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Helicopter

helicoptersrotorcraftchopper
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

tailanti-torque rotortail 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

rotary-wingrotary-wing aircraftrotary wing
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

gyrocoptergyroplaneautogiro
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 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.

Helicopter flight controls

cycliccollective pitchhelicopter pilot
The blade pitch is typically controlled by a swashplate connected to the helicopter flight controls.
The cyclic is used to control the main rotor in order to change the helicopter's direction of movement.

Slowed rotor

changing RPMrotor advance ratiorotor speed reduction
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.

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.

Disk loading

disc 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.

Radio-controlled helicopter

helicoptersmodel helicopterradio controlled 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.

Blade pitch

pitchpropeller pitchblade angles
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.

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.

MBB Bo 105

Bo 105Messerschmitt-Bölkow-Blohm Bo 105Bolkow 105
MBB Bo 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.

Hughes TH-55 Osage

Hughes 269269CHughes 269A
Hughes TH-55 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.

Arthur M. Young

Arthur YoungArthur Middleton 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.

Dissymmetry of lift

lift 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.

AgustaWestland AW109

Agusta A109A109MH-68 Stingray
AgustaWestland AW109
The engines drive a fully articulated four-blade rotor system.

Robinson R22

Robinson R22 BetaR22R22 Beta
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.

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.

Flight

flyingflyflies
The use of a rotor for vertical flight has existed since 400 BC in the form of the bamboo-copter, an ancient Chinese toy.
Lift is commonly associated with the wing of an aircraft, although lift is also generated by rotors on rotorcraft (which are effectively rotating wings, performing the same function without requiring that the aircraft move forward through the air).

Eurocopter EC135

EC135Eurocopter EC-135P2+EC 135
Eurocopter EC135
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 300CSchweizer 269C
Sikorsky S-300
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.

Eurocopter AS350 Écureuil

Eurocopter AS350Eurocopter EcureuilAS350B Squirrel
Eurocopter AS350
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.