Special TATRA trucks – Part 5: The longest and heaviest Tatra truck in the history rolled out from the Koprivnice factory

21 August, 2015

TATRA TRUCKS has completed the production and shipped the longest and heaviest Tatra truck in the history. This is a chassis for a special drilling rig, to be mounted on the vehicle by a German manufacturer STREICHER Drilling Technology.

The vehicle will be used for exploratory drilling even in difficult terrain. The total weight of the complete vehicle is approximately 84 tons.

In addition to standard trucks, fire-fighting trucks and military chassis, TATRA TRUCKS develops and manufactures chassis for special applications. And the drilling rigs, which are very costly equipment, require a tailored chassis, which will reliably transport them to the sites beyond the reach of roads. Special chassis receive more and more space in the production schedule of TATRA TRUCKS and there are more and more customers who need a specialized solution, which is why they apply to Tatra with their demands.

The chassis has eight axles in total and features the 16x8 drive configuration in accordance with customer requirements. The powertrain arrangement, however, allows the all-wheel drive if needed, i.e. 16x16. The first three axles are air-suspended, steerable, with the capacity of 10 tons. The middle tandem axle is suspended with a combination of air bellows and leaf springs (so-called heavy-duty combined suspension) with the capacity up to 16 tons depending on the used tires and required maximum speed (in this specific case the maximum load is 14.7 tons). The last tri-axle is steerable and again suspended with air bellows, with a carrying capacity of 10 tons. The rear axle steering is hydraulic with electronic steering from the Dutch manufacturer VSE, linked to the front wheel control. Wheelbases between the axles are 2,150/2,150/2,860/1,450/2,150/1,650/1,650 mm. All steering axles are fitted with 85/65 R22.5 single tires, the middle tandem with 315/80 R22.5 dual tires. In this configuration, the total technically permissible weight is 86.4 tons or up to 92 tons when the corresponding tires are used.

A liquid-cooled fork-type 12-cylinder 32-litre 839 kW/1132 hp Caterpillar C-32 engine with the torque of 5143 Nm is used to drive this impressive special truck. Such high power out is only needed to drive drilling rigs, for vehicle propulsion the power and torque are electronically reduced by about half. The engine is followed by the 6-speed Allison 8610 MR automatic transmission with retarder. The drive torque is transmitted through the cardan to the so-called "distribution" auxiliary transmission fitted with gear-shift actuator either at the drilling rig (full engine power) with the output at the transmission top, or the vehicle drive (reduced engine power) with the output at the transmission bottom. The lower output is again connected through the cardan shaft to the auxiliary transmission, already integrated in the chassis backbone tube, where the drive torque is distributed through the divider and inter-axle differentials to the wheels of constantly driven axles - 1st, 2nd, 4th and 5th axles. Both auxiliary transmissions are of proprietary TATRA design with casings and other components based on the standard gearboxes intended for the series vehicles of TATRA FORCE and TATRA PHOENIX model ranges. Two cooling units are mounted on both vehicle sides behind the vehicle cab, each having an hydraulically driven fan, to cool the engine, transmission and hydraulic circuits.

The vehicle is fitted with a standard version of the TATRA FORCE cab with the driver’s and passenger’s seats. The cab is non-tilting in this version and, compared to standard vehicles, due to the desired height limit and with regard to the engine installation it is moved by 200 mm forward and 50 mm downwards. The vehicle frame consists of two parts, bolted together in compartment behand the third axle – the front part is our company’s product, the linked part has been supplied by a German bodybuilder. The overall vehicle length, including frame, is 18,080 mm, the height over cab 2,490 mm and width 3,000 mm. The contour (wall-to-wall) turning radius is 15.5 meters, curb-to-curb 14.3 meters.

After required testing, the vehicle was loaded on a transport semi-trailer using two cranes and transported to Germany where assembling with the superstructure will take place.

Radomir Smolka, Engineering Director, TATRA TRUCKS a.s.