The Polish light reconnaissance tank 4TP remained only a prototype. It belonged to a family of modern tracked vehicles, developed by Edward Habich in the late 1930s, which also included an amphibious tank PZInż.130, a tractor PZInż.152 and a tank destroyer PZInż.160. The 4TP was meant to be used in the Polish Army in a place of the tankettes TK/TKS.
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A story of the Polish light reconnaissance tank 4TP, also known under its factory designation PZInż.140, is connected with designs of well-known British designers, J.V. Carden and V. Loyd. Working for Vickers-Armstrongs, they designed numerous successful light tanks (among others Vickers 6-Ton), which were exported to many countries and influenced many other designs in the world. Starting from 1928, they developed a line of the Light Tanks for the British Army (Mk I - Mk IV), and similar tanks for export. Main features of these designs were: a paired bogey-type suspension with two wheels per bogey, sprung on leaf springs or helical springs; an engine placed in a right part of a hull; two men crew and a rotating turret, armed typically with a machine gun. An export variant, Commercial Light Tank Vickers Carden-Loyd 4-ton, was developed into models: M1933, M1934, M1935, M1936 and M1937 (the latter was armed with a 4-pdr 40mm gun, built for Latvia). They were exported to many countries, mainly: Belgium (as T.15), the Netherlands (for the Dutch East Indies), Lithuania, Latvia, Siam, Argentina, Switzerland. They also served as a base for Vickers Carden-Loyd Amphibian Tank (more on PZInż 130 page) and several artillery tractors. The latest British Light Tanks of Carden-Loyd design were Mk V and Mk VI, with a 3-men crew.
Only tanks manufactured in Poland in an early 1930s were turretless tankettes TK/TKS (inspired by the Carden-Loyd Mk VI tankette as well), but a program of armoured weapons' development anticipated a construction of a light reconnaissance tank with a turret and a stronger armament. It was meant to replace the tankettes in the future. That is why in September 1932, the 4-ton light tank, the Amphibian Tank and an artillery tractor of Carden-Loyd were demonstrated in Poland. As a result, in May 1933 the Chief of the Engineering Department, Col. Tadeusz Kossakowski proposed to buy five light reconnaissance tanks Carden-Loyd 4-ton and one Amphibian Tank in an evaluation and research purpose, but it was not proceeded because of a lack of funds. Instead, it was decided to develop similar tanks in Poland, basing on a specification worked out in the BBT BP (Technical Testing Centre of Armoured Weapons). An attempt of fitting a tankette with a turret (TKW), similar to ligher Carden-Loyd Patrol Tank, was a failure, because the tankette was too small platform. Therefore, a task of designing an own 4-ton reconnaissance tank and an amphibian tank, sharing the same components, was secretly assigned to the PZInż works (Państwowe Zakłady Inżynierii – State Engineering Works), on 3 october 1936.
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| 4TP during "Autumn 1937" trial. PZInż 152 tractor is on the left. |
The main designer of both tanks was the chief of the PZInż Studies Section, engineer Edward Habich. First works might have started already in 1935. The design and documentation of the light reconnaissance tank factory type "140" (hence commonly named PZInż 140) was ready on 16 December 1936. Apart from a general inspiration by the Carden-Loyd layout, the new design was entirely Polish. It utilised some of the world's newest ideas, like a modern torsion bar suspension, and also Polish inventions, like a reversible periscope (invented by Maj. Rudolf Gundlach). The engine PZInż 425 was a Polish design as well.
Just in January 1937, a plan of armoured weapons' development for 1937-42 years anticipated a replacement of tankettes with the new light reconnaissance tank, which received an Army designation 4TP. The program expected producing 480 such tanks for 18 reconnaissance tank companies in infantry divisions and in four so-called Motorized Units (Oddział Motorowy – OM, former motorized brigades). The latter ones were expected to include a 4TP company and a 10TP company.
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| 4TP from a rear, during "Autumn 1937" trial. On the left, PZInż 130 is visible. |
A prototype of the reconnaissance tank was given to the Army on 15 August 1937. In the beginning of November it took part in a trial called "Autumn 1937", on a route of 1935 km, in pre-war south-eastern Poland, from Warsaw through Brest, Volkovysk, Pinsk, Lutsk, Lviv, Buchach, Kolomyia, Żurawica near Przemyśl and Lublin to Warsaw. Also other prototypes were tested in this trial, among others an amphibian tank PZInż 130 and a tractor PZInż 152, both sharing the same chassis. The tank proved to be reliable, and its maintenance was simple. After the trial it was sent back to the PZInż to apply some repairs and improvements. The testing continued in 1938. In June/July the 4TP was tested with a prototype 20 mm automatic gun wz.38 FK-A. A committee of experts evaluated the tank to be a modern and successful design, fit for a serial production after some minor improvements. The main subject for improvement was the suspension. Although it was reliable and elastic, it was too soft and was causing the tank rock to sides too much, what made impossible an efficient fire while moving. Also materials used for constructing the prototype suspension had too low durability, what caused, first of all, breaking off of return rollers. The commission had some reservations as for a gearbox as well. All these drawbacks, however, were caused by materials used in the prototype and were easy to be eliminated in a series production.
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| 4TP trials in November 1937. |
Last trials of the PZInż 140 prototype took place in May 1939. It ran at least 4300 km (2672 miles) in total, without serious failures. The tank was not ordered for a production, however, because in a meantime the Polish General Staff concluded, that when the tank would enter service, its design would not meet requirements of a future battlefield. It was caused among others by an analysis of tank skirmishes in the Spanish Civil War, and was generally a correct conclusion, confirmed by a decreasing role of light reconnaissance tanks, and light tanks in general in World War II. It was recognized, that the future combat reconnaissance should be a task of better armed and armoured light tanks of 7TP-like class. A price of the tank was 71.5–80 thousand złoty, but without an armament and equipment, costing around 40 thousand złoty (approximately a half of 7TP tank). Some publications claim, that a production of the 4TP was meant to start in 1940 anyway, but it is doubtful. An ultimate fate of the prototype is not know, and there have not been revealed photographs in german hads so far.
