World War I
World War I known as the First World War or the Great War, was a global war originating in Europe that lasted from 28 July 1914 to 11 November 1918. Contemporaneously described as "the war to end all wars", it led to the mobilisation of more than 70 million military personnel, including 60 million Europeans, making it one of the largest wars in history, it is one of the deadliest conflicts in history, with an estimated nine million combatants and seven million civilian deaths as a direct result of the war, while resulting genocides and the 1918 influenza pandemic caused another 50 to 100 million deaths worldwide. On 28 June 1914, Gavrilo Princip, a Bosnian Serb Yugoslav nationalist, assassinated the Austro-Hungarian heir Archduke Franz Ferdinand in Sarajevo, leading to the July Crisis. In response, on 23 July Austria-Hungary issued an ultimatum to Serbia. Serbia's reply failed to satisfy the Austrians, the two moved to a war footing. A network of interlocking alliances enlarged the crisis from a bilateral issue in the Balkans to one involving most of Europe.
By July 1914, the great powers of Europe were divided into two coalitions: the Triple Entente—consisting of France and Britain—and the Triple Alliance of Germany, Austria-Hungary and Italy. Russia felt it necessary to back Serbia and, after Austria-Hungary shelled the Serbian capital of Belgrade on the 28th, partial mobilisation was approved. General Russian mobilisation was announced on the evening of 30 July; when Russia failed to comply, Germany declared war on 1 August in support of Austria-Hungary, with Austria-Hungary following suit on 6th. German strategy for a war on two fronts against France and Russia was to concentrate the bulk of its army in the West to defeat France within four weeks shift forces to the East before Russia could mobilise. On 2 August, Germany demanded free passage through Belgium, an essential element in achieving a quick victory over France; when this was refused, German forces invaded Belgium on 3 August and declared war on France the same day. On 12 August and France declared war on Austria-Hungary.
In November 1914, the Ottoman Empire entered the war on the side of the Alliance, opening fronts in the Caucasus and the Sinai Peninsula. The war was fought in and drew upon each power's colonial empire as well, spreading the conflict to Africa and across the globe; the Entente and its allies would become known as the Allied Powers, while the grouping of Austria-Hungary and their allies would become known as the Central Powers. The German advance into France was halted at the Battle of the Marne and by the end of 1914, the Western Front settled into a battle of attrition, marked by a long series of trench lines that changed little until 1917. In 1915, Italy opened a front in the Alps. Bulgaria joined the Central Powers in 1915 and Greece joined the Allies in 1917, expanding the war in the Balkans; the United States remained neutral, although by doing nothing to prevent the Allies from procuring American supplies whilst the Allied blockade prevented the Germans from doing the same the U. S. became an important supplier of war material to the Allies.
After the sinking of American merchant ships by German submarines, the revelation that the Germans were trying to incite Mexico to make war on the United States, the U. S. declared war on Germany on 6 April 1917. Trained American forces would not begin arriving at the front in large numbers until mid-1918, but the American Expeditionary Force would reach some two million troops. Though Serbia was defeated in 1915, Romania joined the Allied Powers in 1916 only to be defeated in 1917, none of the great powers were knocked out of the war until 1918; the 1917 February Revolution in Russia replaced the Tsarist autocracy with the Provisional Government, but continuing discontent at the cost of the war led to the October Revolution, the creation of the Soviet Socialist Republic, the signing of the Treaty of Brest-Litovsk by the new government in March 1918, ending Russia's involvement in the war. This allowed the transfer of large numbers of German troops from the East to the Western Front, resulting in the German March 1918 Offensive.
This offensive was successful, but the Allies rallied and drove the Germans back in their Hundred Days Offensive. Bulgaria was the first Central Power to sign an armistice—the Armistice of Salonica on 29 September 1918. On 30 October, the Ottoman Empire capitulated. On 4 November, the Austro-Hungarian empire agreed to the Armistice of Villa Giusti after being decisively defeated by Italy in the Battle of Vittorio Veneto. With its allies defeated, revolution at home, the military no longer willing to fight, Kaiser Wilhelm abdicated on 9 November and Germany signed an armistice on 11 November 1918. World War I was a significant turning point in the political, cultural and social climate of the world; the war and its immediate aftermath sparked numerous uprisings. The Big Four (Britain, the United States, It
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
Royal Canadian Air Force
The Royal Canadian Air Force is the air force of Canada. Its role is to "provide the Canadian Forces with relevant and effective airpower"; the RCAF is one of three environmental commands within the unified Canadian Armed Forces. As of 2013, the Royal Canadian Air Force consists of 14,500 Regular Force and 2,600 Primary Reserve personnel, supported by 2,500 civilians, operates 258 manned aircraft and 9 unmanned aerial vehicles. Lieutenant-General Al Meinzinger is the current Commander of the Royal Canadian Air Force and Chief of the Air Force Staff; the Royal Canadian Air Force is responsible for all aircraft operations of the Canadian Forces, enforcing the security of Canada's airspace and providing aircraft to support the missions of the Royal Canadian Navy and the Canadian Army. The RCAF is a partner with the United States Air Force in protecting continental airspace under the North American Aerospace Defense Command; the RCAF provides all primary air resources to and is responsible for the National Search and Rescue Program.
