Standard-Flakpanzer E-100/88mm, mid 46

Link: www.flickr.com/photos/dizzyfug…

Some background:
The Panzerkampfwagen E-100, also known as Gerät 383 and TG-01, was a German super-heavy tank design developed towards the end of World War II. It was proposed to be the basis for a heavy artillery system, an anti-aircraft vehicle, and a heavy tank destroyer. The basic design had been ordered by the Waffenamt as a parallel development to Porsche's heavy tank design "Maus" in June 1943, but it was to become an integral part of the new, standardized Entwicklung (E) series of vehicles, consisting of the E-5, E-10, E-25, E-50, E-75 and finally the E-100.  The latter was the heaviest and biggest chassis of the family, which was meant to standardize as many components and production processes as possible.

In March 1944 the Adlerwerke company from Frankfurt am Main submitted blueprint 021A38300 for a super-heavy battle tank called E-100, after the tank was proposed in April 1943 along with the other Entwicklung series vehicles. According to the blueprints, the tank would be armed with a both a 150 mm gun and a 75 mm gun in a huge turret. Two types of engines were proposed: one was a 700 hp Maybach HL230, with a transmission and turning mechanism borrowed from the Tiger II. The estimated top speed was 23 km/h, and it was clear that this powerplant was utterly undersized for the E-100, which would be almost twice as heavy as the already underpowered Tiger II. The second engine, which was favored for serial production, was a new, turbocharged 1200 hp Maybach HL 232 engine that allowed an estimated top speed of 40 km/h on roads and a decent off-road performance, should the underground allow such an adventure. Other engines in the 1.000+ hp range were considered, too, e. g. modified Daimler Benz aircraft engines, or even torpedo boat powerplants.

The Adler design had a simple hull shape and featured removable side armor skirts and narrow transport tracks to make rail transport more viable. The running gear was very similar to the original 'Tiger-Maus' proposal but had larger 900 mm diameter road wheels and a new coil spring-based suspension rather than the original torsion bars. This greatly simplified the hull’s construction, avoiding openings and therefore weak structural spots, because the coil springs and their mounts remained outside of the hull. This design also made manufacturing much easier, and the simpler coil springs saved high-quality steel. A new turret was designed, too, intended to be simpler and lighter than the massive Maus turret. In the end, the E-100 was 40 tons lighter than the 188 t Maus prototype, and a much simpler and streamlined design.

In July 1944, through the worsening war situation and declining national resources, the development of any super heavy tanks was officially halted. However, work on the E-100 continued at a low priority and with the outlook to produce a limited number of these massive vehicles for special purposes, using existing components. With increasing panic among the military staff and a desperate search for “Wunderwaffen” that could eventually turn the Allied invasion, permission was granted in early 1945 to proceed with the E-100 project as the SdKfz. 193, with the intention to build the E-100 as a supplement to the E-50 and E-75 Einheitspanzer battle tanks, primarily in the role of a long-range tank destroyer with either a 15 cm StuK L/63 or a 17 cm StuK L/53 gun as main armament, and as a heavily armored defensive vehicle.

The first prototype of the basic battle tank version was quickly completed in March 1945, but from the start several variants were slated for the limited serial production. Four battle tank variants were defined, differing basically through the turret designs and the armament. The chassis was furthermore earmarked for E-100 tank hunters and assault guns like the "Krokodil" (the Sd.Kfz. 197) with a low, casemate-style hull. Some of these SPGs also had their internal layout changed, moving the rear engine into the middle of the hull for a bigger combat compartment at the rear, so that the long gun barrel would not hang over at the front. These vehicles received the designation suffix “(m)”, for “Mittelmotor” (middle engine).

After the first E-100 battle tanks had reached frontline units in December 1945, the new chassis was greenlighted as basis for super-heavy self-propelled artillery and anti-aircraft guns. Since these vehicles were not expected to operate directly in frontline fire and to save material and production time, the hull had its armor thickness reduced considerably, and this chassis variant was called the Sd.Kfz. 199. This led to several super-heavy SPAAGs that primarily differed in their superstructures, which included open, semi-armored and fully armored/closed weapon mounts.

