Tag Archive for '28cm'

28 cm Wurfkörper Spr.: 28 cm Rocket Projectile

28 cm Wurfkörper Spr.: 28 cm Rocket Projectile

This package-type rocket is a self-contained unit fired from a metal or wood crate. Firing is accomplished by “pointing” the crate at the target, resting the front part of the crate on a mound of dirt (or a similar rest) at an angle from 5° to 45°, and firing by means of a hand electrical firing system.

The propellant charge, contained in the motor tube, is in the form of one stick weighing 14 lb., 9 oz. with one central hole and eight annular holes.

Eight grooves are formed in the sides of the propellant stick, and celluloid tubes are fitted into these grooves. A length of quickmatch in the central hole is inclosed in a celluloid tube.

There are two igniters, one at the front and one at the rear of the propellant. The rear igniter consists of a cloth bag containing 10 grams (154 grains) of NC powder. The front igniter is a metal holder containing a flash composition with a layer of initiating composition.

The bursting charge is contained in the large section, directly forward of the rocket motor tube.

The booster, known as Zdlg. 36, consists of a cylindrical aluminum container filled with penthrite wax and perforated at the top to house a thimble-shaped detonator.

The fuze, Wgr. Z. 50, is a point-detonating or graze action type. The safety pin is removed before firing, leaving the two centrifugal bolts and a split ring to act as a safety feature in flight. The detonator is situated in the inertia pellet.

There are 26 jets at the end of the motor tube inclined approximately 12° right, giving it rotation in flight for stability. The internal diameter of the jets is 0.5 cm (.19 in.) and the external diameter 1 cm (.38 in.).


Weight (total)         181 lb.
Length (overall) 3 ft., 11 ins.
Length (body) 2 ft., 4 1/2 ins.
Length (tail) 1.85 ft.
Diameter (body) 11 ins.
Diameter (tail) .59 in.
Number of ports 26
Contents 110 lb. TNT
Range (maximum) at 42° 2,337 yds. (estimated)

German: p. 354

28 cm R. Gr. 4331: Rocket Assisted Prerifled Projectile

28 cm R. Gr. 4331: Rocket Assisted Prerifled Projectile

This high explosive projectile is fired from the 28 cm K. 5 (E) railway gun, and is prerifled in the same manner as the 28 cm Gr. 35 described on page 312. The outstanding feature of this new projectile is an increase in range from 67,800 yards to 93,100 yards—nearly 53 miles. This increase of 37% over the maximum range for the standard high explosive round is the result of energy supplied to the projectile by the addition of rocket propellant powder which is ignited 19 seconds after leaving the gun. After building up sufficient pressure to shear the lip on the base plug, the rocket propellant located in the ogive of the projectile discharges through a central venturi tube.

On the main body there are 12 steel splines set at the angle of rifling. The forward body (ogive) is threaded externally to screw into the main body and internally at its nose to receive the fuze and a rocket propellant ignition system. The venturi tube which extends from the base of the projectile to its middle section is secured by being screwed into the fuze and venturi adapter. A spun glass sleeve insulates the venturi tube from the explosive charge which is cast on the resulting assembly. A Zt. Z. S/30 time fuze set to operate 19 seconds after the projectile is fired is screwed into the nose of the projectile. Two percussion fuzes, AZ 4331, are located in the venturi adapter. These are armed by the burning of the rocket propelling charge through a powder pellet incorporated in the fuze. The rocket propellant is moulded as one piece, and extending through it are eight longitudinal holes 3/4-inch in diameter, located around a circular hole 1 5/8-inch in diameter.


Length of projectile (less fuze)       48.79 ins.
Diameter of ribs 11.70 ins.
Diameter of rotating band 11.85 ins.
Diameter of body 11.10 ins.
Total weight 545 3/4 lbs.
Rocket propellant weight 43 lbs.
Explosive weight 30 3/4 lbs.
Maximum range 93,100 yds.

