Telling apart the 810s from the 251s

Looks can be deceiving and perhaps all the more in the case of this half-track. You’d be forgiven for thinking this is a German-built SdKfz 251, but in reality we are looking at a post-war Czechoslovak half-track. In this article I will lay out the history of both vehicles and introduce you to some of the telltale signs which will help you tell these two apart in the future!

Workhorse of the mechanised infantry ​[1], [2]​

Prior to the Second World War many nations experimented with mechanisation of their troops and started trialling combined-arms tactics. During this time Germany began building a small nucleus of highly mobile units. The result of this development was the leichte Division, a concept later converted to the Panzer-Division. Other than tanks, the Panzer-Division included infantry to consolidate territory gains and provide flank protection to armoured thrust. By combining armour and infantry, the unit was able to exploit its own successes effectively and could act as a self-sustaining whole.

Infantry dismounting an Sd.Kfz. 251 Ausf. A half-track

To move up with the armour the infantry used trucks or rode to the front on the tanks. Once near the front, the infantry had to dismount and continue on foot. To get closer to the action, infantry were also mechanised using armoured troop carriers. Due to the limited capacity of the German armaments industry the lion’s share of Schützen (from 1942 Panzergrenadiere) remained reliant on ordinary trucks throughout the war. Only a minority would be mechanised using armoured half-tracks.

Advent of the armoured half-track

The first German half-tracks were originally developed as prime movers during the early 1930s. The SdKfz 251 half-track was based on the 3 t half-track chassis ‘H kl 6’ or SdKfz 11. This type was the culmination of a series of 3 t half-tracks, development of which had begun at Hansa-Lloyd-Goliath in 1933 and was later improved upon by Hanomag. It features a suspension of large, interleaved roadwheels with lubricated, rubber-padded tracks. The sprocket does not have teeth, but rollers instead.

With the help of Büssing-NAG the H kl 6 was turned into the H kl 6p. The chassis was modified to fit an armoured superstructure consisting of armour plates riveted or welded together. Due to the relatively thin plating of 8 mm on the sides to 14.5 mm frontally, the vehicle’s weight could be kept down to 8.5 t. According to Mr. Doyle, the thin armour plating was superior to allied armour plate of the same thickness thanks to German advanced in the field of steel and armour production1. The superstructure was sloped on all sides, increasing relative armour thickness, though at the same time decreasing internal volume. The vehicle accommodated 12 people including the driver. Its first known official listing dates from May 1939 were it is called ‘3 t Mannshaftstransportwagen gepanzert (Kfz 251)‘. The SdKfz 251 later became known as mittlere Schützenpanzerwagen, abbreviated as mSPW.

In spring 1939 first vehicles were handed over to the army. A batch of little more than 84 armoured half-tracks were trialled during the Polenfeldzug. Already in October 1939 Schützen-Regiment 1 of 1. Panzer-Division began incorporating 155 mSPW into their ranks. Initially, the 251 was used primarily as a carrier and fighting was done out on foot, but this vision gradually changed in favour of mounted combat.

Jack of all trades

Improvements were made to the 251’s design throughout the war. The last model, the Ausf. D, featured many simplifications to speed up production. Besides the various models, the 251 was produced in many different variants, adapted to perform all kinds of duties. Apart from the base variant 251/1, there were a further 22 (!) different variations ranging from command vehicle (251/3) to infrared floodlight (251/20 ‘Uhu’) as well as a version mounting triple machine guns (251/21 ‘Flak-MG-Drilling 151’). By the end of the war over 15,000 specimen of the 251 had been produced.

Reinventing the wheel ​​[3]–[6]​

After the war, the SdKfz 251 was adopted unchanged for service in the Czechoslovak People’s Army (ČSLA). 600 of these half-tracks were used under the local designation Obrnený Polopás 3 tonový Nemecký (OPp 3t N) which roughly translates to ‘Armoured half track 3 ton German’. The vehicle was also referred to as ‘Hakl’. Škoda, one of the assembly firms of the 251, helped out with repairs and carried out major overhauls on these half-tracks. Reportedly, 549 Hakl were still in service as late as 1959 at which point they were gradually discharged from service.

During a phase of national rearmament of the ČSLA, starting from 1947, a number of projects for the development of a new APC were put in place. Non of these projects made it past the drawing board. Instead, the further development of the H kl 6p was ordered in 1952 under the name ‘HAKO’ – most likely a reference to the companies Hanomag, Hanover and Tatra, Kopřivnice .

Infantry leaving an early OT-810 in style. Note the straight sides which identifies this as one of the first 320 vehicles.

Still half-expecting APC deliveries from the USSR, the army mainly treated the HAKO as a transitional vehicle and awarded a contract for limited production. Due to ever changing plans and the continued interest of the ČSLA in Soviet APCs, production dates were pushed back multiple times. When the army staff realised that the rival domestic APC design ‘TOPAS’ could only start production in 1962, the HAKO was ordered into production as a faster alternative. The HAKO entered service under the designation Obrnený transportér 810 or simply OT-810. Production began at the Slovakian Podpolianské strojírny firm in Detva by late 1959. After production of 320 vehicles, in 1961 the superstructure was changed to have kinked sides. When production ceased in 1962, a total of 1130 baseline OT-810s had been produced. In addition 320 of the command variant OT-810/R2 were produced. All in all, a mere 1450 vehicles have been produced.

