LK II

The Leichter Kampfwagen II (LK II), also known as the light combat vehicle, was a prototype light tank developed by Germany during World War I as a response to the need for a more agile armored vehicle compared to the heavier A7V.^[1] Designed by engineer Joseph Vollmer at Daimler-Motoren-Gesellschaft and authorized in September 1917, the first prototype was tested in March 1918, with production commencing in October 1918 but halted by the Armistice in November.^[2] Weighing approximately 8.5 tons, it measured 5.1 meters in length, 1.9 meters in width, and 2.5 meters in height, accommodating a crew of three and powered by a four-cylinder Daimler-Benz engine producing 55-60 horsepower for a top road speed of 16 km/h and a range of 60-70 km.^[1]^[2] The LK II's design emphasized mobility and simplicity, featuring riveted armor plates ranging from 3 mm on the floor to 14 mm on the front, sides, and rear, with an 8 mm roof, and a suspension system using leaf springs and 25 cm-wide tracks for crossing 2-meter trenches.^[1] Its primary armament consisted of a single 7.92 mm MG 08 machine gun mounted in a rotating turret, though variants were planned with a 37 mm Krupp cannon, reflecting ongoing efforts to enhance firepower amid wartime shortages.^[2]^[3] Despite an initial order for up to 580 units—and later expanded plans for over 1,000—only a limited number, estimated at around 24, were completed before production ceased, preventing any combat deployment during the war.^[4]^[2] Post-war, the Treaty of Versailles restrictions on German armor led to the surplus LK IIs being sold abroad: ten units were acquired by Sweden in 1921 and modified as Stridsvagn m/21 with a 6.5 mm Schwarzlose machine gun for training and limited service until the 1930s, while fourteen were purchased by Hungary in the early 1920s for police and military exercises.^[1]^[2] Survivors include three examples at the Arsenalen Swedish Tank Museum and one at the German Tank Museum in Munster, highlighting the LK II's role as an influential early light tank design that influenced interwar armored development despite its limited production.^[1]

Origins and Development

German Prototype

The development of the Leichter Kampfwagen II (LK II) was initiated in 1917 by the Daimler-Motoren-Gesellschaft as part of Germany's Leichte Kampfwagen (LK) program, aimed at producing a fast light tank for infantry support and exploitation roles.^[1] The project stemmed from the need for a more agile vehicle than the heavy A7V, with initial proposals dating to May 1917 and formal authorization in September of that year.^[1] Led by engineer Joseph Vollmer, who had previously designed the A7V, the LK II evolved from the earlier LK I prototype to meet requirements for a vehicle weighing approximately 6-8 tons, powered by a 45-60 hp engine, and capable of speeds up to 16 km/h.^[4]^[1] The LK II featured a rhomboidal track layout with track-over-wheel suspension, drawing conceptual similarities to British Medium Mark A Whippet tanks due to shared design imperatives for mobility, though no direct copying occurred.^[1] It was armed with a single 7.92 mm MG 08 machine gun in a rotating turret for the primary variant, operated by a crew of three (commander/gunner, driver, and loader/mechanic).^[4] A secondary gun-armed prototype incorporated a 37 mm or 57 mm cannon, but this configuration proved too heavy and was not pursued further.^[5] The chassis utilized a modified Daimler commercial truck base with a rear-mounted four-cylinder engine, emphasizing speed and low profile for flanking maneuvers.^[1] Prototypes were constructed starting in early 1918, with trials commencing in March and continuing through the summer.^[1] By June 1918, two units were completed, demonstrating a top speed of 14-16 km/h but revealing technical challenges, including engine overheating and poor ventilation that necessitated additional cooling fans.^[5] Track performance on rough terrain was initially hampered by narrow plates, leading to the adoption of wider 25 cm tracks and mud chutes for improved traction; steering issues also arose in the gun variant due to rear weight distribution.^[1]^[5] The Armistice of November 1918 halted the program shortly after the start of production in October, with an initial order for 580 vehicles (later expanded) canceled; only a limited number, estimated at 2 to 24 vehicles, were completed, depending on the source.^[4] Subsequent restrictions under the Treaty of Versailles prohibited further tank development in Germany, limiting the LK II primarily to experimental status.^[1]

