10TP The 10TP was a Polish light cruiser tank that never left the prototype status . While advancing the Polish armour development programme , the prototype was deemed not successful . Discoveries made during testing that led to the design phase of the newer 14TP model , which was never completed due to the onset of World War II . The 10TP prototype itself was of an original design implementing some general ideas suggested by John Walter Christie but also many new technical solutions . History . At the end of the 1920s , the Polish Armed Forces felt that they needed a new tank model . The Military Institute of Engineering Research ( Wojskowy Instytut Badań Inżynierii , WIBI ) sent Captain Ruciński to the United States to legally acquire a Christie M1928 tank , its blueprint and license . The tank was to be used as a base for a new Polish light tank . The Poles however never received the machine and Christie fearing legal charges , refunded the purchase . Due to this failure to purchase the master model and the possible license , at the end of 1930 the WIBI Tank Design Bureau began preliminary design work on their own wheeled / tracked tank , based on the Christie M1928 and Christie M1931 models , known under the working name " " A la Christie " " . The work was based on available data and advertising leaflets as well as notes and sketches that Captain Ruciński obtained from Christie . In 1932 the design drawings and a list of details were ready but soon the work slowed down because the designers were put in charge of a just - bought British Vickers Mark E tank that led to the 7TP light tank which was developed soon after . At the end of 1934 , because of the liquidation of WIBI and establishing of the Design and Testing Centre of the Armoured Forces reporting directly to the Armoured Forces Command , most of the " A la Christie " project documentation was destroyed under the supervision of a special commission . Only a few hand - written notes and calculations were left . On 10 March 1935 design work on a new model called 10TP was started . Major Rudolf Gundlach headed the design team consisting of , among the others , engineers Jan Łapuszewski , Stefan Ołdakowski , Mieczysław Staszewski , Kazimierz Hejnowicz and a process engineer Jerzy Napiórkowski . Despite the fact that in 1936 the vehicle design was not completely finished , it was included in the programme of Armoured Forces that was a part of a general projection of growth and upgrade for the Polish Army for 1936 - 1942 . This programme was approved by the Armament and Equipment Committee ( " Komitet do spraw Uzbrojenia i Sprzętu " , KSUS ) in January 1936 . The 10TP tank was specified on the list of the equipment scheduled for four tank battalions in the new motorised units . Assembly of the first tank prototype was commenced in 1937 in the Experimental Workshop ( WD ) located within the area of the State Engineering Plants ( PZInż . ) Factory in Ursus near Warsaw , where all Polish tanks were produced in the period of 1931 - 1939 . The work was supervised by Captain Kazimierz Grüner . At the same time two motorised cavalry brigades were formed with the intention that they would be equipped with the tank . Building of the tank was completed in July 1938 . It took so much time because some basic assemblies that were not produced in Poland had to be acquired abroad like an engine of a sufficient output . It was not before 16 August that the 10TP tank rolled out for a first longer ride . It was driven by an experienced military specialist Sergeant Polinarek under personal supervision of the Chief of the Trial and Experiment Department in the Bureau of Technical Studies on Armored Weapons ( Biuro Badań Technicznych Broni Pancernych , BBT Br . Panc . ) Captain Leon Czekalski . The trials were kept secret because the activities of the German Abwehr and the members of the " Fifth Column " were then getting more and more intensive in Poland . Successive trials being stopped by minor faults lasted until the 30 September and then the tank was sent to the WD where design modifications were made . On 16 January 1939 the tank was tested , under supervision of its Chief Designer along a short distance trip to Łowicz and in the spring , between 22 and 25 April it went beyond Grodno , traveling along a total distance of 610 km . After this trip , when a total of nearly 2000 km were logged , the vehicle was sent again to the WD where it was nearly completely stripped down to check the wear on particular parts and assemblies , identify causes of malfunctions and to repair the damage . In May , the refurbished tank was demonstrated to generals and other top ranking military authorities . The designers , having analysed their experiences came to the conclusion that a tank of this type should be a purely tracked vehicle and any equipment needed for driving it on wheels was just an unnecessary weight . Getting rid of this weight allowed them to increase the armour thickness significantly while vehicle weight remained unchanged . Thus another development step of the 10TP was to be the 14TP tank . Its construction was started in the end of 1938 but it was not completed due to the war . Before the tank could enter mass production , German invasion of Poland in September 1939 ended the independent existence of the Second Polish Republic . Design . The 10TP tank had a wide hull that made it possible to put two members of the crew inside side by side , a front machine gun and a 2 - man turret . A solution to the problem of driving the vehicle both on wheels and tracks followed the American design , however Polish designers developed new , wider tracks , drive sprockets and a way of link hooking and moving . The tank steering system using hydraulic servomechanisms was their own advanced solution significantly affecting combat performance of the whole vehicle .