The redesigned OT-810 retained the 251’s familiar shape, but changed almost all other components. The hull was altered as well as the drive train, incorporating the Tatra T-928-3 V8 diesel engine. The overall superstructure is reminiscent of the Ausf. D model, but the stowage bins were deleted and the rear doors were mounted like on the earlier 251 models. Much of the original German complexity was done away with. Instead of the differential Cletrac system, simple clutch-brake steering was used. The sprocket was of a regular toothed type and the lubricated, rubber padded track was replaced with an unpadded, non-lubricated version.

It also saw the addition of some ‘features’ including an armoured roof consisting of two hinged plates. The forward roof plate has a dedicated hatch for the commander from which he could access a pintle mounted machine gun. Pistol ports were added to both sides as well as in the read door. Apparently, the nose of the OT-810 is also somewhat longer as the Tatra V8 needs more space than the inline 6-cylinder Maybach HL 42.

The vehicle held at the museum ‘Wings of Liberation’ in Best, the Netherlands is an OT-810/R2 command variant. These are recognisable by he two slots in the hull’s right side. These slots serve as air intake and exhaust for the generator powering the radio equipment. Although this specimen is painted up to represent a vehicle of Panzer-Abteilung 2107, it still pretty much is an original OT-810.

A standard variant in at museum ‘Batterie Todt 39-45’ in France, also painted with German unit markings.

Outdated on Arrival

Soon after the last OT-810s rolled off the assembly line, they were being replaced by the more modern OT-62 ‘TOPAS’. The TOPAS, an improved version of the Soviet BTR-50P, entered service in the late 60s with Czechoslovak tank divisions. The fate of the OT-810 was no better with mechanised infantry units as they soon adopted the wheeled OT-64 ‘SKOT’. In contrast to the OT-810, the OT-62 and OT-64 featured NBC protection along with night fighting and amphibious capabilities. It comes as no surprise that the OT-810 was not granted a long service life and was quickly discharged from service. Many of these half tracks spent their days in ‘untouchable’ long-term storage during the 70s, ready to respond to a threat. Between 1966 and 1969, 280 found their use as a self-propelled gun variant, the OT-810D, carrying an 82 mm M59A recoilless gun. Starting from mid 1980, many OT-810s were decommissioned. After signing of the Treaty on Conventional Armed Forces in Europe in November 1990 excess OT-810s of all types began to be scrapped. Some found their way to museums and collectors.

It is surprising that Czechoslovakia chose ‘rebuild’ the 251 as its shortcomings had long been recognised in the Wehrmacht. Among others, mobility, towing capacity and armour/mine protection of the leichter and mittlerer Schützenpanzerwagen (SdKfz 250 and 251) were found to be insufficient ​[7]​. In November 1941 Wa Prüf 6 drew up a specification for a replacement APC. Armoured half-tracks were declared a makeshift solution and fully-tracked vehicles were the way forward. Auto-Union and B.M.M. developed multiple prototypes of a fully-tracked APC. From February 1943 the project was named Kätzchen. The new APC was never introduced due to anticipated loss of half-track production preceding production of the Kätzchen ​[8]​.

The worst of two worlds?

On the verge of being replaced by the Wehrmacht, and generally disliked in the ČSLA, the half-track seems to be getting a rough deal. There are, however, still plenty of enthusiast lovingly restoring these relics of the past. Today OT-810s are in demand as 251 look-alike and it is not uncommon to see them dressed up as its German predecessor. Some collectors have gone out of their way to make them appear as close as a 251 as possible, involving complete rebuilds of the upper structure. These rebuilds remain easy to spot, because of their drive sprockets and tracks. Enjoy these photos of an Ausf. C and D conversion. By now it should be a breeze to tell a 251 from a 810: even when the superstructure is rebuild, the suspension gives it away.

  1. [1]
    W. Spielberger, Die Halbkettenfahrzeuge des deutschen Heeres: 1909-1945. Motorbuch Verlag, 1993.
  2. [2]
    T. Jentz and H. Doyle, Panzer Tracts No. 15-2 mittlere Schuetzenpanzerwagen Sd.Kfz.251. Panzer Tracts, 2005.
  3. [3]
    J. Frýba, Obrněný transportér OT – 810: historie, takticko-technická data, modifikace. Grada Publishing, 2017.
  4. [4]
    M. Burian, “Obrněný transportér OT-810,” Vojenský historický ústav Praha, 12-Dec-2018. [Online]. Available:
  5. [5]
    R. Folprecht, “Stůj, nebo se netrefím! Dlouhý život obrněných transportérů OT-810 z Detvy,” / Magazíny, 05-Jan-2020. [Online]. Available:
  6. [6]
    F. Vladimír, Československé tankové síly 1945-1992. Grada Publishing, 2012.
  7. [7]
    H. Doyle, L. Friedli, and T. Jentz, Panzer Tracts No.15-4. Final Developments of the Schützenpanzer Sd.Kfz.251 to Vollketten M.S.P. Kätchen. Panzer Tracts, 2017.
  8. [8]
    “The ‘Armaments Miracle,’” in Germany and the Second World War, vol. 5, Clarendon Press, 1990, pp. 686–688.