P40 tank
Encyclopedia
The P40 was an Italian World War II
tank
design. It was armed with a 75 mm gun and an 8 mm Breda machine gun, plus another optional machine gun in an anti-aircraft
mount. The official Italian designation was Carro Armato ("armored tank
") P 26/40. The designation means: P for pesante (Italian
: "heavy"), the weight of 26 tons, and the year of adoption 1940.
Design had started in 1940 but very few had been built by the time Italy signed the armistice with the Allies and the few produced afterwards were used by the Germans.
was not completed until 1942. The initial plan was for a 25 tonne
tank with a 75 mm gun and to be named P26. The development work proceeded quickly except for the engine; the Italian military staff, the Stato Maggiore, wanted a diesel
power-plant, while the builders favoured a petrol engine
.
However, in Italy at the time there were no engines (diesel or petrol) available capable of developing the 300 hp required, and the Italian tank industry (i.e. the duopoly Fiat
-Ansaldo) did not turn to easily available aircraft engines for its tanks as the contemporary U.S. and British tank manufacturers had done. The design of a new engine was very slow and in the end a 420 hp petrol engine was eventually tested.
The design of the P40 was originally similar to tanks such as the M11/39
, but with a bigger gun and more armour
. After learning about Soviet T-34
s in 1941, the armour of the P40 was quickly re-designed, adopting more markedly sloped plates, and the new gun was adopted. The gun designation "75/34" referred to a 75 mm bore diameter gun with a length equal to 34 calibres. It was used in lieu of the 75/18 gun, with a shorter barrel of only 18 calibres. The main role of the P40 shifted from infantry support to anti-tank warfare
, and all the internal space was dedicated to this end, making the vehicle rather cramped.
.
of around 700 m/s. The main gun was normally provided with around 65 cartridge
s.
One shift in the design was the number of machine-guns which was much lower than on the "M" series. The P40 originally fielded three machine guns, but one was removed along with the deletion of the frontal, dual barbette
machine gun mount. The standard ammunition load was lower, only around 600 rounds, compared to 3,000 of the "M" series.
which was reliable, but in rough terrain would not allow speeds similar to the more modern Christie suspension
or torsion bar suspension. Nevertheless, the good power-to-weight ratio
represented a significant improvement in mobility over its predecessors.
front and mantlet (by comparison the M13/40
had 42 mm), but it was still rivet
ed at a time when most tanks were constructed by welding
. Compared to welded armour, riveted armour is vulnerable to breaking apart at the joints meaning that even quite resistant plates can be defeated by rivet failures. The front armour had a compound slope with a best facing of 50 mm/45 degrees.
The armor was capable of protecting the tank against early anti-tank guns such as the British QF 2 pounder
(40 mm, 1.6 in), but was vulnerable to 1943 anti-tank weapons such as the British QF 6 pounder
(57 mm, 2.24 in) and QF 17 pounder (76 mm, 3 in).
The P40 was designated as a heavy tank
in Italy, not because of its weight, but because of the intended role: it was to accompany and support the widely used medium ("M") tanks on the battlefields. Its weight, armor and armament would classify it as medium tank
in Wehrmacht or other contemporary armies. Despite its shortcomings, the P40 was the only Italian tank design that was comparable to Allied and German medium tanks as they appeared in the middle of the war. It was the final evolution of Italian tank designs, that begun with the Vickers
-based tankette
s (such as the CV29 and L3/35
) and developed into models such as the M11/39 medium tank, a much heavier construction whose internal design shared many characteristics of the earlier tankettes.
in September 1943, at which point they were taken over by the German Wehrmacht
. About a hundred P40s were built by Ansaldo from then until the end of the war, although most were not entirely completed because of a lack of engines. A few were used in combat, under the German designation of Panzerkampfwagen P40 737(i), for example at Anzio
. Some, without engines, were used as static strongpoints.
. However of this variant only a couple wooden models in scale were ever produced. There was also a further upgraded variant called the P43 bis which supposedly had a 480hp engine and was powered by gasoline.
The other project was the Semovente 149/40, based on the P40 hull. Only one of these vehicles was ever built. It was intended to be a highly mobile self-propelled gun
, and its armament was the most powerful in the Italian Army
. A 149 mm / 40 calibre artillery piece with a range of over 23 km (slightly more than that of the US M1 Long Tom
). This gun was produced in very few numbers, and the Italian artillery remained equipped mainly with obsolete weapons for the duration of the war. Due to its mass, it was quite bulky to move, and so it was decided to build a self-propelled version, utilizing the most powerful of all Italian military vehicles. All space of the P40 hull was dedicated to supporting the gun, so the ammunition and crew would have required additional vehicles to be moved. The gun would have been ready to fire in three minutes from coming to a stop, compared to the 17 minutes required by towed artillery.
