Cutaway models of two 155mm ERFB shells…. and the story of Gerald Bull.
At the start of the 60’s of the last century attempts were made to shoot a satellite into space by means of two connected 16” ship’s gun barrels during the HARP (High Altitude Research Project), as rockets were still quite unreliable. Many exploded upon take off, or just after, destroying the payloads they were supposed to bring into earth orbit.
The HARP project was led by the brilliant Canadian ballistic engineer Professor Gerald Bull and funded by the Canadian and US departments of defence.
The tests took place on the island of Barbados, and on November 18, 1966 a 180 kg shell was vertically fired to an altitude of 180km with a Vo. of 3600 mtrs/sec.
A record up to this day!
Shortly afterward, the project was cancelled as the relation between the USA and Canada soured due to the different Canadian opinion on the Vietnam war, and rockets had become much more reliable in a few years, and so professor Bull was left without any further funding. Shortly afterwards, all assets were transferred to professor Bull, who then established the Space Research Corporation (SRC).
At SRC Gerald Bull continued the research on improved ballistics for projectiles. Designs were based on the existing 155/39 M109 howitzer firing the standard M107 HE shell, of which the barrel was slightly extended to 45 calibres (155/45), the resulting weapon was called GC-45 (Gun Canada - 45 calibres).
Bull than completely redesigned the existing 155mm M107 shell, making it longer and slimmer with a much longer ogive.
As the part of the shell before the driving band did not touch the barrel anymore (no bourelet), four ‘nubs’ were welded to the outer body at 90 degrees each, which centered the shell during its travel through the barrel by sliding over the lands of the lands and grooves (pict 04). This shape greatly improved the range of the shell. Bull named it ERFB (Extended Range Full Bore)
With the help of base bleed (BB) technology the GC-45 howitzer could place ERFB shells within a radius of 10 meters at 30 km (19 miles), extending this to 38km (24 miles) when using ERFB-BB, however with some loss of accuracy.
The SRC company had its first success when Israel ordered 50.000 ERFB shells in 1973, for use in US supplied howitzers. Another success was the sale of 30.000 ERFB shells and plans for the sale of GC-45 Howitzers to South Africa in 1977. However , the weapons embargo against South Africa had just started, and as president Carter was more interested in the war against apartheid than the war against communism, Gerald bull was arrested for Illegal arms dealing by US customs, and send to prison for six months after a plea bargain, and fined $55.000 in Canada for illegal arms dealing. It was a bitter disappointment for Bull, as all other people involved got away unpunished.
Gerald Bull vowed not ever to return to the US or Canada, and established an subsidiary of SRC in Belgium called “European Poudreries Reunies de Belgique” (PRB), based in Brussels. Here he designed ERFB shells for a range of existing weapons, allowing a relatively cheap upgrade for existing older weapons.
http://www.bocn.co.uk/vbforum/threa...or-M-46-M1954-field-gun-Russia?highlight=erfb
In Europe, the Austrian Noricum company purchased the design rights of the GC-45, manufacturing it with some changes as the GHN-45 (GunHowitzerNoricum-45 calibres). The gun was sold to Thailand, China, Singapore and Israel.
Problems started for Bull when he started manufacturing artillery for Iraq under the condition that he was allowed to restart his supergun project. One of the conditions Saddam Hussein made was that Bull was to upgrade the range and accuracy of existing scud missiles, so they could reach Israel and Iran. The supergun Bull proposed had its ancestry in the German WW2 V3 gun, and would have been able to reach the whole of Israel and Iran.
Bull was warned several times to stop his work on the Iraqi supergun… or else….
This finally led to the assassination of Bull on March 22, 1990 in Brussels. Most probably by the Mossad, either the Iranian Secret service.
Parts of the Superguns (one test version of 350mm calibre, one 1000mm calibre) were seized on several places in Europe by customs, as well as large amounts of propellant from the PRB factory in Belgium.
The following scandal resulted in the bankruptcy of PRB –one of Europe’s oldest powder mills- , and its assets were taken over by several European weapon factory’s.
What is Base bleed (BB):
When a shell travels through the air with supersonic speed after being fired, it has to push the air out of its way. This induces drag that reduces the speed of the projectile. This however is only one part of the drag, as the vacuum created behind the shell also induces drag.
One way to give the projectile a longer range is to apply a more streamlined –longer- body reducing the nose drag, however without changing the centre of gravity of the projectile.
As the projectile shape was optimized, and the induced nose drag was minimalized, the only big factor of drag remaining was the base drag.
One way to slightly decrease drag is the Boat-tail (BT) , which causes the airstream to bend inwards in a more controlled way at the base, slightly reducing the base drag (appr 5%).
