The Doric Columns
This picture gives the relative sizes of the bombs. From front to back are the 50kg, the 250kg, the 500kg (in the wooden frame), the 1000kg (nicknamed by the Germans "Hermann") and the 1800Kg (nicknamed by the Germans "Satan"). The bomb right at the back appears to be a 50kg variant. The picture at the top has 250kg bombs being "decorated" by Luftwaffe personnel, giving some clues at to the size. The bomb is actually 64.5 in. Its filling is either 60/40 Amatol/TNT, or TNT with a variety of additives including wax, woodmeal, aluminium powder, naphthalene and ammonium nitrate. The weight of the filling is 287lbs, making 52% of the total weight of 548lbs.
The 2 represent the maximum bomb load for this aircraft type. Specialist bombs used included the thick cased semi-armour piercing type, known as the Sprengbombe dickwandig (SD). These were medium cased steel weapons and, being either anti-personnel or semi-armour piercing, had a load factor of 35% explosive. Because of their penetration qualities they were used primarily against ships and fortifications. These also came in a range of weights, ranging from 50, 250, 500 to 1,700kg.
There was also the armour piercing bomb, known as the panzerbombe cylindrich (PC). With a thicker, armoured steel casing, as little as 20% of the total weight was explosive. It was used against shipping - and especially warships - and fortifications. The heaviest used was the 1,400kg "Fritz" version.
fuse – triggered
on impact with the ground
Butterfly bombs in a submunitions container could have the full range of fuses fitted to increase disruption to the target. Fuse variants such as the 41A, 41B, 70B1, 70B2, etc., also existed. These variants were inserted into the fuse pocket via a bayonet fitting but were otherwise identical. On October 28, 1940 some butterfly bombs that had failed to arm themselves and were examined in Ipswich by British Ordnance Technicians Sergeant Cann and 2nd Lieutenant Taylor. By screwing the arming rods back into the Fuses (i.e. the unarmed position) the 2 men were able to recover safe examples for scientific examination, in order to discover how the bombs functioned. As with more modern cluster bombs, it was not considered practical to defuse butterfly bombs which had fully armed themselves but failed to detonate (particularly those fitted with the type 70 fuse), due to the extreme risks involved. The standard render safe procedure for any unexploded butterfly bomb was to evacuate the area for at least 30 minutes (in case the bomblet was fitted with a type 67 time delay fuse), then destroy it in situ by detonating a small explosive charge next to it. Other solutions were to attach a long string to the bomb and tug on it after taking cover, or for bombs in open countryside, shooting at them with a rifle from a safe distance. -
The 1st cluster bomb ordinance used by military were in WW2 on the German side, the “explosive bomb Vase 1 kg” short SD 1, the “explosive bomb Vase 2 kg” short SD 2, as well as the shaped charge anti-tank bomb SD 4 HL. These were differently sized disposal containers (e.g. AB70 with 23 SD 2 or 50 SD 1 to AB1000 B1,3 e or 1000 SD 1 with 610 incendiary bombs) packed, which in turn was dropped like a big bomb, after a short time the case opened over a time fuse and the bomblets were released. The camouflage was usually dark green or dirty yellow coloured bombs were allocated over the surface and exploded depending on the fuse used on impact, after the lapse of a predetermined time or at subsequent disruption of the bomb.
Many ‘containers’ – of incendiary or anti personnel bombs – were shaped in a bomb form, presumably to fit into the existing bomb racks. The ‘Butterfly Bomb’ was originally contained in an A.B. 23, which was, more or less, the same shape as a 50kg bomb and contained 23 bombs, hence its title. It had an air burst fuse so that the container opened up soon enough for the bombs to arm themselves before reaching the ground.
The range of bombs which the Germans had at that time were in 3 types:-
Later in the war they introduced the Flam 250 and Flam 500. These were the same size as their equivalent in S.C. but were filled with a flammable oil mixture which was spread over a wide area when the 3 pound burster charge exploded. They were designed to start a fire over a wide area, but frequently just covered it with its disgustingly smelly contents. They also similarly filled S.C. bomb cases with the same results. All of these had simple impact fuses.
