A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals pig iron, but others such as lead or copper. Blast refers to the combustion air being "forced" or supplied above atmospheric pressure. In a blast furnace, fuel and flux are continuously supplied through the top of the furnace, while a hot blast of air is blown into the lower section of the furnace through a series of pipes called tuyeres, so that the chemical reactions take place throughout the furnace as the material falls downward; the end products are molten metal and slag phases tapped from the bottom, waste gases exiting from the top of the furnace. The downward flow of the ore and flux in contact with an upflow of hot, carbon monoxide-rich combustion gases is a countercurrent exchange and chemical reaction process. In contrast, air furnaces are aspirated by the convection of hot gases in a chimney flue. According to this broad definition, bloomeries for iron, blowing houses for tin, smelt mills for lead would be classified as blast furnaces.
However, the term has been limited to those used for smelting iron ore to produce pig iron, an intermediate material used in the production of commercial iron and steel, the shaft furnaces used in combination with sinter plants in base metals smelting. Cast iron has been found in China dating to the 5th century BC, but the earliest extant blast furnaces in China date to the 1st century AD and in the West from the High Middle Ages, they spread from the region around Namur in Wallonia in the late 15th century, being introduced to England in 1491. The fuel used in these was invariably charcoal; the successful substitution of coke for charcoal is attributed to English inventor Abraham Darby in 1709. The efficiency of the process was further enhanced by the practice of preheating the combustion air, patented by Scottish inventor James Beaumont Neilson in 1828. Archaeological evidence shows that bloomeries appeared in China around 800 BC, it was thought that the Chinese started casting iron right from the beginning, but this theory has since been debunked by the discovery of'more than ten' iron digging implements found in the tomb of Duke Jing of Qin, whose tomb is located in Fengxiang County, Shaanxi.
There is however no evidence of the bloomery in China after the appearance of the blast furnace and cast iron. In China blast furnaces produced cast iron, either converted into finished implements in a cupola furnace, or turned into wrought iron in a fining hearth. Although cast iron farm tools and weapons were widespread in China by the 5th century BC, employing workforces of over 200 men in iron smelters from the 3rd century onward, the earliest extant blast furnaces were built date to the Han Dynasty in the 1st century AD; these early furnaces used phosphorus-containing minerals as a flux. Chinese blast furnaces ranged from around two to ten meters depending on the region; the largest ones were found in modern Sichuan and Guangdong, while the'dwarf" blast furnaces were found in Dabieshan. In construction, they are both around the same level of technological sophistication The effectiveness of the Chinese blast furnace was enhanced during this period by the engineer Du Shi, who applied the power of waterwheels to piston-bellows in forging cast iron.
Donald Wagner suggests that early blast furnace and cast iron production evolved from furnaces used to melt bronze. Though, iron was essential to military success by the time the State of Qin had unified China. Usage of the blast and cupola furnace remained widespread during Tang Dynasties. By the 11th century, the Song Dynasty Chinese iron industry made a switch of resources from charcoal to coke in casting iron and steel, sparing thousands of acres of woodland from felling; this may have happened as early as the 4th century AD. The primary advantage of the early blast furnace was in large scale production and making iron implements more available to peasants. Cast iron is more brittle than wrought iron or steel, which required additional fining and cementation or co-fusion to produce, but for menial activities such as farming it sufficed. By using the blast furnace, it was possible to produce larger quantities of tools such as ploughshares more efficiently than the bloomery. In areas where quality was important, such as warfare, wrought iron and steel were preferred.
Nearly all Han period weapons are made of wrought iron or steel, with the exception of axe-heads, of which many are made of cast iron. Blast furnaces were later used to produce gunpowder weapons such as cast iron bomb shells and cast iron cannons during the Song dynasty; the simplest forge, known as the Corsican, was used prior to the advent of Christianity. Examples of improved bloomeries are the Stückofen or the Catalan forge, which remained until the beginning of the 19th century; the Catalan forge was invented in Catalonia, during the 8th century. Instead of using natural draught, air was pumped in by a trompe, resulting in better quality iron and an increased capacity; this pumping of airstream in with bellows is known as cold blast, it increases the fuel efficiency of the bloomery and improves yield. The Catalan forges can be built bigger than natural draught bloomeries; the oldest known blast furnaces in the West were built in Dürstel in Switzerland, the Märkische Sauerland in Germany, at Lapphyttan in Sweden, where the complex was active between 1205 and 1300.
