The construction of Kubuś started on 8 August, 1944, one week after the beginning of the Warsaw Uprising, in a car repair shop belonging to Stanisław Kwiatkowski in Warsaw's borough of Powiśle, at the corner of Tamka Street and Topiel Street. The main engineer of the vehicle was Walerian Bielecki, and with no design prepared on paper, all construction was improvised in situ. Kubuś was based on the chassis of a civilian Chevrolet 157 truck which had been license-built in pre-war Poland by the Lilpop, Rau i Loewenstein company. The chassis was fitted with steel plates for protection of the crew, and were bolted to a steel frame and then welded together. The armoured car could carry between 8 and 12 soldiers, and was armed with a Soviet-built DP-27 machine gun, underground-built K pattern flamethrower and hand grenades, in addition to personal armament of the soldiers. The name Kubuś was taken in honour of the wife of one of the constructors known as Globus, as she was killed in early August and had used the pseudonym Kubuś, Polish for "Little Jacob", but also the Polish name for Winnie the Pooh. The construction of Kubuś was completed on August 22, taking only 13 days from the decision to build to the handing over of the vehicle to Home Army fighting units. The vehicle entered service immediately upon completion, and was attached to the "Wydra" motorised unit. The following day, together with a captured Sd.Kfz.251/3 Ausf.D named Gray Wolf, it took part in a failed assault at the main campus of Warsaw University which had been turned into a military garrison by Nazi Germany, and the same assault repeated again two weeks later on September 2. During the second assault Kubuś received minor damage and was successfully withdrawn from combat to Polish-held areas, but it was not repaired and on September 6 it was instead abandoned at Okólnik Street. The original Kubuś survived the war, and in 1945 was towed to the Polish Army Museum as one of the first exhibits after the museum had been looted by the Germans, where it was restored and is currently on exhibition there. A full-scale operational replica was created in 2004 by Juliusz Siudziński and is, as of 2009, on exhibition at the Warsaw Uprising Museum. One of the crewmembers of Kubuś during the uprising was Krzysztof Boruń, who would later go on to become a prominent journalist and science fiction writer.
