ST vz. 39 (Fall Grün)

ST vz. 39
The prototype of the V-8-H.
Type:	Medium tank
Place of origin:	Czechoslovakia
Service history
In service:	1939
Used by:	Czechoslovakia
Wars:	Invasion of Czechoslovakia (1938-1939)
Production history
Designer:	Českomoravská Kolben-Daněk
Designed:	1934-1938
Manufacturer:	Českomoravská Kolben-Daněk
Unit cost:	895,068 Czechoslovak koruna
Number built:	10
Specifications
Weight:	16.665 tons
Length:	5.35 metres
Width:	2.27 metres
Height:	2.34 metres
Crew:	4
Armour:	20-32 mm
Primary armament:	4.7 cm Škoda ÚV vz. 38 gun
Secondary armament:	2 x 7.92 mm ZB vz. 37 machine guns
Engine:	4-cylinder, water-cooled Praga Type NR V-8 gasoline 240 horsepower (180 kW/2200 rpm)
Power/weight:	14 hp/tonne
Transmission:	6 x 6
Suspension:	Leaf spring
Fuel Capacity:	270 litres
Operational range:	150 km
Speed:	48 km/h

The ST vz. 39 was a Czech-designed medium tank produced used by Czechoslovakia during the Axis invasion of Czechoslovakia between 1938 and 1939. The name is an abbreviation of its formal designation Střední Tank vzor 39 (Medium Tank Model 39).

Following testing in the spring of 1938, it was accepted for mass production by the Ministry of National Defence in April 1938, with delivery to begin in March 1940. However, a small number of ST vz. 39's were produced between November 1938 and January 1939, and took part in the final Czech counterattack at Brno in January 1939.

Development

In 1934 the Czechoslovak Ministry of National Defence instructed the manufacturers of battle tanks, the firms of Českomoravská Kolben-Daněk in Prague and Škoda Works in Plzeň, that effective immediately, only fully tracked armoured vehicles with a combat weight of up to 15 tons were to be developed as battle tanks. At this point the ČKD had not yet gone into development of such vehicles, but their design chief, Ing. Surin, had already laid the foundation at that time for the TNH and V-8-H tanks.

In 1938 the Českomoravská Kolben-Daněk firm introduced the V-8-H medium tank, which did well in testing. Over a four month period it covered 4555 km, 1533 of them in rough terrain. The testing confirmed the V-8-H as the standard medium-class tank. In April 1938 the Ministry of National Defence issued a preliminary order for the production of 300 V-8-H tanks with the army designation ST vz. 39. Delivery was to begin in March 1940, and the whole contracts for the light (TNH) and medium (V-8-H) tanks were to be carried out by the Českomoravská Kolben-Daněk and Škoda firms; ČKD was to build mainly the TNH tanks, while Škoda was to produce 205 of the 300 V-8-H tanks.

The vehicle, progressive for its time, weighed 16.6 tons and had armour from 20 to 32 mm thick. The four-man crew had a Škoda ÚV vz. 38 gun and a ZB vz. 37 machine gun in the turret, with another ZB vz. 37 machine gun in a ball mantlet at the front. 90 rounds of ammunition for the tank gun and 3000 for the machine guns were carried. The water-cooled NR V-8 gasoline motor built by Praga produced 240 HP at 2200 rpm. The top speed was 48 km/h.

On October 1, 1938 German forces invaded Czechoslovakia. While the Czechoslovak forces maintained their tactical and strategic advantage, preventing the Germans to break through the main defensive fortification lines along the border, the Germans finally broke through the defensive lines on October 14, 1938. On October 18 the Germans broke through the defensive line north of Plzeň, and on October 23 the two spearheads of the Tenth Army rendezvoused at Nezvěstice, 15 km southeast of Plzeň, thus encircling the city. As Plzeň (and thus the Škoda Works) now was encircled by German forces, they were unable to produce military equipment for use outside the Plzeň pocket.

Thus, it was now up to Českomoravská Kolben-Daněk to deliver military equipment for the Czechoslovak Army. While focusing on the production of the LT vz. 38s, they began a limited production of five ST vz. 39s a month between November 1938 and January 1939.

See also

• LT vz. 35 - Light tank designed by Škoda Works
• LT vz. 38 - Light tank designed by ČKD