Rinella Battery is a Victorian battery in Kalkara, Malta. It is referred to as Fort Rinella, although it was never classified as a fort while in use, it contains one of two surviving Armstrong 100-ton guns. The British built the battery between 1878 and 1886 above the shore east of the mouth of Grand Harbour, between Fort Ricasoli and Fort St. Rocco; the battery was built to contain a single Armstrong 100-ton gun: a 450 mm rifled muzzle-loading gun made by Elswick Ordnance Company, the armaments division of the British manufacturing company Armstrong Whitworth. The battery is one of a pair; the British installed a second pair of 100-ton guns to defend Gibraltar, mounting one each in Victoria Battery and Napier of Magdala Battery, which did not have Rinella's self-defence capabilities. Only two 100-ton guns survive; the British felt the need for such large guns as a response to the Italians having, in 1873, built the battleships Duilio and Dandolo with 22 inches of steel armour and four 100-ton Armstrong guns per vessel.
By arming both Gibraltar and Malta, the British were seeking to ensure the vital route to India through the Mediterranean and the Suez Canal, which had opened to traffic in 1869. The fort is modest in size as it was designed to operate and protect the single large gun, with its associated gun crew, bunkers, support machinery and the detachment of troops stationed within the fort to defend the installation; the gun was mounted en barbette on a wrought-iron sliding carriage and gun fired over the top of the parapet of the emplacement. This enabled the gun-crew to fire the gun without exposing themselves to enemy fire; the fort was designed to engage enemy warships at ranges up to 7,000 yards. The low profile of the fort and the buried machinery rooms and magazines were intended to enable it to survive counterfire from capital warships; the fort has no secondary armament. The massive gun is far too heavy to be laid by hand, the fort therefore contained a steam powered hydraulic system that traversed and depressed the gun, operated a pair of hydraulic powered loading and washing systems, powered the shell lifts that moved the 2,000-pound shells and 450-pound black-powder charges from the magazines into the loading chambers.
The gun was intended to operate at a rate of fire of a single shell every six minutes. The firing cycle was for the gun to be traversed and depressed until it aligned with one of loading the casemates, with the barrel pushing aside an iron plate that closed the aperture in the casemate; the gun was flushed with water to cool it, clean any debris and deposit from the barrel, douse any remaining embers from the previous cartridge. The ramming mechanism inserted and tamped a silk cartridge containing the propellant charge, followed by one of the range of shells the gun was adapted to fire; the loaded gun was traversed and elevated using the hydraulic system, fired by an electrical firing mechanism. The gun slewed to the other casemate to repeat the loading process, while the first casemate was recharged from the deeper magazine; the two separate loading casemates, each fed by an independent magazine, the provision of man-powered backup pumps for the hydraulic system, such that a team of 40 men could maintain the hydraulic pressure to operate the gun, would have allowed the fort to continue firing if damaged.
The inner faces of the emplacement were revetted with masonry. Subsequent review of the fort's defences after its completion identified this as a weakness, the stone revetting was removed from most of the emplacement and replaced with plain earthworks to better absorb the energy of incoming shellfire; the revetting was retained around the loading casemates. The 100-ton gun arrived in Malta from Woolwich on 10 September 1882. There it sat at the dockyards for some months. One hundred men from the Royal Artillery manhandled it to the fort in a process that took some three months; the gun was in position and ready for use in January 1884. Because a single shell cost as much as the daily wage of 2600 soldiers, practice firing of the gun was limited to one shot every 3 months, it was fired for the last time on 5 May 1905, was withdrawn from active service in 1906. The gun was in active service for only 20 years, without firing a shot in anger. After the Armstrong gun was retired from service, Fort Rinella was used as an observation post for the guns of Fort Ricasoli, at some point the now obsolete steam engine and hydraulic system were removed.
