Praga RN

Praga launched the RN in 1933 as a traditional medium-weight truck with rigid axles and a sheet metal cab wrapped around a wooden skeleton and mounted on a ladder frame. Initial production was 94 vehicles, half in 1934. In 1937, a larger carburettor was introduced that increased power from {{convert|38|kW|hp|abbr=on}} to over {{convert|50|kW|hp|abbr=on}} and payload from {{convert|2000|kg|lb|abbr=on}} to {{convert|2500|kg|lb|abbr=on}}, along with a more modern slightly rounded cab. A more radical redesign took place in 1938 with a new cab design with a radiator with more fashionable horizontal vents. This design then remained unchanged for nearly twenty years.

{{Cite book| last1 = Procházka| first1 = Hubert| last2 = Martof| first2 = Jan| year= 2007| title = Praga: motocykly, osobní a nákladní automobily| publisher = Computer Press| place = Brno| isbn = 978-80-251-1667-8| language = Czech| page = 152}}

At the same time, the greater efficiency of the diesel engine, and lower price of the fuel, led to Praga building four test vehicles in 1934 and 1935 equipped with a four-cylinder diesel engine named RND (the D designating Diesel). These were followed by more test vehicles and an initial production run of sixty trucks in 1937. Production of both trucks continued through World War II, until Allied bombing damaged the plant in Libeň on 25 March 1945. During the war, a wood gas powerplant was fitted called Imbert or Janka instead of the spark ignition engine.

After the war, production resumed in a new plant in {{ill|Vysočany (Prague)|lt=Vysočany|cs|Vysočany}}, initially using the wood gas engine. The vehicles had a reinforced frame which increased payload to {{convert|3000|kg|lb|abbr=on}} and led to a proliferation of different designs, from tankers to refuse vehicles, fire engines to buses.{{Cite book| last = Spremo| first = Milan| year = 1991| title = Atlas našich automobil 4: 1937–1963| publisher = NADAS| place = Prague| language = Czech| pages = 124–126}} In 1946, along with petrol for the RN, the RND was reintroduced, now fitted with the Ricardo Comet III that increased power from {{convert|37|kW|hp|abbr=on}} to {{convert|44|kW|hp|abbr=on}} while also improving fuel consumption.{{Cite book| last = Lanc| first = Jan| year = 1954| title = Nákladní automobil 3 tuny Praga RND| publisher = SNTL| place = Prague| language = Czech| pages = 58–66}}

The last RN was produced in 1953. In total, 23,747 vehicles of all versions, including about 2,100 buses, were built. By the end of production in 1955, 16,288 RND had been produced, including 1,630 buses.

The RN was powered by a six-cylinder side valve petrol engine with a stroke of {{convert|80|mm|in|abbr=on}} and bore of {{convert|115|mm|in|abbr=on}}. A Solex carburetor and 75Ah 12V battery were fitted. Maximum torque was {{convert|186|Nm|abbr=on}} and fuel consumption was {{convert|25|L/100km|mpgimp mpgus|abbr=on}}. A {{convert|95|L|impgal usgal|abbr=on}} fuel tank was located under the right seat.{{Cite book| last = Lanc| first = Jan| year = 1954| title = Nákladní automobil 3 tuny Praga RN| publisher = SNTL| place = Prague| language = Czech| pages = 7–13}}

The RND was powered by a four cylinder overhead valve diesel engine with a stroke of {{convert|105|mm|in|abbr=on}} and bore of {{convert|130|mm|in|abbr=on}}. A Bosch injector and 105Ah 12V battery were fitted. Maximum torque was {{convert|226|Nm|abbr=on}} and fuel consumption was {{convert|15|L/100km|mpgimp mpgus|abbr=on}}. A {{convert|70|L|impgal usgal|abbr=on}} fuel tank was located under the right seat and a {{convert|105|L|impgal usgal|abbr=on}} tank behind the rear axle. Drive was to the rear wheels via a four speed non-synchromesh manual transmission and universal joints. Hydraulic drum brakes were fitted all round and suspension was leaf spring.

File:Prvomajski sprevod v Ljubljani 1961 (8).jpg

In 1938, the Kingdom of Yugoslavia launched a competition to find a truck design that would be license produced in the country. The competing vehicles had to complete a {{convert|8000|km|mi|abbr=on|adj=on}} journey across Yugoslav roads of poor quality. The RN won and in 1938, the Zavodi Aleksandar Ranković (ZAR), ancestor of post WWII Industrija Motora Rakovica (IMR) plant near Belgrade, started to receive parts for assembly, the first Yugoslav manufactured vehicle rolling off the production line in 1940. Unfortunately, production was cut short by the invasion of Yugoslavia in 1941.{{Cite web | last = Demic | first = Miroslav | title = Motorna vozila u Srbiji -2 deo: Prvi kamion domace proizvodnje | url = http://www.motorna-vozila.com/motorna-vozila-u-srbiji-2-deo/ | website = Motorna-vozila.com | language = Serbian | accessdate = 15 April 2018}}

Production resumed in 1947 with the name Pionir, but by 1950 less than 1,200 had been made. Production was therefore moved to Tovarna avtomobilov Maribor in Maribor. 17,146 vehicles, known as TAM Pionir, were then produced during the next fifteen years, the last one rolling off the production line in 1962. The majority were flatbed trucks, but a number of fire engines, buses and other vehicles were also produced.{{cite web| last = Kocbek| first = Darja| title = Zgodovina mariborskega Tama skozi razstavljene dokumente| website = Razgledi.net| year = 2007| url = http://www.razgledi.net/2007/10/10/zgodovina-mariborskega-tama-skozi-razstavljene-dokumente| language = Slovenian| accessdate = 15 April 2018| archive-url = https://web.archive.org/web/20100408195320/http://razgledi.net/2007/10/10/zgodovina-mariborskega-tama-skozi-razstavljene-dokumente/| archive-date = 8 April 2010| url-status = dead}}

The RN was popularly nicknamed Erena and the RND was known as Randál, the latter not only simply a phonetic derivative of the initials but also a comment on the noisy engine.{{Cite web | last = Hošťálek | first = Petr | title = PRAGA - nákladní typ RN 1938–1953 | url = http://www.motomuseum-hostalek.cz/index.php?nav=01&t=_art_print&id_art=364&art=1&grhead=2&id_group=21&t_source=_art_sel_alphabet | accessdate = 15 April 2018 | language = Czech| publisher = Jihočeské motocyklové muzeum | place = České Budějovice}}

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Category:Buses of the Czech Republic

Category:Military trucks of Czechoslovakia

Category:Trucks of the Czech Republic

Category:Praga vehicles