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Principles of flight
5.2.1 Aerodynamic fundamentals
The well-known physicists have helped explain how the forces that create lift and
drag on the aircraft's wing surfaces and control surfaces (profiles) work.
Newton, especially, and not least Bernoulli, are the leading theorists in this field.
5.2.1.1 Newton's 3rd Law
Newton's 3rd law states that every action will always create a reaction.
This was probably the first explanation of how we generate lift, as there is an
action-reaction between the wing and the air due to air pressure.
5.2.1.2 Bernoulli's Principle
A man named Bernoulli studied the flow of fluids in pipes and around objects.
Remember that air can actually be seen as a very thin fluid, so the principles that
apply to the flow of fluids also apply to air.
When a profile is surrounded by airflow, the static pressure will be lowest
where the air speed is highest.
The upper surfaces of the wings are made curved. This causes the air molecules
moving over the wing to travel faster than the molecules passing beneath it.
When the air moves quickly,
dynamic pressure increases, but
static pressure decreases, creating
a low-pressure zone on top of the
wing, resulting in lift.
Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 443