During World War II, the Navy used the Fort to store supplies, it received seven bomb hits. The fort was ideal because from a plane's view it blends into the fields as it was covered in moss and grass; the Navy gave up the site in 1965. In the 1970s, the battery was used as a location in the films Zeppelin, Young Winston and Shout at the Devil. In 1991, Rinella Battery was passed into the care of Fondazzjoni Wirt Artna, the Malta Heritage Trust, it was restored and was opened to the public as an open-air museum in 1996. The gun was restored and was fired for the first time in a hundred years on 21 November 2005 by Peter Caruana, the Chief Minister of Gibraltar, of Maltese descent; the steam engine and hydraulic machinery have not yet been replaced. The gun is now fi
King's Bastion is a coastal bastion on the western front of the fortifications of the British overseas territory of Gibraltar, protruding from the Line Wall Curtain. It overlooks the Bay of Gibraltar, it played a crucial role in defending The Rock during the Great Siege of Gibraltar. In more recent history the bastion was converted into a generating station which powered Gibraltar's electricity needs. Today it continues to serve the community as Gibraltar's leisure centre. King's Bastion is located at the junction of Queensway and Reclamation Road on the western side of the British overseas territory of Gibraltar; the bastion is believed to have started as a Moorish city gate but was developed by the Spanish in 1575 to become the Spanish: Plataforma de San Lorenzo. Construction began in 1773, when Lieutenant-general Sir Robert Boyd Governor of Gibraltar, laid the first stone and declared: "This is the first stone of a work which I name the King's Bastion: may it be as gallantly defended, as I know it will be ably executed."
The bastion was designed by Lieutenant colonel Sir William Green, Chief Engineer of the Soldier Artificer Company which became the Corps. Of Royal Engineers. At the time it was built, the King's Bastion was the most important of Gibraltar's defences on the west, its arrowhead shape extended from the curtain wall fortification, known as the Line Wall, along Gibraltar's western coast into the Bay of Gibraltar. It was consistent with traditional notions of a bastion, it included casemates, which fulfilled the need for barracks, housed 800 men. Less than a decade in 1782, King's Bastion served ably as the command post in the defence against the attacks of the French and Spanish during the Great Siege of Gibraltar, it was from the bastion. The floating batteries had been adapted to withstand heavy shelling and were anchored only 500 metres or so off the Rock. Designed by French engineer Jean Claude le Michaud d'Arcon they were equipped with specially reinforced hulls, irrigation pumps to quench any fires and pitched roofs to protect against plunging fire from shot.
These modifications were thought to have made the ships unsinkable. The garrison realised that red hot shots known as "hot potatoes", were effective against the floating batteries and they were all destroyed by fire, it was from King's Bastion that the first "hot potatoes" were fired at the Spanish floating batteries. Twenty-five guns had been installed in the bastion by 1859, they included seventeen 32-pounders, six 8-inch smoothbore weapons, two 10-inch howitzers. In 1874, the embrasures at the front of the bastion were eliminated to permit installation of five muzzle-loading rifles. All five RMLs had been mounted by 1878, where they remained until 1902. By the late 19th century, the bastion no longer served as a principal military defence; the turn of the century was remarkable for the reclamation of land in front of King's Bastion, as part of the new dockyard. The bastion was repurposed, the casemates, no longer needed as barracks, housed coal stores. In addition, the area's first electricity-generating station was built there, with construction starting in 1896.
A plaque installed on the northern façade of King's Bastion acknowledges the role of General George Augustus Eliott, 1st Baron Heathfield, the Governor of Gibraltar, in his command during the Great Siege. In addition, Major General Sir Robert Boyd was at his request interred inside a vault at the bastion's base, which he had included at the time of construction. However, there is no record of the exact location of the grave. A memorial stone was placed within the King's Chapel but the marble stone in the King's Bastion read: "Within the walls of this bastion are deposited the mortal remains of the late General Sir Robert Boyd, K. B. governor of this fortress, who died on 13 May 1794, aged 84 years. By him the first stone of the bastion was laid in 1773, under his supervision it was completed, when, on that occasion, in his address to the troops, he expressed a wish to see it resist the combined efforts of France and Spain, which wish was accomplished on 13 Sept. 1782, when, by the fire of this bastion, the flotilla expressly designed for the capture of this fortress were utterly destroyed."