At Noraskog in the Swedish parish of Järnboås, there have been fou
Continuous track called tank tread or caterpillar track, is a system of vehicle propulsion in which a continuous band of treads or track plates is driven by two or more wheels. This band is made of modular steel plates in the case of military vehicles and heavy equipment, or synthetic rubber reinforced with steel wires in the case of lighter agricultural or construction vehicles; the large surface area of the tracks distributes the weight of the vehicle better than steel or rubber tyres on an equivalent vehicle, enabling a continuous tracked vehicle to traverse soft ground with less likelihood of becoming stuck due to sinking. The prominent treads of the metal plates are both hard-wearing and damage resistant in comparison to rubber tyres; the aggressive treads of the tracks provide good traction in soft surfaces but can damage paved surfaces, so some metal tracks can have rubber pads installed for use on paved surfaces. Continuous tracks can be traced back as far as 1770 and today are used on a variety of vehicles, including bulldozers, excavators and tractors.
Polish mathematician and inventor Józef Maria Hoene-Wroński conceived of the idea in the 1830s. The British polymath Sir George Cayley patented a continuous track, which he called a "universal railway". In 1837, a Russian inventor Dmitry Zagryazhsky designed a "carriage with mobile tracks" which he patented the same year, but due to a lack of funds and interest from manufacturers he was unable to build a working prototype, his patent was voided in 1839. Although not a continuous track in the form encountered today, a dreadnaught wheel or "endless railway wheel" was patented by the British Engineer James Boydell in 1846. In Boydell's design, a series of flat feet are attached to the periphery of the wheel, spreading the weight. A number of horse-drawn wagons and gun carriages were deployed in the Crimean War, waged between October 1853 and February 1856, the Royal Arsenal at Woolwich manufacturing dreadnaught wheels. A letter of recommendation was signed by Sir William Codrington, the General commanding the troops at Sebastopol.
Boydell patented improvements to his wheel in 1854 – the year his dreadnaught wheel was first applied to a steam engine – and 1858, the latter an impracticable palliative measure involving the lifting one or other of the driving wheels to facilitate turning. A number of manufacturers including Richard Bach, Richard Garrett & Sons, Charles Burrell & Sons and Clayton & Shuttleworth applied the Boydell patent under licence; the British military were interested in Boydell's invention from an early date. One of the objectives was to transport Mallet's Mortar, a giant 36 in weapon, under development, but, by the end of the Crimean war, the mortar was not ready for service. A detailed report of the tests on steam traction, carried out by a select Committee of the Board of Ordnance, was published in June 1856, by which date the Crimean War was over the mortar and its transportation became irrelevant. In those tests, a Garrett engine was put through its paces on Plumstead Common; the Garrett engine featured in the Lord Mayor's show in London, in the following month that engine was shipped to Australia.
A steam tractor employing dreadnaught wheels was built at Bach's Birmingham works, was used between 1856 and 1858 for ploughing in Thetford. Between late 1856 and 1862 Burrell manufactured not less than a score of engines fitted with dreadnaught wheels. In April 1858, "The Engineer" gave a brief description of a Clayton & Shuttleworth engine fitted with dreadnaught wheels, supplied not to the Western Allies, but to the Russian government for heavy artillery haulage in the Crimea, in the post-war period. Steam tractors fitted with dreadnaught wheels had a number of shortcomings and, notwithstanding the creations of the late 1850s, were never used extensively. In August 1858, more than two years after the end of the Crimean War, John Fowler filed British Patent No. 1948 on another form of "Endless Railway". In his illustration of the invention, Fowler used a pair of wheels of equal diameter on each side of his vehicle, around which pair of toothed wheels ran a'track' of eight jointed segments, with a smaller jockey/drive wheel between each pair of wheels, to support the'track'.