Work on the Semovente 149/40 started in 1942 and the prototype was tested in 1943, but the Italian Army was not very impressed. After the Armistice the vehicle was acquired by the Germans, and they weren't impressed by it either. Finally American forces captured it during the invasion of Germany and sent it to the Aberdeen Proving Ground
for testing. Except for the suspension, the rest of this self-propelled gun probably inspired the American M107
.
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
tank
Tank
A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...
design. It was armed with a 75 mm gun and an 8 mm Breda machine gun, plus another optional machine gun in an anti-aircraft
Anti-aircraft warfare
NATO defines air defence as "all measures designed to nullify or reduce the effectiveness of hostile air action." They include ground and air based weapon systems, associated sensor systems, command and control arrangements and passive measures. It may be to protect naval, ground and air forces...
mount. The official Italian designation was Carro Armato ("armored tank
Carro Armato
Carro Armato was the Italian Army's designation for tanks from 1938. This would be followed by a letter and a series of numbers. The letter would be either L, M or P meaning light, medium, and heavy tank respectively. The official Italian military tank classification differed from contemporary...
") P 26/40. The designation means: P for pesante (Italian
Italian language
Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...
: "heavy"), the weight of 26 tons, and the year of adoption 1940.
Design had started in 1940 but very few had been built by the time Italy signed the armistice with the Allies and the few produced afterwards were used by the Germans.
History
Although designed in 1940, the first prototypePrototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
was not completed until 1942. The initial plan was for a 25 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
tank with a 75 mm gun and to be named P26. The development work proceeded quickly except for the engine; the Italian military staff, the Stato Maggiore, wanted a diesel
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
power-plant, while the builders favoured a petrol engine
Petrol engine
A petrol engine is an internal combustion engine with spark-ignition, designed to run on petrol and similar volatile fuels....
.
However, in Italy at the time there were no engines (diesel or petrol) available capable of developing the 300 hp required, and the Italian tank industry (i.e. the duopoly Fiat
Fiat
FIAT, an acronym for Fabbrica Italiana Automobili Torino , is an Italian automobile manufacturer, engine manufacturer, financial, and industrial group based in Turin in the Italian region of Piedmont. Fiat was founded in 1899 by a group of investors including Giovanni Agnelli...
-Ansaldo) did not turn to easily available aircraft engines for its tanks as the contemporary U.S. and British tank manufacturers had done. The design of a new engine was very slow and in the end a 420 hp petrol engine was eventually tested.
The design of the P40 was originally similar to tanks such as the M11/39
Fiat M11/39
The Fiat-Ansaldo M11/39 was an Italian Medium Tank first produced prior to World War II. The M11/39 saw service in Africa and Italy . The official Italian designation was Carro Armato M11/39...
, but with a bigger gun and more armour
Vehicle armour
Military vehicles are commonly armoured to withstand the impact of shrapnel, bullets, missiles, or shells, protecting the personnel inside from enemy fire. Such vehicles include tanks, aircraft, and ships....
. After learning about Soviet T-34
T-34
The T-34 was a Soviet medium tank produced from 1940 to 1958. Although its armour and armament were surpassed by later tanks of the era, it has been often credited as the most effective, efficient and influential design of World War II...
s in 1941, the armour of the P40 was quickly re-designed, adopting more markedly sloped plates, and the new gun was adopted. The gun designation "75/34" referred to a 75 mm bore diameter gun with a length equal to 34 calibres. It was used in lieu of the 75/18 gun, with a shorter barrel of only 18 calibres. The main role of the P40 shifted from infantry support to anti-tank warfare
Anti-tank warfare
Anti-tank warfare was created by the need to seek technology and tactics to destroy tanks and their supporting infantry during the First World War...
, and all the internal space was dedicated to this end, making the vehicle rather cramped.
Design
The turret was operated by two crew members and this was a significant drawback as it put excessive workload on the tank's commander. At that time, most new tanks were designed with three-man turrets, following the successful example of the German Panzer IIIPanzer III
Panzer III was the common name of a medium tank that was developed in the 1930s by Germany and was used extensively in World War II. The official German designation was Panzerkampfwagen III translating as "armoured battle vehicle". It was intended to fight other armoured fighting vehicles and...
.
Armament
The main weapon was the 75/34 cannon, a development of the Model 37 divisional gun (34 calibres), retaining the same dimensions. This weapon had a muzzle velocityMuzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
of around 700 m/s. The main gun was normally provided with around 65 cartridge
Cartridge
Cartridge may refer to:* 8-track tape cartridge, a 1960s-1980s music storage format* Broadcast cartridge used in radio stations* Cartridge , a round of ammunition* Cartridge...
s.