The bastion underwent further modifications in the 20th century. Concrete bunkers were constructed and the structure became a lookout post. In addition, a 6 pounder anti-tank gun was mounted. After the 20th century wars, the bastion became a saluting battery, employing four 25 pounders; the bastion's years as a military structure came to an end in 1961, when the King's Bastion Power Station, designed by local architect Natalio Langdon was built adjacent to the bastion's northern façade and opened in October of that year. While the previous electricity-generating station was under military authority, the King's Bastion Power Station was under the civil authority of the Government of Gibraltar. Oil storage and administration offices, among other facilities required for the day-to-day running of the station were housed within the vaults of the bastion itself. However, the generating station became obsolete during the late 1980s and closed down during the early 1990s; the King's Bastion Power Station was demolished in October 2005, during which the original façade of the bastion was revealed.
King's Bastion is listed with the Gibraltar Heritage Trust. Alexis Almeida, Chairman of the Trust indicated that the bastion was "the last major battery built in this style and so is important. We would love to restore King's Bastion to its former glory, it is magnificent and deserves to be seen." After extensive refurbishment, the
Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. With headquarters in Elswick, Newcastle upon Tyne, Armstrong Whitworth built armaments, locomotives and aircraft; the company was founded by William Armstrong in 1847, becoming Armstrong Mitchell and Armstrong Whitworth through mergers. In 1927, it merged with Vickers Limited to form Vickers-Armstrongs, with its automobile and aircraft interests purchased by J D Siddeley. In 1847, the engineer William George Armstrong founded the Elswick works at Newcastle, to produce hydraulic machinery and bridges, soon to be followed by artillery, notably the Armstrong breech-loading gun, with which the British Army was re-equipped after the Crimean War. In 1882, it merged with the shipbuilding firm of Charles Mitchell to form Armstrong Mitchell & Company and at the time its works extended for over a mile along the bank of the River Tyne. Armstrong Mitchell merged again with the engineering firm of Joseph Whitworth in 1897.
The company expanded into the manufacture of cars and trucks in 1902, created an "aerial department" in 1913, which became the Armstrong Whitworth Aircraft subsidiary in 1920. In 1927, it merged with Vickers Limited to form Vickers-Armstrongs; the Armstrong Whitworth was manufactured from 1904, when the company decided to diversify to compensate for a fall in demand for artillery after the end of the Boer War. It took over construction of the Wilson-Pilcher, designed by Walter Gordon Wilson, produced cars under the Armstrong Whitworth name until 1919, when the company merged with Siddeley-Deasy and to form Armstrong Siddeley; the Wilson-Pilcher was an advanced car with a 2.4-litre engine, made in London from 1901 until 1904 when production moved to Newcastle. When Armstrong Whitworth took over production two models were made, a 2.7-litre flat four and a 4.1-litre flat six, the cylinders on both being identical with bore and stroke of 3.75in. The engines had the flywheel at the front of the engine, the crankshaft had intermediate bearings between each pair of cylinders.
Drive was to the rear wheels via helical bevel axle. The cars were listed at £ 900 for the six, they were still theoretically available until 1907. According to Automotor in 1904, "Even the first Wilson-Pilcher car that made its appearance created quite a sensation in automobile circles at the time on account of its remarkably silent and smooth running, of the total absence of vibration"; the first Armstrong Whitworth car was the 28/36 of 1906 with a water-cooled, four-cylinder side-valve engine of 4.5 litres which unusually had "oversquare" dimensions of 120 mm bore and 100 mm stroke. Drive was via a four-speed shaft to the rear wheels. A larger car was listed for 1908 with a choice of either 5-litre 30 or 7.6-litre 40 models sharing a 127 mm bore but with strokes of 100 mm and 152 mm respectively. The 40 was listed at £798 in bare chassis form for supplying to coachbuilders; these large cars were joined in 1909 by the 4.3-litre 18/22 and in 1910 by the 3.7-litre 25, which seems to have shared the same chassis as the 30 and 40.