The RCAF traces its history to the Canadian Air Force, formed in 1920. The Canadian Air Force was granted royal sanction in 1924 by King George V to form the Royal Canadian Air Force. In 1968, the RCAF was amalgamated with the Royal Canadian Navy and the Canadian Army, as part of the unification of the Canadian Forces. Air units were split between several different commands: Air Defence Command, Air Transport Command, Mobile Command, Maritime Command, as well as Training Command. In 1975, some commands were dissolved, all air units were placed under a new environmental command called Air Command. Air Command reverted to its historic name of "Royal Canadian Air Force" in August 2011; the Royal Canadian Air Force has served in the Second World War, the Korean War, the Persian Gulf War, as well as several United Nations peacekeeping missions and NATO operations. As a NATO member, the force maintained a presence in Europe during the second half of the 20th century; the Canadian Air Force was established in 1920 as the successor to a short-lived two-squadron Canadian Air Force, formed during the First World War in Europe.
John Scott Williams, MC, AFC, was tasked in 1921 with organizing the CAF, handing command over the same year to Air Marshal Lindsay Gordon. The new Canadian Air Force was a branch of the Air Board and was chiefly a training militia that provided refresher training to veteran pilots. Many CAF members worked with the Air Board's Civil Operations Branch on operations that included forestry and anti-smuggling patrols. In 1923, the CAF became responsible including civil aviation. In 1924, the Canadian Air Force, was granted the royal title. Most of its work was civil in nature. After budget cuts in the early 1930s, the air force began to rebuild. During the Second World War, the RCAF was a major contributor to the British Commonwealth Air Training Plan and was involved in operations in Great Britain, the north Atlantic, North Africa, southern Asia, with home defence. By the end of the war, the RCAF had become the fourth largest allied air force. During WWII the Royal Canadian Air Force were headquartered in London.
A commemorative plaque can be found on the outside of the building. After the war, the RCAF reduced its strength; because of the rising Soviet threat to the security of Europe, Canada joined NATO in 1949, the RCAF established No. 1 Air Division RCAF consisting of four wings with three fighter squadrons each, based in France and West Germany. In 1950, the RCAF became involved with the transport of supplies to the Korean War. Members of the RCAF served in USAF units as several flew in combat. Both auxiliary and regular air defence squadrons were run by Air Defence Command. At the same time, the Pinetree Line, the Mid-Canada Line and the DEW Line radar stations operated by the RCAF, were built across Canada because of the growing Soviet nuclear threat. In 1957, Canada and the United States created the joint North American Air Defense Command. Coastal defence and peacekeeping became priorities during the 1950s and 1960s. In 1968, the Royal Canadian Navy, Royal Canadian Air Force and Canadian Army were amalgamated to form the unified Canadian Forces.
This initiative was overseen by Liberal Defence Minister, Paul Hellyer. The controversial merger maintained several existing organizations and created some new ones: In Europe, No. 1 Air Division, operated Canadair CF-104 Starfighter nuclear strike/attack and reconnaissance under NATO's 4 ATAF. Aviation assets of the Royal Canadian Navy were combined with the RCAF Canadair CP-107 Argus long-range patrol aircraft under Maritime Command. In 1975, the different commands, the scattered aviation assets, were consolidated under Air Command. In the early 1990s, Canada provided a detachment of CF-18 Hornets for the air defence mission in Operation Desert Shield; the force performed combat air patrols over operations in Kuwait and Iraq, undertook a number of air-to-ground bombing missions, and, on one occasion, attacked an Iraqi patrol boat in the Persian Gulf. In the late 1
Military vehicles are armoured to withstand the impact of shrapnel, missiles or shells, protecting the personnel inside from enemy fire. Such vehicles include armoured fighting vehicles like tanks and ships. Civilian vehicles may be armoured; these vehicles include cars used by officials and others in conflict zones or where violent crime is common. Civilian armoured cars are routinely used by security firms to carry money or valuables to reduce the risk of highway robbery or the hijacking of the cargo. Armour may be used in vehicles to protect from threats other than a deliberate attack; some spacecraft are equipped with specialised armour to protect them against impacts from micrometeoroids or fragments of space junk. Modern aircraft powered by jet engines have them fitted with a sort of armour in the form of an aramid composite kevlar bandage around the fan casing or debris containment walls built into the casing of their gas turbine engines to prevent injuries or airframe damage should the fan, compressor, or turbine blades break free.
