The greatest success of the Czechoslovakian tank industry was with light tanks. The LT vz. 35 and LT vz. 38 turned out to be excellent vehicles, used by several nations during WWII. Despite the fact that Skoda's T-15 and Pz.Kpfw.38(t) n.A. did not make it past the prototype stage, the chassis of the latter was used for the Jagdpanzer 38(t) tnak destroyer. It is not surprising that, after the end of the war and start of work on the TVP medium tank, work on a new light tank began in parallel. The result of that work was several interesting prototypes, such as the TNH 57/900, Skoda T-17, and the amphibious Letak.
Continuation of the German program
Czechoslovakia's tank fleet was incredibly diverse at the end of WWII. Its units fought on two fronts: the 1st Czechoslovakian Army Corps approached from the east, and the 1st Czechoslovakian Tank Brigade from the west. As such, one unit was equipped with British vehicles, the other with Soviet ones. At the end of the war, the vehicles were distributed between units to keep them as uniform as possible.
Because of this, the 1st, 2nd, and 3rd tank battalions, made up from the former 1st Czechoslovakian Army Corps, had no light tanks. These battalions only had medium T-34 and T-34-85 tanks. As for tank battalions made from the 1st Czechoslovakian Tank Brigade, they were chiefly composed of Cromwell IV and VI tanks. They also had some light tanks: the Czechoslovakian army acquired 38 Stuart VI tanks: American Medium Tanks M5A1 re-equipped by the British. By 1946, their number was reduced to 37, and remained at that level until 1949.
Locally produced light tanks joined them in 1946. Some amount of Pz38(t) and LT vz. 38 tanks remained in Czechoslovakia after the war. Some were left by the Germans, others were used by the Slovakian army. The tanks were indexed LT-38/37 (light tank model 1938 with a 37 mm gun), sent to the CKD factory for repairs, and then issued to units. As of June 3rd, 1946, 25 LT-38/37 were in use by the 14th, 21st, and 22nd tank battalions. Later, they were spread across six battalions. By the end of the year, their number grew to 29 tanks. By 1948, the number of vehicles reached their peak: 31 in tank battalions and 17 in an armoured train battalion.
The appearance of the LT-38/37 was both a necessary evil and a question of prestige. A country that was the leader in exporting tanks in the late 1930s should not have an army armed exclusively with foreign tanks. CKD and Skoda were busy with the Tank všeobecného použití (TVP) or Main Battle Tank in the late 1940s, but both companies also worked on light tanks. CKD was the more successful of the two when it came to light tanks.
Both companies were producing the Jagdpanzer 38(t) tank destroyer until the end of WWII. These vehicles were also used by the Czechoslovakian army under the index ST-I ShPTK vz.39/75N, and in considerable numbers: 259 as of 1949. The chassis was taken from the Pz38(t) n.A. reconnaissance tank, which never entered production, but had the potential for further modernization. One of the prototypes was retained by CKD, and offered a suitable platform for further experiments.
As per tradition, a fierce competition took place between CKD and Skoda. Nevertheless, the competitors forgot about it when mutual interests were involved. This is what happened during the creation of the prospective light tank. This project came up thanks, in part, to Skoda. The company received a lot of experience in designing artillery during the German occupation, including tank guns. One of these guns was the Skoda A 18 75 mm gun for the T-25 medium tank. The gun's main feature was the use of a revolver type autoloader with a five round capacity.
After the end of the war, Skoda continued working in this direction. A «triplex» project was ready by the end of 1947. The main weapon was the 47 mm A 24, with the 37 mm A 23 and 57 mm A 25 offered as alternatives. The systems shared their overall design, a muzzle velocity of 900 m/s, and the loading mechanism. The drum of the A 23 gun contained 19 rounds, the A 24's had 13, and the A 25 had 10. The most powerful of the guns had a calculated penetration of 81 mm at 60 degrees at a range of one kilometer.
Blueprint Zb6099P, dated December 8th, 1947, shows the gun mounted in a two-man turret. This date can be considered the first mention of the project that was later indexed TNH 57/900. CKD designed this tank on the chassis of the Pz38(t) n.A. The numbers 57/900 refer to the caliber and muzzle velocity of the gun. The 57 mm A 25 was chosen as its primary weapon.
The tank took shape by December of 1949. At that point, CKD was designing this vehicle for export. Thanks to the fact that most of its components were already built in metal, no issues with production were foreseen. The main changes consisted of a new turret with a new gun and alteration of the turret platform and front hull. In a way, CKD repeated the Swedish modernization of the Strv m/41, which was a very similar proposal. Both projects consisted of a 57 mm cannon with an autoloader, a new turret platform, and even the armour thickness (50 mm front, 30 mm sides) and mass (15 tons) were similar. However, CKD employed realists, which understood that the modernization would increase the tank's mass significantly. It was estimated at 15-16 tons.
