Schwere Minenräumer Alkett VsKfz 617 (NK-101) - case report

Kameraden!!!

         Let's talk about another weird and rare girl: the Schwere Minenräumer Alkett VsKfz 617 (NK-101)

Schwere Minenräumer Alkett VsKfz 617 (NK-101)
Tank Museum Kubinka - Russia

History:

      In military science, minefields are considered a defensive or desabling weapon, used to slow the enemy advance, to interdict certain terrain to the enemy, to direct the enemy into kill zones or to reduce the morale, affecting randomly equipment and killing or crippling (which is worse for morale...) personnel and soldiers. In some battles during World War II, anti-tank mines accounted for half of all vehicles disabled.

      Since combat engineers with mine-clearing equipment can clear a path through a minefield relatively quickly, mines are usually considered effective only if covered by fire.

      Disabling these minefields quickly and safely has always been a major concern for military theorists. Several machines and methods have been idealized and tried.

       The Schwere Minenräumer ( German: heavy "mine cleaner") was a heavy German experimental minesweeper, which was built using some parts of the SdKfz 101 Panzerkampfwagen I light tank.

      Manufactured in 1942 by the Alkett factory near Berlin, the VsKfz 617 Schwere Minenräumer (NK-101) was heavily armored and designed to detonate mines by simply rolling over them. (VsKfz is the abbreviation for Versuchs Kraftfahrzeug, meaning “test vehicle.”). The three-wheeled vehicle’s wide track was designed to clear a mine-free path for other vehicles in the battle field. The sole prototype carried the Alkett chassis number of  9537 and was registered as NK-101.

Schwere Minenräumer Alkett VsKfz 617 (NK-101)

when of its capture by the Russians

Schwere Minenräumer Alkett VsKfz 617 (NK-101)

different angle of photo...

Schwere Minenräumer Alkett VsKfz 617 (NK-101)

when of its capture by the Russians - rear view

   The Mineräumer was built using the turret and the front case of the light SdKfz 101 Panzerkampfwagen I  The turret was armed with two MG 34 machine guns 7.92mm.

      The minesweeper was moving on three large wheels: two in front and one behind. These wheels were designed to withstand the explosions of mines when passing through minefields. 

Schwere Minenräumer Alkett VsKfz 617
Notice the big wheels...

     Each wheel was equipped with steel "feet" fixed in a floating position so that three of them leaned on the ground in any position of the wheel - in order to create the maximum area of ​​contact with the ground, which was better to dissipate the blast wave from mines triggered by the weight of the machine .

      An additional advantage was the reduction of the trawler's pressure on the ground, because it had a weight of 50 tons. Theoretically, she could withstand the explosion of any mine.

Schwere Minenräumer Alkett VsKfz 617
when of its capture by the Russians - front view

      The Mineräumer had dimensions of 6.500mm in length, 3.170mm in width and 2.800mm in height. The ground clearance was 800mm, and the bottom protection was 40mm. Inside, to protect the units from the explosion of large mines, an additional 20mm armored screen was installed on the floor. Because of its weight, size and pressure on the ground, its maximum speed was only 15 km/h .

     

      The traction was on the front wheels, and the rear was driven through the chain drive from the cabin in the body. The trawler was equipped with a Maybach HL120 V12 engine with a power of 300 hp. On tests the vehicle showed its inefficiency - because of its great weight, sluggishness and low speed, it was an excellent target for artillery. Therefore, the project was curtailed, the whole thing was limited to the construction of the prototype.

Vehicle arrangement:
      The hull is divided into four compartments:

1. Driving copartment
2. Combat copartment
3. Transmission copartment and
4. Engine compartment.

      The driving compartment is situated in the front-most part of the hull. There are driver's seat, controls, and dashboard in there. The combat compartment is situated behind the driving compartment, in the upper part of the hull.

Schwere Minenräumer driver's station

      There are two MG 34 7.92mm machine guns, ammunition complement and the machine gunner's seat in the compartment. The transmission compartment occupies the mid-section of the hull. There are differential gear, gearbox, reduction gear, main transmission, intermediate transmission, main wheels axis, battery and controls in the compartment. The engine compartment is in the after part of the hull, and is separated from the transmissions compartment by the perpendicular fire-wall. There are engine, main clutch, radiators, fans, fuel tank and controls in the compartment. 

Description of Schwere Minenräumer Alkett VsKfz 617: 

General data:

       German mine trawler is a special purpose vehicle. It was based on a specifically built chassis, and it is a wheeled trawler of the rut type. The sweeping apparatus consists of independently suspended steel plates on the main and steerable wheels circumference. The swept area is discontinuous and consists of three parallel ruts of 1.900mm combined width. The distance between the side ruts and the center rut is 635mm on each side.