The design and purpose of the vehicle determines the amount of armour plating carried, as the plating is very heavy and excessive amounts of armour restrict mobility. In order to decrease this problem, some new materials and material compositions are being researched which include buckypaper, aluminium foam armour plates. Rolled homogeneous armour is strong and tough. Steel with these characteristics are produced by processing cast steel billets of appropriate size and rolling them into plates of required thickness. Rolling and forging irons out the grain structure in the steel, removing imperfections which would reduce the strength of the steel. Rolling elongates the grain structure in the steel to form long lines, which enable the stress the steel is placed under when loaded to flow throughout the metal, not be concentrated in one area. Aluminium is used, it is most used on APCs and armoured cars. Wrought iron was used on ironclad warships. Early European iron armour consisted of 10 to 13 cm of wrought iron backed by up to one meter of solid wood.
Titanium has twice the density of aluminium, but is as strong as iron. So, despite being more expensive, it finds an application in areas where weight is a concern, such as personal armour and military aviation; some notable examples of its use include the USAF A-10 Thunderbolt II and the Soviet/Russian-built Sukhoi Su-25 ground-attack aircraft, utilising a bathtub-shaped titanium enclosure for the pilot, as well as the Soviet/Russian Mil Mi-24 attack helicopter. Because of its high density, depleted uranium can be used in tank armour, sandwiched between sheets of steel armour plate. For instance, some late-production M1A1HA and M1A2 Abrams tanks built after 1998 have DU reinforcement as part of the armour plating in the front of the hull and the front of the turret, there is a program to upgrade the rest. Plastic metal was a type of vehicle armour developed for merchant ships by the British Admiralty in 1940; the original composition was described as 50% clean granite of half-inch size, 43% of limestone mineral, 7% of bitumen.
It was applied in a layer two inches thick and backed by half an inch of steel. Plastic armour was effective at stopping armour piercing bullets because the hard granite particles would deflect the bullet, which would lodge between plastic armour and the steel backing plate. Plastic armour could be applied by pouring it into a cavity formed by the steel backing plate and a temporary wooden form. Bulletproof glass is a colloquial term for glass, resistant to being penetrated when struck by bullets; the industry refers to it as bullet-resistant glass or transparent armour. Bullet-resistant glass is constructed using a strong but transparent material such as polycarbonate thermoplastic or by using layers of laminated glass; the desired result is a material with the appearance and light-transmitting behaviour of standard glass, which offers varying degrees of protection from small arms fire. The polycarbonate layer consisting of products such as Armormax, Cyrolon, Lexan or Tuffak, is sandwiched between layers of regular glass.
The use of plastic in the laminate provides impact-resistance, such as physical assault with a hammer, an axe, etc. The plastic provides little in the way of bullet-resistance; the glass, much harder than plastic, flattens the bullet and thereby prevents penetration. This type of bullet-resistant glass is 70–75 mm thick. Bullet-resistant glass constructed of laminated glass layers is built from glass sheets bonded together with polyvinyl butyral, polyurethane or ethylene-vinyl acetate; this type of bullet-resistant glass has been in regular use on combat vehicles since World War II. Newer materials are being developed. One such, aluminium oxynitride, is much lighter but at US$10–15 per square inch is much more costly. Ceramic's precise mechanism for defeating HEAT was uncovered in the 1980s. High speed photography showed that the ceramic material shatters as the HEAT round penetrates, the energetic fragments destroying the geometry of the metal jet generated by the hollow charge diminishing the penetration.
