# Lift Terminology

Before we jump into the details of controlling lift, we first need to review some of the terminology we will be using.

## The Aerofoil

Looking at a wing from side on, we see the wing shape the aircraft designers have chosen – this is known as the aerofoil. The aerofoil is designed to generate lift as air flows past.

## Chord and Camber Line

A straight line joining the leading edge and trailing edge of the aerofoil is called the chord line.

The camber line is the line formed if you were to slice the aerofoil into two equal halves. At any point along the camber line, the top slice is equal to the bottom slice.

## Relative Airflow and Angle of Attack

In flight, the airflow over the aircraft is a result of its forward movement. Imagine sticking your hand out a car window going down a hill at speed – the apparent wind will be opposite to the car’s forward motion.

The same is true for an aircraft in flight and the apparent wind is called relative airflow. The relative airflow will always be opposite the direction of flight.

The angle between the chord line and the relative airflow is the angle of attack. You will soon learn how the angle of attack is critical to controlling lift.

Note the relative airflow is opposite the direction of flight – this is not alway where the nose is pointed! Think of when you have watched an aircraft landing. The pilot raises the nose before touching down but the aircraft is still travelling forwards, not upwards, and the relative airflow is at an angle to the wing (called the angle of attack).