The latter included the Sd.Kfz. 199/4, also called the Flakpanzer E-100/88. It carried a large, box-shaped turret with a crew of five and a twin-mount for a pair of coupled 88 mm Flak 43 anti-aircraft guns, the “Gerät 288”. This heavy weapon had originally been on the Marine's drawing board for the anti-air defense of medium to large battleships since 1942, but the German fleet’s demise led to an adaptation of the coupled-weapon concept to the use on land. The huge and strong E-100 chassis eventually offered enough space to consider a self-propelled mount for a fully enclosed turret with this anti-aircraft weapon.
The Gerät 288 integrated two, originally independent guns into a massive, mutual mount, working on the Gast Gun principle developed by German engineer Karl Gast of the Vorwerk company in 1916: the firing action of one barrel operated the mechanism of the other, creating a reciprocal twin gun. This system required no external power source to operate but was instead powered by the recoiling of the floating barrels. This provided a much faster rate of fire for lower mechanical wear than a single-barrel weapon, and another benefit of this arrangement was that the recoil from one barrel was largely compensated for by the movement of the other one.

To expand range and ceiling beyond the standard Flak 43 gun the Gerät 288 featured extended gun barrels (80 gauge instead of the field weapon’s 72), which were manufactured in two pieces for easier production and replacement. With these, the guns achieved a muzzle velocity of 1,050 m/s (3,440 ft/s), giving them an effective ceiling of 11,500 meters (37,100 ft) and a maximum of 16,000 meters (52,400 ft). The 88 mm guns could also be used against ground targets and were, using dedicated armor-piercing rounds, able to penetrate ~240 mm (9.4 inches) of vertical hardened steel armor at 1,000 m (3,280 feet). This was enough to defeat the armor of almost any contemporary Allied tank from a relatively safe distance.

In the Sd.Kfz. 199/4’s massive turret, the heavy-duty hydraulic gun mount had an elevation between +70° and -5°. The Gerät 288’s combined rate of fire was up to 150 RPM, even though 120 RPM were more practical to limit structural stress and avoid jamming. Thanks to two magazines with 58 rounds each in the turret’s sides, continuous auto-fire was possible, as well as short bursts of two to five rounds per gun and single shots. The guns could also be fed manually by the loaders (one per gun from the inside). The magazines were normally loaded externally through hatches in the turret roof, but they could be accessed from the inside, too, and re-filled under armor cover from a further stock of 86 rounds that were stored in the SPAAG’s lower hull.

To improve target acquisition and fire control, the Gerät 288 was combined with a visual coincidence range finder and an integrated analogue targeting computer, a variant of the Kommandogerät (KDO) 40. In the Sd.Kfz. 199/4, this device was operated by a dedicated crew member who assisted the gunner and the commander.
This so-called Telemeter had already been introduced in 1941 to the field troops as a mobile guidance tool for stationary anti-aircraft units equipped with the 88 mm and 105 mm Flak. But it had so far – due to its size and bulk – only been deployed on an unarmored trailer and in the recent unarmed Sd.Kfz. 282 command vehicle. In the Sd.Kfz. 199/4’s turret the rangefinder’s optical bar had a reduced span of 240 cm (95 in), but fixed target reading was possible on distances from 3,000 to 20,000 m and aerial courses could be recorded at all levels of flight at a slant range between 4,000 and 18,000 m - enough for visual identification beyond a typical anti-aircraft group's effective gun ranges and perfectly suitable for long range observation, too.
The Telemeter was mounted in the turret’s roof under armored fairings behind the Gerät 288 and its magazines. In combination with the Gerät 288, the KDO 40 replaced the traditional gun scope. Due to the weapon’s weight and bulk, all weapon orientation was carried out by means of hydraulic motors via a control column that were slaved to the gunner’s Kommandogerät, so that aiming and firing was semi-automatized. The gunner still had to use the Telemeter as an optical scope to find and pinpoint the target, but the device translated this, together with additional information like range, temperature or wind shear, into electrical input for the guns electro-hydraulic controls that automatically corrected the weapon’s orientation and triggered them with an appropriate lead at an ideal moment. This automatized process made especially the acquisition of new targets easier and sped the whole re-targeting process up.