One shift in the design was the number of machine-guns which was much lower than on the "M" series. The P40 originally fielded three machine guns, but one was removed along with the deletion of the frontal, dual barbette
Barbette
A barbette is a protective circular armour feature around a cannon or heavy artillery gun. The name comes from the French phrase en barbette referring to the practice of firing a field gun over a parapet rather than through an opening . The former gives better angles of fire but less protection...
machine gun mount. The standard ammunition load was lower, only around 600 rounds, compared to 3,000 of the "M" series.
Drive
The mechanical systems were a development of the "M" series, in particular the suspensionSuspension (vehicle)
Suspension is the term given to the system of springs, shock absorbers and linkages that connects a vehicle to its wheels. Suspension systems serve a dual purpose — contributing to the car's roadholding/handling and braking for good active safety and driving pleasure, and keeping vehicle occupants...
which was reliable, but in rough terrain would not allow speeds similar to the more modern Christie suspension
Christie suspension
The Christie suspension is a suspension system developed by American engineer Walter Christie for his tank designs. It allowed considerably longer movement than conventional leaf spring systems then in common use, which allowed his tanks to have considerably greater cross-country speed and a lower...
or torsion bar suspension. Nevertheless, the good power-to-weight ratio
Power-to-weight ratio
Power-to-weight ratio is a calculation commonly applied to engines and mobile power sources to enable the comparison of one unit or design to another. Power-to-weight ratio is a measurement of actual performance of any engine or power sources...
represented a significant improvement in mobility over its predecessors.
Armour
The armour, quite resistant by Italian standards, was sloped and 60 mm thick at the turretGun turret
A gun turret is a weapon mount that protects the crew or mechanism of a projectile-firing weapon and at the same time lets the weapon be aimed and fired in many directions.The turret is also a rotating weapon platform...
front and mantlet (by comparison the M13/40
Fiat M13/40
The Fiat-Ansaldo M13/40 was an Italian medium tank , designed to replace the Fiat L3, the Fiat L6/40 and the Fiat M11/39 in the Italian Army at the start of World War II...
had 42 mm), but it was still rivet
Rivet
A rivet is a permanent mechanical fastener. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite the head is called the buck-tail. On installation the rivet is placed in a punched or pre-drilled hole, and the tail is upset, or bucked A rivet...
ed at a time when most tanks were constructed by welding
Welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
. Compared to welded armour, riveted armour is vulnerable to breaking apart at the joints meaning that even quite resistant plates can be defeated by rivet failures. The front armour had a compound slope with a best facing of 50 mm/45 degrees.
The armor was capable of protecting the tank against early anti-tank guns such as the British QF 2 pounder
Ordnance QF 2 pounder
The Ordnance QF 2-pounder was a British anti-tank and vehicle-mounted gun, employed in the Second World War. It was actively used in the Battle of France, and during the North Africa campaign...
(40 mm, 1.6 in), but was vulnerable to 1943 anti-tank weapons such as the British QF 6 pounder
Ordnance QF 6 pounder
The Ordnance Quick-Firing 6-pounder 7 cwt, or just 6 pounder, was a British 57 mm gun, their primary anti-tank gun during the middle of World War II, as well as the main armament for a number of armoured fighting vehicles...
(57 mm, 2.24 in) and QF 17 pounder (76 mm, 3 in).
Summary
The P40 design was reasonably up-to-date, but the tank was without some modern features such as welded armour, adequate suspension, and a cupola for the commander.The P40 was designated as a heavy tank
Heavy tank
A heavy tank was a subset of tank that filled the heavy direct-fire role of many armies.Heavy tanks have usually been deployed to breakthrough enemy lines, though in practice have been more useful in the defensive role than in the attack...
in Italy, not because of its weight, but because of the intended role: it was to accompany and support the widely used medium ("M") tanks on the battlefields. Its weight, armor and armament would classify it as medium tank
Medium tank
Medium tank was a classification of tanks; the medium being intermediate in size and weight and armament between heavy tanks and light tanks.The medium tank concept has been eclipsed by the main battle tank.-History:...
in Wehrmacht or other contemporary armies. Despite its shortcomings, the P40 was the only Italian tank design that was comparable to Allied and German medium tanks as they appeared in the middle of the war. It was the final evolution of Italian tank designs, that begun with the Vickers
Vickers
Vickers was a famous name in British engineering that existed through many companies from 1828 until 1999.-Early history:Vickers was formed in Sheffield as a steel foundry by the miller Edward Vickers and his father-in-law George Naylor in 1828. Naylor was a partner in the foundry Naylor &...
