The Science Behind Aircraft Flight
The power of flight has inspired us since we first saw birds flying in the sky.
However, the physics behind flight eluded us for millennia. Today, we have mathematics
to describe the principles behind this phenomenon, and it no longer confuses and
eludes us. Instead, we're constantly finding new ways to push flight to the limits,
and we have several major types of aircrafts. Each craft has its own method of flight
and thus a different mathematical background, yet they all achieve flight!
Airplanes
Airplanes can be placed in two major categories: jet planes and propeller planes.
They both work in the same way; however, there are some minor differences that apply
to their overall aerodynamic design. Airplanes achieve flight by using lift, drag,
thrust and weight. They use a specially designed wing to generate high pressure
below the craft and low pressure above it. By using a mechanism to generate thrust,
such as a propeller, the wing gets enough airflow past it to overcome the weight
and drag of the aircraft. Weight is caused by gravity, and it pulls down on the
aircraft; drag is produced by the friction created by the air particles passing
the plane.
Helicopters
Helicopters use the same design principle as planes do, but in a different way.
Instead of having wings on the side of the craft and a propeller in the front, the
helicopter has a directional rotor on the top. The pilot has to learn how to angle
the rotor in order to alter how it generates lift and thrust. If the rotor is angled
down, the helicopter will move forward. Angling it in an upward motion will cause
the helicopter to fly backwards. Right and left motions go in their respective directions.
All helicopters require a stabilizing rotor on the wing to prevent them from spinning
in circles. By adding another rotor the pilot can chose to yaw left or right, while
the pitch and roll are controlled by the main rotor.
Rockets
Out of all the different types of aircrafts, rockets are by far the easiest to understand
how flight is achieved. However, the actual mechanisms are difficult to replicate
on a large scale. If a rocket is going to be designed to transport a human to space,
it must be very aerodynamic in design so as to decrease the amount of drag it encounters
in flight. It also must have enough thrust to break Earth's atmosphere; otherwise,
the rocket would be incapable of storing necessary equipment onboard. Additionally,
to prevent the rocket from spiraling out of control it must have stabilizer wings
placed in the correct position, which depends on the weight distribution of the
rocket. A huge amount of thrust is required, backed by a stable source of fuel,
if the craft is going to make it into space.
Blimps
Although many people confuse the two aircrafts, there is a definite difference between
a blimp and a zeppelin. The latter is a rigid aircraft that uses a sturdy ribcage
to retain its shape. In contrast, a blimp uses gases that are lighter than air,
like helium or hydrogen, to inflate the material that it's designed out of. Because
the gases that both zeppelins and blimps use are lighter than air, they naturally
want to rise above heavier gases, like oxygen and nitrogen. Think of a submarine
toy that's placed under water. If you trap air in the toy before submerging it,
the submarine will push through the water as the air tries to escape. When it reaches
the surface it just sits at the top. In the case of a blimp, the weight prevents
the craft from sitting on top of the air; it is propelled from the rear by a propeller
and the yaw is controlled by a rudder near the propeller.
Kites
To visualize the way a kite works, think of a giant wing. Unfortunately, their design
makes it very difficult to control them if there is an insufficient amount of air
flow surrounding the craft. Stabilizing strings are used to influence the direction
the wing takes, and the kite depends on the wind for thrust. Because of this, it
has to be constructed out of light enough materials that it remains in flight, but
strong enough in design so that it doesn't break under the force of the wind. The
tail end of the kite is used for drag, and without it the kite would not work properly;
it would be unable to generate lift.
Hot Air Balloons
Hot air balloons were one of the first flying machines invented, and in many ways
they are the most primitive air craft we still use – aside from the kite. The balloon
is used to hold hot air and prevent it from escaping. It gets its shape from effectively
holding the circulating air inside. When the hot air reaches the top of the balloon,
it cools down. This causes the air to fall back to the bottom of the balloon, where
it's heated up again from the heat source. Hot air rises, and the only way to bring
the balloon back down is to shut off the heat source or allow the hot air to escape
the balloon. The former method is not recommended. Controllable flaps are used to
let the hot air out. Unfortunately, there is no way to steer the balloon, which
means calm, cool weather offers the best flying conditions.
General Aircraft Science
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