Post-War Transfer to Sweden

Following the Treaty of Versailles in 1919, which prohibited Germany from producing or exporting military equipment including tanks, the German firm Wilhelm Ugé GmbH secretly arranged the sale of components for 10 LK II light tanks to neutral Sweden in 1921 to circumvent these restrictions.^[1]^[6] The transaction was conducted discreetly, with parts disguised as tractor components to avoid Allied scrutiny.^[7] Sweden's military, through the Kungl. Armeförvaltningens Artilleridepartementet (KAAD), pursued the acquisition to address the need for modern armored vehicles amid post-World War I defense modernization efforts. Negotiations began in July 1921, initiated by Swedish Military Attaché Major H.R. Låftman in Berlin, leading to a purchase agreement signed on July 22, 1921, by Captain Walter Elliot as a private intermediary for 10 sets of incomplete LK II hulls and associated parts.^[8] This interest was driven by Sweden's strategic position as a neutral nation seeking to develop an early armored doctrine without direct involvement in the recent conflict.^[1] Deliveries commenced later in 1921, with the first five sets of parts arriving in Stockholm by September 21, followed by the remaining five shipped by September 27; additional shipments, including 10 tons of armor plates from Lübeck, reached Sweden by January 7, 1922.^[8] The components encompassed chassis elements, transmissions, and armor plating, though engines and other fittings required separate integration. The total cost to Wilhelm Ugé GmbH was approximately 2,500,000 Reichsmarks, supported by a Swedish parliamentary grant of 1,651,900 SEK approved by King Gustav V in 1921 for defense-related technical acquisitions.^[8] Initial assembly faced logistical challenges due to the staggered arrivals of parts, which delayed progress at the Stockholm Tygstation workshops where work began on the first vehicle by April 4, 1922. To reduce costs and improve efficiency, assembly of the remaining nine tanks shifted to the Naval Shipyard in April 1922, with assistance from German foreman Steger of Wilhelm Ugé GmbH; armor plates required oil curing to prevent cracking, a process that extended completion of the prototypes until November 1922.^[8] These efforts marked Sweden as one of the first non-belligerent nations to acquire and domestically assemble post-World War I tanks, reinforcing its neutral stance while laying groundwork for indigenous armored capabilities.^[1]

Design and Variants

Core Design Features

The Leichter Kampfwagen II (LK II) employed a compact rhomboidal hull layout optimized for mobility in World War I conditions, with the front-mounted Daimler-Benz four-cylinder gasoline engine positioned to the left of the driver's station, creating a forward driver position for improved visibility and control. The central fighting compartment accommodated the commander, gunner, and loader, serving as the primary area for operations and armament handling, while the rear featured the drive sprocket and access door for crew entry and maintenance. This arrangement emphasized a low silhouette and balanced weight distribution, with pistol ports on the hull sides and rear for defensive fire, though the original design lacked dedicated side sponsons for machine guns.^[1]^[4] The suspension system utilized leaf springs to support eight small road wheels per side, arranged in two articulated bogies (four wheels each) for enhanced terrain negotiation, complemented by four return rollers, a front idler wheel, and rear drive sprocket. Tracks measured 25 cm in width, contributing to effective cross-country performance despite the vehicle's light construction and providing stability on uneven ground without excessive ground pressure.^[1]^[2]^[3] Power was delivered by a water-cooled Daimler-Benz Model 1910 four-cylinder gasoline engine producing 55-60 horsepower, paired with a mechanical transmission that drove the rear sprockets, achieving a top road speed of 16 km/h and an operational range of approximately 60 km on 150 liters of fuel stored in protected tanks.^[1]^[4]^[2] The LK II operated with a three-man crew, comprising the driver at the front, and the commander/gunner and loader in the central compartment, where basic vision slits provided situational awareness amid limited internal space and no installed radio for communication. The design incorporated a manually traversed small turret atop the fixed superstructure for the primary machine gun, prioritizing simplicity and rapid production over advanced ergonomics.^[1]^[2] Armor consisted of riveted steel plates varying from 8 mm on the roof to 12-14 mm on the front, sides, rear, and key hull sections, and 3 mm on the floor, offering protection primarily against small-arms fire and artillery shrapnel while maintaining the vehicle's weight under 8.5 tons.^[1]^[2]