-based tankette
Tankette
A tankette is a tracked combat vehicle resembling a small tank roughly the size of a car, mainly intended for light infantry support or reconnaissance. Colloquially it may also simply mean a "small tank"....
s (such as the CV29 and L3/35
L3/35
The L3/35 or Carro Veloce CV-35 was an Italian tank used before and during World War II. Although designated a light tank by the Italian Army, its turretless configuration, weight and firepower make it closer to contemporary tankettes....
) and developed into models such as the M11/39 medium tank, a much heavier construction whose internal design shared many characteristics of the earlier tankettes.
Production
Of the 1,200 tanks ordered, only a few (between one and five depending on the source), pre-production models were completed before the Italian ArmisticeArmistice with Italy
The Armistice with Italy was an armistice signed on September 3 and publicly declared on September 8, 1943, during World War II, between Italy and the Allied armed forces, who were then occupying the southern end of the country, entailing the capitulation of Italy...
in September 1943, at which point they were taken over by the German Wehrmacht
Wehrmacht
The Wehrmacht – from , to defend and , the might/power) were the unified armed forces of Nazi Germany from 1935 to 1945. It consisted of the Heer , the Kriegsmarine and the Luftwaffe .-Origin and use of the term:...
. About a hundred P40s were built by Ansaldo from then until the end of the war, although most were not entirely completed because of a lack of engines. A few were used in combat, under the German designation of Panzerkampfwagen P40 737(i), for example at Anzio
Operation Shingle
Operation Shingle , during the Italian Campaign of World War II, was an Allied amphibious landing against Axis forces in the area of Anzio and Nettuno, Italy. The operation was commanded by Major General John P. Lucas and was intended to outflank German forces of the Winter Line and enable an...
. Some, without engines, were used as static strongpoints.
Variants
There were at least two planned variants of the P40. One was named P43, a tank with a weight over 30 tonnes, which would have had circa 80mm of frontal armour and a main armament of either a longer-barrelled 75mm gun or the same 90mm piece mounted on the Semovente M41 90/53Semovente 90/53
The Semovente 90/53 was a heavy Italian self-propelled gun and tank destroyer, used by the Italian and German Armies during World War II.-Development:...
. However of this variant only a couple wooden models in scale were ever produced. There was also a further upgraded variant called the P43 bis which supposedly had a 480hp engine and was powered by gasoline.
The other project was the Semovente 149/40, based on the P40 hull. Only one of these vehicles was ever built. It was intended to be a highly mobile self-propelled gun
Self-propelled gun
A self-propelled gun is form of self-propelled artillery, and in modern use is usually used to refer to artillery pieces such as howitzers....
, and its armament was the most powerful in the Italian Army
Italian Army
The Italian Army is the ground defence force of the Italian Armed Forces. It is all-volunteer force of active-duty personnel, numbering 108,355 in 2010. Its best-known combat vehicles are the Dardo infantry fighting vehicle, the Centauro tank destroyer and the Ariete tank, and among its aircraft...
. A 149 mm / 40 calibre artillery piece with a range of over 23 km (slightly more than that of the US M1 Long Tom
155 mm Long Tom
The 155 mm Gun M1 and M2 , widely known as Long Tom, were 155 millimeter calibre field guns used by the United States armed forces during World War II and Korean War. The Long Tom replaced the Canon de 155 mm GPF in United States service.-Development:Before entering World War I, the United...
). This gun was produced in very few numbers, and the Italian artillery remained equipped mainly with obsolete weapons for the duration of the war. Due to its mass, it was quite bulky to move, and so it was decided to build a self-propelled version, utilizing the most powerful of all Italian military vehicles. All space of the P40 hull was dedicated to supporting the gun, so the ammunition and crew would have required additional vehicles to be moved. The gun would have been ready to fire in three minutes from coming to a stop, compared to the 17 minutes required by towed artillery.
Work on the Semovente 149/40 started in 1942 and the prototype was tested in 1943, but the Italian Army was not very impressed. After the Armistice the vehicle was acquired by the Germans, and they weren't impressed by it either. Finally American forces captured it during the invasion of Germany and sent it to the Aberdeen Proving Ground
Aberdeen Proving Ground
Aberdeen Proving Ground is a United States Army facility located near Aberdeen, Maryland, . Part of the facility is a census-designated place , which had a population of 3,116 at the 2000 census.- History :...
for testing. Except for the suspension, the rest of this self-propelled gun probably inspired the American M107
M107 Self-Propelled Gun
The M107 175 mm self-propelled gun was used by the U.S. Army from the early 1960s through to the late 1970s. It was part of a family of self-propelled artillery that also included the M110 and was intended to provide long-range fire support in an air-transportable system...
.
External links
- P26/40 Heavy tank at wwiivehicles.com
- Carro P.40 at comandosupremo.com
- Carro Pesante P26/40 at onwar.com
- Carro Pesante P26/40 walkaround at maquetland.com