You look up in the sky and wonder. How does an object obviously heavier than air, fly?
I bet at one point in your life you might have asked yourself that
Question, especially for those of us that have a special fondness for
flight. For some very curious folks like me, its one of the major
reasons i made up my mind to know more and go into aviation. From there
you enjoy the thrill and find your passion, you branch out to either
become an air traffic controller, pilot, an engineer, a dispatcher, even
doctors, lawyers and journalist can freely specialise in the industry.
These machinces suspends in the air for several hours defying the laws
of gravity. Another funny fact is, airplanes come in different shapes
and sizes. From very light single engine props to Heavy Jets like the
777s, 747s and A380s and let's not forget the jets design for military
purposes as well as helicoptors. They are all termed "HEAVIER THAN AIR
AIRCRAFTS"
Okay back to our main issue. How do Airplanes fly? Well in summary
physics has the answer (that's way I indulge every wannabe pilot to take
their physics lessons seriously). As for those who would become
aeronautic engineers they go indept by applying mathematical theories
and calculations to why an airplane flies.
There are four fundamental principles of flight
-Lift
-Weight
-Drag
-Thrust
These forces oppose each other and create a balance that keeps the
aircraft in flight. I.e LIFT is opposed by the WEIGHT of the aircraft.
THRUST is opposed by DRAG. These forces obeys newtons' 3rd law which
states that for every action there is an equal and opposite reaction.
Airplanes
The wings of an airplane is also a major contributing factor that helps the aircraft create lift.
Example. When a B737 hurdles down the runway, air passes through the
wings. From the leading edge to the trailing edge of the wings both
above and below the wings. The air that passes above the wings passes
with high speed and travels further with low pressure, while the air
that passes below the wings of the aircraft passes at a lower speed with
higher pressure. This process is what creates lift and is known as
Bernoulli's principle which states that within an airflow of constant
energy, when air flows through a region of lower pressure it speeds up
and vice versa.
As the pilot moves his yoke towards him/her the ANGLE OF ATTACK is
increased. The higher the Angle of Attack the more the pressure and the
more the lift. Note that there is a degree to which a pilot can increase
his Angle Of Attack. Any angle above the prescribed is know as critical
angle of attack you could tilt the yolk and loose speed and enter a
STALL.
Aircraft wing surface area is Dependent on the size of the aircraft. The
bigger the aircraft the more thrust and wing surface area required to
lift the aircraft.
For Helicopters.
I understand the basics of helicopter flight as well as its controls
movement. I had to seat on the left to have a visual comprehension, so
all I know is on the surface.
Rotor wings aircraft obey the same fundamental principles of flight.
They are only different by design. Rotor heads generate lift as well as
provide thrust for the helicopter. The Rotor is turned by an
engine-driven shaft. Air passes through the rotor blades "just as we
explained in the airplane section above" the air above the blades moves
at high speeds and pushes air downward to create lift. By tilting the
rotor forward, i.e pushing the cyclic forward, the downward flow is
tilted backward, producing thrust for forward flight. Some helicopters
have more than one rotor and a few have rotors turned by gas jets at the
tips.
For a comprehensive explanation visit
http://www.pilotfriend.com/training/flight_training/rotary/helis.htm
