Cutaway model of a Cartouche de 75mm a obus explosif de Modele 1917 fuzed with the Fusee detonateur percutante de 24/32 Modele 1899, translated in English the 75 mm cartridge with High explosive shell Mk.1917, fuzed with Impact fuze 24/33 Mk. 1899.
The cartridge was used in the famous French 75mm M1897 Field gun. This for its time very modern gun set the pattern for future develpoment for many years and made use of the Nordenfelt eccentic screw breech mechanism which gave the gun a maximum firing rate of 20 rounds per minute (12 rpm was the practical rate). The gun also used a very modern designed hydraulic recoil sysytem.
It has been in use with many countries and was still in use with Camerooon, Greece, Morroco, Mexico and Upper Volta in 1975. The original gun made use of spoked wooden wheels and Horse carriage, the later types made use of pneumatic tyres and was truck towed.
The HE projectile weighs 6,195 kg and has a Vo. of 575 mtrs/sec. The maximum range of the shell is 11.100 mtrs.
Two movies showing the gun in action can be found here on You tube:
[ame="http://www.youtube.com/watch?v=rFygIJHnpq4"]http://www.youtube.com/watch?v=rFygIJHnpq4[/ame]
[ame="http://www.youtube.com/watch?v=WvsVSH5W88s&NR=1"]http://www.youtube.com/watch?v=WvsVSH5W88s&NR=1[/ame]
The projectile exists of a mild steel body with a copper rotating belt. In top of the body a steel booster charge bushing is screwed in which a brass stepped bush is placed to receive the fuze.
The brass shellcase is filled with 700 grams of BSP-585 powder, existing of two stacked bundels of strips of powder.
Functioning of the fuze Fusee detonateur percutante de 24/32 Modele 1899:
Upon firing, inertia moves back the upper arming ring (3) inside the nose cap (2), riding the spring (4). The three inward bent lips of the locking ring inside the upper arming ring grip over the rim of the firing pin masking fork (5)below it. The upper arming ring is locked in lower position and cannot move upward again.
Also upon firing the lower arming ring (6, light green) moves back, riding the spring below it. Around this lower arming ring another ring with inward bet spring lips is placed (7, light blue) which prevents the firing cap housing (8) from moving forward. When the lower arming ring (6) is moved back by inertia upon firing, it bends the lips of the outer ring (7, light blue) outward, releasing the firing cap housing (8). The lower arming ring is locked behind the rim of the firing cap housing and cannot move up again. The only thing that now hold back the firing cap housing (8) is a light pull type spring (10) that is screwed in a thread in the firing cap housing , as well as a thread in the flange below. Upon impact, the firin cap housing is thrown forward stretching the spring (10)- , as well as the firing pin masking bolt (5) which is thrown forward, releasing the firing pin (red). The firing cap (blue) is driven into the firing pin. The flame of the firing cap is led through black powder booster pellets (9,11) which boosts the flame into the detonator (12). This will explode the booster in the projectile as well as the main charge.
In this cutaway one side of the firing pin masking fork (5) has been cut off (dark green surface ) to make the firing pin (red ) visable.
I want to thank all members of the Wk2 ammo forum and the BOCN forum who helped me with information. This enabled me to change it into a correct and reliable cutaway model.
Regards, DJH.
The cartridge was used in the famous French 75mm M1897 Field gun. This for its time very modern gun set the pattern for future develpoment for many years and made use of the Nordenfelt eccentic screw breech mechanism which gave the gun a maximum firing rate of 20 rounds per minute (12 rpm was the practical rate). The gun also used a very modern designed hydraulic recoil sysytem.
It has been in use with many countries and was still in use with Camerooon, Greece, Morroco, Mexico and Upper Volta in 1975. The original gun made use of spoked wooden wheels and Horse carriage, the later types made use of pneumatic tyres and was truck towed.
The HE projectile weighs 6,195 kg and has a Vo. of 575 mtrs/sec. The maximum range of the shell is 11.100 mtrs.
Two movies showing the gun in action can be found here on You tube:
[ame="http://www.youtube.com/watch?v=rFygIJHnpq4"]http://www.youtube.com/watch?v=rFygIJHnpq4[/ame]
[ame="http://www.youtube.com/watch?v=WvsVSH5W88s&NR=1"]http://www.youtube.com/watch?v=WvsVSH5W88s&NR=1[/ame]
The projectile exists of a mild steel body with a copper rotating belt. In top of the body a steel booster charge bushing is screwed in which a brass stepped bush is placed to receive the fuze.
The brass shellcase is filled with 700 grams of BSP-585 powder, existing of two stacked bundels of strips of powder.
Functioning of the fuze Fusee detonateur percutante de 24/32 Modele 1899:
Upon firing, inertia moves back the upper arming ring (3) inside the nose cap (2), riding the spring (4). The three inward bent lips of the locking ring inside the upper arming ring grip over the rim of the firing pin masking fork (5)below it. The upper arming ring is locked in lower position and cannot move upward again.
Also upon firing the lower arming ring (6, light green) moves back, riding the spring below it. Around this lower arming ring another ring with inward bet spring lips is placed (7, light blue) which prevents the firing cap housing (8) from moving forward. When the lower arming ring (6) is moved back by inertia upon firing, it bends the lips of the outer ring (7, light blue) outward, releasing the firing cap housing (8). The lower arming ring is locked behind the rim of the firing cap housing and cannot move up again. The only thing that now hold back the firing cap housing (8) is a light pull type spring (10) that is screwed in a thread in the firing cap housing , as well as a thread in the flange below. Upon impact, the firin cap housing is thrown forward stretching the spring (10)- , as well as the firing pin masking bolt (5) which is thrown forward, releasing the firing pin (red). The firing cap (blue) is driven into the firing pin. The flame of the firing cap is led through black powder booster pellets (9,11) which boosts the flame into the detonator (12). This will explode the booster in the projectile as well as the main charge.
In this cutaway one side of the firing pin masking fork (5) has been cut off (dark green surface ) to make the firing pin (red ) visable.
I want to thank all members of the Wk2 ammo forum and the BOCN forum who helped me with information. This enabled me to change it into a correct and reliable cutaway model.
Regards, DJH.
