Kingdom of Romania
The Kingdom of Romania was a constitutional monarchy at the crossroads of Central and Southeastern Europe. It existed from 1881, when prince Karl of Hohenzollern-Sigmaringen was crowned as King Carol I of Romania, until 1947, when King Michael I of Romania abdicated and the Romanian parliament proclaimed Romania a socialist republic. From 1859 to 1877, Romania evolved from a personal union of two vassal principalities under a single prince to an autonomous principality with a Hohenzollern monarchy; the country gained its independence from the Ottoman Empire during the 1877–1878 Russo-Turkish War, when it received Northern Dobruja in exchange for the southern part of Bessarabia. The kingdom's territory during the reign of King Carol I, between 14 March 1881 and 27 September 1914 is sometimes referred as the Romanian Old Kingdom, to distinguish it from "Greater Romania", which included the provinces that became part of the state after World War I. With the exception of the southern halves of Bukovina and Transylvania, these territories were ceded to neighboring countries in 1940, under the pressure of Nazi Germany or the Soviet Union.
Following a disastrous World War II campaign on the side of the Axis powers and name change, Romania joined the Allies in 1944, recovering Northern Transylvania. The influence of the neighboring Soviet Union and the policies followed by Communist-dominated coalition governments led to the abolition of the monarchy, with Romania becoming a People's Republic on the last day of 1947; the 1859 ascendancy of Alexandru Ioan Cuza as prince of both Moldavia and Wallachia under the nominal suzerainty of the Ottoman Empire united an identifiably Romanian nation under a single ruler. On 5 February 1862 the two principalities were formally united to form the Principality of Romania, with Bucharest as its capital. On 23 February 1866 a so-called Monstrous coalition, composed of Conservatives and radical Liberals, forced Cuza to abdicate; the German prince Charles of Hohenzollern-Sigmaringen was appointed as Prince of Romania, in a move to assure German backing to unity and future independence. He adopted the Romanian spelling of his name and his descendants would rule Romania until the overthrow of the monarchy in 1947.
Following the Russo-Turkish War of 1877–1878, Romania was recognized as an independent state by the Treaty of Berlin, 1878 and acquired Dobruja, although it was forced to surrender southern Bessarabia to Russia. On 15 March 1881, as an assertion of full sovereignty, the Romanian parliament raised the country to the status of a kingdom, Carol was crowned as king on 10 May; the new state, squeezed between the Ottoman, Austro-Hungarian, Russian Empires, with Slavic populations on its southwestern and northeastern borders, the Black Sea due east, Hungarian neighbors on its western and northwestern borders, looked to the West France, for its cultural and administrative models. Abstaining from the Initial Balkan War against the Ottoman Empire, the Kingdom of Romania entered the Second Balkan War in June 1913 against the Tsardom of Bulgaria. 330,000 Romanian troops moved into Bulgaria. One army occupied Southern Dobrudja and another moved into northern Bulgaria to threaten Sofia, helping to bring an end to the war.
Romania thus acquired the ethnically-mixed territory of Southern Dobrudja, which it had desired for years. In 1916 Romania entered World War I on the Entente side. Romania engaged in a conflict against Bulgaria but as a result Bulgarian forces, after a series of successful battles, regained Dobruja, ceded from Bulgaria by the treaty of Bucharest and the Berlin congress. Although the Romanian forces did not fare well militarily, by the end of the war the Austrian and Russian empires were gone; the Romanian Old Kingdom is a colloquial term referring to the territory covered by the first independent Romanian nation state, composed of the Danubian Principalities — Wallachia and Moldavia. It was achieved when, under the auspices of the Treaty of Paris, the ad hoc Divans of both countries - which were under Imperial Ottoman suzerainty at the time - voted for Alexander Ioan Cuza as their prince, thus achieving a de facto unification; the region itself is defined by the result of that political act, followed by the inclusion of Northern Dobruja in 1878, the proclamation of the Kingdom of Romania in 1881, the annexation of Southern Dobruja in 1913.
