Aircraft

Aircraft: a machine capable of atmospheric flight (see air transport). Aircraft can be sub-divided into two broad categories: heavier than air (airplanes, autogyros, helicopters, and variants), and lighter than air (balloons, blimps, and dirigibles).

Conventional or fixed-wing aircraft generally use a propeller or jet engine to provide thrust, which moves the craft forward through the air. The movement of air over the wings produces lift, which allows the aircraft to fly. An exception is gliders which have no engines and gain their thrust from gravity. That is, they must descend in relation to the air in order to maintain their forward speed. Helicopters use a spinning rotor (a rotary wing) to provide both lift and thrust. The abbreviation VTOL is applied to aircraft other than helicopters that can take off or land vertically. Similarly, STOL stands for Short Take Off and Landing.

Lighter-than-air craft float in air in the same way that a ship floats in water, by displacing the air around the craft with a lighter gas such as helium, hydrogen, or hot air. They may have propellers to provide forward thrust or they may simply drift with the wind.

Types of Aircraft

There are several ways to classify aircraft. Below, we describe classifications by design, propulsion and usage.

By design

A first division by design among aircraft is between lighter-than-air and heavier-than-air aircraft.

Examples of lighter-than-air aircraft include non-steerable balloons, such as hot air balloons and gas balloons, and dirigible balloons, such as blimps (which have a non-rigid construction) and airships, which have a rigid carcass. A well-known example of the latter is the Zeppelin.

In heavier-than-air aircraft, we can discern two major ways to produce the lift: aerodynamic lift and engine lift. In the case of aerodynamic lift, the aircraft is kept in the air because of aerodynamics, usually by means of wings of some kind. With engine lift, the aircraft defeats gravity by sheer engine power.

Examples of engine lift aircraft are rockets, and so-called VTOL planes, such as the Harrier jet.

Among aerodynamically lifted aircraft, the largest number falls in the category of fixed wing aircraft, where horizontal surfaces produce lift, usually by profiting from Bernoulli's principle (aeroplane or airplane).

In a "conventional" configuration, the lift surfaces is placed in front of a control surface; for example by having steering flaps at the rear end of a wing. The number of lift surfaces varied greatly in the past, as biplanes (two wings) and triplanes (three wings) were numerous in the early days of aviation. Currently, most planes are monoplanes.

The reverse configuration is the "canard" type, where small horizontal control surfaces are placed on the nose of the aircraft, so in front of the lift surfaces.

Other possibilities include the delta-wing, where lift and horizontal control surfaces are combined and the flying wing, where there is no separate vertical control surface (f.e. the B-2). A variable geometry ('swing-wing') is also possible.

A second large category among aerodynamically lifted aircraft are the rotary wing aircraft. Here, the lift is provided by fastly rotating rotors. The best known example of this category is the helicopter (which was preceded by the autogyro), but also the tiltrotor aircraft ( such as the V-22 Osprey) and the hovercraft belong in this category.

A third category is the wing-in-ground-effect, for example the ekranoplan. (I don't anything abou this, please expand)

Reference

By propulsion

Some types of aircraft, such as the glider or sailplane do not have any propulsion. Take-off takes place from a high location, or the aircraft is lifted by another plane.

Most early aircraft used a piston-engine with propeller as propulsion. Although the configuration of the engine can vary (rotary, radial, inline), these all work according to the same principle.

During World War II, the first jet engines emerged. Different types exist, such as the Ramjet, Pulse jet, Turbojet and the Turboprop, of which the latter still uses a propeller.

By usage

Three major uses for aircraft may be seen: recreational, military and commercial.

For recreation, almost any type of aircraft can be used, although they are usually small ones. Gliders and sailplane are exlusively used for recreational purposes.

The first military aircraft were used for reconnaissance and surveillance in World War I. Soon it was invented that is was possible to use them for attacking the ground as well, and the first bombers were born. In order to prevent the enemy from bombing, fighter aircraft were developed to intercept and shoot down enemy aircraft.

Later, trainers were developed for the purpose of instructing new pilots. The use of transport aircraft allowed for moving of cargo, troops and evacuation; these were also used to drop paratroopers. Tankers are used to refuel plane in mid-air.

Commercial aviation can be divided in passenger transport and cargo transport. For the former, large planes have been developed that can transport up to 500 passengers over large distances. The cargo aircraft are often the same or similar to the military transport aircraft.

Other uses include rescue (helicopters) and fire-extinguishing.

Further divisions can be made by whether with conventional (wheeled) undercarriage, or else a float-plane or flying-boat.

Aircraft manufacturers (in alphabetic order)

(it might be useful to distinguish between current and historic list, at some point.)

Types of Aircraft

By design

By propulsion

By usage

Aircraft manufacturers (in alphabetic order)

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