Planned Variants

Although production models were armed with a single machine gun, variants were planned to enhance firepower. A gun-armed version featured a 37 mm Krupp cannon, either in a casemate superstructure or adapted turret, with at least one prototype tested using a 57 mm Maxim-Nordenfelt gun. Additionally, the LK III was proposed with a rear-mounted engine for better weight distribution but was never built due to the war's end.^[1]^[2]

Swedish Modifications

Upon receiving the components from Germany in 1921, the Swedish Army assembled 10 LK II vehicles into the Strv m/21 configuration between early 1922 and mid-1922 at the Stockholm Tygstation and the Naval Shipyard in Karlskrona.^[8] These initial modifications replaced the original German MG 08 machine gun with two Swedish 6.5 mm m/14 Madsen machine guns to align with local armament standards and logistics.^[9] The assembly process addressed immediate integration needs for the chassis into Swedish service, with the total acquisition and completion costing approximately 2,500,000 Reichsmarks for the parts alone, plus additional domestic labor expenses.^[8] In 1929, a comprehensive modernization program transformed the Strv m/21 into the Strv m/21-29 variant, beginning with five vehicles upgraded at the newly established AB Landsverk facilities.^[10] The primary upgrade involved installing a Scania-Vabis 1544 four-cylinder engine producing 85 horsepower, significantly improving the power-to-weight ratio over the original 55-60 horsepower Daimler-Benz unit and raising top speed to approximately 16 km/h.^[11]^[12] Between 1931 and 1934, three additional vehicles received similar updates at Landsverk for training purposes, bringing the total modernized to eight units by the mid-1930s.^[11] Further enhancements focused on operational reliability, incorporating improved frontal armor, electric lighting throughout the vehicle to support night operations and maintenance.^[11]^[10] The program, planned from 1928 and completed by 1929 for the initial batch, ensured the tanks remained viable for training and evaluation until their retirement in 1938.^[10]

Specifications

Dimensions and Performance

The German prototype of the LK II measured 5.1 meters in length, 1.9 meters in width, and 2.5 meters in height, with a combat weight of 8.5 tons. Crew consisted of three. These dimensions differ slightly from the Swedish-assembled versions, including the Strv m/21 and subsequent m/21-29 variants, which measured 5.7 meters in length, 2.05 meters in width, and 2.52 meters in height.^[1]^[4]^[10] The baseline weight increased in Swedish service due to the addition of armor plating and armament, reaching 9.7 tons in both the Strv m/21 and m/21-29 configurations. This progression reflected the evolution from a lightweight prototype to a more robust training and utility vehicle.^[9]^[10] Mobility characteristics of the LK II emphasized its role as a light, maneuverable design, with a ground pressure of approximately 0.45 kg/cm² enabling operation on varied terrain. It could ford water up to 0.6 meters deep, cross trenches of 3 meters, and climb vertical steps of 0.6 meters. The prototype achieved a top speed of 16 km/h on roads, while Swedish upgrades adjusted cross-country performance to 12 km/h, accounting for the added mass.^[1]^[13] The vehicle featured two fuel tanks with a total capacity of 150 liters, providing an operational range of 60-70 km depending on conditions. It was powered by a four-cylinder Daimler-Benz engine producing 55-60 horsepower. Power-to-weight ratios were approximately 7 hp/ton for the German prototype and approximately 6.2 hp/ton in the heavier m/21 due to engine retention amid weight gains. Basic mobility can be illustrated conceptually by the relation v = \frac{P}{m \cdot k}, where v is speed, P is engine power, m is mass, and k is a drag factor incorporating terrain resistance, highlighting how increased mass reduced velocity in upgraded forms without proportional power boosts.^[1]^[9]^[2]

Armament and Protection

The German prototype LK II was armed with a single 7.92 mm MG 08 machine gun mounted in a rotating turret, providing 360-degree traverse capability.^[1] The MG 08 had a rate of fire of approximately 500 rounds per minute and an effective range of up to 600 meters against infantry targets.^[14] Ammunition was stored in hull bins, with no secondary armament such as grenades provided. In Swedish service as the Strv m/21, the LK II was rearmed with two 6.5 mm ksp m/14 machine guns mounted in the turret.^[9] These machine guns had a cyclic rate of fire around 480 rounds per minute and an effective range of 2000 meters.^[15]^[16] Total ammunition capacity was approximately 6,000 rounds, stored in internal bins. Protection consisted of homogeneous riveted steel armor plating, with 12-14 mm thickness on the frontal hull, sides, and rear, 8 mm on the top, and 3 mm on the bottom plates; no spaced or sloped armor was employed.^[2] This provided resistance to 7.92 mm bullets at 100 meters but offered no defense against 20 mm autocannon rounds, which could penetrate the armor at typical combat ranges.^[1] Crew exposure was heightened by vision ports and hatches, presenting vulnerabilities to small-arms fire and shrapnel.^[1]

