Special TATRA trucks – Part 3: "Centipede vehicle" for Oil & Gas
8 December, 2014
In this episode of our series we go back to the turn of summer and autumn of 2013, when another interesting special TATRA truck was made, this time based on T 815-7 range. This special vehicle was created at the request of an Italian manufacturer of drilling rigs.
The basic requirement was a low vehicle posture and mandatory registration of the entire vehicle assembly to normal operation, though with certain exceptions (especially weight and dimensions). Thus, T815-7 chassis with a Euro 5-complaint TATRA engine was chosen as the basis. Due to the necessity to comply with legislative axle-load requirements for each axle, a 6-axle configuration was finally chosen, customized to 12x8 version. Another customer’s requirement was then the limited turning circle of the whole vehicle to 30 meters.
The vehicle is thus designed with a standard air-cooled TATRA T3D-928.31 Euro 5 engine with an output of 325 kW. Also the transmission is standard 14-speed TATRA with the electronic Norgren gear shift system. The axles are made with hub reduction gears. The first two axles are steerable, of course, and suspended with air bellows (as usual for T 815-7). To ensure the maximum ease of design and permanent load to the drill rig superstructure, the 3rd, 4th, 5th and 6th axles are only suspended with leaf springs, whose dimension was "tuned" according to the superstructure weight and its proportion per each axle. The last two axles are steerable, with - now basically standard for TATRA specials - the electro-hydraulic control system from VSE, a Dutch company. All axles are fitted with single tires 445/65 R22.5.
As can be seen from the chassis photos, a unique advantage of the TATRA concept was used in the design of this vehicle, enabling the so-called "frameless" chassis where the bodybuilder can mount their own frame directly to the chassis cross members of the central back-bone tube. In this configuration, the vehicle was shipped to an Italian bodybuilder who bolted the whole body (superstructure, containing, among others, the Caterpillar engine with the Allison transmission to drive the drilling rig) to the chassis and the front of the frame in the agreed points. Subsequently, the vehicle was registered as a set for operation in the Slovak Republic, where it operated.
TATRA 815-7 in this custom design has a wheelbase 2,150 + 3,660 + 1,450 + 2,000 +1,650 mm and the total length with the superstructure 17,650 mm. The vehicle width and height fall within the applicable legislation and amount to 2,500 mm and 3,980 mm respectively. The weight of complete vehicle with all working fluids and the driver is 54,825 kg. The requirement for turning diameter was met, it is exactly 30 meters, the outer turning circle diameter is then 28 meters.