In 1911, a new small car appeared in the shape of the 2.4-litre 12/14, called the 15.9 in 1911, featuring a monobloc engine with pressure lubrication to the crankshaft bearings. This model had an 88-inch wheelbase compared with the 120 inches of the 40 range; this was joined by four larger cars ranging from the 2.7-litre 15/20 to the 3.7-litre 25.5. The first six-cylinder model, the 30/50 with 5.1-litre 90 mm bore by 135 mm stroke engine came in 1912 with the option of electric lighting. This grew to 5.7 litres in 1913. At the outbreak of war, as well as the 30/50, the range consisted of the 3-litre 17/25 and the 3.8-litre 30/40. The cars were if not always bodied by external coachbuilders and had a reputation for reliability and solid workmanship; the company maintained a London sales outlet at New Bond Street. When Armstrong Whitworth and Vickers merged, Armstrong Whitworth's automotive interests were purchased by J D Siddeley as Armstrong Siddeley, based in Coventry. An Armstrong Whitworth car is displayed in the Discovery Newcastle upon Tyne.
Armstrong Whitworth established an Aerial Department in 1912. This became the Sir W. G. Armstrong Whitworth Aircraft Company; when Vickers and Armstrong Whitworth merged in 1927 to form Vickers-Armstrongs, Armstrong Whitworth Aircraft was bought out by J. D. Siddeley and became a separate entity; the Elswick Ordnance Company was created in 1859 to separate William Armstrong's armaments business from his other business interests, to avoid a conflict of interest as Armstrong was Engineer of Rifled Ordnance for the War Office and the company's main customer was the British Government. Armstrong held no financial interest in the company until 1864 when he left Government service, Elswick Ordnance was reunited with the main Armstrong businesses to form Sir W. G. Armstrong & Company. EOC was the armaments branch of W. G. Armstrong & Company and of Armstrong Whitworth. Elswick Ordnance was a major arms developer before and during World War I; the ordnance and ammunition it manufactured for the British Government were stamped EOC, while guns made for export were marked "W.
G. Armstrong". After the Great War, Armstrong Whitworth converted its Scotswood Works to build railway locomotives. From 1919 it penetrated the locomotive market due to its modern plant, its two largest contracts were 200 2-8-0s for the Belgian State Railways in 1920 and 327 Black 5 4-6-0s
Bay of Gibraltar
The Bay of Gibraltar is a bay at the southern end of the Iberian Peninsula. It is around 10 km long by 8 km wide, covering an area of some 75 km2, with a depth of up to 400 m in the centre of the bay, it opens to the south into the Strait of the Mediterranean Sea. The shoreline is densely settled. From west to east, the shore is divided between the Spanish municipalities of Algeciras, Los Barrios, San Roque, La Línea de la Concepción and the British Overseas Territory of Gibraltar; the larger part of the shoreline is Spanish territory, with part of the eastern half of the bay belonging to Gibraltar. The east and west entrances to the bay are marked by the Europa Point Lighthouse at Europa Point and the Punta Carnero lighthouse to the west of Algeciras; the area around the Bay of Gibraltar has been inhabited for millennia and the bay itself has been used by merchant shipping for at least 3,000 years. The Phoenicians are believed to have had a settlement near Gibraltar and the Romans established the town of Portus Alba on the site of modern Algeciras.
