# data[].attributes.body
4- 15 April 2018, Gold Coast

# data[].attributes.attachment_link.title
Athletics | Gold Coast 2018 Commonwealth Games

# data[].attributes.attachment_link.description
Right onto Fern Street, Left onto Garfield Terrace, continue north onto Northcliffe Terrace and Esplanade, continue north onto Main Beach Parade, head north, continue north onto Macarthur Parade, Left onto Waterways Drive, Right onto Gold Coast Highway and over the Southport Bridge, continue north past the Southport Broadwater Parklands, Right into Mitchell Park to the Finish.

# data[].attributes.body
- at home
-around the community
-train rides
-flight
-trips

# data[].attributes.attachment_link.readable_text
Transport (in British English), or transportation (in American English), is the movement of humans, animals, and goods from one location to another. In other words, the action of transport is defined as a particular movement of an organism or thing from a point A (a place in space) to a point B.

Modes of transport include air, land ( rail and road), water, cable, pipeline, and space. The field can be divided into infrastructure, vehicles, and operations. Transport enables trade between people, which is essential for the development of civilizations.

Transport infrastructure consists of the fixed installations, including roads, railways, airways, waterways, canals, and pipelines and terminals such as airports, railway stations, bus stations, warehouses, trucking terminals, refueling depots (including fueling docks and fuel stations), and seaports. Terminals may be used both for interchange of passengers and cargo and for maintenance.

Means of transport are any of the different kinds of transport facilities used to carry people or cargo. They may include vehicles, riding animals, and pack animals. Vehicles may include wagons, automobiles, bicycles, buses, trains, trucks, helicopters, watercraft, spacecraft, and aircraft.

A mode of transport is a solution that makes use of a certain type of vehicle, infrastructure, and operation. The transport of a person or of cargo may involve one mode or several of the modes, with the latter case being called inter-modal or multi-modal transport. Each mode has its own advantages and disadvantages, and will be chosen on the basis of cost, capability, and route.

Governments deal with the way the vehicles are operated, and the procedures set for this purpose, including financing, legalities, and policies. In the transport industry, operations and ownership of infrastructure can be either public or private, depending on the country and mode.

Passenger transport may be public, where operators provide scheduled services, or private. Freight transport has become focused on containerization, although bulk transport is used for large volumes of durable items. Transport plays an important part in economic growth and globalization, but most types cause air pollution and use large amounts of land. While it is heavily subsidized by governments, good planning of transport is essential to make traffic flow and restrain urban sprawl.

Human-powered transport, a form of sustainable transport, is the transport of people and/or goods using human muscle-power, in the form of walking, running, and swimming. Modern technology has allowed machines to enhance human power. Human-powered transport remains popular for reasons of cost-saving, leisure, physical exercise, and environmentalism; it is sometimes the only type available, especially in underdeveloped or inaccessible regions.

Although humans are able to walk without infrastructure, the transport can be enhanced through the use of roads, especially when using the human power with vehicles, such as bicycles and inline skates. Human-powered vehicles have also been developed for difficult environments, such as snow and water, by watercraft rowing and skiing; even the air can be entered with human-powered aircraft.

Animal-powered transport is the use of working animals for the movement of people and commodities. Humans may ride some of the animals directly, use them as pack animals for carrying goods, or harness them, alone or in teams, to pull sleds or wheeled vehicles.

A fixed-wing aircraft, commonly called an airplane, is a heavier-than-air craft where movement of the air in relation to the wings is used to generate lift. The term is used to distinguish this from rotary-wing aircraft, where the movement of the lift surfaces relative to the air generates lift. A gyroplane is both fixed-wing and rotary wing. Fixed-wing aircraft range from small trainers and recreational aircraft to large airliners and military cargo aircraft.

Two things necessary for aircraft are air flow over the wings for lift and an area for landing. The majority of aircraft also need an airport with the infrastructure for maintenance, restocking, and refueling and for the loading and unloading of crew, cargo, and passengers. While the vast majority of aircraft land and take off on land, some are capable of take-off and landing on ice, snow, and calm water.

The aircraft is the second fastest method of transport, after the rocket. Commercial jets can reach up to 955 kilometres per hour (593 mph), single-engine aircraft 555 kilometres per hour (345 mph). Aviation is able to quickly transport people and limited amounts of cargo over longer distances, but incurs high costs and energy use; for short distances or in inaccessible places, helicopters can be used. As of April 28, 2009, The Guardian article notes that "the WHO estimates that up to 500,000 people are on planes at any time."

Land transport covers all land-based transport systems that provide for the movement of people, goods, and services. Land transport plays a vital role in linking communities to each other. Land transport is a key factor in urban planning. It consists of two kinds, rail and road.

Rail transport is where a train runs along a set of two parallel steel rails, known as a railway or railroad. The rails are anchored perpendicular to ties (or sleepers) of timber, concrete, or steel, to maintain a consistent distance apart, or gauge. The rails and perpendicular beams are placed on a foundation made of concrete or compressed earth and gravel in a bed of ballast. Alternative methods include monorail and maglev.

A train consists of one or more connected vehicles that operate on the rails. Propulsion is commonly provided by a locomotive, that hauls a series of unpowered cars, that can carry passengers or freight. The locomotive can be powered by steam, by diesel, or by electricity supplied by trackside systems. Alternatively, some or all the cars can be powered, known as a multiple unit. Also, a train can be powered by horses, cables, gravity, pneumatics, and gas turbines. Railed vehicles move with much less friction than rubber tires on paved roads, making trains more energy efficient, though not as efficient as ships.

