Hispano-Suiza was a Spanish automotive/engineering company and, after World War II, a French aviation engine and components manufacturer. It is best known for its pre-World War II luxury cars and aviation engines. In 1923, its French subsidiary became a semi-autonomous partnership with the Spanish parent company. In 1946, the Spanish parent company sold all its Spanish automotive assets to Enasa. In 1968, the French arm was taken over by the aerospace company Snecma, now a part of the French Safran Group. In 1898 a Spanish artillery captain, Emilio de la Cuadra, started electric automobile production in Barcelona under the name of La Cuadra. In Paris, De la Cuadra met the Swiss engineer Marc Birkigt and hired him to work for the company in Spain. La Cuadra built their first gasoline-powered engines from a Birkigt design. At some point in 1902, the ownership changed hands to José María Castro Fernández and became Fábrica Hispano-Suiza de Automóviles but this company went bankrupt in December 1903.
Yet another restructuring took place in 1904, creating La Hispano-Suiza Fábrica de Automóviles, under Castro's direction based in Barcelona. Four new engines were introduced in a half; this company managed to avoid bankruptcy and its largest operations remained in Barcelona until 1946, where cars, buses, aero engines and weapons were produced. Other factories in Spain were at Ripoll and Guadalajara. In 1910 Jean Chassagne competed with a Hispano-Suiza together with works drivers Pilleveridier and Zucarelli in the Coupe des Voiturettes Boulogne and the Catalan Cup Races, gaining second and fourth places respectively. France was soon proving to be a larger market for Hispano-Suiza's luxury cars than Spain. In 1911, an assembly factory called Hispano France began operating in the Paris suburb of Levallois-Perret. Production was moved to larger factories at Bois-Colombes, under the name Hispano-Suiza in 1914 and soon became Hispano-Suiza's main plant for producing the largest, most costly models.
With the start of World War I, Hispano-Suiza turned to the design and production of aircraft engines under the direction of Marc Birkigt. His chief engineer during this period was Louis Massuger. Traditionally, aircraft engines were manufactured by machining separate steel cylinders and bolting these assemblies directly to the crankcase. Birkigt's novel solution called for the engine block to be formed from a single piece of cast aluminum, into which thin steel liners were secured. Manufacturing an engine in this way simplified construction and resulted in a lighter, yet stronger more durable engine. Thus, Birkigt's new construction method created the first practical, what are known today as, "cast block" engines, his aluminum cast block V-8 design was noteworthy for incorporating overhead camshafts, propeller reduction gearing and other desirable features that would not appear together on competitor's engines until the late 1920s. Another major design feature, for the HS.8B line was the use of a hollow propeller shaft for both the 8B and 8C gear-reduction versions, which when used for the HS.8C versions engineered to accommodate one, to allow heavy calibre projectile firing through the hollow propeller shaft, avoiding the need for a synchronization gear, a feature used in future Hispano-Suiza military engines.
Hispano-Suiza's aero engines, produced at its own factories and under license, became the most used aero engines in the French and British air forces, powering over half the alliance's fighter aircraft. After World War I, Hispano-Suiza returned to automobile manufacturing and in 1919 they introduced the Hispano-Suiza H6; the H6 featured an inline 6-cylinder overhead camshaft engine based on the features of its V8 aluminum World War I aircraft engines and had coachwork done by well known coachbuilders like Hibbard & Darrin and D'Ieteren. Licences for Hispano-Suiza patents were much in demand from prestige car manufacturers world-wide. Rolls-Royce used a number of Hispano-Suiza patents. For instance, for many years Rolls Royce installed Hispano-Suiza designed power brakes in its vehicles. In 1923 the French arm of Hispano-Suiza was incorporated as the Société Française Hispano-Suiza, the Spanish parent company retaining control with 71% of the share capital; the French subsidiary was granted a large degree of financial and project independence to bring design and production direction into closer contact with its main markets but overall direction remained at Barcelona.
This arrangement increased the importance of the Bois-Colombes plant near Paris as Hispano-Suiza's premier luxury car plant, while the Spanish operations continued to produce luxury cars the smaller, less expensive models, production in Spain moved to the production of buses and aircraft engines at several plants located around the country. Through the 1920s and into the 1930s, Hispano-Suiza built a series of luxury cars with overhead camshaft engines of increasing performance. On the other hand, in the 1930s, Hispano-Suiza's V-12 car engines reverted to pushrod valve actuation to reduce engine noise. During this time, Hispano-Suiza released the 37.2 Hispano-Suiza car built at the Bois-Colombes works. The mascot statuette atop the radiator after World War I was the stork, the symbol of the French province of Alsace, taken from the squadron emblem painted on the side of a Hispano-Suiza powered fighter aircraft, flown by the World War I French ace Georges Guynemer. In 1925, Carlos Ballester obtained permission to represent Hispano-Suiza in Argentina.
The agreement consisted of a phase in which the chassis were impor
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
Marc Birkigt was a Swiss engineer who moved to Barcelona, Spain when he was hired as an engineer by Emilio de la Cuadra, founder of Hispano-Suiza automobiles. He created the Dewoitine company along with Émile Dewoitine. Birkigt was nominated for the Car Engineer of the Century prize for the luxurious Hispano-Suiza H6 car in the 1920s, he won fame for the aircraft engines and guns he designed at Hispano-Suiza as chief engineer, the former including the liquid-cooled V8 engine that powered the famous French SPAD VII and SPAD XIII World War I fighters, the British Sopwith Dolphin and S. E. 5a, whilst in the field of ordnance he created the Hispano-Suiza HS.404 20mm autocannon, of great importance in WW II as the main fighter gun of the RAF from 1941 onwards. Media related to Marc Birkigt at Wikimedia Commons
World War II
World War II known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries; the major participants threw their entire economic and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. World War II was the deadliest conflict in human history, marked by 50 to 85 million fatalities, most of whom were civilians in the Soviet Union and China, it included massacres, the genocide of the Holocaust, strategic bombing, premeditated death from starvation and disease, the only use of nuclear weapons in war. Japan, which aimed to dominate Asia and the Pacific, was at war with China by 1937, though neither side had declared war on the other. World War II is said to have begun on 1 September 1939, with the invasion of Poland by Germany and subsequent declarations of war on Germany by France and the United Kingdom.
From late 1939 to early 1941, in a series of campaigns and treaties, Germany conquered or controlled much of continental Europe, formed the Axis alliance with Italy and Japan. Under the Molotov–Ribbentrop Pact of August 1939, Germany and the Soviet Union partitioned and annexed territories of their European neighbours, Finland and the Baltic states. Following the onset of campaigns in North Africa and East Africa, the fall of France in mid 1940, the war continued between the European Axis powers and the British Empire. War in the Balkans, the aerial Battle of Britain, the Blitz, the long Battle of the Atlantic followed. On 22 June 1941, the European Axis powers launched an invasion of the Soviet Union, opening the largest land theatre of war in history; this Eastern Front trapped most crucially the German Wehrmacht, into a war of attrition. In December 1941, Japan launched a surprise attack on the United States as well as European colonies in the Pacific. Following an immediate U. S. declaration of war against Japan, supported by one from Great Britain, the European Axis powers declared war on the U.
S. in solidarity with their Japanese ally. Rapid Japanese conquests over much of the Western Pacific ensued, perceived by many in Asia as liberation from Western dominance and resulting in the support of several armies from defeated territories; the Axis advance in the Pacific halted in 1942. Key setbacks in 1943, which included a series of German defeats on the Eastern Front, the Allied invasions of Sicily and Italy, Allied victories in the Pacific, cost the Axis its initiative and forced it into strategic retreat on all fronts. In 1944, the Western Allies invaded German-occupied France, while the Soviet Union regained its territorial losses and turned toward Germany and its allies. During 1944 and 1945 the Japanese suffered major reverses in mainland Asia in Central China, South China and Burma, while the Allies crippled the Japanese Navy and captured key Western Pacific islands; the war in Europe concluded with an invasion of Germany by the Western Allies and the Soviet Union, culminating in the capture of Berlin by Soviet troops, the suicide of Adolf Hitler and the German unconditional surrender on 8 May 1945.
Following the Potsdam Declaration by the Allies on 26 July 1945 and the refusal of Japan to surrender under its terms, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August respectively. With an invasion of the Japanese archipelago imminent, the possibility of additional atomic bombings, the Soviet entry into the war against Japan and its invasion of Manchuria, Japan announced its intention to surrender on 15 August 1945, cementing total victory in Asia for the Allies. Tribunals were set up by fiat by the Allies and war crimes trials were conducted in the wake of the war both against the Germans and the Japanese. World War II changed the political social structure of the globe; the United Nations was established to foster international co-operation and prevent future conflicts. The Soviet Union and United States emerged as rival superpowers, setting the stage for the nearly half-century long Cold War. In the wake of European devastation, the influence of its great powers waned, triggering the decolonisation of Africa and Asia.
