Author: SP15

Between 1928 and 1941 the Swedish based Landsverk company would develop, construct and deliver over 100 AFV’s to nations all over the world, one of which was the Lago (afv not nation). The Lago would ultimately serve as the basis for Sweden’s Strv m/42 and Pvkv m/43 but the original intention behind its design had been to construct a medium tank for the European market.

The rising political tensions between European nations in the mid to late 1930’s made for a lucrative market for anybody invested in the development of military equipment. High tech weapons like tanks were in high demand, and the prospect of selling or licensing the production of potentially hundreds of vehicles made companies like Fiat, CKD and Landsverk invest heavily into AFV development.

Background

Already in 1932 Landsverk had drawn up an extensive catalogue of export offerings which included everything from self propelled anti aircraft guns to armored motorcycles. Their most successful product during this period would be the L-180 series of armored cars but Landsverk also exported a number of tank designs. Going into 1936 it was clear that one design in particular needed to be reworked.

Landsverk L-10

Landsverk’s L-10 medium tank had been adopted by the Swedish military 2 years prior as the Strv m/31. Due to oversights made during its development the m/31 and had proven to be a unreliable design with serious suspension and transmission problems, this prompted landsverk to look into updating the design. The main issues with the Strv m/31 had already been solved by the torsion bar suspension and front mounted transmission introduced with landsverk’s new L-60 light tank design that they had been working on for Ireland.

Landsverk L-60

Landsverk’s replacement for the L-10 was first marketed in 1936 as the Landsverk Lago. The Lago was basically a scaled up version of the L-60 with a reworked hull and turret. With the exception of the front mounted transmission the layout of the Lago was very similar to that of the L-10. The tank now had a 3 man turret and a 5 man crew made up of Commander, gunner, loader, driver and machinegunner. Armament consisted of a 47 mm main gun supplemented by one hull mounted and two turret mounted machine guns. Like its predecessor the Lago made extensive use of sloped and welded armor. A top speed of 45 kph was made possible by the use of two Scania-vabis truck engines, which gave the tank a power to weight ratio of 18 hp per ton. The tank was purely intended as an export design as its 15 ton weight put it way past the weight limit set in place by the Swedish army general staff. Besides, the Swedish army had little interest in medium tanks at the time and were looking to adopt a modified L-60 in the near furure.

Lago drawing circa 1938

Development

In 1938 the Hungarian military had signed a deal with Landsverk for the license to produce the L-60 light tank and L-62 SPAAG, these vehicles would become known as the Toldi and Nimrod In Hungarian service. Around the same time the Hungary had been looking to acquire a medium tank. The Italian M13/39 the Czechoslovak Škoda T-21 and Praga V-8-H were all under consideration but in addition an order was placed with Landsverk for a soft steel Lago prototype to be delivered by 1940.

Lago drawing circa 1940

Landsverk advertisement

To adapt the Lago design to fit Hungarian requirements a number of changes were made including increasing the elevation of the rear turret mg to serve as an anti aircraft weapon, adding a ejection system for spent shell casings to the hull floor and changing the main gun to an Hungarian 40 mm gun. In addition to the three 8 mm machineguns a 12,7 mm mg was added to tanks hull, an alternative design with a turret mounted 12,7 mm was also discussed but dropped since this gun already took up more space than the main gun.

Lago I drawing

The prototype called Lago I was finished in May 1941. By this time Hungary had already moved on and adopted the Skoda T-21 as the Turán I, but luckily for Landsverk the Swedish army was now very interested in getting a medium tank of its own. The decision was made to develop a new 21 ton medium tank with 70 mm of armor protection and a 75 mm gun based on the existing Lago prototype. The Lago I itself would be used to test various various elements in preparation for the production model.

21 ton Lago

Despite lacking much of  the intended equipment the prototype ended up with a weight of 18,3 tons, a significant increase from the original 15 ton estimated weight. Despite this the tank proved to have good mobility in both snow and mud, being able to reach a top speed of 45 kph on roads. Since the tank was mostly used for mobility testing the only armament mounted on the Lago I was its 40 mm cannon, though the possibility of mounting a 57 mm naval gun was discussed.

Lago I prototype

The Lago I was Initially equipped with a German electromagnetic gearbox and a pair of Scania-Vabis 1664 engines outputting 284 hp. Not wanting to be  reliant on foreign components however the tank was refitted with a Swedish produced hydraulic gearbox from Atlas Diesel. In preparation for the increased weight of the production version a more modern pair of Scania-Vabis L 603 engines were fitted in 1942. To fit both the new engines and gearbox the engine compartment was completely rebuilt and the tank renamed Lago I H. During testing with the new powertrain the Lago I H was able to achieve a sustained top speed of 55 Kph, though it was later limited to 45 kph as the gearbox proved unreliable at higher speeds.

7,5 cm Band pv m/42

The narrow chassis of the Lago did not allow for the mounting of a large caliber high velocity AT gun in the turret, due to this the Swedish army recognized the need for a dedicated tank destroyer in 1941. After completing tests of the new powertrain the Lago I H would would have its turret removed and a provisional superstructure fitted to serve as a testbed tank destroyer. In this configuration the tank was armed with a modified 75 mm Lvkan m/30 anti aircraft gun mounted in a ball mount, it was also tested as a heavy assault gun with a 105 mm howitzer. In 1944 this vehicle was refitted with a finalized superstructure and the newly developed 75 mm Pvkan m/43 anti tank gun.  Note the re-worked engine compartment.

Data: Lago I

 

Crew: 5

Weight: 18,3 ton

Lenght: 6 m

Width: 2,32 m

Height: 2,45 m

Ground clearence: 0,4 m

Armament (secondary): 3x 8 mm Ksp m/39

Armament (main): 40 mm Kan Strv

Depression/elevation: -10°/+25°

Armor: 34/34/20 mm

Engine: x2 Scania-Vabis 1664 (142 hp, Gasoline), x2 Scania-Vabis L 603 (162 hp, Gasoline)

Top speed: 55 kph

Ground pressure: 0,5m/cm^2

Trench: 2,4-2,8 m

Fording: 1 m