Another way of reducing drag is to use a so called Base Bleed (BB) canister, screwed to the base of the projectile (appr 30%).
The base bleed is a 1960’s Swedish invention by the “Forsvartes Forskningsanstalt” and the “Kungliga Materielforvaltningen” artillery design bureau.
The base bleed consists of an aluminium bushing, screwed to the base of an artillery projectile. It is filled with a slow burning powder cylinder that does not burn fast , but produces a large volume of hot gas. Upon firing it is ignited, burning during its flight. The base bleed does NOT act as a rocket motor (it does not generate any thrust), but it releases just enough hot gas to fill the vacuum behind the projectile, thereby streamlining the airflow passing over the base of the shell, reducing the base drag considerably.
It was first used on the 7,5cm anti shipping Sjomelsgranat M66 and the 12cm fixed coastal artillery Sjomalsgranat m/70.
As the 12cm shells were produced in the USA, the ‘secret’ classification was removed.
In 1971, the international patents were sold to Gerald Bull’s SRC company.
Shown on picture 02 are -for comparison-;
The 155mm ERFB-BT, the 155mm ERFB-BB and the 155mm M107 HE. It can be clearly observed that the ERFB shells are much better aerodynamically shaped, but also that the explosives volume is much larger and the amount of fragments is much larger.
In numbers it translates as follows:
M107-HE; weight 43kg (95 lb),Vo.: 675 mtrs/sec (2.120 ft/sec), range 17,8 km (11,1 miles). Projectile length (fuzed): 695mm.
ERFB-BT; weight 45,5kg (100,4 lb), Vo.: 897 mtrs/sec (2.940 ft/sec), range 29,9 km (18,6 miles). Projectile length (fuzed): 935mm.
ERFB-BB; weight 48kg (105,9 lb), Vo.: 897 mtrs/sec (2.940 ft/sec), range 39,6 km (24,6 miles). Projectile length (fuzed): 960mm.
The ERFB-BT has a range that is 1,6 times longer than the M107 HE
The ERFB-BB has a range that is 2,19 times longer than the M107 HE
The ERFB-BB has a range that is 1,34 times longer than the ERFB-BT
It must be noted that a 155/45 gun barrel is to be used.
The GC-45 –and ERFB ammo- is being used by the following countries;
China, Iran, Iraq, Israel, Kuwait, Thailand, Saudi Arabia, Singapore , South Africa.
One can see the difference between older and newer ERFB shells by looking at the ‘nubs’ on the outside of the projectile body: with older shells the nubs are welded to the body and machined to the correct diameter, with newer shells they are an integral part of the shell body, machined into shape.
When firing the projectile with the maximum charge, the acceleration force is so tremendous that the normal M557 PD fuze’s hollow nose piece will buckle. Therefore, the M557 PD was modified by filling the hollow nose cap with polyester resign, and so reinforce the nose cap. This fuze was renamed M572 PD (pict 03) and is modified to be used on high speed shells like the 175mm M437A1 and the 155mm type ERFB shells. The Booster assembly used below the fuze is the M125A1 which differs from the M125 in that it has no reduction gear train slowing down the rotation of the detonator rotor assembly. With the M125A1 , a spring loaded set back pin retracts upon firing, releasing the (spring loaded) radial safety pin, allowing it to move outward by the centrifugal force, releasing the detonator rotor assembly to rotate the detonator in line with the fuze and the booster charge.
The M107 shell , -which is much slower- uses the M557 PD fuze in combination with the M125 booster assembly.
Some internet info :
Gerald Bull:
https://www.youtube.com/watch?v=4lPwNMylYyE
or look for ; Gerald bull, Babylon project
Here one can see the ERFB-BT shells being loaded;
https://www.youtube.com/watch?v=b9SQhKFhUfM
or look for : Elbit ,155mm athos
An interesting fact I found on Wikipedia about the Israeli 155mm/52 Atmos Self -propelled artillery system;
“With a 155 mm/52 barrel, a 41 km maximum range can be achieved, using Extended Range Full-Bore - Base Bleed (ERFB-BB) projectile, 30 km firing the NATO L15 High Explosive (HE) projectile and 24.5 km firing the older M107 HE projectile. The ATMOS 2000 carries a total of 27 155 mm projectiles… “
It means that all projectiles shown in pict.02 can be fired by the same gun/howitzer.
Regards, DJH
At the start of the 60’s of the last century attempts were made to shoot a satellite into space by means of two connected 16” ship’s gun barrels during the HARP (High Altitude Research Project), as rockets were still quite unreliable. Many exploded upon take off, or just after, destroying the payloads they were supposed to bring into earth orbit.
