I fell deeply in love with international travel the instant I was provided with unrestricted access to various destinations world wide, thanks to benefits bestowed upon me, the spouse of an employee of a major international airline.
Notwithstanding the sheer corporal pleasures associated with flying, planes themselves, and the complicated physics associated with their lift and thrust, put my brains to work, what with figuring out the application of Newton’s Laws of lift…
Flight over Yas Viceroy Hotel, Yas Island, Abu Dhabi: f/10; Exposure 1/200sec; ISO-200
Newton’s first law states a body at rest will remain at rest, or a body in motion will continue in straight-line motion unless subjected to an external applied force. That means, if one sees a bend in the flow of air, or if air originally at rest is accelerated into motion, there is a force acting on it. Newton’s third law states that for every action there is an equal and opposite reaction. In order to generate lift a wing must do something to the air. What the wing does to the air is the action while lift is the reaction.
A380 Seat Juliet 31: NIKON D3000 f/3.5; Exposure 1/8sec; ISO-400
As Newton’s laws suggests, the wing must change something of the air to get lift. Changes in the air’s momentum will result in forces on the wing. To generate lift a wing must divert air down: lots of air.
The lift of a wing is equal to the change in momentum of the air it is diverting down. Momentum is the product of mass and velocity. The lift of a wing is proportional to the amount of air diverted down times the downward velocity of that air. Simple, hey? For more lift the wing can either divert more air (mass) or increase its downward velocity. This downward velocity behind the wing is called “downwash”. To the pilot the air is coming off the wing at roughly the angle of attack. To the observer on the ground, the air seems as though it comes off wing vertically.
The greater the angle of attack, the greater the vertical velocity. Likewise, for the same angle of attack, the greater the speed of the wing the greater the vertical velocity. Both the increase in the speed and the increase of the angle of attack increase the length of the vertical arrow. It is this vertical velocity that gives the wing lift. Et viola! The sweet sensation of flying…
The Captain sits on the left-hand side of a fixed-wing aircraft
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