Peoples, notably the Moors and the Spanish established settlements on the shoreline during the Middle Ages and early modern period, including the fortified and strategic port at Gibraltar, which fell to England in 1704. The bay's strategic position at the mouth of the Mediterranean has made it a much-contested body of water over the centuries, it has been the site of several major sea battles, notably the Battle of Gibraltar and the Battle of Algeciras bay. During the Second World War, Italy launched human torpedoes from Algeciras on several occasions in attempts to sink British ships moored in the Gibraltar harbour, with mixed success due to the work of Commander Crabbe. More there has been a persistent dispute between Spain and Gibraltar over British sovereignty in the Bay of Gibraltar. Spain claims not to recognise British sovereignty in the area save for a small portion around the Port of Gibraltar, but the UK has asserts a normal 3 nmi limit around Gibraltar, with a demarcation in the middle of the bay.
This claim contradicts, according to the Spanish government, the treaty of Utrecht of 1713, by which Spain ceded to Great Britain the city and port of Gibraltar and the internal waters of that port, without granting any territoriality over the surrounding waters in the Bay of Algeciras. This has caused tensions between the two sides over the issue of Spanish fishermen operating in British Gibraltar territorial waters. Both have signed, are bound, by the United Nations Convention on the Law of the Sea which specifies territorial waters. After the arrest of a Spanish fishing vessel by the Royal Gibraltar Police in 1998, the problem subsided. An incident in the area in 2007 concerning the Odyssey Marine Exploration was resolved in court cases by 2012 with Spain being awarded the ownership of the treasure-trove; the bay is a breeding area for several dolphin species, notably the Common Dolphin, Striped Dolphin and Bottlenose Dolphin, is visited by migratory whales. It is a popular destination for tourist whale-watching trips from Gibraltar.
The other major draw for tourists is scuba diving: the area is rich with wrecks and historical artifacts such as crashed Avro Shackleton aircraft and Sherman tanks from the Second World War, ancient anchors from Phoenician and Roman ships. To encourage marine diversity an artificial reef was constructed in the bay at the end of the runway; the area around the bay in Spain is industrialised with extensive petrochemical installations near San Roque and working ports in both Algeciras and Gibraltar. The bay's waters are used by a considerable number of large and medium-sized ships, notably oil tankers and freighters. Oil bunkering activities are heavily carried out; the CEPSA Gibraltar-San Roque Refinery, located in Spain, occupies 1.5m m² and employs 1,000. In 2015 the refinery produced 13.8m tons of fuel, 260,000 tons of purified Terephthalic acid, 170,700 tons of purified Isophthalic acid and 157,300 tons of Polyethylene terephthalate. In 2007 a serious sulphur incident happened as well as intermittent flaring episodes.
The impacts of such upsets on surrounding neighbourhoods had provoked outrage and public protest which led to the Consejería de Medio Ambiente of the Junta de Andalucía to order an independent audit aimed at investigating such incidents. The refinery continues to cause concern with close co-operation between various groups monitoring its activities. Fuel tanks on ships are known as bunkers, the process of fueling termed bunkering. Due to its geographical position on a major shipping route, Gibraltar is one of the largest bunkering ports in the Mediterranean, followed by neighbour Algeciras in Spain; the ports in the Straits — Algeciras and Gibraltar — are the second bunker market in Europe, behind the so-called Amsterdam-Rotterdam-Antwerp area. In Gibraltar 4,300,000 t of bunker fuel were delivered in 2007 compared with just 840,000 t in 1990 and bunkering is now the main activity within the Port of Gibraltar. Of a total of 8,351 deep-sea vessels which called at Gibraltar in 2007, 5,640 were supplied with fuel.