The term came into use after World War I, when the Old Kingdom was opposed to Greater Romania, which included Transylvania, Banat and Bukovina. Nowadays, the term has a historical relevance, is otherwise used as a common term for all regions in Romania included in both the Old Kingdom and present-day borders. Romania delayed in entering World War I, but declared war on the Central Powers in 1916; the Romanian military campaign ended in stalemate when the Central Powers crushed the country's offensive into Transylvania and occupied Wallachia and Dobruja, including Bucharest and the strategically important oil fields, by the end of 1916. In 1917, despite fierce Romanian resistance at Mărăşeşti, due to Russia's withdrawal from the war following the October Revolu
A Kégresse track is a kind of rubber or canvas continuous track which uses a flexible belt rather than interlocking metal segments. It can be fitted to a conventional car or truck to turn it into a half-track, suitable for use over rough or soft ground. Conventional front wheels and steering are used, although skis may be fitted. A snowmobile is a smaller ski-only type; the Kégresse propulsion and suspension system incorporates an articulated bogie, fitted to the rear of the vehicle with a large drive wheel at one end, a large unpowered idler wheel at the other and several small guide wheels in between, over which run a reinforced flexible belt. The belt is fitted with rubber treads to grip the ground, it differs from conventional track systems by using a flexible belt rather than interlocking metal segments. The name comes from the system's inventor Adolphe Kégresse, who designed the original while working for Tsar Nicholas II of Russia between 1906 and 1916, he applied it to several cars in the Royal garage including Packard trucks.
The Russian army fitted the system to a number of their Austin Armoured Cars. After the Russian Revolution Adolphe Kégresse returned to his native country, where the system was used on Citroën cars between 1921 and 1937 for off-road and military vehicles. A series of Expeditions across the undeveloped parts of Asia and Africa was undertaken by Citroën, demonstrating the all-terrain capabilities of these vehicles. In World War II, both sides used this system in the war effort. In the 1920s, the U. S. Army purchased several Citroën-Kégresse vehicles for evaluation followed by a licence to produce them; this resulted in the Army Ordnance Department building a prototype in 1939. In December 1942, it went into production with the M2 Half Track M3 Half-track versions; the Nazi's captured many of these Citroën half-track vehicles and armored them for their own use. An 30cwt armored personnel carrier called "Burford-Kegress" was built by the British firm Burford produced on the basis of its four-axle trucks with wheel formula 4 × 2: It was equipped with Rear Axle mover Kegresse tracks produced under license from the French company Citroën.
Released in 1926 prototype machine has passed trials, the results of, positively received by the military, in the same year Burford commissioned by the British Army to build a small batch. Despite the success of the test, as a result of continuous operation it was discovered that the Kegresse had an low wear resistance, broke down; as a result, in 1929, only three years after its creation, the machines were taken out of service and scrapped. Citroën-Kegresse vehicles served in the Polish motorized artillery during the 1930s. In addition the Polish produced their own Kegresse track trucks called the "Półgąsienicowy 34" or better known as C4P was a Polish half-track derived from the 4.5-ton Polski Fiat 621 truck, produced under license since 1932. This vehicle was designed by the BiRZ Badań Technicznych Broni Pancernych - Warsaw Armored Weapons and Technical Research Bureau in 1934. For the construction several parts of the Fiat 621 truck Were used, some were modified or upgraded The short reinforced chassis was retained, the engine and the cab received some modifications The front axle was reinforced to integrate the 4x4 transmission.
The rear axle was replaced with a small track, as on the Citroën Kégresse P14 / P17 / P19 and the Vickers E. The tests and adjustments were carried out in 1935 and production began in 1936 in the factory of the state company Państwowe Zakłady Inżynierii in Warsaw. During the production, the model received other modifications were made by the manufacturer and engineering office PZInz. Between 1936 and the beginning of the war, more than 400 vehicles were produced in different versions; the exact number is unknown. At least 80 C4P artillery tractors have been accounted for; the FN-Kégresse 3T was a half-track vehicle used by the Belgian armed forces as an artillery tractor between 1934-1940. 130 FN Kégresse 3T's were built, with some 100 in use with the Belgian armed forces on 10 May 1940, the start of the battle of Belgium. In the late 1920s the U. S. Army purchased several Citroën-Kégresse vehicles for evaluation followed by a licence to produce them; this resulted in the Army Ordnance Department building a prototype in 1939.
