This bomb is designed to detonate upon approach to the earth. It is a combination of a number of mechanical and electrical devices, all of which must operate if the bomb is to function properly. Proximity detonation is to be initiated through the action of an allways action electrical fuze contained in a plummet which falls ahead of the bomb in flight. An atmospheric fuze functions at the tail to open a set of four drogue plates at the tail, and release the nose plummet. A type 15 Model 2 tail fuze is provided to detonate the bomb in case of failure of either of the other fuzes.

The nose section contains a 20-kilogram spherical pummet housing an allways action electrical fuze, connected by 20 meters of silk clad copper cable to a tape 3 electric gaine projecting into the main explosive charge of the bomb. The plummet is held in place in the nose of the bomb by two hinged latches held in the closed position by two steel wedges controlled, through wires, by the action of the tail drogue plates.

The barrel of the bomb is standard in construction, but added provision for fragmentation has been made by the addition of a layer of cylindrical steel pellets just under the case of the bomb.

The tail cone is standard with the type 15 Model 2 tail fuze (B-3 (a)) in place at its apex.

The tail fin assembly is unique. It is designed to perform the function of slowing the fall of the bomb. It consists of a standard set of fins to which are hinged four rectangular drogue plates. These plates are hinged at their after end so that they may lie either flat against the fins or may be extended to serve as retarding plate. They are held in position flat against the fin surface by four pins which are in turn held in place by a blow-out plug. The blow-out plug is operated by an atmospheric fuze welded in place at the tail on the longitudinal axis of the bomb. The tail drogue plates operate the release mechanism for the nose plummet through two wires which run forward through eyelets on the out-side of the barrel of the bomb.

When the bomb is dropped, the aneroid in the atmospheric tail fuze operates at the pre-set altitude, firing a squib electrically, which blows out the blow-out plug at the tail, al-lowing the drogue release pins to move, releasing the drogue plates. The plates assume an angle of 90° with the fin surface, and act to slow the fall of the bomb. Through the action of the plummet release wires, the plummet is released, and falls to the end of its cable. The allways action fuze in the plummet is armed by air travel, and operates through its cable and gaine to fire the main charge of the bomb upon striking the target. The type 15 Model 2 tail fuze operates in case of failure of the allways action nose fuze.

Both the atmospheric tail fuze and the all-ways action nose fuze carry their own electri-cal supply for firing in the form of self contained batteries.

The data on this bomb is the result of incomplete investigation, and must not be consi-dered as specific, accurate information.

Figure 70 - Type 5 No. 25 Mk 33 Bomb.