The 15 L Tatra Typ 103 was proposed as the engine for the TNH 57/900. This 220 hp V-shaped engine was already in mass production, and no supply issues were expected. The third Pz38(t) n.A. prototype that was kept at CKD was trialled with this engine.
The chassis was loaded with ballast to estimate the tank's performance. According to calculations, a tank with this engine could reach a top speed of 48 kph, which was enough for a light tank. A 250 hp V-8 engine developed by CKD was proposed as an alternative. With this engine, the tank's power to weight ratio would be 16.6 hp/ton, which was even more than that of the American Light Tank M24 «Chaffee». The Czechoslovakian tank could have been a worthy competitor on the export market.
Variety on paper
While working on the TNH 57/900 with CKD, Skoda did not forget about its own interests. While Prague was thinking about renewing export shipments, Pilsen was more concerned with domestic programmes. Recall that the first more or less realistic TVP project was designed by Skoda and was indexed Skoda T 40. It should not come as a surprise that Skoda received the leading role in the TVP project. A concept of a domestically produced light tank was developed in Pilsen, which was supposed to meet the requirements of the military much more closely.
By the mid-1940s, countries that were still developing light tanks came to the conclusion that 37-57 mm cannons were no longer enough. Armour became so thick, that guns with these calibers could no longer effectively combat it. As a result, the optimal calibers became the ones that were previously used on medium tanks, primarily 75-76 mm.
The Americans were the first to use such a weapon on a light tank, installing a 75 mm gun on the Light Tank M24. After the war, the Light Tank M41 received a more powerful 76 mm gun. As for the 75 mm caliber, it was not forgotten. The French installed a shortened version of the Panther's 75 mm gun on the AMX 13, and the Swedes later used the same caliber.
Skoda also had guns of this caliber. Aside from the 75 mm Skoda A 18 gun, which, like the T 25 tank, did not make it past the design stage, there were other weapons that made it to the prototype stage, such as the 75 mm Skoda R 4 AA gun with a hydraulic loading mechanism. With a 4300 mm long barrel, it could propel a 6 kg armour piercing shell to a velocity of 920 m/s. The loading mechanism allowed it to reach an impressive rate of fire: 45 RPM.
With this wealth of experience and direct contacts at the VTU (Vojenský technický ústav, Military Technical Institute), the overseer of new tank developments, Skoda began working on its own project. The tank received the index T-17 (T: tank, 1: light, 7: seventh prototype). Work began in 1948 and coincided with the changing outlook regarding the TVP project. Requirements changed, and the tank changed with them.
Presumably, the Czechoslovakian military obtained some information on the Soviet IS-3 heavy tank. There can be no other explanation for why the TVP, a mix of German and Czech technologies, suddenly began to resemble the Soviet tank. This was also true for the T-17, a draft project of which was ready by September 8th, 1948. The 19-ton tank received a pike nose, similar to the IS-3, but its rear was more reminiscent of the T-34. A 275 hp 15 L V-8 engine brought it to life. According to calculations, the top speed of the T-17 with this engine would be 46 kph. Like the T-34 and IS-3, the transmission was in the rear. The tank would have four wheels per side and a torsion bar suspension.
The cast turret was also reminiscent of the IS-3. It contained three crewmen and the 75 mm Skoda A 26 gun. Its characteristics were almost identical to the R 4 AA gun. In addition, the tank would receive three machineguns. The armour was up to 50 mm thick in the front and 25 on the sides. The thickness of the cast turret varied from 60 to 15 mm. This was a satisfactory light tank for its time, equipped with worthy armour and armament.
Skoda was not just building a light tank, but a special platform called LP (Lehký podvozek, light chassis), which served as the foundation for a large number of SPGs. Conceptually, they were similar to those later built by Skoda for the TVP program. These light vehicles were designed in 1948-49, four in total. Aside from the chassis, they were united by domestically produced armament that was being developed at Skoda at the time.
Vehicles on the LP chassis were reviewed at a meeting of the Czechoslovakian Ministry of Defense on November 18-20th, 1948. The first was the 105 mm ShH 14,3/540-LP SPG. Blueprint Zb 5915-S showed the same LP platform. The only difference from the T-17 was that a new open-topped turret replaced the old closed up one.
By that point, the 270 hp engine, which was a bit too weak for the T-17, was replaced with a 500 hp air-cooled turbocharged diesel. A Praga-Wilson gearbox was selected. According to calculations, the expected top speed was no less than 55 kph. It’s possible that Skoda was being too homble, since the T-17’s power to weight ratio grew from 14.2 to 26.3 hp/ton, and the SPG weighed even less than the tank, just 16 tons. The 105 mm ShH 14,3/540-LP was armed with the 105 mm Typ 17-1 (H-9) howitzer, which was being designed at Skoda since 1946. This weapon reached the experimental prototype stage.