In December 1942 it went into production with the M3 half-track versions. The United States produced more than 41,000 vehicles in over 70 versions between 1940 and 1944. Alfred Becker AMC Schneider P 16 SOMUA MCG Citroën-Kegresse halftracks in the Polish Army Informationen über Leben und Werk von Adolphe Kégresse Register of Kegresse Track vehicles
Torsion bar suspension
A torsion bar suspension known as a torsion spring suspension, is any vehicle suspension that uses a torsion bar as its main weight-bearing spring. One end of a long metal bar is attached to the vehicle chassis. Vertical motion of the wheel causes the bar to twist around its axis and is resisted by the bar's torsion resistance; the effective spring rate of the bar is determined by its length, cross section, shape and manufacturing process. Torsion bar suspensions are used on combat vehicles and tanks like the T-72, Leopard 1, Leopard 2, M26 Pershing, M18 Hellcat, the M1 Abrams, on modern trucks and SUVs from Ford, Chrysler, GM, Mazda, Nissan and Toyota. Manufacturers change the torsion bar or key to adjust the ride height to compensate for engine weight. While the ride height may be adjusted by turning the adjuster bolts on the stock torsion key, rotating the stock key too far can bend the adjusting bolt and place the shock piston outside its standard travel. Over-rotating the torsion bars can cause the suspension to hit the bump-stop prematurely, causing a harsh ride.
Aftermarket forged-metal torsion key kits use relocked adjuster keys to prevent over-rotation, shock brackets to keep the piston travel in the stock range. The main advantages of a torsion bar suspension are soft ride due to elasticity of the bar, easy adjustability of ride height, small profile along the width of the vehicle, it takes up less of the vehicle's interior volume than coil springs. Torsion bars reached the height of their popularity on mass-production road cars in the middle of the 20th century at the same time that unitary construction was being adopted. At a time when the mechanics of stress and metal fatigue in monocoque body frames was poorly understood, torsion bars were attractive to vehicle designers as the bars could be mounted to reinforced parts of the central structure the bulkhead. Using MacPherson struts to achieve independent front suspension with coil springs meant providing strong turrets in the frontal structure of the car. A disadvantage is that torsion bars, unlike coil springs cannot provide a progressive spring rate.
In most torsion bar systems, ride height may be changed by adjusting bolts that connect the torsion bars to the steering knuckles. In most cars with this type of suspension, swapping torsion bars for a different spring rate is an easy task. Longitudinal torsion bars extend under the passenger compartment, cutting into interior space by raising the floor, while in transverse systems, torsion bar length is limited by vehicle width; some vehicles use torsion bars to provide automatic levelling, using a motor to pre-stress the bars to provide greater resistance to load and, in some cases, to respond to changes in road conditions. Height adjustable suspension has been used to implement a wheel-change mode where the vehicle is raised on three wheels so that the remaining wheel is lifted off the ground without the aid of a jack. Before World War II, the front wheel drive Citroen Traction Avant had independent front torsion bar suspension and a flexible trailing dead axle sprung by torsion bars; the flexibility of the axle beam provided wheel location features like a twist beam axle.
In the 1930s, prototypes of the first Volkswagen Beetle incorporated torsion bars—especially their transverse mounting style. Czechoslovakian Tatra's 1948 T600 Tatraplan employed rear torsion bar suspension, the only Tatra to do so; the system first saw military use in the Swedish Stridsvagn L-60 tank of 1934. It was used extensively in European cars like Renault, Citroën and Volkswagen, as well as by Packard in the 1950s; the Packard used torsion bars at both front and rear, interconnected the front and rear systems to improve ride quality. Morris Minor and Oxford from the late 1940s onwards used a front torsion bar system similar to the Citroen, as did the Riley RM models; the revolutionary Jaguar E-Type introduced in 1961 had a torsion bar front suspension similar to the Citroen and Morris Minor, an independent coil spring rear suspension using four shock absorbers with concentric springs. An early application of a torsion bar in an American car was by Hudson Motor Car Company of Detroit who had introduced the innovative front axle flex suspension in 1934 Hudson and Terraplane cars and realized for 1935 that a transverse torsion bar linked to the rear axle was needed as an anti-roll bar to stabilize the cars.
