotor blades of the old helicopters had been banished.

The sudden, total deceleration ripped the rotor blades away from the helicopter.

Subsequent military experience with tilt-rotor aircraft has been less than happy.