Comprising only eight sections, the'track' sections are essentially'longitudinal', as in Boydell's initial design. Fowler's arrangement is a precursor to the multi-section caterpillar track in which a large number of short'transverse' treads are used, as proposed by Sir George Caley in 1825, rather than a small number of long'longitudinal' treads. Further to Fowler's patent of 1858, in 1877, a Russian, Fyodor Blinov, created a tracked vehicle called "wagon moved on endless rails", it was pulled by horses. Blinov received a patent for his "wagon" in 1878. From 1881 to 1888 he developed a steam-powered caterpillar-tractor; this self-propelled crawler was tested and featured at a farmers' exhibition in 1896. Steam traction engines were used at the end of the 19th century in the Boer Wars, but neither dreadnaught wheels nor continuous tracks were used, rather "roll-out" wooden plank roads were thrown under the wheels as required. In short, whilst the development of the continuous track engaged the attention of a number of inventors in the 18th and 19th centuries, the general use and exploitation of the continuous track belonged to the 20th century.
A little-known American inventor, Henry T. Stith, developed a continuous track prototype which was, in multiple forms, patented in 1873, 1880, 1900; the last
The Industrial Revolution was the transition to new manufacturing processes in Europe and the US, in the period from about 1760 to sometime between 1820 and 1840. This transition included going from hand production methods to machines, new chemical manufacturing and iron production processes, the increasing use of steam power and water power, the development of machine tools and the rise of the mechanized factory system; the Industrial Revolution led to an unprecedented rise in the rate of population growth. Textiles were the dominant industry of the Industrial Revolution in terms of employment, value of output and capital invested; the textile industry was the first to use modern production methods. The Industrial Revolution began in Great Britain, many of the technological innovations were of British origin. By the mid-18th century Britain was the world's leading commercial nation, controlling a global trading empire with colonies in North America and the Caribbean, with some political influence on the Indian subcontinent, through the activities of the East India Company.
The development of trade and the rise of business were major causes of the Industrial Revolution. The Industrial Revolution marks a major turning point in history. In particular, average income and population began to exhibit unprecedented sustained growth; some economists say that the major impact of the Industrial Revolution was that the standard of living for the general population began to increase for the first time in history, although others have said that it did not begin to meaningfully improve until the late 19th and 20th centuries. GDP per capita was broadly stable before the Industrial Revolution and the emergence of the modern capitalist economy, while the Industrial Revolution began an era of per-capita economic growth in capitalist economies. Economic historians are in agreement that the onset of the Industrial Revolution is the most important event in the history of humanity since the domestication of animals and plants. Although the structural change from agriculture to industry is associated with the Industrial Revolution, in the United Kingdom it was almost complete by 1760.
The precise start and end of the Industrial Revolution is still debated among historians, as is the pace of economic and social changes. Eric Hobsbawm held that the Industrial Revolution began in Britain in the 1780s and was not felt until the 1830s or 1840s, while T. S. Ashton held that it occurred between 1760 and 1830. Rapid industrialization first began in Britain, starting with mechanized spinning in the 1780s, with high rates of growth in steam power and iron production occurring after 1800. Mechanized textile production spread from Great Britain to continental Europe and the United States in the early 19th century, with important centres of textiles and coal emerging in Belgium and the United States and textiles in France. An economic recession occurred from the late 1830s to the early 1840s when the adoption of the original innovations of the Industrial Revolution, such as mechanized spinning and weaving and their markets matured. Innovations developed late in the period, such as the increasing adoption of locomotives and steamships, hot blast iron smelting and new technologies, such as the electrical telegraph introduced in the 1840s and 1850s, were not powerful enough to drive high rates of growth.
