An aileron is a moving section at the back end of a plane that deflects upwards or downwards.

Ailerons are used to control a plane’s longitudinal axis by altering the lift generated by each wing, with a pilot controlling the ailerons using a control wheel in the cockpit.

The pilot changes the lift each wing produces to roll the aircraft in either direction.

Ailerons aren’t the only tool pilots use to achieve this, but they’re the most effective.

Before ailerons, planes used a technique called wing wrapping, but it was comparatively less efficient. 

What is an Aileron on a Plane?

Ailerons are the trailing sections of a wing’s plane that can be rotated to control an aircraft’s longitudinal axis.

You’ll have seen a plane’s ailerons rotating if you’ve ever sat in a window seat and looked at the plane’s wings. 

The pilot controls the ailerons’ movement either manually or by autopilot.

The movement of the aileron is referred to as a ‘roll.’

Larger aircraft may have two ailerons mounted on their wings

Different Types of Ailerons

There are 2 main types of ailerons: 

1. Differential Type Ailerons

A differential type aileron has 2 ailerons: one which is deflected upwards and the other downwards.

The upward-deflected aileron is deflected a greater distance than the downward one. 

Differential-type ailerons are the newer type.

2. Frise Type Ailerons

Frise-type ailerons also consist of 2 ailerons, one deflecting upwards and the other downwards.

But the upward aileron is not deflected at a greater distance than the downward one, unlike in differential type ailerons. 

Purpose of Ailerons

Ailerons control the plane’s longitudinal axis, so they are used to roll and turn the plane to the left or right as necessary.

A pilot can increase the upward deflection of the right aileron and increase the downward deflection of the left one to roll the plane to the right.

Conversely, a pilot can increase the upward deflection of the left aileron and increase the downward deflection of the right one to roll the plane toward the left. 

How Ailerons Work

The pilot controls the ailerons with a control wheel for moving the plane left or right. 

Ailerons work by increasing lift on one wing and reducing it on the other.

The wing with the lower lift drops while the one with more lift rises.

The plane turns, or rolls, in the direction of increased lift as a result. 

An aileron’s skin and spar are made of solid laminate. The trailing edge of an aileron is constructed with a foam material. 

A Plane Can Fly Without Ailerons

Planes can fly without ailerons by using a rudder instead. But ailerons are preferable since they’re easy to use and perform better than rudders. 

Planes used wing warping before ailerons were invented.

Wing warping involves twisting the outboard portion of the wing to alter the aircraft’s angle of attack. But wing warping caused heavy stress to aircraft and risked asymmetric wing stall

Some planes also depended on the rudder for turning.

Pressing the rudder back and forth allowed planes to change their angle of attack, but it was less efficient than rudders. 

Ailerons & Adverse Yaw

Adverse yaw is when a plane initially yaws in the opposite of the intended direction.

For instance, if the plane was intended to roll to the right but initially yaws to the left.

There are two main ways to overcome adverse yaw: 

  • 1. Differential Ailerons

The upward deflected aileron is raised at a greater distance than the downward deflected aileron that is lowered.

The result is increased drag in the descending aileron, which decreases adverse yaw. 

  • 2. Frise ailerons

The upward-deflected aileron pivots on an offset hinge, pushing the aileron’s leading edge into the airflow, creating drag and reducing adverse yew. 

Difference Between Flaps and Ailerons

Ailerons control an aircraft’s roll, while flaps increase the lift produced on a wing. Ailerons are closer to the wing tips and deflect in opposite directions.

Flaps are located near the wing’s root.

The flaps on both wings also move together, and flaps are also more complex than ailerons. 

Difference Between the Rudder and Ailerons

Ailerons and the rudder perform the same purpose: controlling the yaw of a plane.

The primary difference is that the rudder is located at the back of a plane’s tail, while the ailerons are located at the wing’s trailing edges.

When Were Ailerons First Used?

Ailerons were first used in 1868 by Englishman Matthew Piers Watt, who patented a system of lateral flight control.

French experimenter Robert Esnault-Pelterie designed the next ailerons in 1904 to replace wing warping. 

What is an Aileron Roll?

An Aileron roll is an aerobatic maneuver that involves a plane completing a 360 degree revolution along its longitudinal axis.

The aileron roll ends with the plane having no change in its altitude or heading. 

The aileron roll is often one of the first maneuvers taught in aerobatics courses.

It’s also commonly confused with a barrel roll.

The difference between the two is that a barrel roll changes both an aircraft’s heading and its altitude, while an aileron roll does not. 

In conclusion:

  • Ailerons are the deflecting flaps you see at the trailing ends of a plane’s wings.
  • Ailerons serve an important purpose: they’re used to roll the plane to either the left or right.
  • The pilot operates the ailerons with a control wheel that lets them increase or decrease the deflection of the ailerons in each wing.
  • Changing the aileron’s deflection changes the lift generated by each wing.
  • The pilot increases the lift on one wing and decreases it on the other, allowing the plane to roll in the direction of a higher lift.
  • Before ailerons, planes used wing warping, but it was much less effective.

Helen Krasner holds a PPL(A), with 15 years experience flying fixed-wing aircraft; a PPL(H), with 13 years experience flying helicopters; and a CPL(H), Helicopter Instructor Rating, with 12 years working as a helicopter instructor.

Helen is an accomplished aviation writer with 12 years of experience, having authored several books and published numerous articles while also serving as the Editor of the BWPA (British Women Pilots Association) newsletter, with her excellent work having been recognized with her nomination of the “Aviation Journalist of the Year” award.

Helen has won the “Dawn to Dusk” International Flying Competition, along with the best all-female competitors, three times with her copilot.