10. Aeroplanes
History
There have been many pioneers in the history of aeroplanes but the first to successfully fly an aeroplane were the Wright Brothers, Orville and Wilbur. Orville and Wilbur were skilled craftsmen and keen experimenters. They owned a business making and repairing bicycles. They were able to bring the value of a scientific approach to the invention of a heavier-than-air machine.
On the 17th of December 1903 they were successful in producing the world’s first powered flight. Wilbur ran alongside the plane, Flyer, as Orville took off on the sand dunes outside a town called Kitty Hawk in North Carolina, USA. The flight lasted just 12 seconds and travelled 37 metres. This distance is less than the wingspan of a modern airliner, but it was a major accomplishment at the time.
The brothers received very little recognition in their home country. People were very sceptical about their achievement. On the 8th of October 1908, Wilbur flew their famous plane, Flyer, in front of a large crowd in France. The next day it was all over the French newspapers.
How they fly
Aeroplanes planes are able to fly due to differences in air pressure. When a plane is on the ground, not moving, the pressure around it is the same top and bottom. The downward pressure of gravity is the same as the upward pressure of the ground. The plane has no lift.
The shape of the wing gives the aeroplane the ability to lift of the ground. The wings are more curved on top than they are the bottom. As the wings move through the air, the air that travels over the top of the wings has further to move than the air travelling below. Air that moves faster has lower air pressure than air that moves slower. This means that there is lower air pressure above the wing than below. The result is an upward force or pressure and the plane is able to lift.
A plane is able to move forward because of the engine powered propellor. As it starts to move forward, the air pressure on the plane starts to change as the air moves over the wings. The upward pressure is now greater than the downward pressure of gravity and the plane starts to lift of the ground and is able to fly.
Parts of an airplane
The airplane has six main parts—fuselage, wings, stabilizer (or tail plane), rudder, one or more engines, and landing gear. The fuselage is the main body of the machine, customarily streamlined in form. It usually contains control equipment, and space for passengers and cargo. The wings are the main supporting surfaces. Modern airplanes are monoplanes (airplanes with one wing) and may be high-wing, mid-wing, or low-wing (relative to the bottom of the fuselage). At the trailing edge of the wings are auxiliary hinged surfaces known as ailerons that are used to gain lateral control and to turn the airplane.
The lift of an airplane, or the force that supports it in flight, is basically the result of the direct action of the air against the surfaces of the wings, which causes air to be accelerated downward. The lift varies with the speed, there being a minimum speed at which flight can be maintained. This is known as the stall speed. Because speed is so important to maintain lift, objects such as fuel tanks and engines, that are carried outside the fuselage are enclosed in structures called nacelles, or pods, to reduce air drag (the retarding force of the air as the airplane moves through it).
Directional stability is provided by the tail fin, a fixed vertical airfoil the rear of the plane. The stabilizer, or tail plane, is a fixed horizontal airfoil at the rear of the airplane used to suppress undesired pitching motions. To the rear of the stabilizer are usually hinged the elevators, movable auxiliary surfaces that are used to produce controlled pitching. The rudder, generally at the rear of the tail fin, is a movable auxiliary airfoil that gives the craft a yawing (turning about a vertical axis) movement in normal flight. The rear array of airfoils is called the empennage, or tail assembly. Some aircraft have additional flaps near the ailerons that can be lowered during takeoff and landing to augment lift at the cost of increased drag. On some airplanes hinged controls are replaced or assisted by spoilers, which are ridges that can be made to project from airfoils.
Airplane engines may be classified as driven by propeller, jet, turbojet, or rocket. Most engines originally were of the internal-combustion, piston-operated type, which may be air- or liquid-cooled. During and after World War II, duct-type and gas-turbine engines became increasingly important, and since then jet propulsion has become the main form of power in most commercial and military aircraft. The landing gear is the understructure that supports the weight of the craft when on the ground or on the water and that reduces the shock on landing. There are five common types—the wheel, float, boat, skid, and ski types.
Types of airplanes
Land planes
Land planes are designed to operate from a hard surface, typically a paved runway. A land plane usually has wheels to taxi, take off, and land. Carrier airplanes have a strengthened structure, including their landing gear, to handle the stresses of catapult-assisted takeoff, in which the craft is launched by a steam-driven catapult; and arrested landings, made by using a hook attached to the underside of the aircraft’s tail to catch one of four wires strung across the flight deck of the carrier.
Seaplanes
Seaplanes are often ordinary land planes modified with floats instead of wheels so they can operate from water. A number of seaplanes have been designed from scratch to operate only from water bases. Such seaplanes have bodies, or fuselages, that resemble and perform like boat hulls. Known as flying boats, they may have small floats attached to their outer wing panels to help steady them at low speeds on the water, but the weight of the airplane is borne by the floating hull.
Amphibians
Amphibians, like their animal namesakes, operate from both water and land bases. In many cases, an amphibian is a true seaplane, with a boat hull and the addition of specially designed landing gear that can be extended to allow the airplane to taxi right out of the water onto land.
VTOLs
Vertical Takeoff and Landing airplanes typically use the jet thrust from their engines, pointed down at the earth, to take off and land straight up and down. For takeoff and landing, the engines and rotors are positioned vertically, much like a helicopter. After takeoff, however, the engine/rotor combination tilts forward, and the wing takes on the load of the craft.
STOLs
Short Takeoff and Landing airplanes are designed to be able to function on relatively short runways. Their designs usually employ wings and high-lift devices on the wings optimized for best performance during takeoff and landing, as distinguished from an airplane that has a wing optimized for high-speed cruise at high altitude. airplanes are usually cargo airplanes, although some serve in a passenger-carrying capacity as well.
Octo-Boogie 