Rapid economic growth began to occur after 1870, springing from a new group of innovations in what has been called the Second Industrial Revolution. These new innovations included new steel making processes, mass-production, assembly lines, electrical grid systems, the large-scale manufacture of machine tools and the use of advanced machinery in steam-powered factories; the earliest recorded use of the term "Industrial Revolution" seems to have been in a letter from 6 July 1799 written by French envoy Louis-Guillaume Otto, announcing that France had entered the race to industrialise. In his 1976 book Keywords: A Vocabulary of Culture and Society, Raymond Williams states in the entry for "Industry": "The idea of a new social order based on major industrial change was clear in Southey and Owen, between 1811 and 1818, was implicit as early as Blake in the early 1790s and Wordsworth at the turn of the century." The term Industrial Revolution applied to technological change was becoming more common by the late 1830s, as in Jérôme-Adolphe Blanqui's description in 1837 of la révolution industrielle.
Friedrich Engels in The Condition of the Working Class in England in 1844 spoke of "an industrial revolution, a revolution which at the same time changed the whole of civil society". However, although Engels wrote in the 1840s, his book was not translated into English until the late 1800s, his expression did not enter everyday language until then. Credit for popularising the term may be given to Arnold Toynbee, whose 1881 lectures gave a detailed account of the term; some historians, such as John Clapham and Nicholas Crafts, have argued that the economic and social changes occurred and the term revolution is a misnomer. This is still a subject of debate among some historians; the commencement of the Industrial Revolution is linked to a small number of innovations, beginning in the second half of the 18th century. By the 1830s the following gains had been made in important technologies: Textiles – mechanised cotton spinning powered by steam or water increased the output of a worker by a factor of around 500.
The power loom increased the output of a worker by a factor of over 40. The cotton gin increased productivity of removing seed from cotton by a factor of 50. Large gains in productivity occurred in spinning and weaving of w
A reaper is a farm implement or person that reaps crops at harvest when they are ripe. The crop involved is a cereal grass; the first documented reaping machines were Gallic reaper, used in modern-day France during Roman times. The Gallic reaper involved a comb which collected the heads, with an operator knocking the grain into a box for threshing. Most modern mechanical reapers cut the grass. Modern machines that not only cut and gather the grass but thresh its seeds, winnow the grain, deliver it to a truck or wagon it are called combine harvesters or combines. Hay is harvested somewhat differently from grain; as a manual task, cutting of both grain and hay may be called reaping, involving scythes and cradles, followed by differing downstream steps. Traditionally all such cutting could be called reaping, although a distinction between reaping of grain grasses and mowing of hay grasses has long existed. Mechanical reapers changed agriculture from their appearance in the 1830s until the 1860s through 1880s, when they evolved into related machines called by different names, that collected and bound the sheaves of grain with wire or twine.
Today reapers and grain binders have been replaced by combines in commercial farming, but some smaller farms still use them. Hand reaping is done by various means, including plucking the ears of grains directly by hand, cutting the grain stalks with a sickle, cutting them with a scythe, or a scythe fitted with a grain cradle. Reaping is distinguished from mowing, which uses similar implements, but is the traditional term for cutting grass for hay, rather than reaping cereals; the stiffer, dryer straw of the cereal plants and the greener grasses for hay demand different blades on the machines. The reaped grain stalks are gathered into sheaves, tied with a twist of straw. Several sheaves are leant against each other with the ears off the ground to dry out, forming a stook. After drying, the sheaves are gathered from the field and stacked, being placed with the ears inwards covered with thatch or a tarpaulin. In the British Isles a rick of sheaves is traditionally called a corn rick, to distinguish it from a hay rick.
Ricks are made in an area inaccessible to livestock, called a stack-yard. The corn-rick is broken down and the sheaves threshed to separate the grain from the straw. Collecting spilt grain from the field after reaping is called gleaning, is traditionally done either by hand, or by penning animals such as chickens or pigs onto the field. Hand reaping is now done in industrialized countries, but is still the normal method where machines are unavailable or where access for them is limited; the more or less skeletal figure of a reaper with a scythe – known as the "Grim Reaper" – is a common personification of death in many Western traditions and cultures. In this metaphor, death harvests the living. A mechanical reaper or reaping machine is a semi-automated device that harvests crops. Mechanical reapers and their descendant machines have been an important part of mechanised agriculture and a main feature of agricultural productivity; the 19th century saw several inventors in the United States claim innovation in mechanical reapers.