Intercity trains are long-haul services connecting cities; modern high-speed rail is capable of speeds up to 350 km/h (220 mph), but this requires specially built track. Regional and commuter trains feed cities from suburbs and surrounding areas, while intra-urban transport is performed by high-capacity tramways and rapid transits, often making up the backbone of a city's public transport. Freight trains traditionally used box cars, requiring manual loading and unloading of the cargo. Since the 1960s, container trains have become the dominant solution for general freight, while large quantities of bulk are transported by dedicated trains.

A road is an identifiable route, way, or path between two or more places. Roads are typically smoothed, paved, or otherwise prepared to allow easy travel; though they need not be, and historically many roads were simply recognizable routes without any formal construction or maintenance. In urban areas, roads may pass through a city or village and be named as streets, serving a dual function as urban space easement and route.

Automobiles provide high flexibility with low capacity, but require high energy and area use, and are the main source of harmful noise and air pollution in cities; buses allow for more efficient travel at the cost of reduced flexibility. Road transport by truck is often the initial and final stage of freight transport.

Water transport is movement by means of a watercraft-such as a barge, boat, ship, or sailboat-over a body of water, such as a sea, ocean, lake, canal, or river. The need for buoyancy is common to watercraft, making the hull a dominant aspect of its construction, maintenance, and appearance.

In the 19th century, the first steam ships were developed, using a steam engine to drive a paddle wheel or propeller to move the ship. The steam was produced in a boiler using wood or coal and fed through a steam external combustion engine. Now most ships have an internal combustion engine using a slightly refined type of petroleum called bunker fuel. Some ships, such as submarines, use nuclear power to produce the steam. Recreational or educational craft still use wind power, while some smaller craft use internal combustion engines to drive one or more propellers or, in the case of jet boats, an inboard water jet. In shallow draft areas, hovercraft are propelled by large pusher-prop fans. (See Marine propulsion.)

Although it is slow compared to other transport, modern sea transport is a highly efficient method of transporting large quantities of goods. Commercial vessels, nearly 35,000 in number, carried 7.4 billion tons of cargo in 2007. Transport by water is significantly less costly than air transport for transcontinental shipping; short sea shipping and ferries remain viable in coastal areas.

Pipeline transport sends goods through a pipe; most commonly liquid and gases are sent, but pneumatic tubes can also send solid capsules using compressed air. For liquids/gases, any chemically stable liquid or gas can be sent through a pipeline. Short-distance systems exist for sewage, slurry, water, and beer, while long-distance networks are used for petroleum and natural gas.

Spaceflight is transport out of Earth's atmosphere into outer space by means of a spacecraft. While large amounts of research have gone into technology, it is rarely used except to put satellites into orbit and conduct scientific experiments. However, man has landed on the moon, and probes have been sent to all the planets of the Solar System.

Suborbital spaceflight is the fastest of the existing and planned transport systems from a place on Earth to a distant "other place" on Earth. Faster transport could be achieved through part of a low Earth orbit or by following that trajectory even faster, using the propulsion of the rocket to steer it.

Infrastructure is the fixed installations that allow a vehicle to operate. It consists of a roadway, a terminal, and facilities for parking and maintenance. For rail, pipeline, road, and cable transport, the entire way the vehicle travels must be constructed. Air and watercraft are able to avoid this, since the airway and seaway do not need to be constructed. However, they require fixed infrastructure at terminals.

Terminals such as airports, ports, and stations, are locations where passengers and freight can be transferred from one vehicle or mode to another. For passenger transport, terminals are integrating different modes to allow riders, who are interchanging between modes, to take advantage of each mode's benefits. For instance, airport rail links connect airports to the city centres and suburbs. The terminals for automobiles are parking lots, while buses and coaches can operate from simple stops. For freight, terminals act as transshipment points, though some cargo is transported directly from the point of production to the point of use.

The financing of infrastructure can either be public or private. Transport is often a natural monopoly and a necessity for the public; roads, and in some countries railways and airports, are funded through taxation. New infrastructure projects can have high costs and are often financed through debt. Many infrastructure owners, therefore, impose usage fees, such as landing fees at airports or toll plazas on roads. Independent of this, authorities may impose taxes on the purchase or use of vehicles. Because of poor forecasting and overestimation of passenger numbers by planners, there is frequently a benefits shortfall for transport infrastructure projects.

Animals used in transportation include pack animals and riding animals.

A vehicle is a non-living device that is used to move people and goods. Unlike the infrastructure, the vehicle moves along with the cargo and riders. Unless being pulled/pushed by a cable or muscle-power, the vehicle must provide its own propulsion; this is most commonly done through a steam engine, combustion engine, electric motor, jet engine, or rocket, though other means of propulsion also exist. Vehicles also need a system of converting the energy into movement; this is most commonly done through wheels, propellers, and pressure.

Vehicles are most commonly staffed by a driver. However, some systems, such as people movers and some rapid transits, are fully automated. For passenger transport, the vehicle must have a compartment, seat, or platform for the passengers. Simple vehicles, such as automobiles, bicycles, or simple aircraft, may have one of the passengers as a driver.

Private transport is only subject to the owner of the vehicle, who operates the vehicle themselves. For public transport and freight transport, operations are done through private enterprise or by governments. The infrastructure and vehicles may be owned and operated by the same company, or they may be operated by different entities. Traditionally, many countries have had a national airline and national railway. Since the 1980s, many of these have been privatized. International shipping remains a highly competitive industry with little regulation, but ports can be public-owned.

This section Please expand the section to include this information. Further details may exist on the is missing information about most of what constitutes official traffic management and planning, how it integrates with other fields of politics and how it is enforced. talk page.