Algeciras recorded bunker sales of about 2,400,000 t in 2008. From the 24,535 vessels called at the Port of Algeciras Bay, 2,173 took on fuel. Gibraltar in 2009 supplied over 4,200,000 t of fuel; the local CEPSA refinery produces supplies much of the fuel for bunkering in the bay which it delivers on seven dedicated barge to either
The Italian Army is the land-based component of the Italian Armed Forces of the Italian Republic. The army's history dates back to the unification of Italy in the 1860s; the army fought in colonial engagements in China, Northern Italy against the Austro-Hungarian Empire during World War I, Abyssinia before World War II and in World War II in Albania, North Africa and Italy itself. During the Cold War, the army prepared itself to defend against a Warsaw Pact invasion from the east. Since the end of the Cold War, the army has seen extensive peacekeeping service and combat in Afghanistan and Iraq, its best-known combat vehicles are the Dardo infantry fighting vehicle, the Centauro tank destroyer and the Ariete tank and among its aircraft the Mangusta attack helicopter deployed in UN missions. The headquarters of the Army General Staff are located in Rome, at the back of the Presidential Palace; the army is an all-volunteer force of active-duty personnel. The Italian Army originated as the Royal Army which dates from the proclamation of the Kingdom of Italy following the seizure of the Papal States and the unification of Italy.
In 1861, under the leadership of Giuseppe Garibaldi, Victor Emmanuel II of the House of Savoy was invited to take the throne and of the newly created kingdom. Italian expeditions were dispatched to China during the Boxer Rebellion of 1900 and to Libya during the Italo-Turkish War of 1911–1912; the Italian Royal Army's first real taste of modern warfare was during World War I. Most of the actions were fought in northern Italy and the Royal Army suffered many casualties; this included over 700,000 dead. In particular, the frequency of the offensives in which Italian soldiers participated between May 1915 and August 1917, one every three months, was higher than demanded by the armies on the Western Front. Italian discipline was harsher, with punishments for infractions of duty of a severity not known in the German and British armies. During the Interwar Years the Royal Army participated in the Italian Invasion of Ethiopia, provided men and materials during the Spanish Civil War to fight in the Corps of Volunteer Troops, launched the Italian invasion of Albania.
On paper, the Royal Army was one of the largest ground forces in World War II, though in reality it could not field the numbers claimed, it was one of the pioneers in the use of paratroopers. Due to their smaller size, many Italian divisions were reinforced by an Assault Group of two battalions of Blackshirts. Reports of Italian military prowess in the Second World War were always, dismissive; this perception was the result of disastrous Italian offensives against Egypt and the performance of the army in the Greco-Italian War. Both campaigns were executed inadequately; the Italian 10th Army advanced into Egypt but surrendered after being pushed back into central Libya and all destroyed by a force one fifth its size in the British three-month campaign of Operation Compass. Incompetent military leadership was aggravated by the Italian military's equipment, which predominantly dated back to the First World War and was not up to the standard of either the Allied or the German armies. Italian'medium' M11, M13, M14 and M15 tanks were at a marked disadvantage against the comparatively armed American Sherman tanks, for example.
More crucially, Italy lacked suitable quantities of equipment of all kinds and the Italian high command did not take necessary steps to plan for possible setbacks on the battlefield, or for proper logistical support to its field armies. There were too few anti-aircraft weapons, obsolete anti-tank guns, too few trucks; the Italian Expeditionary Corps in Russia fought under General Giovanni Messe, who acknowledged the limitations of his Corps in material and equipment and thus was relieved of his command on November 1, 1942. When the Soviet offensive Operation Saturn began on December 12, 1942 the Italian 8th Army was crushed. Only about a third of its troops managed to escape the Soviet cauldron, most notably from the three Alpini Divisions Tridentina and Cuneense, which fought stubbornly and to their total annihilation to escape the Soviet encirclement. In North Africa, the Italian 132 Armored Division Ariete and the 185 Airborne Division Folgore fought to total annihilation at the Second Battle of El Alamein.
Although the battle was lost, the determined resistance of the Italian soldiers at the Battle of Keren in East Africa is still commemorated today by the Italian military. After the Axis defeat in Tunisia the morale of the Italian troops dropped and when the Allies landed in Sicily on July 10, 1943 most Italian Coastal divisions dissolved; the sagging morale led to the overthrow of Italian dictator Benito Mussolini by King Victor Emmanuel III of Italy 15 days later. In September 1943, Italy made an armistice with the Allies and split into the Italian Social Republic – a puppet state of Germany – in the north and that of the Badoglio government in the south; the Italian Co-Belligerent Army was the army of the Italian royalist forces fighting on the side of the Allies in southern Italy after the Allied armistice with Italy in September 1943. The Italian soldiers fighting in this army no longer fought for Benito Mussolini as their allegiance was to King Victor Emmanuel and to Marshal of Italy Pietro Badoglio, the men who ousted Mussolini.
