This cross-section drawing of the Porsche Typ 245-011 reconnaissance tank clearly shows the ammunition stowage, the wheel suspension arrangement, and the vertical travel of both the cannon and the machine gun, source: Flickr.com with permission of the publishing user, edited

A New Tank Wanted

In the summer of 1943, several highly interesting contracts for the development of new combat vehicles were put out to tender within the German armoured forces. At the end of May that year, a joint meeting of the so-called Panzerkommission and Waffenkommission had formulated outline requirements for the development of a new Flakpanzer and a new type of combat tank more resistant to enemy aircraft attack. Running in parallel with this, and at the instigation of the Inspector General of Panzer Troops, Heinz Guderian, a project was launched to develop a new universal tank that would not only replace the ageing Panzer IV but also serve as a platform for building other vehicle types, such as self-propelled guns, tank destroyers, reconnaissance vehicles, or Flakpanzers.

Ferdinand Porsche threw himself into all three of these initiatives with considerable enthusiasm, working in collaboration with Rheinmetall. In response to the first set of requirements from late May 1943, Porsche submitted the design of a tank designated Typ 245-010, conceived as a hybrid between a conventional battle tank and a Flakpanzer. Most likely in response to the second initiative – Guderian's – Porsche then prepared a reconnaissance tank design under the development designation Typ 245-011. The vehicle's full official name was Aufklärungspanzer mit 5,5 cm vollautomatischer Waffe.

According to some sources, the Typ 245-011 reconnaissance tank design was actually completed even before the first version of the Typ 245-010 – specifically, perhaps as early as 3 July 1943. The circumstances, however, give the impression that the two designs were produced in the opposite order. This is suggested not only by the sequential numbering of the two projects (–010 and –011), but also by the relative level of development effort invested in each (the Typ 245-010 was worked up in multiple variants and a full wooden mock-up was built for presentation to the Army). Everything points rather to Porsche having primarily responded to the demand for a new tank/Flakpanzer (i.e. the Typ 245-010), and only subsequently derived the reconnaissance vehicle design (i.e. the Typ 245-011) from it – since the future seemed to belong to a universal platform capable of underpinning "all manner" of vehicles, and Porsche wanted to demonstrate that his design was precisely such a universal machine. In what follows, we will therefore proceed on the assumption that the Typ 245-011 was designed after – and derived from – the Typ 245-010.

This drawing of the Porsche Typ 245-011 shows the seating positions of both crew members and the horizontal traverse arc of the cannon, source: Flickr.com with permission of the publishing user, edited

Design Description

Porsche's Typ 245-011 looked nothing like a conventional reconnaissance tank. With its armament housed not in a fighting turret but directly in a low, fixed superstructure, it more closely resembled a tank destroyer or an assault gun – though Porsche insisted it was a tank nonetheless. But was it a sensible solution? A reconnaissance tank is typically expected to be fast and to provide its crew with good observation capability and reliable communication with other units. When it finds itself in a tight spot, it should be able to defend itself, but firepower is rarely considered its primary priority. A reconnaissance tank often operates over unfamiliar territory, never knowing from which direction the enemy may appear and open fire – which is precisely why a rotating turret is so valuable, allowing it to return fire quickly in any direction. Porsche, however, chose to trade away this advantage in favour of something else: minimising the vehicle's overall height.

Thanks to the absence of a turret, his Typ 245-011 stood just 145 cm tall – with a ground clearance of 41 cm. Porsche was betting that a low-profile vehicle would be less conspicuous and harder to hit. Unfortunately, a low silhouette also means a restricted field of view, which is not exactly ideal for a vehicle intended to carry out reconnaissance. The chassis drew on Porsche's preceding Typ 245-010 design and therefore featured six road wheels on each side, fitted with a thin rubber layer beneath a steel rim. In the interest of reducing overall height, wheels of a slightly smaller diameter were to be used than on the Typ 245-010 – 590 mm instead of 600 mm. The wheels were to be suspended in pairs on a shared swinging arm, sprung by a vertically mounted conical coil spring (a so-called volute spring). The toothed drive sprockets were to be at the rear, with idler wheels at the front. Compared to the Typ 245-010 with its 480 mm tracks, the Typ 245-011 was given narrower 450 mm tracks. These were more than sufficient to maintain an excellent ground pressure of 0.59 kg/cm², while the narrower tracks also allowed for higher speed and of course reduced overall weight.