As the population of the world increases, cities grow in size and population-according to the United Nations, 55% of the world's population live in cities, and by 2050 this number is expected to rise to 68%. Public transport policy must evolve to meet the changing priorities of the urban world. The institution of policy enforces order in transport, which is by nature chaotic as people attempt to travel from one place to another as fast as possible. This policy helps to reduce accidents and save lives.

Relocation of travelers and cargo are the most common uses of transport. However, other uses exist, such as the strategic and tactical relocation of armed forces during warfare, or the civilian mobility construction or emergency equipment.

Passenger transport, or travel, is divided into public and private transport. Public transport is scheduled services on fixed routes, while private is vehicles that provide ad hoc services at the riders desire. The latter offers better flexibility, but has lower capacity and a higher environmental impact. Travel may be as part of daily commuting or for business, leisure, or migration.

Taxis and buses can be found on both ends of the public transport spectrum. Buses are the cheapest mode of transport but are not necessarily flexible, and taxis are very flexible but more expensive. In the middle is demand-responsive transport, offering flexibility whilst remaining affordable.

International travel may be restricted for some individuals due to legislation and visa requirements.

An ambulance is a vehicle used to transport people from or between places of treatment, and in some instances will also provide out-of-hospital medical care to the patient. The word is often associated with road-going "emergency ambulances", which form part of emergency medical services, administering emergency care to those with acute medical problems.

Air medical services is a comprehensive term covering the use of air transport to move patients to and from healthcare facilities and accident scenes. Personnel provide comprehensive prehospital and emergency and critical care to all types of patients during aeromedical evacuation or rescue operations, aboard helicopters, propeller aircraft, or jet aircraft.

Freight transport, or shipping, is a key in the value chain in manufacturing. With increased specialization and globalization, production is being located further away from consumption, rapidly increasing the demand for transport. Transport creates place utility by moving the goods from the place of production to the place of consumption. While all modes of transport are used for cargo transport, there is high differentiation between the nature of the cargo transport, in which mode is chosen. Logistics refers to the entire process of transferring products from producer to consumer, including storage, transport, transshipment, warehousing, material-handling, and packaging, with associated exchange of information. Incoterm deals with the handling of payment and responsibility of risk during transport.

Containerization, with the standardization of ISO containers on all vehicles and at all ports, has revolutionized international and domestic trade, offering a huge reduction in transshipment costs. Traditionally, all cargo had to be manually loaded and unloaded into the haul of any ship or car; containerization allows for automated handling and transfer between modes, and the standardized sizes allow for gains in economy of scale in vehicle operation. This has been one of the key driving factors in international trade and globalization since the 1950s.

Bulk transport is common with cargo that can be handled roughly without deterioration; typical examples are ore, coal, cereals, and petroleum. Because of the uniformity of the product, mechanical handling can allow enormous quantities to be handled quickly and efficiently. The low value of the cargo combined with high volume also means that economies of scale become essential in transport, and gigantic ships and whole trains are commonly used to transport bulk. Liquid products with sufficient volume may also be transported by pipeline.

Air freight has become more common for products of high value; while less than one percent of world transport by volume is by airline, it amounts to forty percent of the value. Time has become especially important in regards to principles such as postponement and just-in-time within the value chain, resulting in a high willingness to pay for quick delivery of key components or items of high value-to-weight ratio. In addition to mail, common items sent by air include electronics and fashion clothing.

Transport is a key necessity for specialization-allowing production and consumption of products to occur at different locations. Throughout history, transport has been a spur to expansion; better transport allows more trade and a greater spread of people. Economic growth has always been dependent on increasing the capacity and rationality of transport. But the infrastructure and operation of transport have a great impact on the land, and transport is the largest drainer of energy, making transport sustainability a major issue.

Due to the way modern cities and communities are planned and operated, a physical distinction between home and work is usually created, forcing people to transport themselves to places of work, study, or leisure, as well as to temporarily relocate for other daily activities. Passenger transport is also the essence of tourism, a major part of recreational transport. Commerce requires the transport of people to conduct business, either to allow face-to-face communication for important decisions or to move specialists from their regular place of work to sites where they are needed.

Transport planning allows for high utilization and less impact regarding new infrastructure. Using models of transport forecasting, planners are able to predict future transport patterns. On the operative level, logistics allows owners of cargo to plan transport as part of the supply chain. Transport as a field is also studied through transport economics, a component for the creation of regulation policy by authorities. Transport engineering, a sub-discipline of civil engineering, must take into account trip generation, trip distribution, mode choice, and route assignment, while the operative level is handled through traffic engineering.

Because of the negative impacts incurred, transport often becomes the subject of controversy related to choice of mode, as well as increased capacity. Automotive transport can be seen as a tragedy of the commons, where the flexibility and comfort for the individual deteriorate the natural and urban environment for all. Density of development depends on mode of transport, with public transport allowing for better spatial utilization. Good land use keeps common activities close to people's homes and places higher-density development closer to transport lines and hubs, to minimize the need for transport. There are economies of agglomeration. Beyond transport, some land uses are more efficient when clustered. Transport facilities consume land, and in cities pavement (devoted to streets and parking) can easily exceed 20 percent of the total land use. An efficient transport system can reduce land waste.

Too much infrastructure and too much smoothing for maximum vehicle throughput mean that in many cities there is too much traffic and many-if not all-of the negative impacts that come with it. It is only in recent years that traditional practices have started to be questioned in many places; as a result of new types of analysis which bring in a much broader range of skills than those traditionally relied on-spanning such areas as environmental impact analysis, public health, sociology, and economics-the viability of the old mobility solutions is increasingly being questioned.