The single torsion bar was mounted through the frame sides behind the rear axle and attached by arms and links to the front side of the spring U-bolt plates. Axle flex was discontinued for the 1936 model year. Post-war the use of torsion bar front suspension was a defining feature of British Morris cars, starting with the Morris Minor of 1948, its larger Morris Oxford MO counterpart and the upmarket Morris Six MS, plus the Wolseley-badged upmarket variants of the latter two models; the designer of these cars, Alec Issigonis, was inspired by the Traction Avant's suspension, although the Morris cars were rear-wheel drive and used conventional leaf springs for their rear axles. The Minor used lever arm dampers with its torsion bars while the Oxford and the Six used innovative telescopic dampers; the Minor remained in production unchanged until 1972 and was replaced by the Morris Marina which used the torsion bar-lever arm damper system for its front suspension—one of the last new cars worldwide to be intro
M2 half-track car
The M2 half-track car is an armored half-track produced by the United States during World War II. Its design drew upon half-tracks imported from France in the 1930s, employing standard components supplied by U. S. truck manufacturers to reduce costs. The concept was designed, the pilot models manufactured by the Firestone Tire and Rubber Company Production by the White Motor Company began in 1940 and was expanded to include Autocar; the M2 was intended for use as an artillery tractor, but found use with reconnaissance units. International Harvester Company built the M9 half-track, a variant of their M5 half track, to fulfill the same purpose; the half-track design had been evaluated by the US ordnance department using Citroën-Kégresse vehicles. The cavalry branch of the US Army found that their wheeled armored scout cars had trouble in wet terrain due to their high ground pressure. In 1938, the White Motor Company took the Timken rear bogie assembly from a T9 half-track truck and added it to an M3 scout car, creating the T7 half-track car.
This vehicle was underpowered. When a further requirement came down from US Army artillery units in 1939 for a prime mover to be used as an artillery tractor, a vehicle with an uprated engine was developed, designated the half-track scout car T14. By 1940, the vehicle had been standardized as the M2 half-track car; the M2 design was recognized as having the potential for general mechanized infantry use, which spawned the larger bodied M3 half-track. Both the M2 and M3 were ordered into production in late 1940, with M2 contracts let to Autocar and Diamond T; the first vehicles were received by the Army in 1941. The M2 was supplied to artillery units as the prime mover and ammunition carrier for the 105mm howitzer, to armored infantry units for carrying machine gun squads, it was issued to armored reconnaissance units as an interim solution until more specialized vehicles could be fielded. Between 1942 and 1943, both the M2 and M3 would receive a number of modifications to the drive train and stowage, among other things.
Total production of M2 and derivatives by White was about 13,500 units. To meet the needs of Lend-Lease to the Allies, the International Harvester Company produced 3,500 units of the M9; the M9 was the same as the IH-produced M5 but with different internal stowage and apart from using IH mechanical components the M9 was longer than the M2. The first M2s were fielded in 1941, would be used in the Philippines, North Africa, Europe by the U. S. Army, around the Pacific by the marines. About 800 M2 and M9 half-tracks were sent to the Soviet Union. Many remaining vehicles destined for Lend-Lease were transferred to other U. S. allies in South America. These vehicles received a number of upgrades designed at extending service life. Nicaragua's national guard received 10 M2s in 1942, which saw heavy action during the 1978-79 Nicaraguan Revolution; the Argentine Army donated them to Bolivia. In 1947, the Finnish heavy vehicle producer Vanajan Autotehdas bought 425 M2 half-track vehicles from the Western Allied surplus stocks located in France and Germany.
