A standard tank of the Polish Army during the 1939 Invasion of Poland, its production never exceeded 150 vehicles.
Its chassis was used as the base for C7P artillery tractor.
The twin-turreted version of the 7TP, here pictured occupying Zaolzie in October 1938 following the Munich Agreement , was a less produced variant
7TP was fitted with 360-degree Gundlach periscope.
The 7TP was the Polish development of the British Vickers 6-ton Mark E tank licence. Comparing to Vickers, the main new features of 7TP were: a better, more reliable and powerful diesel engine, a 37 mm anti-tank gun, thicker armour (17 mm instead of 13 mm on the front), modified ventilation, the Gundlach tank periscope , and a radio. About 132 tanks were produced between 1935 and the outbreak of the war, plus four iron prototypes. The designation 7TP meant "7 Tonne, Polish" (in fact its weight increased to 9 tonnes after the initial prototype).
Although 7TP is often claimed to be the world's first (production) diesel-powered tank, this distinction actually goes to Japanese Type 89B I-Go Otsu , produced with a diesel engine from 1934 onwards. Barring that, the claim of a first purpose-designed diesel-powered tank is tied with Type 95 Ha-Go, whose series production also commenced in 1935. The diesel oil used as fuel had an important advantage of being much less flammable than gasoline .
Like its British predecessor, the 7TP was initially produced in two variants: twin turret version armed with 2 Ckm wz.30 machine guns, and a single turret version, armed with 37 mm Bofors wz. 37 gun. After initial tests, it became clear that the twin-turret variant was obsolete and lacked firepower, so it was abandoned in favour of the more modern single turret design.
Prior to the outbreak of World War II most of the twin turret tanks were converted to single turret versions and only 24 twin-turret types remained in Polish service (as opposed to roughly 108 of the other type). It is to be noted that twin and single turret variants had no specific designations. In some modern books they are unofficially designated "7TP dw." and "7TP jw." (Polish abbreviations for dwuwieżowy – dual turreted; jednowieżowy – single turreted).
In 1938 Państwowe Zakłady Inżynierii also produced 13 prototype models of a better armored version of the 7TP – the 9TP. Although the 9TP never entered production, these prototypes were used in the defense of Warsaw in September 1939.
Romania sent a military commission in late autumn 1935 to evaluate the 7TP for a future acquisition. Although the tank fared well during field trials, the Romanian officers were not impressed by the armour of the Polish prototype and instead recommended the acquisition of the Czechoslovak LT vz. 35 tank.
All 7TP tanks took part in combat in the defence of Poland during the German Invasion of Poland in 1939. Most of them were attached to two light tank battalions (the 1st and the 2nd). The remaining tanks, that is the ones used for training as well as tanks that were finished after the outbreak of the war, were used in an improvised tank unit fighting in the defence of Warsaw . Although technically superior to any of the German light tanks of the era, the 7TP was too scarce to change the outcome of the war.
The 1st Light Tank Battalion (49 single turret tanks) fought in the ranks of the Prusy Army as part of the strategic reserve force of the Polish Army. It entered combat on September 4, 1939 and fought with distinction in a variety of roles, mostly as a mobile reserve and for covering the withdrawal. It fought in a number of battles, most notably in the battles of Przedbórz, Sulejów, Inowłódz, Odrzywół and Drzewica.
As part of that unit, the battalion took part in the Battle of Józefów and formed part of the spearhead of the Polish units trying to break through to Lwów and the Romanian Bridgehead. After the Battle of Tomaszów Lubelski, on September 21, 1939, the remaining tanks were destroyed by their crews and the unit surrendered to the Germans.
The 2nd Light Tank Battalion (49 single turret tanks) was attached to the Piotrków Operational Group of the Łódź Army. It entered combat on September 4 near the river of Prudka, Bełchatów. The following day it was ordered to lead the Polish counter-assault on Piotrków, but the attack failed and the unit suffered heavy losses. The battalion was then rallied and withdrew to Warsaw and then to Brześć, where it shielded the mobilization of the Polish 60th Infantry Division. On September 15 it took part in a two-days long Battle of Włodawa, but suffered heavy losses due to air bombardment and was withdrawn southwards.
The remaining tanks had to be destroyed by the crews due to lack of oil and on September 17, after the Soviet Union joined Germany in her war against Poland, the crews and the staff of the unit crossed the border with Romania.
The remaining tanks found in Warsaw were formed into the 1st and 2nd Company of Light Tanks by the Command of the Defence of Warsaw. The 1st company had 11 twin-turreted tanks, previously used for training. In the opening stages of the Siege of Warsaw the unit took part in heavy fights for Warsaw's suburb of Okęcie and the major airport located there. Due to lack of anti-tank armament, the tanks of the 1st company suffered losses and were withdrawn to the rear on September 12, where the unit was joined with the 2nd company.
The tower armed with 20 mm antitank cannon, another tower removed and replaced mounted radio. Operation Commander and radio intelligence wagon
On September 15 the company was ordered to form a spearhead of the Polish attack aimed at linking up with the forces of the Poznań Army withdrawing after the Battle of Bzura through the Kampinos forest north of Warsaw. The attack ended up as a minor success, although the German aerial bombardment caused heavy losses both in personnel and in tanks.
The remaining 7TP tanks were used on various sectors of the front until the end of the defence of Warsaw on September 27, when they were destroyed by their crews. At the same time, one 7TP was captured by the Soviets during their invasion of Poland .
The combat experience proved that the Bofors wz. 37 anti-tank gun used in the 7TP was able to penetrate the armour of any of the German tanks of the time, including the newest, the Panzer IV. On the other hand, the 7TP was too lightly armoured, especially against aerial bombardment.