The various designs competed with each other, were the subject of several lawsuits. Obed Hussey in Ohio patented a reaper in the Hussey Reaper. Made in Baltimore, Hussey's design was a major improvement in reaping efficiency; the new reaper only required two horses working in a non-strenuous manner, a man to work the machine, another person to drive. In addition, the Hussey Reaper left an and clean surface after its use; the McCormick Reaper was designed by Robert McCormick in Virginia. However, Robert became frustrated, his son Cyrus asked for permission to try to complete his father's project. With permission granted, the McCormick Reaper was patented by his son Cyrus McCormick in 1834 as a horse-drawn farm implement to cut small grain crops; this McCormick reaper machine had several special elements: a main wheel frame projected to the side a platform containing a cutter bar having fingers through which reciprocated a knife driven by a crank upon the outer end of the platform was a divider projecting ahead of the platform to separate the grain to be cut from that to be left standing a reel was positioned above the platform to hold the grain against the reciprocating knife to throw it back upon the platform the machine was drawn by a team walking at the side of the grain.
Cyrus McCormick claimed that his reaper was invented in 1831, giving him the true claim to the general design of the machine. Over the next few decades the Hussey and McCormick reapers would compete with each other in the marketplace, despite being quite similar. By the 1850's, the original patents of both Hussey and McCormick had expired and many other manufacturers put similar machines on the market. In 1861, the United States Patent and Trademark Office issued a ruling
A ball mill is a type of grinder used to grind and blend materials for use in mineral dressing processes, pyrotechnics and selective laser sintering. It works on the principle of impact and attrition: size reduction is done by impact as the balls drop from near the top of the shell. A ball mill consists of a hollow cylindrical shell rotating about its axis; the axis of the shell may be either horizontal or at a small angle to the horizontal. It is filled with balls; the grinding media is the balls, which may be made of stainless steel, ceramic, or rubber. The inner surface of the cylindrical shell is lined with an abrasion-resistant material such as manganese steel or rubber. Less wear takes place in rubber lined mills; the length of the mill is equal to its diameter. The general idea behind the ball mill is an ancient one, but it was not until the industrial revolution and the invention of steam power that an effective ball milling machine could be built, it is reported to have been used for grinding flint for pottery in 1870.
In case of continuously operated ball mill, the material to be ground is fed from the left through a 60° cone and the product is discharged through a 30° cone to the right. As the shell rotates, the balls are lifted up on the rising side of the shell and they cascade down, from near the top of the shell. In doing so, the solid particles in between the balls and ground are reduced in size by impact; the ball mill is used for grinding materials such as coal and feldspar for pottery. Grinding can be carried out either wet or dry but the former is performed at low speed. Blending of explosives is an example of an application for rubber balls. For systems with multiple components, ball milling has been shown to be effective in increasing solid-state chemical reactivity. Additionally, ball milling has been shown effective for production of amorphous materials. A ball mill, a type of grinder, is a cylindrical device used in grinding materials like ores, ceramic raw materials and paints. Ball mills rotate around a horizontal axis filled with the material to be ground plus the grinding medium.
Different materials are used as media, including ceramic balls, flint pebbles and stainless steel balls. An internal cascading effect reduces the material to a fine powder. Industrial ball mills can operate continuously, discharged at the other end. Large to medium-sized ball mills are mechanically rotated on their axis, but small ones consist of a cylindrical capped container that sits on two drive shafts. A rock tumbler functions on the same principle. Ball mills are used in pyrotechnics and the manufacture of black powder, but cannot be used in the preparation of some pyrotechnic mixtures such as flash powder because of their sensitivity to impact. High-quality ball mills are expensive and can grind mixture particles to as small as 5 nm, enormously increasing surface area and reaction rates; the grinding works on the principle of critical speed. Critical speed can be understood as that speed after which the steel balls start rotating along the direction of the cylindrical device. Ball mills are used extensively in the mechanical alloying process in which they are not only used for grinding but for cold welding as well, with the purpose of producing alloys from powders.