Most countries whose industries had been damaged moved towards economic expansion. Political integration in Europe, emerged as an effort to end pre-war enmities and create a common identity; the start of the war in Europe is held to be 1 September 1939, beginning with the German invasion of Poland. The dates for the beginning of war in the Pacific include the start of the Second Sino-Japanese War on 7 July 1937, or the Japanese invasion of Manchuria on 19 September 1931. Others follow the British historian A. J. P. Taylor, who held that the Sino-Japanese War and war in Europe and its colonies occurred and the two wars merged in 1941; this article uses the conventional dating. Other starting dates sometimes used for World War II include the Italian invasion of Abyssinia on 3 October 1935; the British historian Antony Beevor views the beginning of World War II as the Battles of Khalkhin Gol fought between Japan and the fo
Mine shell (projectile)
A mine shell is an ammunition type consisting of a high-capacity high-explosive shell. The type was developed in Nazi Germany during WW2 to increase the effectiveness of the Luftwaffe's aircraft guns; the word mine in the name mine shell does not refer to the common use of the word as in a land mines or naval mines. It is an ammunition term used in several Germanic languages meaning explosion with minimal fragmentation effect or maximum explosive effect. In other words, the explosion itself is meant to do the majority of the damage to the target. A mine shell differs from conventional high explosive rounds in that it has much thinner walls which allows for more explosive content; this gives the shell a much bigger explosion at the expense of shrapnel. Beyond impact effect mine shells have different weight properties compared to regular high explosive shells. Explosive filler is lighter than metal which makes the projectiles a lot lighter which in turn gives them higher muzzle velocity compared to heavier shells.
A disadvantage is that the same lower mass reduces range as the projectile has correspondingly less momentum. The type was developed in Nazi Germany at the end of the 1930's due to problematic trials with the 20 mm MG FF cannon, its conventional high explosive rounds didn't have satisfactory results against aircraft as the fragments had insufficient effect on construction integrity or control surfaces compared to the actual explosion. As a result of these trials, the German ministry of air defense "Reichsluftministerium", or "RLM" for short, ordered a development of new 20 mm cannon shell in 1937 which should have increased explosive force at the expense of impact and fragmentation effect. Conventional explosive ammunition was made by drilling the explosive cavity into a solid steel shot, a design which due to the massive impact and structural integrity of such a round, made sense when seeking to penetrate hard targets. By contrast, aircraft are constructed and overall soft targets, unless they struck hard areas such as engines or armour such shells tended to punch through their structure rather than transfer their kinetic force to it - which meant that such a massive impact was to some degree superfluous.
It could even be conducive to over-penetration, where a shell passes through the target before exploding. German ordinance engineers therefore took a new approach, designed a round made from drawing steel into a suitable shape, giving thinner-wall construction and therefore space for a far greater amount of explosive filler than previously; the metal had to be high-quality steel to keep the structural integrity. The new ammunition type was given the designation Minengeschoss, German for'mine-shell,' due to the larger explosives payload; the new invention was successful. It was, less effective at penetrating deep into target aircraft or breaching their internal armour than the conventional rounds used by the RAF in WW II, but the power of the explosions inflicted serious damage wherever they occurred within the structure of the plane, rendering these apparent disadvantages less relevant; as well as creating larger explosions this new ammunition type came with another desirable trait. Explosive matter is a lot lighter than steel, which gave this new ammunition type a low weight and thus, for an equal amount of propellant, correspondingly higher velocity.
Like the greater explosive payload this was a big advantage, as air combat involves shooting at fast-moving targets. Conversely and significantly, another way the Luftwaffe benefitted from the new ammunition's lower weight was that when they deployed small, light guns only capable of firing low-powered propellant cartridges they could still achieve useful velocities, this, in combination with the larger explosive warhead gave such weapons a much greater effect than they could have had firing conventional rounds. Examples are the 20mm MG FF/M, well-suited to mounting in the wings of the Luftwaffe's light and compact Bf 109 fighters, 30mm MK 108. Both weapons were militarily significant, the first during some early stages of the conflict, the latter during the second half. For the Reich, one disadvantage of Minengeschoss shells is that the lower momentum of the lighter round caused it to lose its velocity quickly. C, which overcame air resistance more - albeit at the loss of a little explosives capacity.
As volume increases with the square of the radius of a cylinder, as autocannon shells are close to cylindrical in shape, the advantages of low weight and high explosive payload furnished by the Minengeschoss approach were manifest in large calibre weapons such as the 30mm MK 108, which were used with devastating results on allied bombers in the air campaigns of the war in Europe. Minengeschoss ammunition was first fired in combat from the MG FF/M during the Battle of Britain in 1940 by the Luftwaffe's Bf 109E and Bf 110C fighters. Subsequently it was used in the Luftwaffe's standard 20mm gun, the MG 151/20 cannon, one of the best 20mm weapons of WW II, in the high-velocity 30 mm MK 103, amongst others. To give some impression of the actual difference in payloads between these shells: the 20 mm M-Geschoss shell had an 18 g HE filling while the typical filler load in conventional 20 mm shells at the time was 6 to 10 g. In 30 mm caliber different M-Geschoss designs were available: the original blunt-nosed Ausf.
