Monday 16 September 2019

German Explosive Ordnance - Containers (Part 2)







German Explosives








AB 70-1 OR Mark 70 S Container


Overall Length: 43 and 1/2 inches
Body Diameter: 8 inches
Wall Thickness: 1/16 inches
Tail Length: 16 inches
Tail Width: 11 inches
Filling: 3 Mark S Flares


Colour and Markings: Light Khaki overall.  Dull red stripes between tail fins.

Stenciled on container:  Either Mark 70 S or

"Rot" or "Weiss" (Red or White)

When container is stenciled "Brenndaner 0-5" flares are normally fitted with friction non-delay igniters.  If stenciled "Brenndaner 5-15" the flare in the front compartment functions as above but the two remaining flares are fitted with 67/V fuzes set to function after 5 and 10 minutes.


Construction: Container is identical in external construction to the AB 23 SD 2 container.   The bottom section of the container is divided by two walls, forming three compartments.  The forward compartment houses a shortened version of Mark S flare.  The center compartment provides clearance for the fuze pocket and the rear compartment houses two Type 1 Mark S flares.

When charge is passed to fuze, predetermined delay starts running out.  Fuze then fires initiating burster charge within gaine.  Explosion forces anvil from the fuze pocket, shearing the shear wire and causing the container to hinge open.  Static cords connect each flare fuze to the container.  When the flare falls away, flare fuze is thus initiated.


Suspension: Horizontal or vertical.  An internally threaded suspension bolt is welded to the nose of the bottom section and a twin bar of steel, surmounted by an internally threaded suspension eyebolt housing is welded to bottom section 2 inches in rear of the rear wall.






AB 70-3 Container


Overall Length: 39.75 inches
Body Diameter: 7.5 inches
Wall Thickness: 0.06 inches
Total Weight: 52 kilograms
Filling: 22 SD2 bombs.


Color: Light brown overall.

Stenciled in black:
(69)D AB 70-3F
22 SD 2 Stor.
Gew 52 kg






Construction: The container consists of a center beam and two casings, each of which are attached to the center beam by two hinges.  The center beam consists of two sheet steel plates, spot welded together along their longer flat axis, then forming divergent arcs that conform to the curvature of the SD 2 bombs.

A U-shaped bracket is fixed between the two steel plates of the center beam by means of rivets.  This bracket serves as an attachment for the suspension eyebolt, the fuze assembly and the bomb release unit.  A steel tube, parallel with the lateral axis of the container, is secured to the two steel plates of the center beam, within the U-shaped bracket by means of flanged surfaces at the ends of the steel tube.

The two upper arc-shaped portion of the center beam each have 11 U-slots to permit, dependent upon the methods of stowage, the protrusion of either the arming cables or safety pin lugs of the vanes of the SD 2 bombs.  Two steadying brackets are welded to the center beam.  The charging head is screwed to a small steel platform welded to the center beam.  A flanged strengthening plate is welded to the lower arc-shaped portions of the center beam.  The rectangular flanges, at the extremities of the main beam and the casings, retain the SD 2 bombs within the carrier in the longitudinal axis.  A steadying plate is spot welded to each of the casings.  There is a small slot in each of the casings opposite the U-shaped bracket to accommodate the two securing rods.

The base plate of the fuze pocket is secured to the U-shaped bracket by means of two nuts and bolts.  The fuze pocket and enclosed spring-loaded electric terminal are secured to the base by two screws.  A steel circlip around the 69D fuze provides the negative contact for the fuze.  Two red covered cables, enclosed in a yellow waterproof cover, complete the electric circuit from the charging adapter to the fuze assembly.

A strong steel sleeve, with a threaded steel cap, is a sliding fit over the fuze pocket.  The threaded steel capo is fitted with a small circular polystyrene window for visually checking that the fuze is present.  The steel release rod is attached to the steel sleeve by means of a steel clip.  This release rod passes through an aperture in the fuze pocket base and thence through the opening in the U-shaped bracket and steel tube.  When assembled, the steel sleeve is secured to the fuze pocket by wire.  Two securing rods, with "eyes" formed at either end, secure the casing to the central beam after the loading of the SD 2 bombs.  The inner eyes enter the steel tube in the central beam, in which position the end of the release rod passes through the eyes, thereby retaining the securing rods.  The outer eyes pass through the slots in the respective casings, and are secured on the outside of each casing by the steel split pins.  The container is loaded with 11 bombs between the center beam and casing on each side.




Operation: On release from the aircraft, an electric charge is imparted to the 69D fuze via the charging adapter; after a delay of 1 second, the propellant charge within the fuze is ignited.

The gas pressure generated drives forward the steel sleeve, disengaging the release rod from the inner eyes of the securing rods.  The casings are forced outwards by the weight of the bombs and the tendency for drogues to spring open.


Suspension: Horizontal.







AB 70D1 Container


Overall Length: 43.5 inches
Body Diameter: 8 inches
Wall Thickness: 0.03 inches
Tail Length: 16 inches
Tail Width: 11 inches
Filling: 50 SD 1 bombs
Total Weight: 56 kilograms


Color and Markings: Field grey or olive green overall.

Stenciled (near tail): AB 70D1
Stenciled (forward of the fuze pocket): Gewicht CA 56 kg



Construction: In the forward compartment between the forward and central bulkhead are stored a cluster of ten bombs, loosely held together by a strip metal cluster band.  The forward bulkhead is perforated by 11 holes but bomb fuzes do not protrude through these holes.

