Yoke (aircraft)
Encyclopedia
A yoke, alternatively known as control column, is a device used for piloting in most fixed-wing aircraft
.
uses the yoke to control the attitude of the plane, usually in both pitch and roll
. Rotating the control wheel controls the ailerons and the roll axis. Fore and aft movement of the control column controls the elevator
and the pitch axis.
Small to medium-size aircraft, usually limited to propeller driven, feature a mechanical system whereby the yoke is connected directly to the control surfaces with cables and rods. Human muscle power alone is not enough for larger and more powerful aircraft, so hydraulic systems are used, in which yoke movements control hydraulic valves and actuators. In more modern aircraft, inputs may first be sent to a fly-by-wire system, which then sends a corresponding signal to actuators attached to the control surfaces. Yokes may feature a stick shaker
, which is designed to help indicate the onset of stall
, or even a stick pusher
, which assists in stall recovery.
and Concorde
. There are some rarer exotic or archaic styles, such as circular designs much like a steering wheel.
In larger aircraft they are usually mounted on a post protruding vertically from the floor, referred to as a control column. In most other planes, they are mounted on a horizontal tube that comes out of the instrument panel.
s and centre-sticks are better for making rapid control inputs and dealing with high g-forces, hence their use in military, sport, and aerobatic aircraft. However, yokes are less sensitive (i.e., more precise) thanks to a larger range of motion and provide more visual feedback to the pilot.
Yokes take up more room than sidesticks in the cockpit, and may even obscure some instruments; by comparison, side-sticks have minimal cockpit intrusion, allowing for the inclusion of retractable tray-tables and making it easier to enter/leave small cockpits.
A yoke, unlike a side-stick, may be used comfortably with either hand. This can be useful if one needs to write or manipulate other controls in the cockpit. This advantage is shared with the centre-stick.
microphone, disengage the autopilot
, and trim the aircraft. In addition, there may be a clipboard, checklist, or chronometer
located in the yoke's centre.
and the majority of military fighter aircraft
use a centre or side-stick. Some light aircraft use a stick because some sport pilots prefer that control system. The latest Airbus family of passenger jets use a side-stick
, not unlike a computer game controller, to actuate control surfaces.
There are also computer
input device
s designed to simulate a yoke, intended for flight simulator
s.
Fixed-wing aircraft
A fixed-wing aircraft is an aircraft capable of flight using wings that generate lift due to the vehicle's forward airspeed. Fixed-wing aircraft are distinct from rotary-wing aircraft in which wings rotate about a fixed mast and ornithopters in which lift is generated by flapping wings.A powered...
.
Principle
The aviatorAviator
An aviator is a person who flies an aircraft. The first recorded use of the term was in 1887, as a variation of 'aviation', from the Latin avis , coined in 1863 by G. de la Landelle in Aviation Ou Navigation Aérienne...
uses the yoke to control the attitude of the plane, usually in both pitch and roll
Flight dynamics
Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw .Aerospace engineers develop control systems for...
. Rotating the control wheel controls the ailerons and the roll axis. Fore and aft movement of the control column controls the elevator
Elevator (aircraft)
Elevators are flight control surfaces, usually at the rear of an aircraft, which control the aircraft's orientation by changing the pitch of the aircraft, and so also the angle of attack of the wing. In simplified terms, they make the aircraft nose-up or nose-down...
and the pitch axis.
Small to medium-size aircraft, usually limited to propeller driven, feature a mechanical system whereby the yoke is connected directly to the control surfaces with cables and rods. Human muscle power alone is not enough for larger and more powerful aircraft, so hydraulic systems are used, in which yoke movements control hydraulic valves and actuators. In more modern aircraft, inputs may first be sent to a fly-by-wire system, which then sends a corresponding signal to actuators attached to the control surfaces. Yokes may feature a stick shaker
Stick shaker
A stick shaker is a mechanical device to rapidly and noisily vibrate the control yoke of an aircraft to warn the pilot of an imminent stall...
, which is designed to help indicate the onset of stall
Stall (flight)
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded...