German: p. 312.1 (June 1, 1945)

28 cm Rifled Projectile

German 28 cm Rifled Projectile

This pre-engraved projectile recovered in Italy is used for long range bombardment. It has longitudinal inclined steel splines and a single one-inch-wide copper band that acts as a gas seal. The splines are set at a slight angle to the axis of the projectile and are 19.2 inches in length. In loading the projectile, the splines are lined up with the rifling of the gun tube. The shell is 33 inches in length, exclusive of the windshield. Fragments indicate that the windshield would add an extra two feet to the length.

A nose percussion fuze (AZ 35 K) and a base fuze (BD Z 35K) are fitted. The Germans are reputed to have four types of 28 cm railway guns able to employ this type of projectile. They are: 28 cm Br. N. Kan E.; 28 cm K. 5 (E); 28 cm K. 5/1 (E); and 28 cm K. 5/2 (E).


Caliber         280 mm (11.023 ins.)
Weight (approx.) 550 lbs.
Length (excluding windshield) 33 ins.
German: p. 312

28 cm K5 (E): Railway Gun

28 cm K5 (E): Railway Gun

The German 28 cm K5 (E) has an unconfirmed range of 31 miles and fires a pre-engraved projectile weighing approximately 550 pounds. It is fired from a turntable affording a 360° traverse.

The gun has a 70-foot 8-inch barrel held in a sleeve-type cradle. The barrel recoil mechanism, fitted between two arms projecting downward from the cradle, consists of two hydropneumatic cylinders and a single hydraulic buffer cylinder. The cradle is supported by trunnions which rest in bearings on top of a box-like frame, of girder construction, which in turn is supported on two pintles resting in bearings in the center of two 12-wheel trucks. The front pintle bearing rides in a rail on the front truck and can be positioned six inches either side of center, thereby allowing a car traverse of approximately 1°.

The equipment in effect has a double recoil action. Besides the barrel recoil which is approximately 32 inches, the gun car recoils. It is coupled to the front of the turntable platform by a hydraulic buffer and a hydropneumatic counterrecoil mechanism which returns the car to battery position.

A turntable platform is transported as part of the equipment and in transport forms a flat car with a 103-foot bed resting on two 8-wheel trucks.

A central jack helps support the tremendous weight of the gun and carriage which amounts to around 230 tons and also serves as a central pivot for the turntable.

The powder chamber is approximately 10 feet 5 inches long. Obturation is obtained by means of a short brass cartridge case and the breech is closed with a horizontal sliding type of breechblock. Firing is of the percussion type.


Caliber      280 mm (11 ins.)
Length of barrel 70 ft., 8 ins.
Length of tube 67 ft., 5 ins.
Length of rifling 57 ft.
Rifling Right Hand uniform twist
Weight of barrel (Leopold)* 187,880 lb.
Length of car 95 ft., 7 ins.
Length of carriage 69 ft., 8 ins.
Width of carriage (overall) 8 ft., 8 1/2 ins.
Number of grooves 12
Width of grooves 5/8 in.
Depth of grooves 17/64 in.
Max. range 54,680 yds.**
Traverse on turntable 360°
Carriage traverse (approx.) 1/2° R; 1/2°
Elevation (estimated) 50°
Ammunition Separate loading—steel splined projectile
Weight of projectile (approx.) 550 lb.

*Two of these guns were found in Italy; one was called “Leopold,” and the other “Robert.” The weight of the barrel on the latter model is 187,165 pounds.
**Not verified.

German: p. 100.2

Schweres Wurfrahmen 40: Rocket Projectors on Semitrack Vehicles

Schweres Wurfrahmen 40: Rocket Projectors on Semitrack Vehicles This rocket projector is designed for use on half-tracked armored personnel carriers. The principal feature of the device is the carrier plate, three of which are mounted on each side of the half-track. Each is adjustable for elevation of 5° to 45°, and is believed to be equipped with an elevating scale. The actual projector consists of the crate in which the 28 cm or 32 cm rocket is packed, and which may be secured to the plates. Reports indicate that each vehicle carries six rounds, five of which are 28 cm high explosive and one 32 cm incendiary. Range figures are identical to those applying to the Schweres Wurfgerät 40 and 41 and the 28/32 cm Nebelwerfer 41. The photos above show the 3-ton armored semi-track (m. gp. Zgkw.) fitted with rocket projectors as described above.

German: p. 350 (May 1, 1945)