Transport is a major use of energy and burns most of the world's petroleum. This creates air pollution, including nitrous oxides and particulates, and is a significant contributor to global warming through emission of carbon dioxide, for which transport is the fastest-growing emission sector. By sub-sector, road transport is the largest contributor to global warming. Environmental regulations in developed countries have reduced individual vehicles' emissions; however, this has been offset by increases in the numbers of vehicles and in the use of each vehicle. Some pathways to reduce the carbon emissions of road vehicles considerably have been studied. Energy use and emissions vary largely between modes, causing environmentalists to call for a transition from air and road to rail and human-powered transport, as well as increased transport electrification and energy efficiency.

Other environmental impacts of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands. By reducing transport emissions globally, it is predicted that there will be significant positive effects on Earth's air quality, acid rain, smog, and climate change.

While electric cars are being built to cut down CO2 emission at the point of use, an approach that is becoming popular among cities worldwide is to prioritize public transport, bicycles, and pedestrian movement. Redirecting vehicle movement to create 20-minute neighbourhoods that promotes exercise while greatly reducing vehicle dependency and pollution. Some policies are levying a congestion charge to cars for travelling within congested areas during peak time.

The United Nation's first formally recognized the role of transport in sustainable development in the 1992 United Nation's Earth summit. In the 2012 United Nation's World Conference, global leaders unanimously recognized that transport and mobility are central to achieving the sustainability targets. In recent years, data has been collected to show that the transport sector contributes to a quarter of the global greenhouse gas emissions, and therefore sustainable transport has been mainstreamed across several of the 2030 Sustainable Development Goals, especially those related to food, security, health, energy, economic growth, infrastructure, and cities and human settlements. Meeting sustainable transport targets is said to be particularly important to achieving the Paris Agreement.

There are various Sustainable Development Goals (SDGs) that are promoting sustainable transport in order to meet the defined goals. These include SDG 3 on health (increased road safety), SDG 7 on energy, SDG 8 on decent work and economic growth, SDG 9 on resilient infrastructure, SDG 11 on sustainable cities (access to transport and expanded public transport), SDG 12 on sustainable consumption and production (ending fossil fuel subsidies), and SDG 14 on oceans, seas, and marine resources.

Humans' first ways to move included walking, running, and swimming. The domestication of animals introduced a new way to lay the burden of transport on more powerful creatures, allowing the hauling of heavier loads, or humans riding animals for greater speed and duration. Inventions such as the wheel and the sled (U.K. sledge) helped make animal transport more efficient through the introduction of vehicles.

The first forms of road transport involved animals, such as horses ( domesticated in the 4th or the 3rd millennium BCE), oxen (from about 8000 BCE), or humans carrying goods over dirt tracks that often followed game trails.

Water transport, including rowed and sailed vessels, dates back to time immemorial and was the only efficient way to transport large quantities or over large distances prior to the Industrial Revolution. The first watercraft were canoes cut out from tree trunks. Early water transport was accomplished with ships that were either rowed or used the wind for propulsion, or a combination of the two. The importance of water has led to most cities that grew up as sites for trading being located on rivers or on the sea-shore, often at the intersection of two bodies of water.

Until the Industrial Revolution, transport remained slow and costly, and production and consumption gravitated as close to each other as feasible.[citation needed ] The Industrial Revolution in the 19th century saw several inventions fundamentally change transport. With telegraphy, communication became instant and independent of the transport of physical objects. The invention of the steam engine, closely followed by its application in rail transport, made land transport independent of human or animal muscles. Both speed and capacity increased, allowing specialization through manufacturing being located independently of natural resources. The 19th century also saw the development of the steam ship, which sped up global transport.

With the development of the combustion engine and the automobile around 1900, road transport became more competitive again, and mechanical private transport originated. The first "modern" highways were constructed during the 19th century[citation needed ] with macadam. Later, tarmac and concrete became the dominant paving materials.

In 1903 the Wright brothers demonstrated the first successful controllable airplane, and after World War I (1914-1918) aircraft became a fast way to transport people and express goods over long distances.

After World War II (1939-1945) the automobile and airlines took higher shares of transport, reducing rail and water to freight and short-haul passenger services. Scientific spaceflight began in the 1950s, with rapid growth until the 1970s, when interest dwindled. In the 1950s the introduction of containerization gave massive efficiency gains in freight transport, fostering globalization. International air travel became much more accessible in the 1960s with the commercialization of the jet engine. Along with the growth in automobiles and motorways, rail and water transport declined in relative importance. After the introduction of the Shinkansen in Japan in 1964, high-speed rail in Asia and Europe started attracting passengers on long-haul routes away from the airlines.

Early in U.S. history,[when? ] private joint-stock corporations owned most aqueducts, bridges, canals, railroads, roads, and tunnels. Most such transport infrastructure came under government control in the late 19th and early 20th centuries, culminating in the nationalization of inter-city passenger rail-service with the establishment of Amtrak. Recently,[when? ] however, a movement to privatize roads and other infrastructure has gained some[quantify ] ground and adherents.

# data[].attributes.attachment_link.description
Transport (in British English), or transportation (in American English), is the movement of humans, animals, and goods from one location to another. In other words, the action of transport is defined as a particular movement of an organism or thing from a point A (a place in space) to a point B.

