This development of the Sturmgeschütz mounts the Stu. K. 40 assault gun, with muzzle brake, on a Pz. Kpfw. III chassis. The gun. is identical to the Kw.K. 40 with the exception that in the Stu. K. 40 the buffer and recuperator systems are mounted on each side of the barrel to accommodate the S. P. mounting, while the Kw.K. 40 mounts the recoil mechanism above the barrel. The road performance of this vehicle will approach that of the Pz. Kpfw. III tank.
The superstructure is a box-like arrangement, closed in on the top and welded to the chassis. A commander’s cupola, loader’s entrance hatch, and an opening for the sight are provided on the roof of the superstructure. There is no hull entrance door. A circular hole approximately 9 inches in diameter, cut in the rear of the superstructure, houses a small electric fan which draws air into the fighting compartment. A circular plate 12 inches in diameter and 30 mm thick is fitted over the hole at a distance of 3 inches from the superstructure by means of 3 bolts. The thickness of superstructure armor is as follows: front vertical plate 50 + 30 mm, gun mantlet 50 mm, sides 30 mm, top 20 mm. Side skirting armor is often mounted on this vehicle.
The gun has a length of 126 inches, without the muzzle brake, a muzzle velocity of 2525 f/s for the 15.0 lb. projectile and an effective range of 2000 yards firing A.P.C. shell. Its approximate radius of elevation is -5 to + 20°; traverse 10° left and right. It utilizes the following types of ammunition—A.P.C., H.E., and hollow charge. The penetration of A.P.C. shell against homogeneous plate is reported as follows: 500 yards, 4.0 inches at 30° obliquity; 4.8 inches normal—1000 yards, 3.6 inches at 30°, 4.3 inches normal—2000 yards, 2.8 inches at 30°, 3.4 inches normal.
SPECIFICATIONS
| Weight | 26.5 tons | |
| Length | 17 ft., 9 ins. | |
| Width | 9 ft., 7 ins. | |
| Height | 6 ft., 5 ins. | |
| Ground clearance | 14 ins. | |
| Tread centers | 8 ft., 2 1/2 ins. | |
| Ground contact | 9 ft., 4 1/2 ins. | |
| Width of track | 15 ins. | |
| Pitch of track | 43 ins. | |
| Track links | 90 | |
| Fording depth | 3 ft. | |
| Theoretical radius of action | ||
| Roads | 100 miles | |
| Cross-country | 60 miles | |
| Speed | ||
| Roads | 25 m.p.h. | |
| Cross-country | 15 m.p.h. | |
| Armor | ||
| Front plate | 50 + 30 mm | |
| Sides | 30 mm | |
| Armament | 7.5 cm Stu. K. 40 2 Machine pistols |
|
| Ammunition | 54 rds. | |
| Engine | Maybach, HL 120 TRM, V-12, 320 hp. | |
| Transmission | 6 speeds forward, 1 reverse | |
| Steering | Epicyclic, clutch brake | |
| Crew | 4 |
German: p. 28