Tag Archive for '8cm'

8 cm s. Gr. W. 34: Heavy Mortar

8 cm s. Gr. W. 34: Heavy Mortar (WW2)

The German 8.1 cm heavy mortar, first manufactured in 1934, is of conventional design, consisting of a tube, base cap, and firing-pin mechanism. Wall thickness of the tube or barrel tapers from 0.288 inch at the base cap to 0.190 inch; a collar at the muzzle slightly increases the wall thickness at that point. A leather-covered handle attached to the collar clamp near the muzzle is used apparently to change elevations when the tube is hot. The firing pin mechanism can be adjusted for two positions. In the “On” position, the pin protrudes into the tube the correct length for firing; in the “Safe” position, the firing-pin head is retracted, permitting greater safety in unloading the mortar in the event of a misfire or other malfunction. The change in setting is readily made by means of an adjuster located on the side of the base ring. The mortar is supported by a bipod and base plate.

The bipod includes cross-leveling, elevating and traversing mechanisms. The legs, and all other nonsliding parts, are made of light white metal. These legs, which have spikes and feet attached to the bottom, are adjusted to any one of six positions by a lever and held in place by locking gears. General construction of the bipod is sturdy and compact. It is easily folded for carrying purposes by swinging the cradle, which is hinged on the traversing mechanism sliding housing, until the left hook at the rear of the cradle is mated in the slot at the top of the rear bipod connector plate. The cradle is then traversed to the left, locking the hooks into the connector plate, and the legs are brought together.

The sighting system, having a total weight of 2 1/2 pounds, includes a collimator, cross level, longitudinal level, and an elevating and lateral deflection mechanism. Machining of the sight parts is excellent, and when in use it is attached to a mount on the left side of the traversing mechanism mount.

SPECIFICATIONS

Caliber 81 mm (3.189 ins.)
Weight
     Mortar and Mount         124 lb.
     Mortar 40 lb.
     Mount 84 lb.
     Bipod 41 1/4 lb.
     Base plate 43 3/4 lb.
Length (overall) 44 7/8 ins.
Method of loading Muzzle
Firing mechanism Firing pin with safety feature
Rate of fire
     Maximum 45 rds./min.
     Practical 10 to 12 rds./min.
Muzzle velocity Not determined
Range
     Maximum 2,625 yds. with light bomb
2,100 yds. with heavy bomb
     Minimum 66 yds.
Elevation 40° to 85°
Traverse 370 mils
Cross leveling, max. correction for cant 15°
Sights Collimator type (similar to Brandt sight for 60 mm Mortar, M2)
     Lateral adjustment 6,400 mils
     Elevation adjustment 1,600 mils
Ammunition
     Weight of complete round (smoke shell) 7.80 lb.
     Ignition cartridge charge 150 grs.
     3 Increment propellents .35 oz. each

German: p. 114

8 cm Raketen Sprenggranate: H.E. Unrotated Rocket

8 cm Raketen Sprenggranate: H.E. Unrotated Rocket

This rocket is actually 78 mm in diameter. Two features distinguish it from other German rockets: the use of tail fins to secure stability in flight without rotation, and the employment of a novel fuze arming device.

The complete round weighs 15.19 pounds and is nearly 28 inches long. Its two principal components are the nose fuzed high explosive war head and the rocket motor tube. The shell is attached by means of an adaptor ring and the motor tube is closed by a cone-shaped assembly carrying the fins and containing the venturi and propellant supporting grid. Six tubular sticks of cordite form the propellant ignited by a circular gun powder igniter set off by a wire ignition bridge. The launcher used is the Mantelrohr.

The nose fuze consists of a steel nose piece housing a light alloy striker held by a light spring, a percussion detonator, a magazine containing four pressed pellets, and a thermal arming device. When the rocket is fired, the heat of the propellant gases melts a ring of fusable metal, permitting the detonator and magazine to approach the striker. The main filling of the high explosive head is pressed flake TNT.

SPECIFICATIONS

Weight of complete round      15 lbs., 3 oz.
Weight of motor unit with central adaptor      10 lbs.
Weight of high explosive head with central adaptor       6 lbs., 5 oz.
Weight of high explosive filling      1 lb., 5 1/2 oz.
Weight of fuze (approx.)      4 oz.
Weight of propellant sticks      2 lbs., 3 oz.
Length of rocket      27.7 ins.
Ground range (estimated)      6,300 yds.

German: p. 359 (May 1, 1945)

Kz. 8 cm. Gr. W. 42: Short Mortar

German Kz. 8 cm. Gr. W. 42: Short Mortar

This weapon is of the same general design as the standard 8 cm mortar (s. Gr. W. 34) described on page 114. It is, however, shorter and lighter. It differs from the original weapon in the following respects:

The Model 42 has a shorter barrel with no striker control bolt at the base. It has a smaller baseplate, square in shape, with no carrying handle. The barrel is fastened to the baseplate by a spring catch. It also has a smaller bipod.

The elevating handle is situated at the base of the elevating column between the bipod legs. The cross levelling screw is halfway down the elevating column, and is connected to the left bipod leg by a sliding screw clamp.

The sight is situated on the left side of the traversing screw. Ammunition fired is the same as for the 8 cm s. Gr. W. 34.

A firing table printed on a steel plate is clamped to the tube.

SPECIFICATIONS

Caliber        81 mm (3.2 ins.)
Weight in firing position 62 lbs.
Length of barrel, overall 29.5 ins.
Length of bore 25.5 ins.
Size of baseplate 12 ins. x 12 1/2 ins.
Principle of operation Muzzle loaded; percussion fired (only)
Elevation 47° to 88°
Maximum range 1,200 yds.
Ammunition Same as for 8 cm s. Gr. W. 34

German: p. 114.1 (June 1, 1945)

8 cm (7.62) High Angle Gun, Type 3

8 cm (7.62) High Angle Gun, Type 3 - Japanese

This weapon, previously erroneously called the Type 10, is a naval type antiaircraft gun, mounted on a pedestal which permits a traverse of 360 degrees. The gun tube, of built-up construction, recoils inside a sleeve type cradle. A guide on the bottom of the tube rides in a groove, preventing rotation of the tube. Since the trunnions are located at the rear of the tube, muzzle preponderance is compensated for by an equilibrator inside the pedestal.

A hand-operated, semi-vertical sliding type breechblock and a hydrospring recoil mechanism are used. Recoil and recuperator are located over the tube. A small cylinder above the recoil cylinder is apparently for storing an oil reserve.

The elevating handwheel is located to the left of the weapon, and the traversing handwheel to the right. Two platforms, one on either side attached to the superstructure, allow the layers to move with the gun in traverse.

A bracket on the left of the piece is believed to mount a telescope and range drum.

SPECIFICATIONS

Caliber       76.2 mm (3 ins.)
Weight of gun and mount5,290 lbs.
Weight of gun1,100 lbs.
Length of barrel40 cals.
Length of tube9 ft., 6 ins.
Height (traveling position)
Height (firing position)
Width (overall)
Length of chamber1 ft., 8 ins.
RiflingR. H. twist
No. of grooves24
Width of grooves
Depth of grooves
Width of lands
Muzzle velocity (H.E. shell)2,200 f/s
Max. range (horizontal)
Max. range (vertical)26,000 ft.
Rate of fire10 to 12 r.p.m.
Traverse360°
Elevation75°
Depression
Length of recoil
AmmunitionH.E. w/ powder train time fuze

Wt. of projectile12 lb., 11 ozs.

Japanese: p. 114.1 (August 1, 1945)