# data[].attributes.attachment_link.readable_text
by Chris Woodford. Last updated: January 30, 2022.

We take for it granted that we can fly from one side of the world to the other in a matter of hours, but a century ago this amazing ability to race through the air had only just been discovered. What would the Wright brothers-the pioneers of powered flight-make of an age in which something like 100,000 planes take to the sky each day in the United States alone? They'd be amazed, of course, and delighted too. Thanks to their successful experiments with powered flight, the airplane is rightfully recognized as one of the greatest inventions of all time. Let's take a closer look at how it works!

Photo: You need big wings to lift a big plane like this US Air Force C-17 Globemaster. The wings are 51.75m (169ft) wide-that's just slightly less than the plane's body length of 53m (174ft). The maximum takeoff weight is 265,352kg (585,000lb), about as much as 40 adult elephants! Photo by Michael Battles courtesy of US Air Force.

Sponsored links

How do planes fly?

If you've ever watched a jet plane taking off or coming in to land, the first thing you'll have noticed is the noise of the engines. Jet engines, which are long metal tubes burning a continuous rush of fuel and air, are far noisier (and far more powerful) than traditional propeller engines. You might think engines are the key to making a plane fly, but you'd be wrong. Things can fly quite happily without engines, as gliders (planes with no engines), paper planes, and indeed gliding birds readily show us.

Photo: Four forces act on a plane in flight. When the plane flies horizontally at a steady speed, lift from the wings exactly balances the plane's weight and the thrust exactly balances the drag. However, during takeoff, or when the plane is attempting to climb in the sky (as shown here), the thrust from the engines pushing the plane forward exceeds the drag (air resistance) pulling it back. This creates a lift force, greater than the plane's weight, which powers the plane higher into the sky. Photo by Nathanael Callon courtesy of US Air Force.

If you're trying to understand how planes fly, you need to be clear about the difference between the engines and the wings and the different jobs they do. A plane's engines are designed to move it forward at high speed. That makes air flow rapidly over the wings, which throw the air down toward the ground, generating an upward force called lift that overcomes the plane's weight and holds it in the sky. So it's the engines that move a plane forward, while the wings move it upward.

Photo: Newton's third law of motion-action and reaction-explains how the engines and wings work together to make a plane move through the sky. The force of the hot exhaust gas shooting backward from the jet engine pushes the plane forward. That creates a moving current of air over the wings. The wings force the air downward and that pushes the plane upward. Photo by Samuel Rogers (with added annotations by explainthatstuff.com) courtesy of US Air Force. Read more about how engines work in our detailed article on jet engines.

How do wings make lift?

In one sentence, wings make lift by changing the direction and pressure of the air that crashes into them as the engines shoot them through the sky.

Pressure differences

Okay, so the wings are the key to making something fly-but how do they work? Most airplane wings have a curved upper surface and a flatter lower surface, making a cross-sectional shape called an airfoil (or aerofoil, if you're British):

Photo: An airfoil wing typically has a curved upper surface and a flat lower surface. This is the wing on NASA's solar-powered Centurion plane. Photo by Tom Tschida courtesy of
NASA Armstrong Flight Research Center.

In a lot of science books and web pages, you'll read an incorrect explanation of how an airfoil like this generates lift. It goes like this: When air rushes over the curved upper wing surface, it has to travel further than the air that passes underneath, so it has to go faster (to cover more distance in the same time). According to a principle of aerodynamics called Bernoulli's law, fast-moving air is at lower pressure than slow-moving air, so the pressure above the wing is lower than the pressure below, and this creates the lift that powers the plane upward.

Although this explanation of how wings work is widely repeated, it's wrong: it gives the right answer, but for completely the wrong reasons! Think about it for a moment and you'll see that if it were true, acrobatic planes couldn't fly upside down. Flipping a plane over would produce "downlift" and send it crashing to the ground. Not only that, but it's perfectly possible to design planes with airfoils that are symmetrical (looking straight down the wing) and they still produce lift. For example, paper airplanes (and ones made from thin balsa wood) generate lift even though they have flat wings.

" The popular explanation of lift is common, quick, sounds logical and gives the correct answer, yet also introduces misconceptions, uses a nonsensical physical argument and misleadingly invokes Bernoulli's equation."
Professor Holger Babinsky, Cambridge University

But the standard explanation of lift is problematic for another important reason as well: the air shooting over the wing doesn't have to stay in step with the air going underneath it, and nothing says it has to travel a bigger distance in the same time. Imagine two air molecules arriving at the front of the wing and separating, so one shoots up over the top and the other whistles straight under the bottom. There's no reason why those two molecules have to arrive at exactly the same time at the back end of the wing: they could meet up with other air molecules instead. This flaw in the standard explanation of an airfoil goes by the technical name of the "equal transit theory." That's just a fancy name for the (incorrect) idea that the air stream splits apart at the front of the airfoil and meets up neatly again at the back.

So what's the real explanation? As a curved airfoil wing flies through the sky, it deflects air and alters the air pressure above and below it. That's intuitively obvious. Think how it feels when you slowly walk through a swimming pool and feel the force of the water pushing against your body: your body is diverting the flow of water as it pushes through it, and an airfoil wing does the same thing (much more dramatically-because that's what it's designed to do). As a plane flies forward, the curved upper part of the wing lowers the air pressure directly above it, so it moves upward.

How airfoil wings generate lift#1: An airfoil splits apart the incoming air, lowers the pressure of the upper air stream, and accelerates both air streams downward. As the air accelerates downward, the wing (and the plane) move upward. The more an airfoil diverts the path of the oncoming air, the more lift it generates.