The vehicles were delivered without armor. Some 359 units were converted into field and forest clearing vehicles, some were scrapped for parts and 60 units were equipped with conventional rear axles and converted into 4×4 or 4×2 trucks, they were badged as Vanaja VaWh. The last units were sold in 1952. Argentina Belgium Brazil Cambodia Chile Czechoslovakia Finland France - used during the First Indochina War Greece Mexico Netherlands Nicaragua – 10 M2s in service with the National Guard of Nicaragua in 1979. Paraguay – 23 still in service. Philippines Poland Portugal South Vietnam Soviet Union United Kingdom United States M2 - White half-track with White 160AX engine. Fitted with a skate rail mount. M9 - International Harvester built half-track, developed to complement the M2 for Lend-Lease, but did not feature the short hull of the M2, it did not feature the rear access doors, is outwardly similar to the M5, but with a different internal configuration. M9A1 - The M2A1, an M9 with the M49 machine gun mount.
The M9A1 had a rear door. M2E6/M2A1 - Any vehicle with the improved M49 machine gun ring mount over the right hand front seat. Three fixed pintle mounts for 0.30 machine guns were fitted at the unit level in the field. M4/M4A1 81mm MMC - M2 based motor mortar carriage equipped with the 81 mm M1 mortar; the mortar was intended to be fired dismounted from the vehicle, but could be fired in an emergency to the rear from a base inside the vehicle. The A1 modification allowed the weapon to be fired from within the vehicle. M2 w/ M3 37 mm - Mechanized infantry units in the US Army were supposed to receive the M6 gun motor carriage, based on Dodge light trucks. With the overall failure in combat of these vehicles, some units removed the M3 37 mm guns and their assemblies and mounted them on M2 half-track cars. T1E1 - M2 based mobile anti-aircraft gun featuring an open rear with a Bendix mount featuring two.50 inch M2 machine guns. The Bendix mount proved to be unsatisfactory. Prototype only. T1E2 - T1 with Maxson M33 mount in the place of the Bendix mount.
The M33 mount featured two.50 inch M2 machine guns. Would be developed into the M3 based T1E4. T1E3 - T1 fitted with a partial hard top and a Martin turret, identical to that used on the Boeing B-17 Flying Fortress. Proved to be overcomplicated and was ill-suited to the space available in the M2. Prototype only. T28 CGMC - M2 based combination gun motor carriage with a single 37 mm Gun M1A2 autocannon flanked by two.50 i
2.8 cm sPzB 41
2.8 cm schwere Panzerbüchse 41 or "Panzerbüchse 41" was a German anti-tank weapon working on the squeeze bore principle. Classified as a heavy anti-tank rifle, it would be better described, is referred to, as a light anti-tank gun. Although the sPzB 41 was classified as a heavy anti-tank rifle, its construction was much more typical of an anti-tank gun. Like the latter, it had a recoil mechanism and shield; the only significant feature the weapon had in common with anti-tank rifles was a lack of elevation and traverse mechanisms—the light barrel could be manipulated manually. The design was based on a tapering barrel, with the caliber reducing from 28 mm at the chamber end to only 20 mm at the muzzle; the projectile carried two external flanges. The barrel construction resulted in a high muzzle velocity - up to 1,400 m/s; the bore was fitted with a muzzle brake. The horizontal sliding breech block was "quarter-automatic": it closed automatically once a shell was loaded; the gun was equipped with an open sight for distances up to 500m.
The recoil system consisted of spring-driven recuperator. The carriage was with suspension. Wheels with rubber tires could be removed, making the gun lower and therefore easier to conceal; the guns' construction allowed toolless dismantling to five pieces, the heaviest of which weighed 62 kg. The cone-bore principle was first patented in 1903 by Karl Puff. In the 1920s and 1930s, another German engineer, conducted experiments with coned-bore barrels that resulted in an experimental 7 mm anti-tank rifle with a muzzle velocity of 1,800 m/s. Based on these works, Mauser-Werke AG developed a 28/20 mm anti-tank weapon designated Gerät 231 or MK.8202 in 1939–1940. In June–July 1940, an experimental batch of 94 pieces was given to the army for trials, they resulted in some modifications and in 1941 mass production of what became 2.8 cm schwere Panzerbüchse 41 started. One piece cost 4,520 Reichsmarks; the last gun was built in 1943. The sPzB 41 was used by some motorized divisions and by some Jäger, Gebirgsjäger and Fallschirmjäger units.
