Helicopter rotorwikipedia
A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight.
rotorhelicopter rotorrotor bladerotorsrotor bladesmain rotormainflybarbladerigid-rotor

Helicopter

helicopterhelicopterschopper
A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight.
A helicopter is a type of rotorcraft in which lift and thrust are supplied by rotors.

Tail rotor

tail rotortailtail rotor blades
Each main rotor is mounted on a vertical mast over the top of the helicopter, as opposed to a helicopter tail rotor, which connects through a combination of drive shaft(s) and gearboxes along the tail boom.
The tail rotor's position and distance from the center of gravity allow it to develop thrust in the same direction as the main rotor's rotation, to counter the torque effect created by the main rotor.

Lift (force)

liftaerodynamic liftlift (force)
A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight.
Lift is most commonly associated with the wings of fixed-wing aircraft, although it is more generally generated by many other streamlined bodies such as propellers, kites, helicopter rotors, racing car wings, maritime sails, and wind turbines in air, and by sailboat keels, ship's rudders, and hydrofoils in water.

Rotorcraft

rotorcraftrotary-wingrotary-wing aircraft
Helicopters are one example of rotary-wing aircraft (rotorcraft).
Several rotor blades mounted on a single mast are referred to as a rotor.

Swashplate (aeronautics)

swashplateswashplatescyclic movement
The blade pitch is typically controlled by a swashplate connected to the helicopter flight controls.
A swashplate is a device that translates input via the helicopter flight controls into motion of the main rotor blades.

Autogyro

autogyrogyrocoptergyroplane
Before development of powered helicopters in the mid 20th century, autogyro pioneer Juan de la Cierva researched and developed many of the fundamentals of the rotor.
While similar to a helicopter rotor in appearance, the autogyro's rotor must have air flowing across the rotor disc to generate rotation, and the air flows upwards through the rotor disc rather than down.

Bamboo-copter

bamboo-copterbamboo flying toystaketombo
The use of a rotor for vertical flight has existed since 400 BC in the form of the bamboo-copter, an ancient Chinese toy.
The bamboo-copter, also known as the bamboo dragonfly or Chinese top (Chinese zhuqingting, Japanese taketombo 竹蜻蛉), is a toy helicopter rotor that flies up when its shaft is rapidly spun.

Bell OH-58 Kiowa

OH-58D Kiowa WarriorOH-58 KiowaKiowa
This type of rotor can be found on several aircraft produced by Bell Helicopter, such as the OH-58D Kiowa Warrior.
The Bell OH-58 Kiowa is a family of single-engine, single-rotor, military helicopters used for observation, utility, and direct fire support.

Slowed rotor

slowed rotorrotor advance ratiovariable speed rotors
The rotors are designed to operate at a fixed RPM (within a narrow range of a few percent), but a few experimental aircraft used variable speed rotors.
Rotors of conventional helicopters are designed to operate at a fixed RPM (within just a few percent), causing suboptimal operation in large parts of the flight envelope.

Disk loading

disk loadingdisc loadingwing-disc loading
As it is more efficient at low speeds to accelerate a large amount of air by a small degree than a small amount of air by a large degree, a low disc loading (thrust per disc area) greatly increases the aircraft's energy efficiency, and this reduces the fuel use and permits reasonable range.
Airscrews with a relatively low disk loading are typically called rotors, including helicopter main rotors and tail rotors; propellers typically have a higher disk loading.

MBB Bo 105

Bo 105Messerschmitt-Bölkow-Blohm Bo 105Bolkow 105
The Bo 105 features a revolutionary hingeless rotor system, at that time a pioneering innovation in helicopters when it was introduced into service in 1970.

Juan de la Cierva, 1st Count of la Cierva

CiervaJuan de la CiervaJuan de la Cierva y Cordoniu
Before development of powered helicopters in the mid 20th century, autogyro pioneer Juan de la Cierva researched and developed many of the fundamentals of the rotor.
De la Cierva started building the aircraft as early as 1912, and in 1919 he started to consider the use of a rotor to generate lift at low airspeed, and eliminate the risk of stall.

