Cutaway model of a 4Lb Mk.III E Incendiary bomb. This type of incendiary bomb was the most widely used type of incendiary used by the RAF, as it was easier and cheaper to produce than other types of Incendiary bombs. It was packed in the 250 Lb SBC (Small Bomb Container), a dispenser which housed 3 batches of 30 pcs. 4 Lb Incendiary bombs.
In Picture 04 one can see a Lanaster being armed with one 4000 Lb Coockie and 12x90 =1080 pcs. of 4Lb incendiaries, a standard bombload called “Usual”, for use against urban area’s.
http://www.lancaster-archive.com/lanc_bomb_loads.htm
The 4 Lb Incendiary bomb has a hexagonal shape to ease stacking and allow the safety pin to be kept in inward position during tranport. The nose is made of steel to enshure the bomb will be orientated nose forward when falling to earth and to allow the bomb to break through roof tiles or floors upon impact.
The bomb body and the fuze housing are made of magnesium, the tail is made of tin coated sheet steel.
The bomb body is filled with thermite cilinders to ignite the magnesium bomb body, and a black powder pellet at the end, causing an explosion to harras fire fighters. Later types of 4Lb incendiaries (Type X Mk.II) have a small Tetryl charge in the steel nosepiece, effectively changing the nosepiece into a small handgrenade.
The fuze is an inertia activated impact base fuze, the firing pin and firing cap (red) seperated by a weak spring and a brass ring with four inward pointing lips. When placed in the SBC, a spring loaded pin is kept in inward position, preventing the firing pin from moving forward. Upon release, the pin moves outward, releasing the firing pin. Upon impact, inertia swings the firing pin forward with such force that the four lips are bend forward, allowing the firing pin to reach the firing cap, igniting the ignition paper on top of the black powder ignition charge which -on it’s turn- ignites the black powder pellet on top of the thermite charge. The bomb will now start to spit fire through the two side holes (closed by a cork plug), igniting the entire bomb.
As can be seen in this short movie; https://www.youtube.com/watch?v=6t8_1VwaR0I
, the incendiary bomb can be exstinguised quite easilly, the problem however is the fact that they come in such large numbers that one can not exstinguish all of them.
Length of the bomb: 54,4 cm
Diameter : Keywidth 4,2 cm , 4,8cm over corners.
Weight : 4 Lb (1,78 Kg)
Regards, DJH
In Picture 04 one can see a Lanaster being armed with one 4000 Lb Coockie and 12x90 =1080 pcs. of 4Lb incendiaries, a standard bombload called “Usual”, for use against urban area’s.
http://www.lancaster-archive.com/lanc_bomb_loads.htm
The 4 Lb Incendiary bomb has a hexagonal shape to ease stacking and allow the safety pin to be kept in inward position during tranport. The nose is made of steel to enshure the bomb will be orientated nose forward when falling to earth and to allow the bomb to break through roof tiles or floors upon impact.
The bomb body and the fuze housing are made of magnesium, the tail is made of tin coated sheet steel.
The bomb body is filled with thermite cilinders to ignite the magnesium bomb body, and a black powder pellet at the end, causing an explosion to harras fire fighters. Later types of 4Lb incendiaries (Type X Mk.II) have a small Tetryl charge in the steel nosepiece, effectively changing the nosepiece into a small handgrenade.
The fuze is an inertia activated impact base fuze, the firing pin and firing cap (red) seperated by a weak spring and a brass ring with four inward pointing lips. When placed in the SBC, a spring loaded pin is kept in inward position, preventing the firing pin from moving forward. Upon release, the pin moves outward, releasing the firing pin. Upon impact, inertia swings the firing pin forward with such force that the four lips are bend forward, allowing the firing pin to reach the firing cap, igniting the ignition paper on top of the black powder ignition charge which -on it’s turn- ignites the black powder pellet on top of the thermite charge. The bomb will now start to spit fire through the two side holes (closed by a cork plug), igniting the entire bomb.
As can be seen in this short movie; https://www.youtube.com/watch?v=6t8_1VwaR0I
, the incendiary bomb can be exstinguised quite easilly, the problem however is the fact that they come in such large numbers that one can not exstinguish all of them.
Length of the bomb: 54,4 cm
Diameter : Keywidth 4,2 cm , 4,8cm over corners.
Weight : 4 Lb (1,78 Kg)
Regards, DJH