Why does this happen? As air flows over the curved upper surface, its natural inclination is to move in a straight line, but the curve of the wing pulls it around and back down. For this reason, the air is effectively stretched out into a bigger volume-the same number of air molecules forced to occupy more space-and this is what lowers its pressure. For exactly the opposite reason, the pressure of the air under the wing increases: the advancing wing squashes the air molecules in front of it into a smaller space. The difference in air pressure between the upper and lower surfaces causes a big difference in air speed (not the other way around, as in the traditional theory of a wing). The difference in speed (observed in actual wind tunnel experiments) is much bigger than you'd predict from the simple (equal transit) theory. So if our two air molecules separate at the front, the one going over the top arrives at the tail end of the wing much faster than the one going under the bottom. No matter when they arrive, both of those molecules will be speeding downward -and this helps to produce lift in a second important way.

Sponsored links

Downwash

If you've ever stood near a helicopter, you'll know exactly how it stays in the sky: it creates a huge "downwash" (downward moving draft) of air that balances its weight. Helicopter rotors are very similar to airplane airfoils, but spin around in a circle instead of moving forward in a straight line, like the ones on a plane. Even so, airplanes create downwash in exactly the same way as helicopters-it's just that we don't notice. The downwash isn't so obvious, but it's just as important as it is with a chopper.

This second aspect of making lift is a lot easier to understand than pressure differences, at least for a physicist: according to Isaac Newton's third law of motion, if air gives an upward force to a plane, the plane must give an (equal and opposite) downward force to the air.[1] So a plane also generates lift by using its wings to push air downward behind it. That happens because the wings aren't perfectly horizontal, as you might suppose, but tilted back very slightly so they hit the air at an angle of attack. The angled wings push down both the accelerated airflow (from up above them) and the slower moving airflow (from beneath them), and this produces lift. Since the curved top of the airfoil deflects (pushes down) more air than the straighter bottom (in other words, alters the path of the incoming air much more dramatically), it produces significantly more lift.

How airfoil wings generate lift#2: The curved shape of a wing creates an area of low pressure up above it (red), which generates lift. The low pressure makes air accelerate over the wing, and the curved shape of the wing (and the higher air pressure well above the altered air stream) forces that air into a powerful downwash, also pushing the plane up. This animation shows how different angles of attack (the angle between the wing and the incoming air) change the low pressure region above a wing and the lift it makes. When a wing is flat, its curved upper surface creates a modest region of low pressure and a modest amount of lift (red). As the angle of attack increases, the lift increases dramatically too-up to a point, when increasing drag makes the plane stall (see below). If we tilt the wing downward, we produce lower pressure underneath it, making the plane fall. Based on Aerodynamics, a public domain War Department training film from 1941.

You might be wondering why the air flows down behind a wing at all. Why, for example, doesn't it hit the front of the wing, curve over the top, and then carry on horizontally? Why is there a downwash rather than simply a horizontal "backwash"? Think back to our previous discussion of pressure: a wing lowers the air pressure immediately above it. Higher up, well above the plane, the air is still at its normal pressure, which is higher than the air immediately above the wing. So the normal-pressure air well above the wing pushes down on the lower-pressure air immediately above it, effectively "squirting" air down and behind the wing in a backwash. In other words, the pressure difference that a wing creates and the downwash of air behind it aren't two separate things but all part and parcel of the same effect: an angled airfoil wing creates a pressure difference that makes a downwash, and this produces lift.

Now we can see that wings are devices designed to push air downward, it's easy to understand why planes with flat or symmetrical wings (or upside-down stunt planes) can still safely fly. As long as the wings are creating a downward flow of air, the plane will experience an equal and opposite force-lift-that will keep it in the air. In other words, the upside-down pilot creates a particular angle of attack that generates just enough low pressure above the wing to keep the plane in the air.

How much lift can you make?

Generally, the air flowing over the top and bottom of a wing follows the curve of the wing surfaces very closely-just as you might follow it if you were tracing its outline with a pen. But as the angle of attack increases, the smooth airflow behind the wing starts to break down and become more turbulent and that reduces the lift. At a certain angle (generally round about 15°, though it varies), the air no longer flows smoothly around the wing. There's a big increase in drag, a big reduction in lift, and the plane is said to have stalled. That's a slightly confusing term because the engines keep running and the plane keeps flying; stall simply means a loss of lift.

Photo: How a plane stalls: Here's an airfoil wing in a wind tunnel facing the oncoming air at a steep angle of attack. You can see lines of smoke-filled air approaching from the right and deviating around the wing as they move to the left. Normally, the airflow lines would follow the shape (profile) of the wing very closely. Here, because of the steep angle of attack, the air flow has separated out behind the wing and turbulence and drag have increased significantly. A plane flying like this would experience a sudden loss of lift, which we call "stall." Photo by James Schultz, NASA Langley Research Center and Internet Archive.

Planes can fly without airfoil-shaped wings; you'll know that if you've ever made a paper airplane-and it was proved on December 17, 1903 by the Wright brothers. In their original "Flying Machine" patent ( US patent #821393), it's clear that slightly tilted wings (which they referred to as "aeroplanes") are the key parts of their invention. Their "aeroplanes" were simply pieces of cloth stretched over a wooden framework; they didn't have an airfoil (aerofoil) profile. The Wrights realized that the angle of attack is crucial: "In flying machines of the character to which this invention relates the apparatus is supported in the air by reason of the contact between the air and the under surface of one or more aeroplanes, the contact-surface being presented at a small angle of incidence to the air." [Emphasis added]. Although the Wrights were brilliant experimental scientists, it's important to remember that they lacked our modern knowledge of aerodynamics and a full understanding of exactly how wings work.

Photo: As you can see from this modern reconstruction, the Wright Flyer didn't have airfoil wings. By courtesy of NASA on the Commons.