The kingdom was replaced by a Republic in June 1946 and the Royal Army changed its name to become the Italian Army. The army fielded five infantry divisions, create
Anti-aircraft warfare or counter-air defence is defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action". They include surface based and air-based weapon systems, associated sensor systems and control arrangements and passive measures, it may be used to protect naval and air forces in any location. However, for most countries the main effort has tended to be'homeland defence'. NATO refers to airborne naval air defence as anti-aircraft warfare. Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting any projectile in flight. In some countries, such as Britain and Germany during the Second World War, the Soviet Union, NATO, the United States, ground-based air defence and air defence aircraft have been under integrated command and control. However, while overall air defence may be for homeland defence including military facilities, forces in the field, wherever they are, invariably deploy their own air defence capability if there is an air threat.
A surface-based air defence capability can be deployed offensively to deny the use of airspace to an opponent. Until the 1950s, guns firing ballistic munitions ranging from 7.62 mm to 152.4 mm were the standard weapons. The term air defence was first used by Britain when Air Defence of Great Britain was created as a Royal Air Force command in 1925. However, arrangements in the UK were called'anti-aircraft', abbreviated as AA, a term that remained in general use into the 1950s. After the First World War it was sometimes prefixed by'Light' or'Heavy' to classify a type of gun or unit. Nicknames for anti-aircraft guns include AA, AAA or triple-A, an abbreviation of anti-aircraft artillery. NATO defines anti-aircraft warfare as "measures taken to defend a maritime force against attacks by airborne weapons launched from aircraft, ships and land-based sites". In some armies the term All-Arms Air Defence is used for air defence by nonspecialist troops. Other terms from the late 20th century include GBAD with related terms SHORAD and MANPADS.
Anti-aircraft missiles are variously called surface-to-air missile and pronounced "SAM" and Surface to Air Guided Weapon. Non-English terms for air defence include the German FlaK, whence English flak, the Russian term Protivovozdushnaya oborona, a literal translation of "anti-air defence", abbreviated as PVO. In Russian the AA systems are called zenitnye systems. In French, air defence is called DCA; the maximum distance at which a gun or missile can engage an aircraft is an important figure. However, many different definitions are used but unless the same definition is used, performance of different guns or missiles cannot be compared. For AA guns only the ascending part of the trajectory can be usefully used. One term is "ceiling", the maximum ceiling being the height a projectile would reach if fired vertically, not useful in itself as few AA guns are able to fire vertically, maximum fuse duration may be too short, but useful as a standard to compare different weapons; the British adopted "effective ceiling", meaning the altitude at which a gun could deliver a series of shells against a moving target.
By the late 1930s the British definition was "that height at which a directly approaching target at 400 mph can be engaged for 20 seconds before the gun reaches 70 degrees elevation". However, effective ceiling for heavy AA guns was affected by nonballistic factors: The maximum running time of the fuse, this set the maximum usable time of flight; the capability of fire control instruments to determine target height at long range. The precision of the cyclic rate of fire, the fuse length had to be calculated and set for where the target would be at the time of flight after firing, to do this meant knowing when the round would fire; the essence of air defence is to destroy them. The critical issue is to hit a target moving in three-dimensional space; this means that projectiles either have to be guided to hit the target, or aimed at the predicted position of the target at the time the projectile reaches it, taking into account speed and direction of both the target and the projectile. Throughout the 20th century, air defence was one of the fastest-evolving areas of military technology, responding to the evolution of aircraft and exploiting various enabling technologies radar, guided missiles and computing (initially electromechanical analogue computing from the 1930s on, as with equipment describ