Aerodynamics.In tutorial, we will discuss what makes

an airplane fly, and we'll learn some important terms and concepts

along the way.But first

let's learn about the Bernoulli's principal. Daniel Bernoulli,

who is a Swiss mathematician, expanded

on Newton's ideas and discovered the motion of fluids.

He described in his 1738 publication,

"Hydrodynamica," the basic principles

of airflow pressure differential. The principle

simply states that as the velocity of a fluid, such as air,

increases its pressure decreases.

let's take a look at the diagram

to understand this concept a little better. As the air

or fluids in general travel through the tighter passage of the tube,

the velocity increases since fluids

travel at a faster speed to reach

the end of the curve.What's interesting,

when he measured the pressure, Bernoulli discovered that every time the

velocity increased

or decreased the pressure would have the opposite effect

In this slide

will define a very important force that will help us

understand the future concepts.That force is the "Relative

Wind."The relative Wind is simply the airflow that is parallel

and opposite to the flight path the airplane. An airfoil

is any surface, such as a wing, that provides

aerodynamic force when it interacts with a moving stream

of air.When given a flight path

and an opposite relative wind

it' s important to remember

that the airflow over the surface of the wing

will have a higher velocity than the airflow

under the wing. it's also important to note

that the circulation on the airstream about the

airflow is an important factor in the generation

of lift. The Camber

it is

the characteristic curve of the airfoil's upper

and lower surfaces. The Chord line

is an imaginary straight-line

drawn through the airfoil and the direction of

the relative wind. The chord line

is a very important determinant of what's called

the "Angle of Attack."The angle of attack

is simply the angle between the Chord line

and airflow at the direction

of the relative wind. In this slide

we will learn that as the angle of attack increases

the lift also increases.

Please note that the lift acts perpendicular

to the relative wind regardless of the angle

of attack. According to Bernoulli's Theorem,

the increased speed of the air on top of an airfoil

produces a pressure drop. This lowered

pressure is one component of a total

lift. However,

when the angle of attack is increased

beyond the maximum allowed the lift

is decreased; this causes

what's called a "Stall." As we mentioned earlier,

a stall is the result of

a critical angle attack. It is also caused

by the disruption on the airflow

from the upper surface of the wing

or airfoil. The airflow then separates

at what's called the "Trailing Edge."

The airflow progresses forward until the wing

is fully stalled

Therefore, a stall is a rapid decrease

of lift caused by separation of

airflow. In this slide,

we will learn about the four very important forces

of flight. The challenge

to understand what makes an airplane fly

starts with learning the four forces of flight.

During a flight, the four forces

acting on the airplane are : Lift,

Weight, Thrust, and Drag

Lift as we discussed earlier is created

by the effect of airflow over and under

the wing. The weight of the airplane

that is the force caused by gravity.

The Thrust: That is the force that propels

the airplane. And finally,

the drag, which is the force that limits

the speed of the aircraft.

By now we have established that lift is the key

aerodynamic force. Please remember

that when

weight and lift are equal

an airplane is said to be in a state of

equilibrium, and that means

Lift = Weight also,

when vertical and horizontal forces are applied

as shown on the left of the slide, the resulting force

acts in a diagonal direction

therefore the resultant of two

opposing forces which are equal in magnitude

is zero. I hope you enjoyed the tutorial

and thank you for watching :)