Lone Sentry: German 105-mm Antiaircraft Gun (WWII Tactical and Technical Trends, No. 30, July 29, 1943)

The 105-mm gun, of which two models (10.5-cm Flak 38 and 39) are in service, is a standard German heavy antiaircraft gun. The gun is produced in both fixed and mobile versions, and is also mounted on railway mounts.

In the antiaircraft role the gun is controlled from a command post equipped with a director. A telescopic sight is provided for fire against ground targets. The gun, though reliable and well made, has the following disadvantages:

Excessive weight--about 14 tons in traveling position
15 to 20 minutes necessary to bring the gun in and out of action

[WWII German 105-mm Antiaircraft Gun]

a. General Data

Muzzle velocity 2,890 f/s

Maximum horizontal range 19,100 yds

Maximum vertical range 36,700 ft

Maximum effective vertical range 31,000 ft

Rate of fire 10 - 15 rpm

Length of piece 21.8 ft (61 cals)

Length of bore 18.2 ft (52.7 cals)

Twist of rifling - increasing Angle not known

No. of grooves 36

Width of grooves .217 in

Depth of grooves .051 in

Width of lands .142 in

Elevation -3° to +85°

Traverse 360°

Recoil 30.71 to 35.43 in

Weight in action 11 tons (approx)

Weight in traveling position 14 tons (approx)

b. Ammunition

Three types are fired:

(1) H.E. shell with time fuze; this shell is used for antiaircraft and is fitted with the same clockwork fuze as that used with 88-mm antiaircraft ammunition.

Weight of complete round   58.3 lbs

Weight of projectile (fuzed)   33.2 lbs

Weight of bursting charge (trotyl)    3.3 lbs

Weight of propellant (diglycol)   10.9 lbs

(2) H.E. shell with percussion fuze

(3) APCBC* shell

c. Penetration Performance

The following are estimated penetration figures for the weapon firing APCBC shell against homogeneous armor:

Range Thickness of Armor

(yards) 30° Normal

1,000 5.53 in 6.54 in

1,500 5.16 in 6.06 in

2,000 4.78 in 5.65 in

d. The Piece

Information regarding the piece is at present fragmentary. The breech is horizontally sliding and semi-automatic. The breech mechanism is automatically cocked as the gun moves back into battery, and the electrical firing circuit is completed by the closing of the breech.

e. The Carriage

The carriage has two side arms which are folded up for transport. A boss joins the main body of the carriage to the upper mount, which rotates on the boss by means of a traversing plate and a shaft which is connected to the traversing mechanism. The traversing and elevating gears have two speeds for manual operation; provision is also made for power operation.

f. Automatic Fuze Setter and Loading Mechanism

Both the fuze setter, which is fixed to the gun, and the loading mechanism are power operated.

The loading mechanism consists essentially of two trays. The loader places the round in tray 1, which is automatically gripped by the fuze setter. The loader then operates a handle on tray 1 which causes the fuze setter to release the round and transfers it to tray 2. Tray 2 moves automatically into position behind the breech and the round is loaded. As the round goes forward the rim of the cartridge case strikes a cam on tray 2, thus returning it to its original position.

g. Power Supply

Each gun battery is provided with an 8-cylinder gasoline engine which drives a DC generator producing:

Voltage 220

Amperage 200

Power 24 kw.

From the generator the current is led to a central distributing box whence it is supplied to the guns. Each gun has four electric motors as follows:

   Voltage    Power (kw)    Rpm

Elevation   220   1.5 1,200

Traversing   220   1.1 1,050

Loading   220   1.0 1,420

Fuze setting   220   0.1 1,400

*Armor-piercing capped, with ballistic cap