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"German N C 50 Smoke Bomb" from Tactical and Technical Trends

The following U.S. military intelligence report on German smoke bombs was originally printed in Tactical and Technical Trends, No. 29, July 15, 1943.

[DISCLAIMER: The following text is taken from the U.S. War Department publication Tactical and Technical Trends. As with all wartime intelligence information, data may be incomplete or inaccurate. No attempt has been made to update or correct the text. Any views or opinions expressed do not necessarily represent those of the website.]


This bomb is designed to be dropped from aircraft. It is reported to produce large quantities of greenish-black smoke for about 20 minutes. An authoritative German military writer states that in cooperation with friendly ground forces, aircraft may drop smoke bombs to cover or screen hostile troops for a short time in limited areas. Presumably aerial smoke bombs would only be used for this purpose where, for one reason or another, more economical means than the airplane are either unsuitable or not available. Conceivably aerial smoke bombs might also be used to screen the dropping of parachute troops or to designate a target to bombers.

a. Description

This bomb is similar in appearance to the normal 50-kilogram (110-pound) HE bomb. The marking "N C 50" painted on the bomb is probably an abbreviation for "Nebel Cylinder 50 (kilograms)," that is "Smoke Cylinder 50 (kilograms)." The nose is painted white for 4 1/2 inches from the tip; from that point 4 white bands, 1 inch wide, run back to the shoulder where the nose is welded to the bomb body.

The over-all length of the bomb and tail is 3 feet 7.3 inches, the bomb itself being 2 feet 2.5 inches long with a diameter of 8 inches. The thickness of the casing is 1/8 inch. The smoke-producing filling consists of:

Hexachlorethane                   91.1%
Aluminum powder                    8.5%
Probably iron oxide and silica     0.4%

The bomb is made up in two parts (see accompanying sketch), the cylindrical portion (1) being welded to the nose (2) along the circumference at (3). In the nose is a screw plug (4) which can be removed to accommodate a lug for vertical suspension. The lug for horizontal suspension screws into a block (5) which is secured to the inside of the bomb casing. The closing plate (6) at the rear end of the bomb is made of sheet steel. The edge of this plate is pressed inwards and then turned over so as to form a recess in which a rubber ring (7) is placed to seal the filling. To the plate is welded the igniter pocket (8) which contains the igniter (9). The latter consists of a steel tube 3 inches long and 1 inch in diameter. It is closed at its lower end by an aluminum disk, and at its upper end has an igniter cap pressed in.

[German WWII Smoke Bomb, NC 50]

The plate (6) has four equally spaced holes (10) which are covered by aluminum disks soldered in the position shown in the sketch.

Above the plate (6) and resting on it is the steel casting (11) which is secured to the bomb by eight screws. The base of this casting is perforated by 4 holes to correspond with those in the plate below it. At the center of the casting are 4 webs (12) supporting the fuze body (13).

The fuze is simple in construction and consists of a striker (14) supported on a creep spring (15). Into the base of the body is screwed the cap holder (16). The cap (17) is housed in the recess in this holder and secured by burring over the top edge of the recess. The hole (18) takes the safety pin (19), which projects through a hole in the casting (11) and a slot (20) in the tail cone. Between the fuze and the igniter is a perforated coiled spacer (21).

The tail is similar in general appearance to that of a 50-kilogram HE bomb. It is made of sheet steel and is in 4 pieces. Each piece has a flat area to form the fin and a portion shaped to form the cone of the tail. The 4 pieces are welded together to form the complete tail. In the upper portion of the tail cone, 4 holes (22) are cut to provide suitable outlets for the smoke when the bomb functions. The tail is attached to the face of the casting (11) by 8 screws.

b. Functioning

On release of the bomb from the aircraft the safety pin (19) is withdrawn and the fuze is then armed. On impact the striker (14) compresses the creep spring below it and fires the cap (17). This in turn fires the igniter cap in the head of the igniter (9). This igniter contains a thermite mixture consisting of magnetic oxide of iron, magnesium, and aluminum powders. The weight of this mixture is 2.6 ounces.

The thermite on ignition melts the solder on the disks (10) and provides an exit for the smoke. The main filling is ignited when the aluminum closing disk in the base of the igniter burns through.

c. To Render Safe

If the safety pin (19) is not in place, the bomb may be rendered safe by first unscrewing the 8 screws securing the tail to the bomb, and removing the tail; a cotter pin or nail should then be inserted into the hole (18) and in the striker (14). If the safety pin is not in place, jolting the bomb before rendering it safe may cause it to function.


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