Aeroplanes are one of the most important forms of transport in the world. They are used to transport people and cargo, as well as to fight in wars. They are made from a special kind of fuel called jetfuel and are powered by jet engines. They can travel over long distances and are very efficient at delivering goods to their destination.
Airplanes have changed a lot over the years and today they are a very safe form of transport, especially compared to buses. They have an occupant safety rating of around 90 per cent, and they are often fitted with collision avoidance systems that detect other aircraft in the area and advise the pilot to take evasive action if necessary.
The earliest aircraft were wooden or canvas models that carried heavy loads and were used for military purposes during World War 1. They were then replaced with heavier-than-air aircraft in the 1920s, which could carry more passengers and were powered by turbofan engines.
These planes were also able to fly over longer distances than earlier aircraft. Some of these designs still exist, including the German Dornier Do X that could carry up to 169 passengers and a range of 1,700 kilometers.
There are many different types of aircraft in use today and these vary in their size and function. They are divided into two main groups: passenger and cargo planes.
Lift is the first force that a plane uses to stay in the sky and it is achieved by creating an area of low pressure on top of the wing. This area of low pressure is created because the air on top of the wing has a lower velocity than the air on the underside of the wing. When this difference in velocity is just right, the lift created by the wing will be equal to the weight of the aircraft.
Induced drag is the second force that a plane uses to stay in flight and it is achieved by deflecting air down onto the underside of the wing. The resulting turbulence is much greater than that created by the air deflected upward, but it can be controlled by adding a slat to the top of the wing or leading-edge slots to the front of the wing.
The shape of the wing planform (the cross-section of the wing) is another factor that affects the way lift, drag and stall are generated. An elliptical wing, for example, like that on the Supermarine Spitfire fighter of World War II, can be very aerodynamically ideal, but the high angle of attack it produces at lower speeds creates a much more undesirable stall pattern than a simple rectangular wing.
This stall can be avoided by adding a flap, which is a small circular section of the wing that is raised slightly to provide additional surface area to smooth out airflow over the wing at higher angles of attack.
A rudder, a vertical surface, is also used to control movement of an aircraft. This is used to counter an adverse yaw caused by the ailerons, which are designed to rotate the aircraft around its vertical axis.