, or even a stick pusher
Stick pusher
A stick pusher is a device installed in some fixed-wing aircraft to prevent the aircraft from entering an aerodynamic stall. Some large fixed-wing aircraft display poor post-stall handling characteristics or are vulnerable to deep stall...
, which assists in stall recovery.
Styles
Yokes come in a variety of shapes and sizes, the most common being of a "U" or "W" design. Some aircraft use an "M" style, such as EmbraerEmbraer
Embraer S.A. is a Brazilian aerospace conglomerate that produces commercial, military, and executive aircraft and provides aeronautical services....
and Concorde
Concorde
Aérospatiale-BAC Concorde was a turbojet-powered supersonic passenger airliner, a supersonic transport . It was a product of an Anglo-French government treaty, combining the manufacturing efforts of Aérospatiale and the British Aircraft Corporation...
. There are some rarer exotic or archaic styles, such as circular designs much like a steering wheel.
In larger aircraft they are usually mounted on a post protruding vertically from the floor, referred to as a control column. In most other planes, they are mounted on a horizontal tube that comes out of the instrument panel.
Advantages and disadvantages
Side-stickSide-stick
A side-stick or sidestick controller is an aircraft control column that is located on the side console of the pilot, usually on the righthand side, or outboard on a two-seat flightdeck...
s and centre-sticks are better for making rapid control inputs and dealing with high g-forces, hence their use in military, sport, and aerobatic aircraft. However, yokes are less sensitive (i.e., more precise) thanks to a larger range of motion and provide more visual feedback to the pilot.
Yokes take up more room than sidesticks in the cockpit, and may even obscure some instruments; by comparison, side-sticks have minimal cockpit intrusion, allowing for the inclusion of retractable tray-tables and making it easier to enter/leave small cockpits.
A yoke, unlike a side-stick, may be used comfortably with either hand. This can be useful if one needs to write or manipulate other controls in the cockpit. This advantage is shared with the centre-stick.
Ancillary functions
The yoke often incorporates other key functions such as housing thumb or finger buttons to enable the radioAirband
Airband or Aircraft band is the name for a group of frequencies in the VHF radio spectrum allocated to radio communication in civil aviation, sometimes also referred to as VHF, or phonetically as "Victor"...
microphone, disengage the autopilot
Autopilot
An autopilot is a mechanical, electrical, or hydraulic system used to guide a vehicle without assistance from a human being. An autopilot can refer specifically to aircraft, self-steering gear for boats, or auto guidance of space craft and missiles...
, and trim the aircraft. In addition, there may be a clipboard, checklist, or chronometer
Chronometer
Chronometer may refer to:* Chronometer watch, a watch tested and certified to meet certain precision standards* Hydrochronometer, a water clock* Marine chronometer, a timekeeper used for celestial navigation...
located in the yoke's centre.
Alternative control systems
Yokes are not used on all aircraft. Helicopters use a cyclicHelicopter flight controls
A helicopter pilot manipulates the helicopter flight controls in order to achieve controlled aerodynamic flight. The changes made to the flight controls are transmitted mechanically to the rotor, producing aerodynamic effects on the helicopter's rotor blades which allow the helicopter to be...
and the majority of military fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
use a centre or side-stick. Some light aircraft use a stick because some sport pilots prefer that control system. The latest Airbus family of passenger jets use a side-stick
Side-stick
A side-stick or sidestick controller is an aircraft control column that is located on the side console of the pilot, usually on the righthand side, or outboard on a two-seat flightdeck...
, not unlike a computer game controller, to actuate control surfaces.
There are also computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
input device
Input device
In computing, an input device is any peripheral used to provide data and control signals to an information processing system such as a computer or other information appliance...
s designed to simulate a yoke, intended for flight simulator
Flight simulator
A flight simulator is a device that artificially re-creates aircraft flight and various aspects of the flight environment. This includes the equations that govern how aircraft fly, how they react to applications of their controls and other aircraft systems, and how they react to the external...
s.