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"Clearing Unexploded Butterfly Bombs" from Tactical and Technical Trends

The following intelligence report on the recognition and removal of German SD 2 butterfly bombs was originally published in Tactical and Technical Trends, No. 36, October 21, 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.]


The following instructions for the recognition and destruction of German SD 2 "butterfly bombs," (see Tactical and Technical Trends No. 34, p. 23) has been taken from an official German directive.

*          *          *

a. General

The SD 2 is a fragmentation bomb weighing 4.4 pounds, whose external shape and construction differ considerably from those of the bombs formerly used.

It must be expected that some will be duds, owing to their peculiar characteristics. Duds usually detonate on the slightest movement and may therefore be dangerous to our own troops. They should be removed as soon as discovered.

b. Recognition

The armed SD 2 consists of a cylindrical iron body 3.15 inches long and 3.15 inches in diameter, which may be painted gray-green or black, or sometimes red, or may be unpainted. A wire cord 5.9 inches long projects from its body. There is attached to the free end of this cord a sheet-metal flap consisting of two saucer-shaped half cylinders fastened together by means of a hinge. Two smaller plate-shaped flaps are attached to this hinge, and extend to the left and right from the hinge and the saucer-shaped flaps, in an approximately horizontal direction.

SD 2 bombs which have fallen onto hard ground without exploding will, as has previously been described, be visible. Owing to their peculiar shape and construction they can easily be recognized. In order that duds may be more easily recognized. they will in the future be provided with bodies painted gray with yellow stripes .08 inch wide; which are:

(1) Parallel to the longitudinal axis on both sides of the fuze, and

(2) Painted on the nose of the bomb at an angle of 90 degrees with the foregoing stripes.

The whole surface of newly manufactured SD 2 bombs is painted yellow.

The flaps are marked as follows:

(1) The saucer-shaped and plate-shaped flaps bear yellow stripes .08 inch wide;

(2) The plate-shaped flaps bear a red stripe running at right angles to the yellow stripe.

Newly manufactured flaps are painted yellow and the plate-shaped flaps bear a red stripe .08 inch wide.

If the wire cord is torn out, as seldom happens, the bomb and flap lie in different places. It is then necessary to be especially cautious. The flaps of SD 2 bombs which have detonated are perforated by bomb fragments. If flaps not so perforated are found, it is probable that the bomb to which they belong has not detonated. The ground must be searched for bombs or be roped off to prevent any one from crossing it.

c. Sensitivity of Duds

The bomb is armed during its fall by the twisting of a pin attached to the stem-like cord from the fuze. SD 2 bombs that have not exploded are extremely sensitive. The slightest change in their position may detonate them, as the fuze is provided with a firing-pin system inside the body of the bomb, which is released by the slightest concussion. Even duds that have long been exposed to the weather retain this sensitivity. Owing to the very great fragmentation effect of the SD 2, any careless act may endanger the life of the person involved, or result in seriously wounding him. It is consequently strictly forbidden to touch a dud.

d. Destruction of Duds

(1) When the bomb lies on the surface of the ground, an effort should first be made to detonate the bomb by firing a rifle-shot at it; this is usually successful owing to the concussion thus caused. In employing this method, the rifleman must fire from a safe, covered position at a distance of at least 50 meters from the dud. If the bomb cannot be exploded by firing at it, it must be destroyed by a blasting charge. When placing the blasting charge in position, one must take care not to touch the body of the bomb. It will suffice to place the blasting charge in the immediate vicinity of the dud without placing it in direct contact with the latter.

(2) When the bomb has penetrated the ground a noose of cord or wire is placed loosely around the flap without touching it. The noose is then drawn tight by a man in a safely covered position and the body of the bomb is pulled out of the ground. If it does not detonate, it must be destroyed in accordance with the instructions given under d (1).

Only artificers and personnel familiar with these instructions may destroy or remove SD 2 duds.


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