pzgr40
Well-Known Member
Hi Smirky, here a full description of the fuze:
El.A.Z.25 , German WW2 electrical bomb fuze
Some general notes: The development of electrical bomb fuzes in Germany can be traced back to 1926. Under direction of Dr. H. Rhulemann it was carried out at the Rheinmetal Borsig factory. The original goal was to develop an electrical time fuze for artillery shells that could be set at the moment of firing. Somewhere down the path of development work started on Electrical bomb fuzes. This to such satisfaction that the Luftwaffe adopted the Electrical bomb fuze in 1937. The design of most Electrical fuzes is generally the same; an aluminium outer housing, to be devided in an upper and lower housing. The upper housing has a shoulder with a locating pin, enshuring that the fuze is placed in the right direction. On top is the fuze head with the electrical plugs. The upper part normally contains the horizontal - and vertical trembler switches, resistances and the depressable pistons of the electrical plug. The lower part normally contains the condensers, the delay devices (either pyrotechnic, either mechanical) and the anti disturbance devices. The gaine is screwed in the base of the fuze. The advantages of electrical fuzes are: Easy manufacturing (low number of different components for many different functions), great flexebility, instant action, low number of duds, arming only after the pilot connects the master switch, very safe. Extensive test with electrical fields around the fuze, up to 2.000.000 volts (ligtning), showed that an electric fuze, when propperly designed, is absolutely safe. One feature of German bombs is the way the fuze pocket is placed, mostly not in the longtudinal centreline (like allied bombs), but mostly in the side, perpendicular to the centerline.
Functioning of the fuze:The fuze has three firing circuits an can be set for three delays; non delay (13); 0,08 sec. delay and 14 sec. delay (12). The upper housing (1) contains a perspex mould (3) which contains the depressable pistons (4). In the aircraft the pistons are held in downward position (right lower picture) by the plug on the charging cable. The depressed piston makes contact with the upper (U) wire, charging the condensers (9), as soon as the pilot switches the master switch. If the bomb is dropped, the pistons rise, arming the electrical circuit (contact with lower wire L, no contact with wire U). At impact the trembler switch closes and the electric signal from the condenser passes through one of the three the igniter bridges (6), igniting the delay fuze (12). Which fuze is ignited, depends upon the depressable piston charged, either A or B. A set screw on top of the fuze 7) can be turned 90 degrees, from I to II; I is electrical (8)open, II is closed. By turning this switch, the short (0,08 sec) delay is cut out , leaving only the long delay by charging depressable piston B. The flame of either three ends up in the lower black powder pellet (14), where the strengthened flame travells into the Kz. Zdlg. (Kurze Zundladung / short booster) C/98 (15). The Booster is made of an aluminium can, containing 17 grams of Np (Nitropenta)10 (pink). In top of the booster a sprengkapsel (detonator) 38 (16) is placed. A leather washer with a celluloid disc is placed above the detonator, the aluminium can is rimmed over the leather washer to close the booster. The booster is placed in the gaine (17), which is screwed in the base (10) of the fuze. The base plate is locked up and held in place by a threaded ring (11). The El.A.Z. 25 was one of the most common used German bomb fuzes.
El.A.Z.25 , German WW2 electrical bomb fuze
Some general notes: The development of electrical bomb fuzes in Germany can be traced back to 1926. Under direction of Dr. H. Rhulemann it was carried out at the Rheinmetal Borsig factory. The original goal was to develop an electrical time fuze for artillery shells that could be set at the moment of firing. Somewhere down the path of development work started on Electrical bomb fuzes. This to such satisfaction that the Luftwaffe adopted the Electrical bomb fuze in 1937. The design of most Electrical fuzes is generally the same; an aluminium outer housing, to be devided in an upper and lower housing. The upper housing has a shoulder with a locating pin, enshuring that the fuze is placed in the right direction. On top is the fuze head with the electrical plugs. The upper part normally contains the horizontal - and vertical trembler switches, resistances and the depressable pistons of the electrical plug. The lower part normally contains the condensers, the delay devices (either pyrotechnic, either mechanical) and the anti disturbance devices. The gaine is screwed in the base of the fuze. The advantages of electrical fuzes are: Easy manufacturing (low number of different components for many different functions), great flexebility, instant action, low number of duds, arming only after the pilot connects the master switch, very safe. Extensive test with electrical fields around the fuze, up to 2.000.000 volts (ligtning), showed that an electric fuze, when propperly designed, is absolutely safe. One feature of German bombs is the way the fuze pocket is placed, mostly not in the longtudinal centreline (like allied bombs), but mostly in the side, perpendicular to the centerline.
Functioning of the fuze:The fuze has three firing circuits an can be set for three delays; non delay (13); 0,08 sec. delay and 14 sec. delay (12). The upper housing (1) contains a perspex mould (3) which contains the depressable pistons (4). In the aircraft the pistons are held in downward position (right lower picture) by the plug on the charging cable. The depressed piston makes contact with the upper (U) wire, charging the condensers (9), as soon as the pilot switches the master switch. If the bomb is dropped, the pistons rise, arming the electrical circuit (contact with lower wire L, no contact with wire U). At impact the trembler switch closes and the electric signal from the condenser passes through one of the three the igniter bridges (6), igniting the delay fuze (12). Which fuze is ignited, depends upon the depressable piston charged, either A or B. A set screw on top of the fuze 7) can be turned 90 degrees, from I to II; I is electrical (8)open, II is closed. By turning this switch, the short (0,08 sec) delay is cut out , leaving only the long delay by charging depressable piston B. The flame of either three ends up in the lower black powder pellet (14), where the strengthened flame travells into the Kz. Zdlg. (Kurze Zundladung / short booster) C/98 (15). The Booster is made of an aluminium can, containing 17 grams of Np (Nitropenta)10 (pink). In top of the booster a sprengkapsel (detonator) 38 (16) is placed. A leather washer with a celluloid disc is placed above the detonator, the aluminium can is rimmed over the leather washer to close the booster. The booster is placed in the gaine (17), which is screwed in the base (10) of the fuze. The base plate is locked up and held in place by a threaded ring (11). The El.A.Z. 25 was one of the most common used German bomb fuzes.