Not surprisingly, the bigger the wings, the more lift they create: doubling the area of a wing (that's the flat area you see looking down from above) doubles both the lift and drag it makes. That's why gigantic planes (like the C-17 Globemaster in our top photo) have gigantic wings. But small wings can also produce a great deal of lift if they move fast enough. To produce extra lift at takeoff, planes have flaps on their wings they can extend to push more air down. Lift and drag vary with the square of your speed, so if a plane goes twice as fast, relative to the oncoming air, its wings produce four times as much lift (and drag). Helicopters produce a huge amount of lift by spinning their rotor blades (essentially thin wings that spin in a circle) very quickly.

Wing vortices

Now a plane doesn't throw air down behind it in a completely clean way. (You could imagine, for example, someone pushing a big crate of air out of the back door of a military transporter so it falls straight down. But it doesn't work quite like that!) Each wing actually sends air down by making a spinning vortex (a kind of mini tornado) immediately behind it. It's a bit like when you're standing on a platform at a railroad station and a high-speed train rushes past without stopping, leaving what feels like a huge sucking vacuum in its wake. With a plane, the vortex is quite a complex shape and most of it is moving downward-but not all. There's a huge draft of air moving down in the center, but some air actually swirls upward either side of the wingtips, reducing lift.

Photo: Newton's laws make airplanes fly: A plane generates an upward force (lift) by pushing air down toward the ground. As these photos show, the air moves down not in a neat and tidy stream but in a vortex. Among other things, the vortex affects how closely one plane can fly behind another and it's particularly important near airports where there are lots of planes moving all the time, making complex patterns of turbulence in the air. Above: Colored smoke shows the wing vortices produced by a real plane. The smoke in the center is moving downward, but it's moving upward beyond the wingtips. Below: How the vortex appears from below. White smoke shows the same effect on a smaller scale in a
wind tunnel test. Both photos courtesy of NASA Langley Research Center. (Originals courtesy of Internet Archive can be found here and here.)

How do planes steer?

What is steering?

Steering anything-from a skateboard or a bicycle to a car or a jumbo jet-means you change the direction in which it's traveling. In scientific terms, changing something's direction of travel means you change its velocity, which is the speed it has in a particular direction. Even if it goes at the same speed, if you change the direction of travel, you change the velocity. Changing something's velocity (including its direction of travel) means you accelerate it. Again, it doesn't matter if the speed stays the same: a change in direction always means a change in velocity and an acceleration. Newton's laws of motion tell us that you can only accelerate something (change its speed or direction of travel) by using a force-in other words, by pushing or pulling it somehow. To cut a long story short, if you want to steer something you need to apply a force to it.

Photo: Steering a C-17 plane by banking at a steep angle. Photo by Russell E. Cooley IV courtesy of US Air Force.

Another way of looking at steering is to think of it as making something stop going in a straight line and start going in a circle. That means you have to give it what's called a centripetal force. Things that are moving in a circle (or steering in a curve, which is part of a circle) always have something acting on them to give them centripetal force. If you're driving a car round a bend, the centripetal force comes from friction between the four tires and the road. If you're cycling around a curve at speed, some of your centripetal force comes from the tires and some comes from leaning into the bend. If you're on a skateboard, you can tilt the deck and lean over so your weight helps to provide centripetal force. In each case, you steer in a circle because something provides the centripetal force that pulls your path away from a straight line and round into a curve.

Steering in theory

If you're in a plane, you're obviously not in contact with the ground, so where does the centripetal force come from to help you steer around a circle? Just like a cyclist leaning into a bend, a plane "leans" into a curve. Steering involves banking, where the plane tilts to one side and one wing dips lower than the other. The plane's overall lift is tilted at an angle and, although most of the lift still acts upward, some now acts sideways. This sideways part of the lift provides the centripetal force that makes the plane go round in a circle. Since there's less lift acting upward, there's less to balance the plane's weight. That's why turning a plane in a circle will make it lose lift and altitude (height) unless the pilot does something else to compensate, such as using the elevators (the flight control surfaces at the back of the plane) to increase the angle of attack and therefore raise the lift again.

Artwork: When a plane banks, the lift generated by its wings tilts at an angle. Most of the lift still acts upward, but some tilts to one side, providing centripetal force that makes the plane steer round in a circle. The steeper the angle of the bank, the more the lift is tilted to the side, the less upward force there is to balance the weight, and the greater the loss of altitude (unless the pilot compensates).

Steering in practice

There's a steering control in the cockpit, but that's the only thing a plane has in common with a car. How do you steer something that's flying through the air at high speed? Simple! You make the air flow in a different way past the wings on each side. Planes are moved up and down, steered from side to side, and brought to a halt by a complex collection of moving flaps called control surfaces on the leading and trailing edges of the wings and tail. These are called ailerons, elevators, rudders, spoilers, and air brakes.

Photo: There are over 20 control surfaces on a C-17 Globemaster. Seen here from above, they include: four elevators (inboard and outboard), two rudders (upper and lower), and two stabilizers on the tail; plus eight spoilers, four flaps, and two ailerons on the wings. Photo by Tiffany A. Emery courtesy of US Air Force with annotation by explainthatstuff.com.

Now flying a plane is very complex and I'm not writing a pilot's manual here: this is just a very basic introduction to the science of forces and motion as they apply to airplanes. For a simple overview of all the different plane controls and how they work, take a look at Wikipedia's article on control surfaces. NASA's basic introduction to flight has a good drawing of airplane cockpit controls and how you use them to steer a plane. You'll find much more detail in the official FAA Pilot's Handbook of Aeronautical Knowledge (Chapter 6 covers the flight controls).

