King Tiger in the SMM Full-Reuenthal
2016 / 2017 Winter season
Works on the turret and the armour hull
Works on the hull occured predominantly on the outside. Numerous holders with stuck links for tools and stuff which is attached to the outer hull walls were made operable again resp. missing ones were replaced. In particular on the rear side the holders and locks for the C-hooks and jack support had to be revised extensively.
A further important work item was the correction of the positioning of the front track covers which were not in line with the track skirts. We cut the covers off their links and welded in a several cm wide metal strip: Fit.
The most impressive and eye-catching work in this season certainly was the removal of the barrel. With the help of an awesome frame construction we were able to loosen the large union nut piece which holds the front barrel piece in place within the rear piece. Unfortunately we haven’t yet been able to remove the mantlet. Even though two large bolts up at the upper and lower side of the mantlet could be removed it seems that the piece is rusted in on its seat on the barrel. We plan to try hydraulic presses hoping that the fixation of the gun cradle will be able to withstand that.
For a couple of years now we are hosting a replacement front barrel piece which has previously been used as a post to moor boats. It stuck in the mud of a river bank and only thanks to the sharp eye of an expert it could be brought back to its original destination. With the all new muzzle break it really looks fantastic and the team is dying to see it back in its designated place.
The removal of the barrel now officially heralded the works on the turret. All sheet metal pieces which are attached around the sprocket of the turret to store stuff behind were removed, as well the close defence weapon and the right hand-side hatch with its dampener.
An equally important but unfortunately unflashy work is loosen and remove stubs from torn bolts. Willy developed himself to a real master in this respect and brought even the shortest stubs to its knees, applying a very particular heating- chilling procedure. He ultimately salvaged all threads.
As already mentioned previously the turret traverse drive with its two units was to become a focus of this season’s work.
The turret traverse drive consists of the traverse gearbox and the hydraulic motor. The entire unit is mounted on a steel frame which is a nearly rectangular construction to the rear of which is attached a massive sheet metal. This gives the entire unit a U-shapes appearance which is bolted to the turret at both upper ends. At the bottom there are two semi-circular frames with sheet metals which provide the working platform for the gunner and loader. Those platforms were already decayed to their largest extend when the turret was removed in 2007.
On the bottom of the frame the hydraulic motor unit is bolted. It is linked with the turret drive below by a toothed peg. The turret drive is directly linked to the prop shafts.
The hydraulic unit is linked to the traverse gearbox by three helically toothed gear wheels in a casing.
Further components mounted on the frame are a cylindrical reservoir for pressure air to blow the barrel after shots, the rod unit to apply the coax-MG and the distribution box of the turret electrical system.
The hydraulic motor consists of two nearly identical propeller pumps, one of which acts as an oil pump and the other as an oil motor. Both rotate on a central hollow shaft which is fixed in the casing. The oil pump is driven by the turret drive with the engine in running condition and traction. It draws oil which is pressed through the central shaft and by doing so drives the oil motor which drives the traverse gearbox.
Oil pump and oil motor can be eccentrically moved to the left and to the right from the central shaft. The direction of this movement determines the turret rotating direction and the extend of that movement to the left or right from the central position determines the transmitted torque resp. turret rotation speed.
Oil pump and oil motor can be manipulated individually.
The disassembly of the hydraulic unit was accompanied by a whole bunch of photos. Only after the disassembly we learned that this type of motor is called a Boehringer-Sturmgetriebe.
Its interior was in pretty good shape. Some ball bearings need to be replaced, as well as some shaft seals. The central shaft was found to have a small crack which developed into a large break so that the shaft needed to be welded.
The interior of the casing was covered with a yellow emaille-type of coating. It was no paint since that would have been attacked by the oil after decades. On the bottom solid particles have begun to detach and as the unit doesn’t feature an oil filter we decided to sand blast the interior and protect it with corrosion protection oil. No paint supplier was willing to give as a long-term warranty on oil resistance even with the best epoxy-coating.
The traction by the turret drive occurs via a lamella clutch attached at the rear of the hydraulic unit housing. The traction can be interrupted by a lever on the right hand side. The normal position is traction interrupted with lever down for driving without turret operation. Lifting the lever engages the clutch and allows turret turning.
It turned out that the identical friction lining rings were used in contemporary DKW motorcycles are replacements are still available from motorcycle oldtimer shops.
Finally the hull was spray painted in beige camouflage cover.