Operational History

Service in the Swedish Army

The Strv m/21 tanks entered the Swedish Army's inventory in 1922 after their reassembly at the naval dockyards in Stockholm from components purchased from a German firm and shipped in disguised form, with official designation and experimental deployment beginning that year. Sweden purchased 10 incomplete LK II tanks from Wilhelm Ugé GmbH in Berlin in July 1921 for approximately 200,000 SEK, with assembly overseen by German foreman Steger. They were assigned to the Life Guards Dragoons (P 1) in Stockholm, forming the nucleus of the Panzervagnarna armored vehicle unit established in August 1922 for initial trials and evaluation.^[17]^[18]^[8] From 1923 to 1938, the vehicles served primarily in crew training and doctrinal development roles, participating in regular military exercises to test armored integration with infantry. Notable early maneuvers included the August 1923 operations in Skåne, where five tanks supported infantry advances but revealed mechanical vulnerabilities and mobility constraints due to frequent breakdowns and limited spare parts availability. By 1927, Swedish-manufactured components had alleviated some shortages, allowing sustained use despite ongoing reliability issues.^[17] In 1929, five of the original ten Strv m/21 were upgraded to the Strv m/21-29 variant at AB Landsverk, incorporating a more powerful Scania-Vabis engine, improved transmission, and enhanced armament options such as a 37 mm gun, which extended their operational viability. These upgrades, completed between 1930 and 1934, maintained a fleet of ten vehicles (with the remainder cannibalized for parts) focused on reconnaissance-oriented training rather than frontline combat. The tanks saw no actual engagements, as Sweden remained neutral during World War II, but their service laid foundational experience for subsequent armored formations.^[9]^[17] Decommissioning began in 1938 amid growing obsolescence, with the Strv m/21 and m/21-29 phased out by 1939 and replaced by the more modern Strv m/37 medium tank. The vehicles' emphasis on light, mobile operations during training influenced early Swedish armored doctrine, prioritizing reconnaissance and support roles in defensive strategies.^[19]^[9]

Preservation and Legacy

The only surviving examples of the LK II are Swedish variants known as Strv m/21 and Strv m/21-29, with no original German prototypes extant, as all were destroyed or scrapped following the Armistice of 1918 and the restrictions imposed by the Treaty of Versailles.^[1]^[20] Among these, Arsenalen Tank Museum in Strängnäs, Sweden, preserves the most complete collection, including one Strv m/21-29 restored to running condition in 2018 and another Strv m/21-29 hull in storage, originally displayed at the now-closed Axvall Tank Museum before the collection's transfer in 2009.^[1]^[7] A third Strv m/21-29 is held at the Deutsches Panzermuseum in Munster, Germany, restored to approximate original German LK II configuration for display purposes.^[1] Restoration efforts at Arsenalen focused on returning the primary Strv m/21-29 to operational status, completed in 2018, including engine rebuilds using period-appropriate components, replacement of deteriorated tracks, and repainting in the original German gray scheme to reflect its 1918 heritage.^[7]^[21] Since 2018, the museum has conducted public demonstrations of the operational vehicle, allowing visitors to observe its mobility and providing insights into early 20th-century tank mechanics during events and guided tours.^[22]^[23] The LK II holds significant legacy as the foundational vehicle for Sweden's armored forces, marking the nation's first acquisition of tanks in 1921 and enabling the development of domestic production capabilities that shaped subsequent designs, such as the Strv m/37 light tank in the 1930s.^[18]^[8] Recognized as among the oldest operational tanks preserved in any museum, its survival underscores the evolution of light tank concepts from World War I prototypes to interwar reconnaissance vehicles.^[21] Culturally, the LK II has been featured in educational media, including a 2020 documentary-style video series produced at Arsenalen that details its restoration and historical context, highlighting its role as a symbol of early tank warfare innovation and Sweden's neutral yet proactive military modernization.^[23]^[22]