A military commission was thus sent to France in 1924 with the aim of testing these vehicles. Not very keen on military models, she was content to buy civilian chassis (135 Citroen-Kégresse B2-10CV) on which an armoured superstructure made in Poland was to be adapted. This was copied from the AMC Citroen M23 and simplified. 90 examples were ordered for armored cars, the remaining ones were to be built as trucks or special cars. Two prototype vehicles were built in 1925. One prototype had different, rejected type of armoured body and cylindrical turret. Prototype cars were next evaluated in numerous exercises in the Central Cavalry School and in manoeuvres in Volyn in August 1925. As a result, one of these was accepted. The production began with the first 20 vehicles manufactured in 1927 then assigned for further trials and finally the project was accepted in 1928. The armored car received the designation wz.28 (wzor) and began to supplement and replace the Peugeots in units.

All vehicles were completed in the CWS (Centralne Warsztaty Samochodowe – Central Car Workshops) in Warsaw, armoured plates were delivered by Bismarck Steelworks in Hajduki Wielkie (now Chorzów). In late 1929, an improved narrower hull was developed, with a sloped rear plate and the whole hull was refined except for the turret which seemed to be offset towards the rear. Only one vision hatch was kept at the front. The last 15 cars were manufactured with the new hull, in July-August 1930. By 1930, all 90 cars wz.28 were manufactured, 1/3 of them gun-armed. 

In 1931, the 90 vehicles were in service, 1/3 of them armed with a cannon. 30 were reserved for training (in Modlin) and the other 60 were received by the 5 squadrons of the 5 cavalry divisions (1928-1930), reorganized in 1930 into two detachments of armoured cars, renamed battalions in 1933, then finally split into several units within armoured battalions in 1935.In first five months of 1931, 18 cars supported the Police in supressing communist-inspired riots in Malopolska province. It was next offered to sell these cars to the Police, but the price was considered too high. In 1939 there still was one car wz.28 in the 4th armoured battalion in Brzesc upon the Bug, used for training. Two (or three) vehicles were also left for teaching in the CWBrPanc (Armoured Weapons’ Training Centre) in Modlin. It may be assumed, that these cars were MG-armed.

Unfortunately, after the first years of service, the disadvantages of the wz.28 appeared: low speed (30km/h), questionable reliability for the rubber tracks, heavy maintenance, low off-road capabilities and tendency to roll over because the centre of gravity was quite high.
In 1933, it was therefore decided to convert these armoured cars by removing the Kégresse system for conventional wheels. The first car (nr. 5423) was modified this way in 1934, and its tests came out well. This gave the wz.34 model, the most numerous Polish armoured car which was in service in 1939 during the invasion of the country. These modifications were carried out between 1934 and 1938 on probably 87 vehicles.

Approximately 30  wz.28 were armed with 37 mm SA-18 Puteaux L/21 low-velocity gun with 96 rounds. It was a WWI-vintage weapon, fit best to fighting the machinegun emplacements and infantry, but it could also destroy light armoured vehicles at close range. It had a telescopic sight with 1.5x zoom. Maximum rate of fire was 10 per minute. It fired HE and AT rounds.

The rest (about 60) were armed with one machine gun 7.92mm Hotchkiss wz.25 with 2000 (other source 4200) rounds in 252-round belts. Both weapons were mounted in similar, rectangular Cardan mounts. Usually cars with gun were the squadron or troop leaders’.

Description : 

The armour ranged from 3 to 8 mm for the walls (vertical plates – 8 mm, sloped plates – 6 mm). The floor was made of unarmoured wood. The superstructure was classical for the time in armoured plates and riveted or bolted to a metal frame. The crew consisted of three men (driver, tank commander, gunner). Two doors were allocated to them, one on the left side and one at the rear. The 4-cylinder Citroen B-14 engine of 20 HP was in front of the combat compartment, the radiator protected by two armoured panels operated from the inside. There were some slight differences between the models depending on the year of construction. There was no radio on board at any time, communications were made by flags through a hatch at the top of the turret. A single removable headlight was on the left side, before the driver’s window (they differed on some cars).

The earlier, most common variant of the body had a vertical rear plate, and the crew compartment widened into two sponsons over the tracks. There were two windows before the driver in this variant. The turret was moved rearwards, in relation to the combat compartment. These vehicles differed in details, especially th shape of the radiator cover. Some cars had a blunt nose, other a sharper nose, with a full-length bonnet. The earliest production cars had 7 observational hatches in the turret’s sides, the rest had only two. It should be noted, that there are no reliable plans of these vehicles. The newer version of the body had a sloped rear plate and narrower hull (the turret was slightly wider, than the hull). This version had only one window before the driver. Proportions of the car were changed, comparing with the earlier variant, because the whole armoured body seemed to be shifted rearwards on the chassis, with an exception of the turret, which remained in a similar position above the chassis’ bogie. The turret was octagonal, with a small, hexagonal, opening two-part ventilation and signalling cupola on the roof. In the sides there were two small windows with flaps, and some vision slots (the earliest cars had 7 windows). The turret was mounted on a roller bearing, and turned manually. 

Camouflage and markings :

The wz.28s were initially painted with a four-colors (dark brown, dark green, greyish sand and blue gray) camouflage with sharp edges in 1928. Only the colors were specified, shapes of patches could be different, but they were mostly vertical waves. Some vehicles were dark green only. The nationality mark was the red and white shield with slant division painted on the sides then sometimes the production number painted on the front and sides. In 1932, a three-tone camouflage (yellowish sand, olive green, light blue gray) with sharp edges separated by a thin black line called Japanese style camouflage appeared. The vehicles which survived until 1937, might have been repainted in a final standard three-colour camouflage of Polish vehicles, although it is not sure.

Specifications: