21st Army Group Technical Intelligence Report #002 – May 21 1945

The existence of experimental German AFVs (Armored Fighting Vehicles) in the super heavy weight class (over 100 tons) has recently been reported by a large number of prisoners and other intelligence sources of undetermined reliability. It is not possible to shed some light on these reports following the discovery in Germany of an incomplete tank called Mouse (Maus) estimated to weigh about 200 tons, another incomplete tank called E-100 estimated to weigh about 150 tons and an incomplete ‘portee’ type SP Gun (Self Propelled) called Cricket (Grille) estimated to weigh about 120 Tons.

Information on these three new experimental Armored Fighting Vehicles is based on examination of the vehicles in their half finished condition supplemented by information obtained by interrogation of one of the chief experimental AFV construction engineers in Germany. The latter, who was actually responsible for much of the work in the building of both, the E-10 and the Cricket, has expressed his willingness to supply all possible intelligence on German AFVs and his information is considered to be the most reliable. He has handed over fairly complete documents including photos of the E-100 and the Cricket to the Allied authorities having previously refused to destroy both vehicles and a number of additional records and installations which were located on the experimental AFV proving ground of which he was the technical engineer in chiefs. This report has been written without the benefit access to his documents.

Information supplied by this man on the Mouse tank was in the main hearsay as he was never officially concerned in its construction. A report on the Mouse including all available information to date is given below. Similar reports on the E-100 and the Cricket will be given in a later report. Anyway, a brief summary of information on these two experimental Armored Fighting Vehicles is as follows.

(a) Experimental Super Heavy Tank E-100

Planned theoretical weight : 140 – 150 tons
Firm responsible for the production : Adlerwerke (Frankfurt on Main) with technical assistance from Henschel.
Hull manufacturer : Dortmund Hoerde. Huttenverein.
Planned main armament : one 150-MM on s FH 18 with one coaxial 75-MM gun.
Overall length : 29ft 1/2 (8.85-M)
Overall width with hull : 12ft2 1/2 (3.87-M)
Diameter of opening in the hull roof to receive the turret ring assembly : 9 ft 9 (3.01-M)
Armour – Glacis plate : 200-MM at 60°
Armour – Nose plate : approx 150-MM undercut 40°
Armour – Hull aides : 102-MM vertical
Armour – Superstructure sides : 120-MM vertical
Armour – Tail plate : 150-MM undercut 32°

Suspension & Tracks There are two disc steel rimmed bogie wheels on each of 8 load carrying axles on each sides of the tank. The bogie wheels overlap and are sprung independently on coils springs. There are two large coil springs per axle with two smaller coil springs lying within the larger springs. There is a front driving sprocket and rear idler, but no return rollers.
The tracks are 100-CM wide and are of the jointed type with main and connecting links, the latter being constructed in three separate units. Track pitch for both main and connecting links is 15-CM.
Engine An improved version of the well-known Panther & Tiger Maybach engine HL 230 is installed in the experimental hull, developing 720 to 730 metric horse power. It is understood that the E-100 was designed to be powered by a new Maybach engine developing 1000 to 1200 metric horse power, but that this engine is still in the experimental stage.
General It is not known whether a turret for the E-100 had been constructed. Broadly speaking the tank consists of a much stepped-up version of the Royal Tiger.

(b) Experimental Super Heavy ‘Portee’ type SP equipment Cricket

Estimated weigh in action : 120 tons
Firm responsible for production : Krupp and Henschel jointly
Planned main armament : one 170-MM gun (17-CM K) with muzzle brake, on Mrs 18 carriage.
In the early days of the development of the Cricket, it had been hoped to mount ths 210-MM Howitzer (21-CM Mrs 18)
Overall length of the SP carriage : approx 32ft (9.75-M)
Overall width of the SP carriage : approx 10ft4 (3.20-M)

Engine Same as for the E-100
General The Cricket carriage consists of a much lengthened version of the Panzer VI Tiger (Royal) hull, but with thin armor. The thickest plates are the glacis and nose plates which are about 30-MM thick only. Most of the other plates, including the superstructure, are 16-MM thick. Torsion bar suspension with 11 load carrying axles each side of the vehicle is used.

1. Experimental Super Heavy Tank Mouse (Maus)

Three Mouse hulls and turrets have been found on the Krupp’s proving ground at Meppen, Germany, the hulls lying on their sides and the turrets lying upside down, making their examination a rather difficult undertaking. Hulls and turrets were numbered , the highest number being 6. Some miles away from the hulls and turrets, but on the same proving range, a new tank main armament was found consisting of a 128-MM Kw K 44 with a coaxially mounted 75-MM Kw K 44 to the right of the 128-MM.

Documents found in the office buildings on the range indicate that the 128-MM gun was once referred to as 12.8 CM Kw K 44 (Maus), and that the gun may have later been rechristened 12.8 CM Kw K 82. The cradle in which the 128-MM and the 75-MM guns are mounted is referred to as Mauswiege (Mouse cradle). It is interesting to note that although the aperture in the front plate of the Mouse is offset to the right, the dimensions of the guns and cradle are such that the 128-MM gun would lie in a longitudinal axis down the center of the turret if it were mounted in the turret. There is no evidence that more than 6 mouse guns, hulls and turrets were ever produced. The turrets and hulls appear to have been delivered to Meppen to be shot up in trial and the Mouse gun was sent to Meppen in November 1943 for firing trials. A printed cartridge case label for the Mouse gun is dated Meppen January 3 1944.

It is difficult to estimate what the overall weight of the Mouse would be in action as it has not been possible to weigh the guns, turrets or the hull, but it is considered that the tank would weigh at least 200 tons. Sketches showing side, plan and rear elevation of the Mouse with the guns ‘mounted’ in the turret are included with this report, together with an armor arrangement sketch, a diagram showing the probable layout of the hull and the sketch showing an artists impression of what the tank might look like in action. Information available on the Mouse and included in this report is based on examination of the various components found at Meppen and interrogation of the key engineer in the German AFV industry mentioned above.

This engineer states that the Mouse was designed by Dr. Ferdinand Porsche and produced by Krupp. He believes that the project to construct the Mouse thank was planned in the spring or summer 1942 and was sponsored by Dr. Speer, Minister of War Production. At this time, Mouse was referred to as Mammut (Mammoth), he believes. It was designed to be able to travel under water and to carry out under water tests, he was ordered by the Army authorities to build a deep AFV wading pit in 1943. When we asked what thickness of concrete should be used to make the floor of the pit, he got the reply that the floor must be able to support a 200 tons tank and he had the pit constructed with a concrete floor 60-CM (2ft) thick.

From conversation with various officers and engineers connected with the AFV industry he gathered that there was some doubt in the minds of those responsible for the production of the Mouse as to whether it should be powered by ‘Boxer’, compression ignition or air cooled petrol engines. Dr. Porsche was in favor of building a compression ignition engine. The tank was to have petrol electric drive, a suspension arrangement embodying longitudinal torsion bars on the lines of […] equipment and was to be proof against war gases.

He had heard at least one Mouse had been completed and had undergone trials in the area of Linz in Austria and believes that this tank might still be found there. He believes that the tank has a crew of 6 or 7 men.

An order to stop all work on the Mouse project was issued by Adolf Hitler personally early in 1944. The reasons for this were, he thinks, twofold. On the one hand, the tank was too costly to produce in large numbers and on the other hand, a serious shortage of raw material had by then arisen particularly on electrolytic copper.

2. Construction and Layout of the Hull

The hull is quite unlike that of any previous German AFV although it has one or two points in common with the Elephant Self Propelled equipment. The front is shaped in the manner of the Panzer V Panther and has a pointed nose. The whole shape of the hull is governed by the exceptionally wide tracks and the fact that thick armor protection is provided for a large part of the suspension arrangement, with the result that the width over hull side plates is only 3ft9 1/2 (1.34-M) whereas the width over the pannier side plates is 11ft11 3/4 (3.51-M). In fact the hull consists mainly of the hull superstructure with much pannier space above the tracks. The hull is divided up into four main compartments as show in the sketch below.

In the front center of the hull there is a driving compartment which extends back about 7ft2 1/2 (2.20-M) in front of the hull. The internal measurements of this compartment are : (width) 5ft3 (1.61-M); (length) 5ft11 (1.55-M); (height) 4ft4 1/2 (1.34-M).

Only a part of the space at the front on the hull over the tracks is included in the driving compartment. The rest forms part of the engine compartment and is separated from the driving compartment by 20-MM plates. It is not known whether two members of the crew are accommodated in the driving compartment or only one, but there appears to be just enough room for two and it is possible that a V/T operator sits alongside the driver.

In the center of the 100-MM roof plate covering the driving compartment there is an oval shaped opening for an escape hatch. It measures about 2ft11 1/2 by 1ft3 (64-CM by 42-CM). In front and on the near side of the opening there is a smaller oval shaped opening probably designed to receive the driver’s periscope, measuring about 1ft3 by 8′ (39-CM by 20.3-CM). On the offside of this there is a small circular opening possibly for ventilation purposes, the diameter of wich measures 8′ (20.3-CM).

As on the Mark V Panther and the Mark VI Tiger, a part of the top of the glacis plate is cut away in front of the periscope opening to allow better vision fro the driver.

There are two circular opening (diameter 5″ 1/2) (13-CM) in the hull nose plate, which may be designed for positioning the front idler to effect tracks adjustment. There is also a circular escape hatch (diameter 1ft8 1/2) (55-CM) in the driving compartment floor (front portion of belly plate).

The engine compartment lies immediately behind the driving compartment from which it is separated by a 20-MM bulkhead and extends 6ft8 (203.2-CM) back from the rear of the rear of the driving compartment. It includes two pockets of pannier space on either side of the driving compartment which, it is thought, may be designed to contain the tank’s fuel. The engine compartment itself is divided up into six sub-compartments. No roof plate for the engine compartment was found, but it would appear that a 6-CM plate is intended to be fitted.

On either side and at the rear are two sub-compartments 3ft8 wide (111.76-CM), 4ft7 long (139.7-CM) and 2ft10 high (86.36-CM). Forward of these two sub-compartments are two similar compartments of the same width and height, but only 1ft11 (59.69-CM) long. The two pockets of pannier space referred to above lead of those two sub-compartments. In the center rear of the engine compartment, is a rectangular sub-compartment, 3ft3.5 (100.33-CM) wide, the floor of which is the main hull belly plate, giving an extra 1ft10 (55.88-CM) in height. There is a rectangular opening 4ft3 by 8.5″ (129.54-CM by 21.59-CM) in the belly plate. In the front center of the engine compartment there is a small sub-compartment, the same width as the driving compartment. The square-shaped hull fighting compartment or cab extends about 10ft4.5 back (316.23-CM) from the bulkhead separating the engine compartment.The roof over the fighting-cab is made up of four 60-MM plates welded together. The circular opening in the roof to receive the turret ring assembly measures 9ft8.5 (295.91-CM).

The internal measurements of the compartment are : Width 10ft6.75 (321.94-CM); Length 10ft3.5 (313.69CM); Height in center 4ft8.75 (144.14-CM); Height at sides 2ft10.5 (87.63-CM). At the rear of the hull and separated from the fighting cab by a 20-MM bulkhead is a further small compartment believed to house the final drive and electric motors and sub-divided into 3 compartments separated by 20-MM gusset plates.

From the general layout of the hull it would seen possible that the transmission system on this new heavy tank may resemble that on the Self Propelled equipment ‘Elephant’, in which case the rear compartment may be used to house electric driving motors, in addition to the final drive mechanism. Holes have been drilled in the pannier side plates and gusset plates to take a substantial shaft, the axis of which is about 1ft4.5 (41.91-CM) below the top of the hull and about 4ft11 (149.86-CM) from the rear of the hull.

3. Turret Construction

The turret is a really massive structure being particularly high in rotation to its width and length and in relation to the hull. It is considered that the turret may weigh about 34 tons without the main armament or any fittings. It is roughly rectangular with sloping sides parallel with each other in the horizontal plane. The front of the turret is rounded consisting of a single band plate. It closely resembles the ‘hand tailored’ front provided for the first 66 Mark VI Tigers (Royal) turrets, which were designed by Dr. Porsche.

The turret floor appears to consist of two plates. One stretches from the front of the turret to about 2ft7.5 (80.01-CM) from the rear of the turret. This plate is 93-MM thick in the main, but tapers in places. The second platen which is also 93-MM thick is raised above the level of the first plate thus providing a clear space at the bottom rear of the turret so that when the turret is traversed, it clears any projections on the hull roof. The turret basket ring consists of a circular 55-MM plate and is 2ft1.5 high (64.75-CM). It has an external diameter of 7ft10 (238.76-CM) The basket is welded to three large segments of the main turret floor plate. The distance from the base of the basket ring to the underside on the main turret floor plate is 1ft5.75 (45.08-CM). An opening is cut in the basket ring about 1 o’clock, presumably to allow room for a turret power traverse mechanism.

There is a large rectangular-shaped opening in the rounded turret front plate through which the main armament can protrude. It measures roughly 3ft2.5 by 2ft4.75 (104.14-CM by 73.25-CM). This opening of offset about 8′ (20.32-CM) to the right. The external surface of the turret front plate on two or three turrets examined was machined at its center over a width or 4ft5 (134.62-CM) to an average depth of 3/8′ (9.2-CM). It would appear probable therefore that the main armament is provided with a gun mantlet about 4ft.5 (134.62-cm) wide which ride vertically about the rounded turret front plate. There were no apertures in the front plate other than large rectangular-shaped one described above. In the turret roof plate, at the rear and centrally positioned, there is a circular opening 1ft2 (35.56-CM) in diameter.

There is a small circular opening in the center of the turret rear plate measuring 10′ (25.40-CM) in diameter. There were no hatches in the turret sufficiently large to allow a man to enter the turret from the outside, nor were there any apertures of any sort in the turret side plates. It is presumed that the turret were due for further machining, but had been taken to Merpen in their incomplete condition for the purpose of being shut up in trials.

4. Turret and Hull Armor

The armor consists of flat and bend rolled plates. None of the armor was cast. No mantlet for the protection of the turret guns was found. It was extremely difficult to measure the thickness of individual plates or the angle to the vertical of the plates, but the following figures (above) are considered to be reasonably accurate through subject to confirmation at a later date when the armor can be examined under more satisfactory condition and when the examiners has had time to study the art of the steeplejack.

a Turret

Plate Thickness
MM –&– IN
Angle to Vertical
in degrees
Front Plate 215 – 8.5 rounded
Side Plate 205 – 8.1 30
Rear Plate 205 – 8.1 15
Roof Plate 65 – 2.4 horizontal
Main Bottom Plate 93 – 3.7 horizontal
Rear Bottom Plate 93 – 3.7 nearly horizontal

The main turret bottom plate varies in thickness, but has a maximum thickness of 93-MM. The rounded turret front plate is interlocked and welded with the side plates, which are interlocked with the rear plate and the main bottom plate.

b Hull

Plate Thickness
MM –&– IN
Angle to Vertical
in degrees
Glacis Plate 205 – 8.1 55
Nose Plated Hull Center 205 – 8.1 35
Hull Side Plates 80 – 3.2 vertical
Upper Section of Pannier Side Plates 173 – 6.8 vertical
Lower Section of Pannier Side Plates or Apron 90 – 3.5 vertical
Pannier Floor at Front 50 – 2 undercut 75
Pannier Floor at Center 50 – 2 horizontal
Plate for Top Front of Tracks (Track Guard) 100 – 3.9 10
Upper Tail Plate 153 – 6 40
Lower Tail Plate 153 – 6 undercut 30
Roof Plate over Driving Compartment 103 – 4.1 horizontal
Roof Plate over Engine Compartment (estimated) 60 – 2.4 horizontal
Roof Plates (4) over Hull Fighting Compartment 60 – 2. horizontal
Roof Plate over Final Drive and Electric Motors Compartment (estimated) 60 – 2.4 horizontal
Bulkheads Dividing Various Hull Compartments 20 – 0.9 vertical
Front Part of Belly Plate 100 – 3.9 horizontal
Main Belly Plate 50 – 2 horizontal

(Above) E-100 (Below) Mouse

As is to be expected all the main armor plates are interlocked in addition to being welded. The glacis plate is interlocked with the upper section of the pannier aides and with the nose plate. The pannier side plates are interlocked with the hull roof plates over the driving compartment and the firing compartment and with the upper tail plate. The upper tail plate is interlocked with the lower tail plate in the center of the hull. The pannier floor plates are interlocked with the hull side plates.

5 The Mouse Gun

The 128-MM (12.8 cm Kw K 44 L/55) is mounted in a tank cradle together with a coaxial 75-MM (7.5 cm Kw K L/36.5). The name ‘Maus’ (Mouse) has been associated with the 128-MM gun and in particular with the whole equipment during the course of this development. The gun and cradle appear to have been developed mainly by Krupp. The 128-MM (Kw K 44) consists of a mono-bloc barrel and a rectangular open jaw breech ring, the two being connected together by the standard type of screwed ring. No muzzle brake is fitted, though the muzzle on certain guns may be found to be screw-threaded. An horizontal sliding wedge breech mechanism opening to the right is employed. It is operated by a lever mounted in the left side of the breech ring and hinging to the rear. A standard electric firing mechanism is employed. The top edges of the breech ring arc beveled off at the front and the two gun lugs mounted on the flats formed.

The 75-MM (7.5 cm Kw K L/36.5) is a completely new gun though it appears probable that this is chambered for the 75-MM (7.5 cm Kw K L/24) cartridge case and possibly fires the same ammunition. The barrel is a mono-bloc and is fixed to the rectangular open jaw breech ring by a screwed ring. A standard vertical sliding breech block is employed, the SA gear being on the right of the cradle. The standard electric firing mechanism is fitted. Gun lugs are screwed to the top and bottom of the breach ring. The cradle for the two guns is a massive steel casting, formed in one piece, with ring cradles for both of them. The front of the cradle is formed with a flange which is provided with holes for the attachment of the mantlet plate.

The 75-MM gun is mounted on the right of the cradle, well forward so that on full recoil it cannot foul the breech block of the 128-MM gun. The buffer is mounted on the cradle below the gun and the HP recuperation system above the gun. The 128-MM gun is mounted on the left side of the cradle and rather far to the rear so that the whole equipment is balanced about the trunnions. The buffer en HP recuperation system are mounted on the cradle, side by side above the barrel, the buffer being to the left. The part of the cradle carrying the 128-MM gun is extended to the rear by a trough shaped bracket which is bolted to the main cradle. The elevating arc is bolted to the left side of the main cradle.

Gun Data – 128-MM

Length overall – 7020-MM
Depth of the Breech Opening – 400-MM
Length of Rifling – 5533-MM
Length of the Chamber (to base of shell) – 977.6-MM
Capacity of the Chamber (to base of shell) – 20.6 litres.

Gun Data – 75-MM

Length Overall – 2756-MM
Depth of the Breech Opening – 200-MM


Center of Trunnions the the Rear of the Cradle – 2680-MM
Width of Trunnions – 1100-MM
Center of Trunnions to the rear the the Breech Ring – 1710-MM
Center of Trunnions to the Front of the Mantlet Support Plate – 650-MM

Performance 128-MM

12.8 cm, AT Shell 43, 28.3 Kg
– Medium Charge MV 750 Ms.
– Full Charge HV – 920 Ms.
12.8 cm, HE Shell Flak 40, 26 Kg
– Medium Charge MV 750 Ms.
– Full Charge HV 920 Ms.
12.8 cm HE Shell L/5, 23 Kg
– Medium Charge MV 750 Ms.
– Full CHarge, HV 920 Ms.

6 Dimension and Weights

(a) Lengths
Estimated overall length with 128-MM gun at 12 o’clock – 32ft4 (9.85-M)
Overall length of the hull – 29ft6.5 (9-M)
Overall length of the turret – 14ft11 (4.54-M)
Turret top – 12ft4 (3.75-M)
Turret base – 13ft5.5 (4.10-M)
Estimated distance between driving sprocket center to front idler center – 25ft5 (7.74-M)
Estimated distance distance between front and rear bogie wheel centers – 17ft6 (5.33-M)
Estimated overhang of the 128-MM gun – 2ft9.5 (0.85-M)

(b) Widths
Overall width of hull – 11ft11.75 (3.65-M)
Overall width of the turret – 10ft2 (3.09-M)
Width over hull side plates – 3ft9.5 (1.15-M)
Estimated width of tracks centers – 7ft4 (2.23-M)
Estimated width of track – 3ft (0.91-M)
Turret at top – 5ft11 (1.80-M)
Turret at the base at rear – 10ft1 (3.07-M)
Turret at base at front – 10ft2 (3.09-M)
Opening in turret front plate – 3ft2.5 (0.97-M)

(c) Heights
Estimated overall height – 12ft (3.65-M)
Estimated overall height of hull – 7ft (2.13-M)
Overall height of turret – 6ft1 (1.85-M)
Pannier side plate – 5ft0.5 (1.53-M)
Turret less basket – 4ft7 (1.39-M)
Opening in turret front plate – 2ft4.75 (0.73-M)

(d) Diameters
Hull roof opening to receive turret ring assembly – 9ft3.5 (2.83-M)
External diameter of turret basket – 7ft10 (2.38-M)
Port in turret rear plate – 10′ (0.25-M)
Circular opening in turret roof – 1ft2 (0.35-M)
Circular opening in driving compartment roof plate – 8′ (0.20-M)
Circular openings in nose plate and lower tail plate – 5.5′ (0.13-M)
Opening in front of belly plate – 1ft8.5 (0.52-M)
Circular openings in rear of belly plate – 10.5′ (0.26-M)

(e) Weights
Knowing the thicknesses of the hull and turret plates and their dimensions, it is possible to estimate the weight of the hull and turret in rough terms as 38 tons and 34 tons respectively. To arrive at an approximate figure of the overall weight of the tank it is necessary to estimate the weight by percentage of the remaining parts of the tank. It is thought that the following percentage weights may serve as a rough guide.

Suspension group – 16.5
Tracks – 10
Crew, fuel, equipment and stowage – 8
Ammunition and racks – 5
Transmission group – 5
Engine group – 5
Mantlet for guns – 1
Total – 50

On this basis it is possible to estimate the total weight of Tank.

Dear reader,

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