In the after compartment four clusters of bombs are stowed.  Each cluster loosely held by a strip metal cluster band.  Of these four after clusters, the fuzes of the first protrude through the 10 perforations in the after bulkhead.  While the fuzes of the remaining clusters are inserted in the hollow tails of the cluster in front.

When the aerial burst fuze operates, wire is sheared by the explosion of the small exploder under the fuze.  The case opens and the bombs fall out.


Suspension: Horizontal or vertical.


Remarks: A German document states that the AB 70D1 loaded with SD 1 bombs are not entirely safe in transport.  Aircraft are not permitted to land with AB 70D1 containers.  It is impossible to jettison AB 70D1 safely.  Minimum height of release is 150 meters.






AB 250-1 Container



Overall Length: 64 and 1/4 inches
Body Diameter: 15 and 1/8 inches
Wall Thickness: 3/32 inches
Filling: 92 SD 2 bombs


Color: Dark green overall


Construction: The container consists of a center beam to which are attached three pairs of semicircular casings.  The whole forming a cylinder bisected vertically by the center beam.

The center beam is composed of two mild steel pressings, welded together to form, in cross section, an octagonal tube extending to an upper and a lower double-sheet web which open at their extreme extremities to form V-channels.  The upper and lower channels are reinforced by pressings welded within the V-channels.

Spaced within the octagonal tube are four pairs of octagonal plates, grooved at right angles on their inner faces.  When fitted together, the grooves correspond and make four interconnected radial tubes in the form of a cross.

Holes drilled in the center beam correspond with each horizontal tube,  Extensions to the vertical tubes are formed within the upper and lower webs.  Guide plates centrally drilled are spaced within each lower vertical tube.  The holes cut in the wall of the center beam accommodate the arming cables of the SD2 bombs.  Distance pieces are fitted to the external faces of the central beam.

A release plate hinged at its forward end is fitted to the outside of each casing.  A small slot cut in the release plate corresponds with a similar slot cut in each casing.  Bomb positioning ribs are welded to the inner face of each casing.

After loading the container, the holes cut in each casing permit the withdrawal of the bomb safety clips.  The nose fairing and the tail dome are formed by welding metal pressings to the front and rear pairs of casings respectively.  The charging adapter is screwed to a small stud plate fitted within the upper channel.  The suspension lug platform, containing the suspension lug housing, is welded to metal arms riveted to the walls of the upper channel.

The lateral guides within the lower channel, form seatings for the bracket of the front, central and rear release rods.  The steel link rods are formed with "eyes" at each end.  The inner eye enters a horizontal tube, in which position the appropriate release rod passes through the eye, thereby securing the link rod.  The outer eye passes through the slots in the casing and release plate and is secured on the outside by a steel split pin.  Double compression springs are fitted in the lower vertical tube between the guide plate and the release rod bracket.  The base plate of the fuze pocket is secured within the lower channels by means of two nuts and bolts.

A fuze pocket and enclosed spring loaded electrical terminal are secured to the base plate by two screws.  A steel circlip around the fuze provides the negative contact for the circuit.  One red covered and one yellow covered cable enclosed within a red waterproof cover complete the electric circuit between the charging adapter and the fuze assembly.  A strong steel sleeve with a threaded steel cap, is a sliding fit over the fuze pocket.  The threaded steel cap is fitted with a small circular polystyrene window for visually checking the presence of the fuze.

One extension rod passes through the front lateral guide and front release rod bracket, thus retaining the front release rod.  The longitudinal bracket forms a guide for the release piston.  The release piston rod, passing through the central lateral guides, retains the central release rod.  The release piston springs are compressed between a sealing machined on the release piston rod and the central lateral guide.

The bell crank lever pivoted in the longitudinal bracket has a small metal plate laterally attached to its long arm.  The nose of the bell crank lever, passing through the longitudinal bracket, retains the release piston.  The notched plate at the tail of the bell crank lever being retained by the extension rod prevents the rotation of the bell crank lever.  A similar mechanism to the rear of the central release rod provides for the operation of the rear release rod, the exception being that the rotation of the second bell crank lever is prevented by the release piston rod.



Operation: On release from the aircraft, the fuze fires after the approximately 1-second delay propellant charge is ignited.  Pressure drives the steel sleeve downward, the steel sleeve extension, and extension rod.  The extension rod disengages from the front release rod bracket.  The front release rod under the influence of its spring moves downward and fires the link rods.  Airflow passing under the release plate causes the casings to move outward, thus firing the bombs.  This movement is assisted by the weight of bombs and the tendency of the drogues to spring open.  The first bombs then fall away.  As the extension rod moves forward, it is also disengaged from the notched plate at the tail of the bell crank lever.

The bell crank lever is now free to rotate and the release piston moves forward under the influence of its springs and bears on the nose of the bell crank lever rotating it out of the piston guide.  This releases the piston rod bracket, thereby releasing the central casing.  The rear casings are now freed in a similar manner.  The small plate on the bell crank lever appears to prevent the simultaneous release of the casings.  On release of the first pair of casings, the bell crank lever rotates until the small metal plate bears against the casing.  The bell crank lever is now unable to rotate further  until the front casings are clear of the lower channel.  This momentarily delays the release of the second pair of casings.  This serves to increase the scatter of the bombs.






Next Time: Containers (Part 3)


Source: German Explosive Ordnance Vol. 1: Bombs, Rockets, Grenades, Mines, Fuzes & Igniters

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