Ceramic layers can be used as part of composite armour solutions. The high hardness of some ceramic materials serves as a disruptor that shatters and spreads the kinetic energy of pr
A fighter-bomber is a fighter aircraft, modified, or used as a light bomber or attack aircraft. It differs from bomber and attack aircraft in its origins, as a fighter, adapted into other roles, whereas bombers and attack aircraft are developed for bombing and attack roles. Although still used, the term fighter-bomber has less significance since the introduction of rockets and guided missiles into aerial warfare. Modern aircraft with similar duties are now called multirole combat aircraft or strike fighters. Prior to World War II, general limitations in available engine and aeronautical technology required that each proposed military aircraft have its design tailored to a specific prescribed role. Engine power grew during the early period of the war doubling between 1939 and 1943; the Bristol Blenheim, a typical light bomber of the opening stages of the war, was designed in 1934 as a fast civil transport to meet a challenge by Lord Rothermere, owner of the Daily Mail. It had two Bristol Mercury XV radial engines of 920 hp each, a crew of three, its payload was just 1,200 lbs of bombs.
The Blenheim suffered disastrous losses over France in 1939 when it encountered Messerschmitt Bf 109s, light bombers were withdrawn. In contrast, the Vought F4U Corsair fighter—which entered service in December 1942—had in common with its eventual U. S. Navy stablemate, the Grumman F6F Hellcat and the massive, seven-ton USAAF Republic P-47 Thunderbolt—a single Pratt & Whitney R-2800 Double Wasp radial engine of 2,000 hp in a much smaller and less expensive single-seat aircraft, was the first aircraft design to fly with the Double Wasp engine in May 1940. With less airframe and crew to lift, the Corsair's ordnance load was either four High Velocity Aircraft Rockets or 2,000 lbs of bombs; the massive, powerful 18-cylinder Double Wasp engine weighed a ton—half as much again as the V12 Rolls-Royce Merlin and twice as much as the 9-cylinder Bristol Mercury that powered some heavy fighters. Increased engine power meant that many existing fighter designs could carry useful bomb loads, adapt to the fighter-bomber role.
Notable examples include Hawker Typhoon and Republic P-47 Thunderbolt. Various bombing tactics and techniques could be used: some designs were intended for high-level bombing, others for low-level semi-horizontal bombing, or for low-level steep dive bombing as exemplified by the Blackburn Skua and North American A-36 Apache. Larger twin-engined aircraft were used in the fighter-bomber role where longer ranges were needed for naval strikes. Examples include the Lockheed P-38 Lightning, the Bristol Beaufighter, de Havilland Mosquito; the Beaufighter MkV had a Boulton-Paul turret with four 0.303 in machine guns mounted aft of the cockpit but only two were built. Bristol's Blenheim was pushed into service as a fighter during the Battle of Britain but it was not fast enough. Equipped with an early Airborne Interception radar set, however, it proved to be an effective night fighter; the first single seat fighters to drop bombs were on the Western Front, when fighter patrols were issued with bombs and ordered to drop them at random if they met no German fighters.
The Sopwith Camel, the most successful Allied aircraft of the First World War with 1,294 enemy aircraft downed, was losing its edge by 1918 over 12,000 ft. During the final German offensive in March 1918, it dropped 25 lb Cooper bombs on advancing columns: whilst puny by standards, the four fragmentation bombs carried by a Camel could cause serious injuries to exposed troops. Pilot casualties were high; the Royal Aircraft Factory S. E.5. was used in the same role. The Royal Flying Corps received the first purpose-built fighter-bomber, it was not called a fighter bomber at the time, but a Trench Fighter as, what it was designed to attack. The Sopwith Salamander was based on the Sopwith Snipe fighter but had armour plating in the nose to protect the pilot and fuel system from ground fire, it was intended to have two machine guns jutting through the cockpit floor so as to spray trenches with bullets as it passed low overhead. But this did not work and it was fitted with four Cooper bombs, instead.
It was ordered in large numbers, but most were cancelled after the Armistice. In February and April 1918 the Royal Flying Corps conducted bombing tests at Orfordness, Suffolk dropping dummy bombs at various dive angles at a flag stuck into a shingle beach. Both WW1 fighter bombers were used with novice and experienced pilots. Best results were achieved with a vertical dive into the wind using the Aldis Sight to align the aircraft, but they were not considered good enough to justify the expected casualty rate. When war broke out in Europe, Western Allied Air Forces employed light twin-engined bombers in the tactical role for low level attack; these were found to be vulnerable both to ground fire and to single engine fighters. The German and Japanese Air Forces had chosen dive bombers which were vulnerable; the Ilyushin Il-2 is a armoured two seat single-engine ground attack aircraft. It first flew a month although few had reached the Soviet Air Force in time for Operation Barbarossa. Naval forces chose both dive bombers.