The 76.2 mm ShPTK 6.6/900-LP tank destroyer, blueprint Zb 5916-S, was almost an identical twin of the SPG. Instead of a howitzer, the tank destroyer was equipped with the 76 mm A 19 anti-tank gun. This was a further development of Skoda’s wartime anti-tank gun projects. The gun used the same ammunition as the Soviet ZIS-3. With a 5300 mm long barrel and a muzzle velocity of 915 m/s, the A 19 easily penetrated 100 mm of armour at 60 degrees from a kilometer away. As with the H-9 howitzer, work reached the experimental prototype stage. The gun never entered production, and is now on display at the Technical Museum in Lešany.
The third vehicle was the 50 mm ShPLK 2.12/1020-LP, blueprint Zb 5918-S. This project was similar to the Flakpanzer 38(t). The fighting compartment moved from the front to the rear, and the hull became wider. This was done so that a 50 mm AA gun that was being designed by Skoda since 1948 could fit into the hull. THe gun was based on the 57 mm R 8 autocannon. Unlike the other weapons, this one did not make it past the design stage.
The last project to be presented was the 76 mm ShPTK 6.6/900-LP tank destroyer, blueprint Zb 5920-S. Unlike the Zb 5916-S, this vehicle was more reminiscent of the Jagdpanzer 38(t). The 17 ton SPG had a fully enclosed fighting compartment with sloped armour. This layout allowed the vehicle to be a little lower, which is quite an important parameter for a tank destroyer. The mobility and armour was the same as in the previous designs.
The LP projects, including the T-17, were reviewed at a large meeting, which was held on April 19th, 1949. Interest was shown in the main idea, but work slowed down. A year later, work on light tanks ceased. Around this time, the TVP suffered a similar fate.
Many reasons are named. Some blame the Czechoslovakian communists, who were in favour of following the Soviet “older brother”. This is a somewhat fair assessment. This theory is most applicable to the TNH 57/900. It was rather obsolete, but it had the potential to be successful in third world markets. Politics, an increasingly important factor after the breakout of the Korean War, was a significant factor to the death of the export tank. However, the closure of the Czechoslovakian light tank program cannot be explained by politics alone.
As of 1950, the T-17 and other vehicles on the LP chassis, just like the Skoda T 50 and other vehicles from the TVP program, existed only on paper. The continuation of the TVP program seemed a questionable endevour. Its replacement with a licensed copy of the T-34-85 was a reasonable measure. Light tanks were another matter entirely. Towards the end of 1950, light tanks were removed from the Czechoslovakian army. The light tank as a class fell out of favour. It was decided that medium tanks could handle the role just as well.
The Czechoslovakian military realized its mistake after they found out about the Soviet PT-76 amphibious tank. In April of 1954, work on a light amphibious tank began at the Stalin factory in Martin, Slovakia. It was based on the VOZ amphibious vehicle, aka Tatra 807, which reached the experimental prototype stage. The tank project was indexed Letak (flyer). It weighed 15 tons and carried a 57 mm Skoda autocannon, based on the R 11 AA gun. The hull of the Letak was altered during the design process, and the front became very similar to the front hull of the IS-3. The project was cancelled in February of 1956, and no replacement ever turned up. The Czechoslovakian army opted to not use the Soviet PT-76 in its army. However, a license for the amphibious BTR-50 armoured carrier was purchased. It was produced under the index OT-62.
The fate of the T-17/LP and Letak programs reflects the short-sighteness of the Czechoslovakian military. By the time the Letak was cancelled, Czechoslovakia was actively shipping tanks to Egypt and to other countries. Unwilling to develop its own light tanks, Czechoslovakian military and political leaders missed out on a sizeable share of the export market, which was gradually occupied by a new player, China, ten years later. Chinese Type 62 light tanks had similar characteristics to the T-17. They were accepted into service in a dozen countries. An analogous situation occurred with amphibious tanks. Even the presence of the Soviet PT-76 did not impede the export of its Chinese clone, the Type 63.
Translated by Peter Samsonov. Read more interesting tank articles on his blog Tank Archives.
- National Archives and Records Administration
- VHU Prahan (Vojenský historický archív)
- Mgr.Martin Dubánek — Od bodáku po tryskáče — Nedokončené Československé zbrojní projekty 1945–1955, Mladá fronta 2011
- The Czechoslovak Army 1945–1954, Peter Brojo, Josef Studeny, Capricorn Publications, 2012, ISBN 978–80–87578–01–8.
- Materials from the archive of Jiri Tintera