A had an 85 g filling
Imperial Japanese Navy Air Service
The Imperial Japanese Navy Air Service was the air arm of the Imperial Japanese Navy. The organization was responsible for the operation of naval aircraft and the conduct of aerial warfare in the Pacific War; the Japanese military acquired their first aircraft in 1910 and followed the development of air combat during World War I with great interest. They procured European aircraft but built their own and launched themselves onto an ambitious aircraft carrier building program, they launched the world's first purpose-built aircraft carrier, Hōshō, in 1922. Afterwards they embarked on a conversion program of several excess battlecruisers and battleships into aircraft carriers; the IJN Air Service had the mission of national air defence, deep strike, naval warfare, so forth. It retained this mission to the end; the Japanese pilot training program was selective and rigorous, producing a high-quality and long-serving pilot corps, who were successful the air in the Pacific during early World War II. However, the long duration of the training program, combined with a shortage of gasoline for training, did not allow the IJN to provide qualified replacements in sufficient numbers.
Moreover, the Japanese, unlike the U. S. or Britain, proved incapable of altering the program to speed up training of the recruits they got. The resultant decrease in quantity and quality, among other factors, resulted in increasing casualties toward the end of the war. Japanese navy aviators, like their army counterparts, preferred maneuverable aircraft, leading to built but extraordinarily agile types, most famously the A6M Zero, which achieved its feats by sacrificing armor and self-sealing fuel tanks. Aircraft with armor and self-sealing fuel tanks, such as the Kawanishi N1K-J would not enter service until late 1944–1945, which at this point, was too late; the Imperial Japanese Navy Air Service was equal in function to the Royal Navy's Fleet Air Arm. The beginnings of Japanese naval aviation were established in 1912, with the creation of a Commission on Naval Aeronautical Research under the authority of the Technical Department; the commission was charged with the promotion of aviation training for the navy.
Was focus was in non-rigid airships but it moved on to the development of winged and powered aircraft. That year, the commission decided to purchase foreign winged aircraft and to send junior officers abroad to learn how to fly and maintain them; the navy purchased two seaplanes from the Glenn Curtiss factory in Hammondsport, New York, two Maurice Farman seaplanes from France. To establish a cadre of naval aviators and technicians, the navy dispatched three officers to Hammondsport and two to France for training and instruction. After their return to Japan at the end of 1912, two of the newly trained naval aviators made the first flights at Oppama on Yokosuka Bay, one in a Curtiss seaplane, the other in a Maurice Farman. In 1912, the Royal Navy had informally established its own flying branch, the Royal Naval Air Service; the Japanese admirals, whose own Navy had been modeled on the Royal Navy and whom they admired, themselves proposed their own Naval Air Service. The Japanese Navy had observed technical developments in other countries and saw that the airplane had potential.
Within a year, the Imperial Japanese navy had begun the operational use of aircraft. In 1913, the following year, a Navy transport ship, Wakamiya Maru was converted into a seaplane carrier capable of carrying two assembled and two disassembled seaplanes. Wakamiya participated in the naval maneuvers off Sasebo, Japan that year. On 23 August 1914, as a result of its treaty with Great Britain, the Empire of Japan declared war on the German Empire; the Japanese, together with a token British force, blockaded laid siege to the German colony of Kiaochow and its administrative capital Tsingtao on the Shandong peninsula. During the siege, starting from September, four Maurice Farman seaplanes on board Wakamiya conducted reconnaissance and aerial bombardments on German positions and ships; the aircraft had crude bombsights and carried six to ten bombs, converted from shells, were released through metal tubes on each side of the cockpit. On 5 September, during the first successful operation, two Farman seaplanes dropped several bombs on the Bismarck battery, the main German fortifications in Tsingtao.