None of these could be considered as fighter bombers. The Bristol Blenheim and Douglas A-20 Havoc were used as night fighters during the Blitz, as they could carry the heavy early airborne radarsThe Hawker
An autocannon or automatic cannon is a large automatic, rapid-fire projectile weapon that fires armour-piercing or explosive shells, as opposed to the bullet fired by a machine gun. Autocannons have a larger calibre than a machine gun, but are smaller than a field gun or other artillery; when used on its own, the word "autocannon" indicates a single-barrel weapon. When multiple rotating barrels are involved, the word "rotary" is added, such a weapon is referred to as a "rotary autocannon". Modern autocannons are not single soldier-portable or stand-alone units, rather they are vehicle-mounted, aircraft-mounted, or boat-mounted, or remote-operated as in some naval applications; as such, ammunition is fed from a belt to reduce reloading or for a faster rate of fire, but a magazine remains an option. They can use a variety of ammunition: common shells include high-explosive dual-purpose types, any variety of armour-piercing types, such as composite rigid or discarding sabot types. Although capable of generating a high rate of fire, autocannons overheat if used for sustained fire, are limited by the amount of ammunition that can be carried by the weapons systems mounting them.
Both the US 25 mm Bushmaster and the British 30 mm Rarden have slow rates of fire so as not to use ammunition too quickly. The rate of fire of a modern autocannon ranges from 90 rounds per minute, to 2,500 rounds per minute with the GIAT 30. Systems with multiple barrels can have rates of fire of over 10,000 rounds per minute; such high rates of fire are employed by aircraft in air-to-air combat and close air support attacks on ground targets, where the target dwell time is short and weapons are operated in brief bursts. The first modern autocannon was the British QF 1 pounder known as the "pom-pom"; this was an upscaled version of the Maxim gun, the first successful automatic machine gun, requiring no outside stimulus in its firing cycle other than holding the trigger. The pom-pom fired 1 pound gunpowder-filled explosive shells at a rate of over 200 rounds a minute: much faster than conventional artillery while possessing a much longer range and more firepower than the infantry rifle. In 1913, Reinhold Becker and his Stahlwerke Becker firm designed the 20mm Becker cannon for the German Empire's perceived need for heavy-calibre aircraft armament, was assisted by the Imperial Government's Spandau Arsenal in perfecting the ordnance - although only about 500+ examples of the original Becker design were made during World War I, the design's patent was acquired by the Swiss Oerlikon Contraves firm in 1924, with the Third Reich's Ikaria-Werke firm of Berlin using Oerlikon design patents in creating the MG FF wingmount cannon ordnance, in Imperial Japan, their navy's adoption and production of the Type 99 cannon in 1939 was based on the Becker/Oerlikon design's principles.
During the First World War, autocannons were used in the trenches as an anti-aircraft gun. The British used pom-pom guns as part of their air defences to counter the German Zeppelin airships that made regular bombing raids on London, but they were of little value, as their shells neither ignited the hydrogen of the Zeppelins, nor caused sufficient loss of gas to bring them down. Attempts to use them in aircraft failed as the weight limited both speed and altitude, thus making successful interception impossible; the more effective QF 2 pounder naval gun would be developed during the war to serve as an anti-aircraft and close range defensive weapon for naval vessels. Autocannons would serve in a much greater capacity during the Second World War. During the inter-war years, aircraft underwent an evolution and the all-metal monoplane, pioneered as far back as the end of 1915 replaced wood and fabric biplanes; the subsequent increase in speed and durability reduced the window of opportunity for defence.
Heavier anti-aircraft cannon had difficulty tracking fast-moving aircraft and were unable to judge altitude or distance, while machine guns possessed insufficient range and firepower to bring down aircraft consistently. Weapons such as the Oerlikon 20 mm and the Bofors 40 mm would see widespread use by both sides during the second World War. Continued ineffectiveness against aircraft despite the large numbers installed during the second World War led, in the West, to the removal of all shipboard anti-aircraft weapons in the early post-war period; this was only reversed with the introduction of computer-controlled systems. The German Panzer II light tank, one of the most numerous in German service during the invasion of Poland and the campaign in France, used a 20 mm autocannon as its main armament. Although ineffective against tank armour during the early years of the war, the cannon was effective against light-skinned vehicles as well as infantry and was used by armoured cars. Larger examples, such as the 40 mm Vickers S, were mounted in ground attack aircraft to serve as an anti-tank weapon, a role to which they were suited as tank armour is lightest on top.