One way to understand control surfaces is to build yourself a paper plane and experiment. First, build yourself a basic paper plane and make sure it flies in a straight line. Then cut or rip the back of the wings to make some ailerons. Tilt them up and down and see what effect they have in different positions. Tilt one up and one down and see what difference that makes. Then try making a new plane with one wing bigger than the other (or heavier, by adding paperclips). The way to make a paper plane steer is to get one wing to generate more lift than the other-and you can do this in all kinds of different ways!

Photo: The Wright brothers took a very scientific approach to flight, meticulously testing every feature of their planes. Here they are pictured during one of their first powered flights on December 17, 1903. Courtesy of NASA/Internet Archive.

More parts of a plane

Here are some other key parts of planes:

Fuel tanks: You need fuel to power a plane-lots of it. An Airbus A380 holds over 310,000 liters (82,000 US gallons) of fuel, which is about 7,000 times as much as a typical car! The fuel's safely packed inside the plane's huge wings.

Landing gear: Planes take off and land on sturdy wheels and tires, which are rapidly retracted into the undercarriage (the plane's underbody) byhydraulic rams to reduce drag (air resistance) when they're in the sky.

Radio and radar: The Wright brothers had to fly their pioneering Kitty Hawk plane entirely by sight. That didn't matter because it flew near the ground, stayed in the air for only 12 seconds, and there were no other planes to worry about! These days, the skies are packed with planes that fly by day, by night, and in all kinds of weather.Radio, radar, and satellite systems are essential for navigation.

Pressurized cabins: Air pressure falls with height above Earth's surface-that's why mountaineers need to use oxygen cylinders to reach extreme heights. The summit of Mount Everest is just under 9km (5.5 miles) above sea level, but jet planes routinely fly at greater altitudes than this and military planes have flown almost three times higher! That's why passenger planes have pressurized cabins: ones into which heated air is steadilypumped so people can breathe properly. Military pilots avoid the problem by wearing face masks and pressurized body suits.

Acknowledgements

I'm very grateful to Steve Noskowicz for invaluable help in refining and improving my explanation of how wings generate lift.

Sponsored links

Find out more

On this website

On other sites

The Beginner's Guide to Aeronautics: A great introduction to the science of flight (particularly aimed at students) from the NASA Glenn Research Center. Covers how planes and engines work, wind tunnels, hypersonics, aerodynamics, kites, and model rockets.

The Wilbur and Orville Wright Papers at the Library of Congress: Quite a few of the Wrights' fascinating papers and photos are available online.

Flying Machine: The original Wright brothers patent (filed March 22, 1903 and granted May 22, 1906) is well worth a read, because it gives an insight into flight in the inventors own words. Since this patent describes an unpowered machine, it's easy to understand the crucial importance of the wings in a "flying machine"-something we tend to overlook in the age of the jet engine!

Pilot's Handbook of Aeronautical Knowledge: US Department of Transport/FAA, 2016. Unfortunately, even this official manual quotes the incorrect Bernoulli/equal-transit explanation of lift.

Books

For older readers

For younger readers

Flight School: How to fly a plane step by step by Nick Barnard. Thames and Hudon, 2012. A well-illustrated, 48-page overview for ages 8-12.

Eyewitness: Flight by Andrew Nahum. Dorling Kindersley, 2011. A visual guide to the history and technology behind planes and other flying machines.

Air and Space Travel by Chris Woodford. Facts on File, 2004. One of my own books, this one charts the history of flight through balloons, planes, and space rockets. Suitable for ages from about 10 to adult.

Articles

[PDF] How do wings work? by Professor Holger Babinsky. Physics Education, Volume 38, Number 6, 2003. A more detailed explanation of why the traditional Bernoulli explanation of lift is wrong, and an alternative account of how wings really work.

Videos

Airflow across a wing andHow wings work: These short scientific films by Holger Babinsky show the air movements across an airfoil (aerofoil) as the angle of attack changes and prove that the classic, simple Bernoulli explanation, based on equal transit time, is wrong.

How do wings really work?: A quick summary from the Bloodhound SSC project covers much the same ground as my article but in just a minute and a half!

How airplanes fly: A long (18.5 minute) 1968 video from the Federal Aviation Administration that explains the basics of flight to pilots.

Aerodynamics: This old and crackly US War Department training film from 1941 explains the theory of airfoils and how they produce different amounts of lift as the angle of attack varies.

Notes and references

↑ Newton's third law is sometimes written as "action and reaction are equal and opposite." That can be confusing, because it makes you wonder why anything goes anywhere at all: why don't the action and the reaction just cancel out? The answer is that the action and reaction work on different things. The action works on one thing; the reaction works on something else. So if the action is a whoosh of hot gas firing back from a jet engine, the reaction is the plane moving forward; if the action is a wing going upward, the reaction is the air going downward. The forces are indeed equal and opposite, but they don't cancel out because they act on different things.

Please do NOT copy our articles onto blogs and other websites

Articles from this website are registered at the US Copyright Office. Copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties.

Text copyright © Chris Woodford 2009, 2022. All rights reserved. Full copyright notice and terms of use.

More to explore on our website...

# data[].attributes.attachment_link.description
An easy-to-understand explanation of how planes get up into the air and stay there.

# data[].attributes.body
Flight

# data[].attributes.attachment_link.title
How to Make a Flying Airplane using Plastic Bottle and Cardboard

# data[].attributes.body
Science Focus - How does our world work?  Curiosity  did not kill the cat.
Let's get curious. Explore with our mind.