Some guns were supplied to sapper units. The weapon was employed on the Eastern Front from the beginning of hostilities, until the end of the war and saw combat in the North African Campaign and on the Western Front in 1944–45. 2.8 cm sPzB 41 leFl 41: a variant developed for paratrooper units. It used a lightweight carriage without suspension; the resulting weapon weighed only 139 kg. The carriage supported a 360° field of fire, elevation ranged from -15° to 25°. 2.8 cm KwK 42: tank gun modification intended for the VK 903 turret. A Versuchs-Serie of twenty-four were produced, of which ten were reported as available for the VK 903 project on July 1, 1942. A total of 200 guns were ordered, though there is no evidence to show these were completed, nor is there evidence showing this weapon was actually mounted in a turret; the sPzB 41 was mounted on several vehicles, such as cars, half-tracks and armored cars: Sd. Kfz. 221 armored cars. Kfz. 250/11 half-tracks. Kfz. 251 half-tracks. Squeeze bore guns saw only limited use in World War II.
Manufacturing such weapons was impossible without advanced technologies and high production standards. Besides Germany, the only country to bring such weapons to mass production was Britain, with the Littlejohn adaptor which, although not a gun in itself, used the same principle. An attempt by a Soviet design bureau headed by V. G. Grabin in 1940, failed because of technological problems. In the US, reports about the sPzB 41 inspired a series of experiments with 28/20 barrels and taper bore adaptors for the 37 mm Gun M3; the sPzB 41 combined good anti-armor performance at short range and a high rate of fire with small, dismantleable construction. However, it had several shortcomings, such as: The barrel was hard to manufacture and had a short service life It had a weak fragmentation shell Its use of tungsten for armor-piercing shells Its short effective range Its weak behind armour effectSome authors that criticize the sPzB 41 concentrate on the short service life of its barrel. However, its chance of survival after 500 short-range shots was slim anyway.
It should be noted that high-velocity guns with "normal" barrel construction had a short service life, e.g. for the Soviet 57-mm ZiS-2 it was about 1,000 shots. In the end, the factor that brought production of the sPzB 41 to a halt was the shortage of tungsten. There were two shell types for the sPzB 41: the armor-piercing 2.8 cm Pzgr.41 and the fragmentation 2.8 cm Sprg.41. The Pzgr.41 had a tung
Armoured personnel carrier
An armoured personnel carrier is a broad type of armoured, military vehicles designed to transport personnel and equipment in combat zones. They are sometimes referred to colloquially as'battle taxis' or'battle buses'. Since World War I, APCs have become a common piece of military equipment around the world. According to the definition in the Treaty on Conventional Armed Forces in Europe, an APC is "an armoured combat vehicle, designed and equipped to transport a combat infantry squad and which, as a rule, is armed with an integral or organic weapon of less than 20 millimetres calibre." APCs have less armament than other Armoured Fighting Vehicles which are designed to participate directly in combat. The American M113 and the Soviet BTR-60 are iconic examples; the genesis of the armoured personnel carrier was on the Western Front of World War I. In the stage of the war, Allied tanks could break through enemy lines, but the infantry following—who were needed to consolidate the gains—still faced small arms and artillery fire.
Without infantry support, the tanks were isolated and more destroyed. In response, the British experimented with carrying machine-gun crews in the Mark V* tank, but it was found that the conditions inside the tanks rendered the men unfit for combat. Britain therefore designed the first purpose-built armoured troop transport, the Mark IX, but the war ended before it could be put to use. During World War II, half-tracks like the American German Sd. Kfz. 251 played a role similar to post-war APCs. British Commonwealth forces relied on the full-tracked Universal Carrier. Over the course of the war, APCs evolved from simple armoured cars with transport capacity, to purpose-built vehicles. Obsolete armoured vehicles were repurposed as APCs, such as the various "Kangaroos" converted from M7 Priest self-propelled guns and from Churchill, M3 Stuart and Ram tanks. During the Cold War, more specialized APCs were developed; the United States introduced a series of them, including successors to the wartime Landing Vehicle Tracked.