The ball mill is a key piece of equipment for grinding crushed materials, it is used in production lines for powders such as cement, refractory material, glass ceramics, etc. as well as for ore dressing of both ferrous and non-ferrous metals. The ball mill can grind other materials either wet or dry. There are two kinds of ball mill, grate type and overfall type due to different ways of discharging material. Many types of grinding media are suitable for use in a ball mill, each material having its own specific properties and advantages. Key properties of grinding media are size, density and composition. Size: The smaller the media particles, the smaller the particle size of the final product. At the same time, the grinding media particles should be larger than the largest pieces of material to be ground. Density: The media should be denser than the material being ground, it becomes a problem. Hardness: The grinding media needs to be durable enough to grind the material, but where possible should not be so tough that it wears down the tumbler at a fast pace.
Composition: Various grinding applications have special requirements. Some of these requirements are based on the fact that some of the grinding media will be in the finished product. Others are based in. Where the color of the finished product is important, the color and material of the grinding media must be considered. Where low contamination is important, the grinding media may be selected for ease of separation from the finished product. An alternative to separation is to use media of the same material as the product being ground. Flammable products have a tendency to become explosive in powder form. Steel media may spark. Either wet-grinding, or non-sparking media such as ceramic or lead must be selected; some media, such as iron, may react with corrosive materials. For this reason, stainless steel and flint grinding media may each be u
A concrete pump is a machine used for transferring liquid concrete by pumping. There are two types of concrete pumps; the first type of concrete pump is attached to a truck or longer units are on semi-trailers. It is known as a boom concrete pump because it uses a remote-controlled articulating robotic arm to place concrete accurately. Boom pumps are used on most of the larger construction projects as they are capable of pumping at high volumes and because of the labour saving nature of the placing boom, they are a revolutionary alternative to line-concrete pumps. The second main type of concrete pump is either mounted on a truck or placed on a trailer, it is referred to as a line pump or trailer-mounted concrete pump; this pump requires steel or flexible concrete placing hoses to be manually attached to the outlet of the machine. Those hoses lead to wherever the concrete needs to be placed. Line pumps pump concrete at lower volumes than boom pumps and are used for smaller volume concrete placing applications such as swimming pools and single family home concrete slabs and most ground slabs.
There are skid mounted and rail mounted concrete pumps, but these are uncommon and only used on specialized jobsites such as mines and tunnels. Until the early 20th century, concrete was mixed on the job site and transported from the cement mixer to the formwork, either in wheelbarrows or in buckets lifted by cranes; this required a lot of labor. In 1927, the German engineers Max Giese and Fritz Hull came upon the idea of pumping concrete through pipes, they pumped concrete to a distance of 120 meters. Shortly after, a concrete pump was patented in Holland in 1932 by Jacob Cornelius Kweimn; this patent incorporated the developer's previous German patent. Concrete pump designers face many challenges because concrete is heavy, abrasive, contains pieces of hard rock, solidifies if not kept moving. Piston pumps are used, because they can produce hundreds of atmospheres of pressure; such piston-style pumps can push cylinders of heterogenous concrete mixes. The pump below uses a transfer tube valve, the one on the right uses seat valves.
To illustrate, below are data on a typical concrete sample pump BRF 42.14 H: Vertical reach of boom: 41.9 meters. Horizontal reach of boom: 38.0 meters Pumping rate: 30 cubic meters per hour. Concrete pressure: 112 bar. Cylinder length: 2,100 mm. Cylinder diameter: 210 mm. Number of substitutions of strokes per minute: 27. Number of outriggers legs: 4. Maximum Head:. High-density solids pump - concrete pump technology in general Concrete mixing transport truck
Armoured fighting vehicle
An armoured fighting vehicle is an armed combat vehicle protected by armour combining operational mobility with offensive and defensive capabilities. AFVs can be tracked. Main battle tanks, armoured cars, armoured self-propelled guns, armoured personnel carriers are all examples of AFVs. Armoured fighting vehicles are classified according to their intended role on the battlefield and characteristics; the classifications are not absolute. For example lightly armed armoured personnel carriers were superseded by infantry fighting vehicles with much heavier armament in a similar role. Successful designs are adapted to a wide variety of applications. For example, the MOWAG Piranha designed as an APC, has been adapted to fill numerous roles such as a mortar carrier, infantry fighting vehicle, assault gun; the concept of a mobile and protected fighting unit has been around for centuries. Armoured fighting vehicles were not possible until internal combustion engines of sufficient power became available at the start of the 20th century.