Schwere Minenräumer Alkett VsKfz 617 (NK-101)

Tank Museum Kubinka - Russia

Hull and Turret:

      Hull is welded of rolled armor plates, 20 to 40 mm thick. Plates are made of low-hardness armor steel (d = 4.4-4.5mm). All joints are welded with an X-shaped weld. Front armor, 35-40mm thick, are sloping at 30-75°. The hull is double-bottomed. The outer bottom is 40mm thick, and the inner is 20mm. The outer bottom is convex, two gabled, made of two armored plates contact welded at an angle in the center. The inner side is reinforced with nine transverse and three longitudinal stiffening ribs, each of 20mm thickness. The height of the ribs is varying, diminishing from the center line towards the sides. The inner bottom is flat, removable - it is bolted to the outer shell. All internal mechanisms are mounted on the inner bottom. On top of the hull, in the front portion, a machine gun turret ring base is fitted - a welded box of rolled steel plates, 10-15mm thick.
      The turret box is bolted to the hull by lieu of the steel formers. The rear part of the hull is covered with a removable hood. The turret ( from SdKfz 101 Panzerkampfwagen I ) was also welded of rolled plates of low hardness.

Armament:

      The  Minenräumer was armed with two 7.92 mm caliber MG 34 machine guns installed in a 360° rotation turret. 

Propulsion:

      All propulsive machinery is installed within the engine compartment of the after hull. The Maybach HL-120 gasoline engine (from Pz III and Pz IV tanks) is set in the forward part of the compartment.

Maybach HL-120 V-12 gasoline engine

      The engine is set perpendicularly to the vehicle axis. The engine is mounted flexibly, on three points. There are two mounting points at the rear and one in the front, set into a transverse mounting bar. Port of the engine where the flywheel is situated was considered the rear one. Lubricating system of the pressure-circulating type. Lubricant tank of 25 liters capacity is situated on top of the engine, to the right of the crankcase. Cooling water radiators were situated, along with the cooling fans, on sides of the engine compartment. The fans of axial variety, powered by articulated shafts by the engine. Fuel tank is situated in the rear niche of the hull.

Power transmission:

      Mine clearing vehicles power transmission chain consists of: 

1. Main clutch
2. Differential gear
3. Gear box with reduction gear
4. Main and intermediate transmission
5. Side transmissions
6. Steering system
7. Brakes
8. Undercarriage

• Main clutch: dry, multidisc, steel with friction pad
• Differential gear: Differential gear is transmitting the torque from driven digs of the main clutch to the gear box. It has three constantly engaged intermediate cogwheels.
• Gear box with reduction gear: The gear box is situated in the after pad of the transmission compartment, on the left side. The gear box is of the three-staged variation with eight speeds with a reduction gear. Speeds are switched by moving cogs. Various combinations of the moving cogs and the ones rigidly placed on the shaft enables to find a suitable ratio for transmitting torque from the engine shaft to the main transmission.
• Main and intermediate transmission: The main transmission transfers the torque from gearbox to the intermediate transmission by means of the side shafts. At the some time it serves as a reduction gear. The intermediate transmission enabled the front axis with main wheels to be moved further forward.
• Side transmissions: Side transmissions are fitted directly inside the main wheels and are of a one-step reduction gear with internal splines variety. The main shaft of each transmission has 9-toothed cog cut into it. The main shaft revolves in two roller bearings. There are 42 bolts of 40mm diameter fined into the main wheel hub, together forming one epicyclical gear.

• Steering system: The mine clearing vehicle is steered by braking one of the main wheels coinciding with steer-able wheel deflection. The steerable wheel deflection is being powered with the torque derived off the differential gear. Steering system consists of the steering wheel, articulated shafts system, power transmission reduction gear, worm wheels and steering chains. When driver turns the steering wheel, the steering shaft is turning the articulat-ed shafts chain, which in turn activates proper side transmission. By the same turning movement, the steering wheel shaft activates the worm wheels with the reduction gears. Accordingly to the direction of shaft turning, ane of the worm wheels starts to turn up, the other down, pulling on the chains, which in turn drag the steerable wheel steering quadrant and deflect it accordingly. The quadrant of the steerable wheel is connected to the turning indicator at the driving compartment by cables. The steerable wheel deflection indicator pointer is fitted at the left side of the front hull plate.