& Land Mines
The parallel sided body of the SB1000 is made of steel plate and is roughly elliptical in end section. It is formed by two halves which are welded together externally. The bomb body is strengthened by a longitudinal bulkhead and 2 perforated diaphragms all welded into position. The base plate is welded into the body 2.5 inches from the end. The recess so formed is used to house the parachute container. The fuse pocket is welded into a slot in the longitudinal bulkhead. Nose plate is welded into position and has in it filling holes. There is a nose extension in the centre of the nose plate which houses the impact switch 55A/M fuse. The fuse pocket is connected to the impact switch by 2 wires which are housed in a metal tube. The parachute container, a thin metal box, is positioned between 2 ribs riveted to the base plate. It is secured to the base of the bomb by bolts. Inside the outer box an inner container is welded to the base of the outer box. Four extension springs are secured to the base of the inner container and are also attached to a plywood platform which is the base for the parachute. The parachute is folded on the plywood, the platform depressed, compressing the spring then held in place by canvas flaps secured over the top. The under flap carries a loop of cord which is threaded through eyelets of the other 3 flaps, a quick release pin is passed through the loop, thus retaining assembly against action of the spring.
Mine Disposal - Magnetic Mines
We don’t kid ourselves we’re heroes
Mysterious underwater explosions in 'H' Channel off Aberdeen started a panic. Lt Commander Leon Verdi was flown up in weather unfit for flying. On arrival at the airport at Aberdeen it was a mad rush to the dock. An Armed Trawler immediately put to sea, but when the Skipper was asked for his chart, he replied he didn't have one but knew the spot. In mid afternoon the Trawler slowed, the Skipper sniffed the breeze and said 'She's there.' A few feet beneath the surface was the mast of a sunken Ship. An underwater inspection revealed the vessel sitting on her side but there was nothing to indicate whether a torpedo, snagline mine, explosive motor boat, drifting mine or a submarine laid influence mine had caused the damage.
Beneath the wreck was an aircraft which had evidently been lying on the seabed when the ship was sunk. While the search for clues to the 'mysterious explosion' continued, tragedy struck elsewhere. The Captain of an ML located a sub-laid mine and manhandled it delicately ashore at Great Yarmouth. Commander Edwards, the local RMSO, a legendary character who had rendered safe vast numbers of enemy moored mines and conical floats, obtained permission from DTM to have a go at it. In the process of stripping the mine, it detonated, killing Edwards and his American observer. (It is possible the aircraft was a ditched German Bomber and contained 2 Magnetic Mines which both triggered when the ship inadvertently passed over it.)
Shortly after the tragedy a similar mine was washed ashore on the same strip of beach. Mouldy was ordered to use all scientific aids in fathoming the mine's secrets. The Leon Verdi with his mobile dark room and Waldron, a civilian scientist who did the lab X-ray, joined Mouldy. Waldron also brought a sensitive trepanner. Sensitive listening devices were used to detect a possible clockwork. At one stage it was feared a gamma ray anti-stripping device might be fitted. Both fears proved negative. Mouldy decided to proceed with a step by step strip. Shadow pictures showed in addition to the normal bits and pieces a canister about midway on the long axis. A very thin wire could be discerned stretched from the canister to the mechanism plate and aft to the main charge.
Was it a booby trip or a self destruction device? If either, how did it work? Was removal of the whole mechanism the trigger? Could the main charge be parted from the body of the mine without risk? Sooner or later the RMSO arrived at the moment of truth. He must touch or move something. The mine was of the magnetic type but there was no certainty that it was dead magnetically. As a start the mine was gimballed and although very sensitive, the many fingered moving parts were very sluggish. Eventually, after weighing all the probabilities, Mouldy, step by step, unveiled the ingenuity exercised by the German armourers and the mine that claimed the life of Edwards and his observer was rendered safe.
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