The Automatic Cannon

When selecting the armament for the new reconnaissance tank, Porsche turned once again – as with the Typ 245-010 – to the Rheinmetall automatic MK 112 cannon. This 55 mm weapon was being developed primarily for the German Luftwaffe, and the development accordingly placed great emphasis on minimising its weight. In its first development version the cannon weighed just approximately 300 kg, and in the second improved version a mere 275 kg. For the Typ 245-011, however, it appears that a modified version of the weapon with a substantially lengthened barrel was envisaged, which would most likely have been considerably heavier. The MK 112 – an abbreviation, incidentally, for Maschinenkanone – was belt-fed and in fully automatic mode achieved a rate of fire of approximately 300 rounds per minute, a truly formidable figure given that each projectile weighed 1.485 kg. In any case, this weapon never reached series production, and by the end of the war only 15 prototypes had been built.

This drawing of the Typ 245-011 clearly shows the very low silhouette that was to be its main asset, source: Flickr.com with permission of the publishing user, edited

Mounting the cannon in the front hull wall severely restricted its mobility. In the horizontal plane the barrel could be traversed a mere 5 degrees to either side. Vertical elevation ranged from –5 to +22 degrees. A total of 240 cannon rounds were stowed on board, arranged in belts. The front hull wall was to be 60 mm thick, sloped at 30 degrees. The side walls were to be 40 mm thick and the rear wall 25 mm. The hull roof was 25 mm thick. At the front right of the hull roof, a small rotating cupola housing an MG 42 machine gun of 7.92 mm calibre was fitted. With a maximum elevation of up to 72 (or even 75) degrees, the machine gun could be used not only against attacking infantry but also against enemy aircraft.

The engine compartment occupied the rear of the hull. For the tank's powerplant, Porsche specified an unspecified air-cooled engine producing 250 hp. Behind the engine a hydraulic gearbox and final drives connected to the rear drive sprockets were to be fitted. Service access to both the engine and gearbox was through a large hatch in the rear hull wall. The 15-tonne vehicle was to be capable of a maximum speed of 58 km/h. The reconnaissance tank's crew numbered just two men: the driver and the commander, who simultaneously served as gunner for both weapons, loader, and in all likelihood radio operator as well. The driver sat at the front, to the left of the cannon, and observed the outside world through a periscope in the hatch directly above his head. The commander sat to the right of the cannon, with the aforementioned machine-gun cupola above him.

As already noted, the cannon fed from ammunition belts, so a dedicated loader was not strictly necessary. Even so, a fresh belt had to be loaded from time to time, and the same applied to the machine gun. In practice this meant the vehicle commander would almost certainly have been severely overloaded in combat – expected to observe the battlefield, aim the cannon, and occasionally reload it as well. The periscopic gun sight for the cannon was located in the machine-gun cupola. The sources do not explain how exactly the sight was connected to the cannon – a notable omission given that the cannon was mounted in the hull with very limited traverse, while the sight sat in a cupola that could rotate freely through 360 degrees. It is equally unclear how the machine-gun barrel would have been changed in action. The MG 42 had its barrel removed from the side of the weapon, which posed a considerable problem when it was installed in an armoured embrasure. In any case, the Typ 245-011 project never progressed beyond the drawing board.

ARTICLE
CONTENTS:

A NEW TANK WANTED

DESIGN DESCRIPTION

THE AUTOMATIC CANNON