In this form the Sd.Kfz. 199/4 was cleared for production in mid-1945, but initial field experience especially with the heavy and less mobile E-100 vehicles had shown that these were very vulnerable to foot soldier attacks with mines or carefully aimed RPGs. Originally, the whole Einheitspanzer family had been designed without light defensive weapons, but this turned out to be a lethal weakness. Therefore, many vehicles were retrofitted in the field and on the production lines with close-combat weapons like a 100 mm “Nahverteidigungswaffe” grenade launcher which fired SMi 35 leaping mines against approaching infantry. Other frequent upgrades were smoke mortars and remote-controlled machine gun mounts that could be manually directed and fired from the inside. There were even complete, motorized gun barbettes available like the “Schwere Waffenlafette 45” (Heavy weapon mount). The latter was a newly developed, modular weapon platform, originally designed as main armament for lightly armored infantry fighting vehicles like the Sd.Kfz. 251 where it was simply mounted onto the armored roof and replaced the former manually operated machine guns. However, since it was an autonomous, electrically driven system on a simple ring mount with a relatively small diameter, the Schwere Waffenlafette 45 could easily be installed anywhere else, e. g. on the turret of most heavy tanks or the roof of assault guns. It had three periscopes at its base that gave a hemispherical field of view, the central mirror was combined with a target scope for aiming the weapons. The barbette either replaced the commander’s cupola, or it was, if there was enough space, directly attached to the roof as an additional outlook. Due to ample space the latter was the typical configuration on board of the Sd.Kfz. 199/4. The barbette’s mount replaced an already existing ventilation opening and was added on the roof in the right rear quadrant, next to the commander’s cupola, and it was operated by one of the loaders.
This barbette could be rotated 360°, had an elevation between -10 and +80° and carried a magnifying periscope for observation and aiming. The weapons were installed in external, co-axial pods with light armor protection on both sides of the central carrier column. Typically, these were a 30 mm (1.18 in) MK 103 machine cannon with 60 rounds (typically explosive APCR rounds against soft targets, but armor-piercing rounds could be fired, too) and a rapid-firing MG 42 machine gun (with 1.200 rounds), but other weapons and combinations were possible. Like the weapons, all ammunition was carried externally, too, so that the crew had to leave the vehicle’s protection to re-arm the weapons or deal with mechanical problems.

With all this heavy and bulky equipment as well as a total stock of 202 88 mm rounds and a crew of seven the Sd.Kfz. 199/4 weighed – despite the chassis’ reduced armor thickness – more than 100 tons, so that its mobility and tactical value were sharply restricted, even though it was markedly better than the battle tanks with their all-up weight of 140 tons and more. Due to this limited usefulness and lack of resources, only a small number were built. Production numbers vary between 15 and 25 vehicles, some might have been created on the basis of refurbished Sd.Kfz. 193 battle tank hulls. Most of the time, the few Sd.Kfz. 199/4s were used as mobile command posts for anti-aircraft units that defended vital locations like headquarters or production sites around Berlin, so that the vehicle’s short legs did not matter much.

Specifications:
    Crew: 7 (Commander, Gunner, Telemeter operator, 2x Loader, Driver, Radio Operator)
    Weight: 108 tonnes (119 short tons)
    Length: 8.86 m (29 ft), hull only
                   11.62 m (38 ft 1 in), overall with guns forward
    Width: 3.96 m
                  4.48 m (14 ft 8 in) with armored side skirts mounted
    Height: 3.29 m (10 ft 10 in)
                  3.92 m (12 ft 10 in) with Schwere Waffenlafette 45
    Suspension: Belleville washer coil spring

Armor:
    Hull front: 80 – 120 mm (3.2 – 4.7 in)
    Hull sides and rear: 60 – 90 mm (2.4 – 3.5in)
    Hull top: 40 mm (1.6 in)
    Hull bottom: 40–80 mm (1.6–3.1 in)
    Turret front: 140 mm (5.5 in)
    Turret sides & rear: 60 – 90 mm (2.4 – 3.5in)
    Turret top: 40 mm (1.6 in)

Engine:
    1x turbocharged Maybach HL232 V12 gasoline engine with 1.200 hp

Performance:
    Maximum road speed: 40 km/h (25 mph)
    Sustained road speed: 36 km/h (22 mph)
    Cross country speed: 14 to 20 km/h (8.7 to 12.4 mph)
    Power/weight: 8,57 hp/ton
    Range: 120 km (74 mi) on road
                    85 km (53 mi) cross country
    Power/weight: 11.1 PS/tonne (10.1 hp/ton)

Armament:
    2x 88mm (3.46 in) FlaK 43 L/80 in a Gerät 288 Zwilling mount, with a total of 202 rounds
    1x Schwere Waffenlafette 45 with:
         1x 30 mm (1.18 in) MK 103 machine cannon (60 RPG) and
         1x 7.92 mm (0,312 in) MG 42 machine gun
    6x 76 mm Wegmann smoke mortars