Humanity has long been obsessed with heavier-than-air flight, and to this day it remains a topic that is shrouded in a bit of mystery. In this video we take a detailed look at lift, starting with how it is linked with the pressure distribution around airfoils. We also cover a few different explanations of lift, including the Bernoulli Principle and Newton's Third Law explanations. Circulation is a key aspect of lift that it is important to grasp to develop a more complete understanding of lift so that's covered too, as is the Kutta condition. Finally we explore how the lift force varies with the angle of attack of the airfoil (which explains why aerobatic aircraft use symmetrical airfoils), and how stalling can result in a dangerous loss of lift.

Drag and lift are the forces which act on a body moving through a fluid, or on a stationary object in a flowing fluid. We call these aerodynamic forces (if the fluid is a gas) or hydrodynamic forces (if the fluid is a liquid).

This video is all about the drag force. There are two main causes of drag - first we have the pressure distribution around the object, which is particularly significant if flow separation occurs. And then we have the shear stresses acting on the object, which are most significant for streamlined bodies.

Induced Drag: The drag developed as a result of lift production

Parasite Drag: The drag resulting from moving the aircraft shape through the air

Angle of attack specifies the angle between the chord line of the wing of a fixed-wing aircraft and the vector representing the relative motion between the aircraft and the atmosphere. Since a wing can have twist, a chord line of the whole wing may not be definable, so an alternate reference line is simply defined. Often, the chord line of the root of the wing is chosen as the reference line. Another choice is to use a horizontal line on the fuselage as the reference line

In flight

In flight

On tarmac

On Tarmac