Sandvik MT720 Tunneling Roadheader
The MT720 is the largest tunneling roadheader in the range, topping the scales at 135 ton. The boom movement allows for a cutting envelope of 6.6 metres high and 9.1 metres wide with a chain driven conveyor capable of transferring 400 cubic metres of material per hour. The 300kW cutter motor drives the transverse cutting head which makes light work of the toughtest rock and this behemoth has been accurately modelled in 1:50th scale by Conrad.
The MT720 tunneling roadheader features a number of moving and functional parts, starting with the track frames which have intricate detailing cast into the outer surfaces with individually linked plastic track segments, complete with grouser detailing and a tensioned idler allowing the tracks to remain taut and rotate smoothly.
The chassis has two stabilisers mouted to the underside at the rear to stabilise the machine while working and these are fairly stiff and allow the tracks to be raised off the ground. The rear body also houses the simulated fire suppression system.
The front of the model consists of a large bladed structure with a simulated chain driven conveyor in the centre leading up through the body of the machine where the cut material is transported. The chain detailing has been very nicely cast into the parts with the chain links and transfer bars all visible.
The stars mounted to the blade on each side rotate to transfer the material onto the conveyor and the underside of the blade has replicated drive motors, while the entire front assembly is connected to the frame and powered by hydraulics, allowing the front edge to dig into the ground, raising the tracks off the ground to provide excellent stability.
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The electrical and drive components are all mounted to the chassis along both sides, protected by clear plastic covers which can be removed if required, simulating the large plastic coveres used on the full sized machine to reduce the dust and debris buildup.
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One side of the chassis houses the motor, with an intricate photo-etched mesh panel providing protection. Electric motors and electrical cabinets are also mounted to the chassis and these are accurately cast with plenty of fine detailing. |
The cab is mounted high up on top of the machine to provide a good view of the work area with a replicated cabin interior consisting of the main console with two computer screens and joystick controls integrated into the arm rests of the seat.
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The front screen is protected by a plastic frame with tubular bars while integrated front and rear light housings are fitted below the roof. The rear of the cab houses the air conditioning system and the entire cab is mounted on simulated dampers to reduce the vibrations and this has been replicated well on the model. |
All the safety railings need to be fitted to the model, including the side access ladders and these fit snugly into the holes along the outer edges of the upper platform. Three safety railings are provided for the top of the boom however, these are optional and I personally prefer the looks of the model with them omitted.
Another nice addition on the model are the maintenance platforms which can be raised up. There are two on each side and all have a textured surface and keep their raised position well, even holding the weight of a Sandvik figure.
The internal chain conveyor is mounted at the heart of the chassis and extends at the rear, where the internal chain link detailing can be seen, complete with the drive motor on the side. A large, fully adjustable belt conveyor is also supplied with the model and this connects to the rear of the chassis.
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This belt conveyor has a real rubber belt which rotates while the conveyor frame is hinged towards the middle, allowing the angle to be adjusted to one of three different positions. The sides of the conveyor frame have intricate structural support detailing which looks very realistic with an angled inner lip to keep the material running along the centre of the belt. |
Further adjustment can be made as the entire frame is hydraulically adjustable and the hydraulic pistons are stiff enough to hold the chosen position while side-to-side positioning is also possible as the frame will rotate to about 20 degrees on each side (pictured below discharging into the TH550 underground hauler).
The main boom is mounted to the chassis on a turret, allowing the side to side movement of the boom which is initially stiff although it does loosen up a little. The main lift hydraulics allow the boom to be raised and lowered and the range of movement is very realistic, with a hinged protection plate pivoting as the boom is raised to keep the hydraulics beneath protected from damage and this has been engineered well.
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The cutter head is mounted to a telescopically adjustable arm which extends smoothly, as does the protective top cover which is another nice touch on the model.
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The transverse cutter is made of two halves and each consists of seven pieces, cleverly engineered to provide the contours and angles of the cutter housings and picks which look very authentic. The cutter rotates freely and has some very good pick detailing. |
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As expected from Conrad, the paint finish is nop notch with crisp printing of the Sandvik logos on the boom and cab. With over 270 parts, the MT720 is the most complex and detailed release in the Sandvik model range, measuring an impressive 40cm long with a 9cm width and height. The model is supplied in a rigid cardboard box with technical details of the roadheader printed along with an image of the real machine at work while the inside of the box consists of a pre-shaped foam inner to keep the model secure during transport. |