Western nations have since retired most M113s, replacing them with newer APCs, many of these wheeled. The Soviet Union produced the BTR-152, BTR-60, BTR-70, BTR-80 in large numbers. Czechoslovakia and Poland together developed the universal amphibious OT-64 SKOT. A cold war example of a "Kangaroo" is the armoured Israeli Achzarit, converted from captured T-55s tanks. By convention, they are not intended to take part in direct-fire battle, but are armed for self-defence and armoured to provide protection from shrapnel and small arms fire. An APC is either wheeled or tracked, or a combination of the two, as in a half-track. Wheeled vehicles are faster on road and less expensive, however have higher ground pressure which decreases mobility offroad and makes them more to become stuck in soft terrains such as mud, snow or sand. Tracked vehicles have lower ground pressure and more maneuverability off road. Due to the limited service life of their treads, the wear they cause on roads, tracked vehicles are transported over long distances by rail or trucks.
Many APCs are amphibious. To move in water they will have propellers or water jets, or be propelled by their tracks. Preparing the APC to operate amphibiously comprises checking the integrity of the hull and folding down a trim vane in front. Water traverse speed varies between vehicles and is much less than ground speed; the maximum swim speed of the M113 is 3.8 mph, about 10% its road speed, the AAVP-7 can swim at 8.2 mph. Armoured personnel carriers are designed to protect against small arms and artillery fire; some designs have more protection. Armour is composed of steel or aluminium, they will use bulletproof glass. Many APCs are equipped with CBRN protection, intended to provide protection from weapons of mass destruction like poison gas and radioactive/nuclear weapons. APCs will be lighter and less armoured than tanks or IFVs being open topped and featuring doors and windows, as seen in the French VAB. Armoured personnel carriers are designed for transport and are armed, they may be unarmed, or armed with some combination of light, heavy machine guns, or automatic grenade launchers.
In Western nations, APCs are armed with the 50 calibre M2 Browning machine gun, 7.62mm FN MAG, or 40mm Mk 19 grenade launcher. In former Eastern bloc nations, the KPV, PKT and NSV machine guns are common options. In'open top' mounts the gunner sticks out of the vehicle and operates a gun on a pintle or ring mount. A ring mount allows the gun to traverse 360 degrees, a pintle mount, it can be preferable to an enclosed gunner because it allows a greater field of view and communication using shouts and hand signals. However, the gunner is poorly at risk of injury in the event of vehicle rollover. During the Vietnam War, M113 gunners suffered heavy casualties. Enclosed vehicles are equipped with turrets that allow the crew to operate the weapons system while protected by the vehicle's armour; the Soviet BTR-60 has an enclosed turret mounted with a KPV heavy machine gun with a PKT coaxial machine gun. The American AAVP machine gun in a enclosed turrets; the AAVP7 mounts a Mk 19 grenade launcher in a turret.
Turrets have optics which make them more accurate. More APCs have been equipped remote weapon systems; the baseline Stryker carries an M2 on a Protector remote weapons
Sturmgeschütz meaning "assault gun" was a series of armored vehicles used by both the German Wehrmacht and the Waffen-SS armored formations during the Second World War that consisted of the StuG III and StuG IV. The more common of the two, the StuG III, was built on the chassis of the proven Panzer III; the StuG III was designated "StuG" but with the creation of the StuG IV it was re-designated the "StuG III" to distinguish the two. They were intended as mobile, armored gun platforms, providing close fire support to the infantry to destroy bunkers and other entrenched positions; as the war progressed, a number of aspects of the StuG series made them a valued supplement to the Panzer forces. Following the invasion of the Soviet Union in 1941, a significant problem developed when it was discovered that the main armament on the Panzer II and III tanks were inadequate to deal with the newer Soviet T-34 and KV-1 tanks; the main German anti-tank gun, the 37 mm Pak 36 proved unable to penetrate the armor of these Soviet designs.