In spite of all this, in the late 1930s the 4TP was a design comparable or better to the world's other light reconnaissance tanks of its class. It is noteworthy, that only three new light tanks ot that class, with similar armament, were produced during World War II: Soviet T-60, of a low combat value, mass produced due to a need of any tanks, Italian obsolete L6/40, sticking out with is high silhouette and vertical armour plates, and German ephemerical Luchs, much heavier, with 4-man crew, better protected and radio-equipped.
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| The 4TP during trials - visible broken return rollers. |
The only prototype of the light tank 4TP was not armed. Only in June/July 1938 a prototype of the Polish 20 mm automatic cannon wz.38 FK-A was tested with 4TP, and then returned to the factory. The tank was expected to be armed with a coaxial 20 mm automatic cannon wz.38 FK-A and a water cooled 7.92 mm wz.30 tank machine gun. The ammunition load was to be 200 or 250 gun rounds and 2500 MG rounds. The turret was modeled after Bofors-designed turret of the 7TP tank, but it was smaller. It also had a hatch in a rear wall, like an original unaccepted model of 7TP turret.
During a prototype construction, an idea of arming the tank with a 37 mm wz.37 gun was considered. A fitting of a complete 7TP two-men turret proved impossible, as was fitting of any other newly-designed two-men turret, due to their diameter and a necessity of rebuilding the tank. On a reccomendation of the Armoured Weapons HQ, E. Habich worked a design of a modified tank 4TP, designated as PZInż 180, fitted with a bigger one-man turret. The turret of PZInż 180 had a shape of a truncate prism and was fitted with a 37 mm gun. However, it was soon correctly recognized, that the commander would be overburdened with a gun handling, and all his duties would suffer (like in most French tanks or the Soviet T-70). Apart from it, the gun would have to be modified heavily to fit into this smaller turret. The 37 mm gun found a better use in a low-profile tank destroyer PZInż 160, designed by E. Habich on the same chassis as well, which remained a sketch only due to the war outbreak. An idea of arming 4TP with a flamethrower was also considered, but it was not proceeded either.
The armour was of riveted rolled plates:
• hull: front - 8–17 mm, sides – 13 mm, back – 10–13 mm, bottom – 4–8 mm, top – 5 mm;
• turret: front and sides: 13 mm, top – 5–6 mm.
Most likely the prototype was made of a regular mild steel, due to costs and simplicity.
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Engine - PZInż 425: petrol, 4-stroke, V8, power output: 95 HP at 3600 rpm, displacement: 3888 cm³, water-cooled, bore diameter 82mm, stroke 92mm. It was considered to replace this engine with PZInż 725 - petrol, 4-stroke, 6-cylinder inline, 5180 cm³, 100-120 HP (older publications claimed, that the tank had this engine). According to some information, such engine was fitted in 1938 or 1939.
Fuel tank - at the rear, capacity about 300 l.
Transmission - dry multi-disc main clutch, mechanical gearbox, 4 forward gears, 1 reverse gear, side clutches with band brakes, side drives.
Suspension: drive sprocket in the front, idler at the rear. Paired bogey-type suspension. On each side four single roadwheels, rubber-rimmed, blocked in a bogey by two. The roadwheels were suspended on individual suspension arms, sprung by torsion bars. Each pair of wheels in a bogey had one horizontal hydraulical shock absorber. Two return rollers on each side. Single-pin, twin-spur metal tracks, each made of 87 links, link width 260 mm, pitch 90 mm, length of track on the ground 2.1 m, track 1.8 m.
Hull: riveted of armour plates. The crew compartment was on the left, the engine compartment on the right. The crew was two: a driver and a commander/gunner. The driver's seat was in front of the crew compartment, to his right there was a transmission. Before the driver there was a one-part hatch, that could be lowered onto the front armour plate. The hatch had a small openining vision port, with a vision slot. The driver had also a modern reversible periscope of the Polish design. Above the crew compartment there was an one-man turret, offset to the left, with the commander's seat in it. The turret had a two-leaf door in the rear wall and a hatch on the roof. It was also to be fitted with a reversible periscope. The turret traverse was manual. Series tanks were to be fitted with a radio.
The prototype was probably painted all in brown-green. Serial tanks were to be painted in a standard camouflage scheme of three colours: greyish sand and dark brown (sepia) over brown-green (base color). The patches were airbrushed, with soft transitions, the shapes were horizontal mainly. The interior was painted in sand (more on camouflage on the tankettes page).
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| Drawing of the 4TP - Copyright © Thierry Vallet - Kameleon Profils - courtesy by Thierry Vallet. |
| Crew | 2 |
| Combat weight | 4330 kg |
| Length | 384 cm |
| Width | 208 cm |
| Height | 175 cm |
| Ground clearance | 32 cm |
| Maximum speed | 55 km/h |
| Road / off-road range | 450 / 240 km |
| Wading depth | 70 cm |
| Max. steepness | 38° |
| Crossing ditches | 160-170 cm |
| Power /weight ratio | 22 HP/t |
| Ground pressure | 0.34 kg/cm² |
| Fuel consumption | 66 l/100 km |
Scale model kits of the reconnaissance light tank 4TP:
Links to Scalemates site
1/72:
1/48:
1/35:
Sources:
Update history:
Main page – Polish armour – Polish artillery – Steel Panthers
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Text copyright: Michal Derela © 2002-2026.