Radio-controlled helicopter

radio-controlled helicopterhelicoptersmodel helicopter
The Hiller system variant using airfoiled paddles at the flybar's ends has been used in many of the earliest designs of remote control model helicopters, from their 1970s origins onwards to the very early 21st century.
Such 3-axis gyro is typically called a flybarless controller, so-called because it eliminates the need for a mechanical flybar.

Hughes TH-55 Osage

Hughes 269Hughes 269AHughes TH-55A Osage
The Hughes 269 was designed with a fully articulated, three-blade main rotor designed by Drago Jovanovich, and a two-blade tail rotor that would remain as distinctive characteristics of all its variants.

AgustaWestland AW109

Agusta A109A109MH-68 Stingray
The engines drive a fully articulated four-blade rotor system.

John T. Parsons

John Parson
In the late 1940s, the making of helicopter rotor blades was a job that inspired John T. Parsons to be a pioneer of numerical control (NC).
Together, they were the first to use computer methods to solve machining problems, in particular, the accurate interpolation of the curves describing helicopter rotor blades.

Dissymmetry of lift

dissymmetry of liftlift dissymmetry
This movement is called flapping and is designed to compensate for dissymmetry of lift.
Dissymmetry of lift in rotorcraft aerodynamics refers to an uneven amount of lift on opposite sides of the rotor disc.

Eurocopter AS350 Écureuil

Eurocopter EcureuilEurocopter AS350AS350B Squirrel
Over time, the AS350 Écureuil/AStar has received further development; while the aircraft's design remains broadly similar, various aspects and systems such as the rotor system, powerplants, and avionics have been progressively improved.

Blade pitch

pitchblade pitchpropeller pitch
The blade pitch is typically controlled by a swashplate connected to the helicopter flight controls.
Blade pitch or simply pitch refers to turning the angle of attack of the blades of a propeller or helicopter rotor into or out of the wind to control the production or absorption of power.

Arthur M. Young

Arthur YoungArthur Middleton YoungArthur M. Young
In the 1930s, Arthur Young improved the stability of two-bladed rotor systems with the introduction of a stabilizer bar.
While war was looming for the USA in late 1941 he was issued the key rotor stabilizer bar (also known as a flybar) patent, assigned it to Bell and moved to Buffalo to work with them.

Robinson R22

R22Robinson Beta 22Robinson R22 Helicopter
The simple rotor of a Robinson R22 showing (from the top):
The helicopter rotor system consists of a two-bladed main rotor and two-bladed anti-torque rotor on the tail, each equipped with a teetering hinge.

Eurocopter EC135

EC135Eurocopter EC-135P2+EC 135
The main rotor is of a four-bladed, hingeless fiber-composite design; progressive improvements to the main rotor have increased its performance and reduced maintenance costs since the type's introduction.

Schweizer 300

Hughes 300Model 300Cmodel 300 (269C)
The Hughes 269 was created with a fully articulated three-bladed main rotor wherein the blades advance to the right and a two-bladed tail rotor that would remain as distinctive characteristics of all its variants.

Sud-Ouest Djinn

Sud-Ouest SO 1221 DjinnHO-1Sud Ouest SO1221 Djinn
The French Sud-Ouest Djinn used unburnt compressed air to drive the rotor, which minimized noise and helped it become the only tip jet driven rotor helicopter to enter production.
Atypically, the rotors were driven by compressed-air jets at the end of each blade, which had the benefit of eliminating the need for an anti-torque tail rotor.

Quadcopter

quadcopterquadrotorquadrotor helicopter
A quadcopter has four rotors in an "X" configuration designated as front-left, front-right, rear-left, and rear-right.
A quadcopter, also called a quadrotor helicopter or quadrotor, is a multirotor helicopter that is lifted and propelled by four rotors.