A more powerful gun, the 75 mm Pak 40, was being developed, but it didn't fit in the turret of the Panzer III, Germany's main battle tank. It was found, that the turretless StuGs had enough room in the crew compartment to handle the 75 mm Pak 40, this modification was made; the new vehicle proved to be an effective tank destroyer. Not only was its main gun powerful enough to knock out the new Soviet tanks, but the Panzer III chassis on which it was based was mobile and reliable, the increased armor plating combined with its low silhouette made it a difficult vehicle to destroy; the StuG III became Nazi Germany's most produced armored fighting vehicle during World War II, with some 10,000 examples produced. The StuG was used within the Sturmartillerie, a branch of the artillery in the Wehrmacht. Following the defeat of the German Empire in World War I, military commanders from the Reichswehr began to consider how mobile armored artillery units could provide support to advancing infantry units.
Colonel Erich von Manstein recommended the concept of infantry Begleitbatterien to General Beck, chief of the general staff in 1935. Manstein theorized the vehicle would not be used as one uses a tank, but rather as an infantry support vehicle to destroy fortified objectives through direct fire, its mission was to destroy pill boxes, machine gun emplacements and tanks. It was not intended to be used to exploit breakthroughs and drive into the enemy rear areas, as the Panzertruppen units were intended to do. Daimler-Benz AG was given the order to develop and produce such a weapon on June 15, 1936, they created five prototypes, based on the chassis of the Panzer III, which were not useful for combat operations but did prove valuable for training. The first production units, the Sturmgeschütz III Ausf A, arrived in 1940 mounted with the 75 mm StuK 37L/24 gun and increased frontal hull armor; the main armament, which had a limited lateral traverse, was mounted directly in a casemate-style hull. This created the lowest possible profile in order to reduce the vehicle's height, making the StuG more difficult to hit and easier to protect in hull defilade.
During 1942 and 1943, the StuG was one of the most effective tracked vehicles of World War II, as shown in terms of opposition vehicles destroyed. Over 10,000 StuGs were produced; the inability to traverse the gun at times became a significant weakness, the lack of an internal light machine gun in the initial models left the StuG vulnerable to close-range infantry attack. A machine gun and shield were added to versions; the omission of a regular tank turret made for simpler and more cost-effective production, enabling greater numbers to be built. However, the lack of a traverse movement in the gun meant the entire vehicle had to be turned left or right to acquire targets, thus the StuG was more successful in defensive roles, such as ambush, rather than as an offensive vehicle. In November 1943, GmbH, a major StuG III manufacturer, was bombed as part of the RAF campaign against Berlin, Alkett's StuG production declined from 255 StuG IIIs in October 1943, to just 24 vehicles in December. In a December 1943 conference, Hitler welcomed the suggestion of taking the StuG III superstructure and mounting it on a Panzer IV chassis to offset the loss of production of the StuG III.
This restarted the Sturmgeschütz IV project, which had earlier been rejected. The superstructure of the StuG III Ausf. G was mounted on a Panzer IV chassis 7; the Krupp plant, which did not produce Panzer IIIs, used the Panzer IV chassis with a modified StuG III superstructure, with a box compartment for the driver added. Combat weight was lighter than the 23.9 tonnes for the StuG III Ausf. G. On December 16–17, 1943, Hitler was shown the StuG IV, approved it. To make up for the large deficit in StuG III production, StuG IV production received full support; because of the decreased costs and ease of production, the Germans began to use the StuGs to replace standard tank losses. They were used in this fashion as German losses of all types of armored vehicles now exceeded production; the StuGs proved effective in a defensive role, but were a poor substitute for conventional tanks offensively. Thus the panzer regiments continued to be equipped with Panzer IV and Panther medium tanks for offensive operations.
Meanwhile, heavier armed tank destroyers were developed, such as the Jagdpanzer IV and the Jagdpanther, which combined the low silhouette of the StuG with the heavier armament of the Panther and Tiger II tanks, respectively. Still, the StuG III was an effective armored fighting vehicle long after the Panzer III had been retired as a main battle tank. A n