Schwere Minenräumer Alkett VsKfz 617
Steering wheel

• Brakes: Braking straps are acting on the main wheels. They are fitted on the outside rim of the main wheel hub. The straps we sewn with friction pads. They are 75mm wide. The brakes are activated by the levers on the left and right side of the driver's seat in their steering role, and with a foot pedal for braking.
• Undercarriage: Main wheels are mounted on both sides of the thick axis, going across the hull and extending on both sides. The outer diameter of the axis is 350mm, while the inner is 250mm. A cuff is fixed on the main axis with a bronze slide bearing. On the spherical portion of the cuff two rings are set, with two tones set on the cylindrical portion. The main wheel hub rests on cones and rings. The cones are centering the hub. There are 14 holes in the outer ring surfaces for the hub connecting bolts. There is a toothed ring set on the main wheel hub, connecting the wheel with the plate-shaped mine-clearing caterpillar track links. The steerable wheel is fitted under the after part of the vehicle's body in a turning fork-shaped mount. The mine-clearing caterpillar track consists of single plate-shaped links and connecting links, connected by pins. The pins are retained with retaining rings. The connecting links have two fork-shaped projections, linked by rigid formers with teeth cut into them, engaging the teeth of the main wheel hub. The mine-clearing "foot" link has smooth surface.

      The testing program of the  Schwere Minenräumer started in Kummersdorf as soon as it was completed in 1942. It was quickly found that the VsKfz 617’s method for steering was unsatisfactory and that the vehicle was slow and hard to handle. To make matters worse, its immense weight caused the vehicle to easily get bogged down. The  Schwere Minenräumer and plans for its manufacture were abandoned after the tests.
    If the prototype evolved into production, it was planned the replace of the Panzer I turret by the SdKfz 121 Panzerkampfwagen II turret, armed with 20mm main gun and a 7.92mm MG-34.

     In April 1945, the prototype was captured by Soviet troops at the test site in Kummersdorf. After transport to Dresden, she was sent to the USSR , where in 1947 was tested, but poor storage conditions caused damage to the chassis, so the tests had to be cancelled. The minesweeper was transferred to the Tank Museum Kubinka (Odintsovsky District, Moscow Oblast, Russia), where she is in exposition to this day. 

Specs:

Schwere Minenräumer Alkett VsKfz 617 (NK-101)
Type	Heavy minesweeper
Place of origin	Nazi Germany
Service history
In service	prototype - Kursk(?)
Wars	World War II
Production history
Designed	1942
Manufacturer	Alkett (with Daimler- Benz and Krupp assistence)
No. built	1
Specifications
Weight	50 t
Length	6.500mm
Width	3.170mm
Height Ground clareance	2.800mm 800mm
Crew	2 (Commander, driver)
Armor	welded of rolled plates (see text above)
Main armament	2x 7,92mm MG34
Sec. armament	none
Engine	Maybach HL-120 V-12 - gasoline 11.900cm³ - 300 HP@3.000 rpm
Power/weight	7,9 hp/tonne
Suspension Fuel capacity	none 720 liters
Operational range	160 km
Speed	4 km/h (off road) - 15 Km/h (road)

The kit:

      In this time, the only option in the market (1/35) was the RPM's kit (#35100) Pojazd Szturmowy (assault vehicle) Minenräumer.

RPM's kit (#35100) Pojazd Szturmowy (assault vehicle) Minenräumer.

      Well...sorry, but I don't have ANY pics in my files about the building of this beast. But one thing I remember and I'll pass the message on to you: This RPM kit was one of the worst kits I've ever built in my life...I seriously thought about the Seppuku option, during the building!!!

I almost did it !!!

      Simply horrible... The worst was the construction of the wheels and their shoes ... The shoes are too narrow in their two halves, it is necessary to add pieces of plasticard to close the gaps.
      Stay away of this model!!! If you want to build this vehicle for your collection, opt (I really insist: opt !!) for the new MENG kit (I have no relation to the manufacturer ...).

Meng's Minenraumer VsKfz 617 box art

      At least you will not have a heart attack during construction. I think that's what "blocked" the record of the constructive steps ...

Oh, man ... I'm relieved !!!

      If you want to know something about my suffering, look at this Dutch Forum: our colleague Grendel (in 2010... Very good job, Grendel!!!) recorded step by step the "Via Crucis" very similar to mine... Look if you are bold!!  But notice: they are graphic images !!!
      My final results are:

My markings guide:

Schwere Minenräumer Alkett VsKfz 617 (NK-101)Operational markings -  Kummersdorf - 1943.

 Schwere Minenräumer Alkett VsKfz 617 with Kojak and
Rover, the dog.

      To board the vehicle, the crewman scaled the machine through the rear wheel; Look at the drawings below:

Minenraumer boarding method...

Kojak preparing to climb the Minenraumer ...

Climbing...

My precious!!!

Mine exploders;  Schwere Minenräumer Alkett VsKfz 617 and M4A2 T10

Mine exploders;  Schwere Minenräumer Alkett VsKfz 617,
M4 T1E3 Aunt Jemima  and M4A2 T10

Schwere Minenräumer Alkett VsKfz 617 (NK-101)

      Thanks for looking, Tankers!!