Polish 20 mm. Unlike the Oerlikon, it was effective against all the tanks fielded in 1939 because it was built as an upgrade to the Oerlikon, Hispano—Suiza, Madsen. It, with great difficulty, proved capable of knocking out early Panzer IIIs and IVs. Only 55 were produced by the time of the Polish Defensive War. In airc
The Hawker Typhoon is a British single-seat fighter-bomber, produced by Hawker Aircraft. It was intended to be a medium–high altitude interceptor, as a replacement for the Hawker Hurricane but several design problems were encountered and it never satisfied this requirement; the Typhoon was designed to mount twelve.303 inch Browning machine guns and be powered by the latest 2,000 hp engines. Its service introduction in mid-1941 was plagued with problems and for several months the aircraft faced a doubtful future; when the Luftwaffe brought the formidable Focke-Wulf Fw 190 into service in 1941, the Typhoon was the only RAF fighter capable of catching it at low altitudes. The Typhoon became established in roles such as long-range fighter. From late 1942 the Typhoon was equipped with bombs and from late 1943 RP-3 rockets were added to its armoury. With those weapons and its four 20mm Hispano autocannons, the Typhoon became one of the Second World War's most successful ground-attack aircraft. Before Hurricane production began in March 1937, Sydney Camm had embarked on designing its successor.
Two preliminary designs were larger than the Hurricane. These became known as the "N" and "R", because they were designed for the newly developed Napier Sabre and Rolls-Royce Vulture engines respectively. Both engines were designed for over 2,000 hp. Hawker submitted these preliminary designs in July 1937 but were advised to wait until a formal specification for a new fighter was issued. In March 1938, Hawker received from the Air Ministry, Specification F.18/37 for a fighter which would be able to achieve at least 400 mph at 15,000 feet and specified a British engine with a two-speed supercharger. The armament fitted was to be twelve.303 inch Browning machine guns with 500 rounds per gun, with a provision for alternative combinations of weaponry. Camm and his design team started formal development of the designs and construction of prototypes; the basic design of the Typhoon was a combination of traditional Hawker construction and more modern construction techniques. The forward fuselage and cockpit skinning was made up of large, removable duralumin panels, allowing easy external access to the engine and engine accessories and most of the important hydraulic and electrical equipment.
The wing had a span of 41 feet 7 inches, with a wing area of 279 sq ft. It was designed with a small amount of inverted gull wing bend; the airfoil was a NACA 22 wing section, with a thickness-to-chord ratio of 19.5% at the root tapering to 12% at the tip. The wing possessed great structural strength, provided plenty of room for fuel tanks and a heavy armament, while allowing the aircraft to be a steady gun platform; each of the inner wings incorporated two fuel tanks. Incorporated into the inner wings were inward-retracting landing gear with a wide track of 13 ft 6¾ in. By contemporary standards, the new design's wing was "thick", similar to the Hurricane before it. Although the Typhoon was expected to achieve over 400 mph in level flight at 20,000 ft, the thick wings created a large drag rise and prevented higher speeds than the 410 mph at 20,000 feet achieved in tests; the climb rate and performance above that level was considered disappointing. When the Typhoon was dived at speeds of over 500 mph, the drag rise caused buffeting and trim changes.
These compressibility problems led to Camm designing the Typhoon II known as the Tempest, which used much thinner wings with a laminar flow airfoil. The first flight of the first Typhoon prototype, P5212, made by Hawker's Chief test Pilot Philip Lucas from Langley, was delayed until 24 February 1940 because of the problems with the development of the Sabre engine. Although unarmed for its first flights, P5212 carried 12.303 in Brownings, set in groups of six in each outer wing panel. P5212 had a small tail-fin, triple exhaust stubs and no wheel doors fitted to the centre-section. On 9 May 1940 the prototype had a mid-air structural failure, at the join between the forward fuselage and rear fuselage, just behind the pilot's seat. Philip Lucas could see daylight through the split but instead of bailing out, landed the Typhoon and was awarded the George Medal. On 15 May, the Minister of Aircraft Production, Lord Beaverbrook, ordered that resources should be concentrated on the production of five main aircraft types.
As a result, development of the Typhoon was slowed, production plans were postponed and test flying continued at a reduced rate. As a result of the delays the second prototype, P5216, first flew on 3 May 1941: P5216 carried an armament of four belt-fed 20 mm (