The bombs landed harmlessly in the mud, but the aircraft were able to confirm that SMS Emden was not at Tsingtao, this was intelligence of major importance to Allied naval command. On 30 September Wakamiya was damaged by a mine and sent back to Japan for repairs, but the seaplanes, by transferring on to the shore, continued to be used against the German defenders until their surrender on 7 November 1914. Wakamiya conducted the world's first naval-launched aerial raids in history and was in effect the first aircraft carrier of the Imperial Japanese Navy. By the end of the siege the aircraft had conducted 50 sorties and dropped 200 bombs, although damage to German defenses was light. In 1916, the Commission on Naval Aeronautical Research was disbanded and the funds supporting it were reallocated for the establishment of three naval air units which would fall under the authority of the Naval Affairs Bureau of the Navy Ministry; the first unit was established at Yokosuka in April 1916, the lack of a specific naval air policy in these early years was made apparent by the fact that the Yokosuka Air Group operated with the fleet only once a year when it was transported to whatever training area the IJN was using for maneuvers.
Japanese naval aviation, continued to make progres
Blowback is a system of operation for self-loading firearms that obtains energy from the motion of the cartridge case as it is pushed to the rear by expanding gas created by the ignition of the propellant charge. Several blowback systems exist within this broad principle of operation, each distinguished by the methods used to control bolt movement. In most actions that use blowback operation, the breech is not locked mechanically at the time of firing: the inertia of the bolt and recoil spring, relative to the weight of the bullet, delay opening of the breech until the bullet has left the barrel. A few locked breech designs use a form of blowback to perform the unlocking function; the blowback principle may be considered a simplified form of gas operation, since the cartridge case behaves like a piston driven by the powder gases. Other operating principles for self-loading firearms include blow forward, gas operation, recoil operation; the blowback system is defined as an operating system in which energy to operate the firearm's various mechanisms and provide automation is derived from the movement of the spent cartridge case pushed out of the chamber by expanding powder gases.
This rearward thrust, imparted against the breech, is a direct result of the expansion of propellant gases. Certain guns will use energy from blowback to perform the entire operating cycle while others will use a portion of the blowback to operate only certain parts of the cycle or use the blowback energy to enhance the operational energy from another system of automatic operation. What is common to all blowback systems is that the cartridge case must move under the direct action of the powder pressure, therefore any gun in which the bolt is not rigidly locked and permitted to move while there remains powder pressure in the chamber will undergo a degree of blowback action; the energy from the expansion of gases on firing appears in the form of kinetic energy transmitted to the bolt mechanism, controlled and used to operate the firearm's operation cycle. The extent to which blowback is employed depends on the manner used to control the movement of the bolt and the proportion of energy drawn from other systems of operation.
How the movement of the bolt is controlled is where blowback systems differ. Blowback operation is most divided into three categories, all using residual pressure to complete the cycle of operation: simple blowback, delayed/retarded blowback, advanced primer ignition. Relating blowback to other types of automatic firearm operation, George M. Chinn wrote that: "In the larger sense, blowback might well be considered a special form of gas operation; this is reasonable because the cartridge case may be conceived of as a sort of piston driven by the powder gases. Blowback involves so many special problems that it is best considered to be in a class by itself; the question whether or not it should be included within the more general class of gas operation or recoil operation is purely academic. The important point is that it partakes some of the properties of both classes and, depending on the particular problem at hand, may be considered to be either one." The blowback system represents the most basic auto loading operation type.
In a blowback mechanism, the bolt is not locked in place. At the point of ignition, expanding gases push the bullet forward through the barrel while at the same time pushing the case rearward against the bolt; the expanding gases push the bolt assembly to the rear, but the motion is slowed by the mass of the bolt, internal friction, the force required to compress the action spring. The design must ensure that the delay is long enough that the bullet exits the barrel before the cartridge case clears the chamber; the empty case is ejected. The stored energy of the compressed action spring drives the bolt forward. A new cartridge is stripped from the magazine and chambered as the bolt returns to its in-battery position; the blowback system is practical for firearms using low-power cartridges with lighter weight bullets. Higher power cartridges require heavier bolts to keep the breech from opening prematurely. For an extreme example, a 20mm cannon using simple blowback and lubricated cartridges would need a 500-pound bolt to keep the cartridge safely in the barrel during the first few milliseconds.
The return spring is not powerful enough to keep the bolt closed when the gun is tilted up. In addition, there is not enough energy stored in the bolt to cycle the weapon. Due to the required bolt weight, blowback designs in pistols are limited to calibers smaller than 9×19mm Parabellum There are exceptions such as the simple blowback pistols from Hi-Point Firearms which include models chambered in.45 ACP.40 S&W.380 ACP and 9×19mm Parabellum. Simple blowback operation can be found in small-bore semi-automatic rifles and submachine guns. Most simple blowback rifles are chambered for the.22 Long Rifle cartridge. Popular examples include the Marlin Model 60 and the Ruger 10/22. Most blowback carbines and submachine guns are chambered for pistol cartridges such as the 9×19mm Parabellum.40 S&W and.45 ACP. Ex