Modern armoured fighting vehicles represent the realization of an ancient concept - that of providing troops with mobile protection and firepower. Armies have deployed war cavalries with rudimentary armour in battle for millennia. Use of these animals and engineering designs sought to achieve a balance between the conflicting paradoxical needs of mobility and protection. Siege engines, such as battering rams and siege towers, would be armoured in order to protect their crews from enemy action. Polyidus of Thessaly developed a large movable siege tower, the helepolis, as early as 340 BC, Greek forces used such structures in the Siege of Rhodes; the idea of a protected fighting vehicle has been known since antiquity. Cited is Leonardo da Vinci's 15th-century sketch of a mobile, protected gun-platform; the machine was to be mounted on four wheels which would be turned by the crew through a system of hand cranks and cage gears. Leonardo claimed: "I will build armored wagons which will be invulnerable to enemy attacks.
There will be no obstacle which it cannot overcome." Modern replicas have demonstrated that the human crew would have been able to move it over only short distances. Hussite forces in Bohemia developed war wagons - medieval weapon-platforms - around 1420 during the Hussite Wars; these heavy wagons were given protective sides with firing slits. Heavy arquebuses mounted on wagons were called arquebus à croc; these carried a ball of about 3.5 ounces. The first modern AFVs were armed cars, dating back to the invention of the motor car; the British inventor F. R. Simms designed and built the Motor Scout in 1898, it was the first armed, petrol-engine powered vehicle built. It consisted of a De Dion-Bouton quadricycle with a Maxim machine gun mounted on the front bar. An iron shield offered some protection for the driver from the front, but it lacked all-around protective armour; the armoured car was the first modern armoured fighting vehicle. The first of these was the Simms' Motor War Car, designed by Simms and built by Vickers, Sons & Maxim in 1899.
The vehicle had Vickers armour 6 mm thick and was powered by a four-cylinder 3.3-litre 16 hp Cannstatt Daimler engine giving it a maximum speed of around 9 miles per hour. The armament, consisting of two Maxim guns, was carried in two turrets with 360° traverse. Another early armoured car of the period was the French Charron, Girardot et Voigt 1902, presented at the Salon de l'Automobile et du cycle in Brussels, on 8 March 1902; the vehicle was equipped with a Hotchkiss machine gun, with 7 mm armour for the gunner. Armoured cars were first used in large numbers on both sides during World War I as scouting vehicles. In 1903, H. G. Wells published the short story "The Land Ironclads," positing indomitable war machines that would bring a new age of land warfare, the way steam-powered ironclad warships had ended the age of sail. Wells' literary vision was realized in 1916, amidst the pyrrhic standstill of the Great War, the British Landships Committee, deployed revolutionary armoured vehicles to break the stalemate.
The tank was envisioned as an armoured machine that could cross ground under fire from machine guns and reply with its own mounted machine guns and cannons. These first British heavy tanks of World War I moved on caterpillar tracks that had lower ground pressure than wheeled vehicles, enabling them to pass the muddy, pocked terrain and slit trenches of the Battle of the Somme; the tank proved successful and, as technology improved. It became a weapon that could cross large distances at much higher speeds than supporting infantry and artillery; the need to provide the units that would fight alongside the tank led to the development of a wide range of specialised AFVs during the Second World War. The Armoured personnel carrier, designed to transport infantry troops to the frontline, emerged towards the end of World War I. During the first actions with tanks, it had become clear that close contact with infantry was essential in order to secure ground won by the tanks. Troops on foot were vulnerable to enemy fire, but they could not be transported