The HARP project was led by the brilliant Canadian ballistic engineer Professor Gerald Bull and funded by the Canadian and US departments of defence.
The tests took place on the island of Barbados, and on November 18, 1966 a 180 kg shell was vertically fired to an altitude of 180km with a Vo. of 3600 mtrs/sec.
A record up to this day!
Shortly afterward, the project was cancelled as the relation between the USA and Canada soured due to the different Canadian opinion on the Vietnam war, and rockets had become much more reliable in a few years, and so professor Bull was left without any further funding. Shortly afterwards, all assets were transferred to professor Bull, who then established the Space Research Corporation (SRC).
At SRC Gerald Bull continued the research on improved ballistics for projectiles. Designs were based on the existing 155/39 M109 howitzer firing the standard M107 HE shell, of which the barrel was slightly extended to 45 calibres (155/45), the resulting weapon was called GC-45 (Gun Canada - 45 calibres).
Bull than completely redesigned the existing 155mm M107 shell, making it longer and slimmer with a much longer ogive.
As the part of the shell before the driving band did not touch the barrel anymore (no bourelet), four ‘nubs’ were welded to the outer body at 90 degrees each, which centered the shell during its travel through the barrel by sliding over the lands of the lands and grooves (pict 04). This shape greatly improved the range of the shell. Bull named it ERFB (Extended Range Full Bore)
With the help of base bleed (BB) technology the GC-45 howitzer could place ERFB shells within a radius of 10 meters at 30 km (19 miles), extending this to 38km (24 miles) when using ERFB-BB, however with some loss of accuracy.
The SRC company had its first success when Israel ordered 50.000 ERFB shells in 1973, for use in US supplied howitzers. Another success was the sale of 30.000 ERFB shells and plans for the sale of GC-45 Howitzers to South Africa in 1977. However , the weapons embargo against South Africa had just started, and as president Carter was more interested in the war against apartheid than the war against communism, Gerald bull was arrested for Illegal arms dealing by US customs, and send to prison for six months after a plea bargain, and fined $55.000 in Canada for illegal arms dealing. It was a bitter disappointment for Bull, as all other people involved got away unpunished.
Gerald Bull vowed not ever to return to the US or Canada, and established an subsidiary of SRC in Belgium called “European Poudreries Reunies de Belgique” (PRB), based in Brussels. Here he designed ERFB shells for a range of existing weapons, allowing a relatively cheap upgrade for existing older weapons.
http://www.bocn.co.uk/vbforum/threa...or-M-46-M1954-field-gun-Russia?highlight=erfb
In Europe, the Austrian Noricum company purchased the design rights of the GC-45, manufacturing it with some changes as the GHN-45 (GunHowitzerNoricum-45 calibres). The gun was sold to Thailand, China, Singapore and Israel.
Problems started for Bull when he started manufacturing artillery for Iraq under the condition that he was allowed to restart his supergun project. One of the conditions Saddam Hussein made was that Bull was to upgrade the range and accuracy of existing scud missiles, so they could reach Israel and Iran. The supergun Bull proposed had its ancestry in the German WW2 V3 gun, and would have been able to reach the whole of Israel and Iran.
Bull was warned several times to stop his work on the Iraqi supergun… or else….
This finally led to the assassination of Bull on March 22, 1990 in Brussels. Most probably by the Mossad, either the Iranian Secret service.
Parts of the Superguns (one test version of 350mm calibre, one 1000mm calibre) were seized on several places in Europe by customs, as well as large amounts of propellant from the PRB factory in Belgium.
The following scandal resulted in the bankruptcy of PRB –one of Europe’s oldest powder mills- , and its assets were taken over by several European weapon factory’s.
What is Base bleed (BB):
When a shell travels through the air with supersonic speed after being fired, it has to push the air out of its way. This induces drag that reduces the speed of the projectile. This however is only one part of the drag, as the vacuum created behind the shell also induces drag.
One way to give the projectile a longer range is to apply a more streamlined –longer- body reducing the nose drag, however without changing the centre of gravity of the projectile.
As the projectile shape was optimized, and the induced nose drag was minimalized, the only big factor of drag remaining was the base drag.
One way to slightly decrease drag is the Boat-tail (BT) , which causes the airstream to bend inwards in a more controlled way at the base, slightly reducing the base drag (appr 5%).
Another way of reducing drag is to use a so called Base Bleed (BB) canister, screwed to the base of the projectile (appr 30%).
The base bleed is a 1960’s Swedish invention by the “Forsvartes Forskningsanstalt” and the “Kungliga Materielforvaltningen” artillery design bureau.
The base bleed consists of an aluminium bushing, screwed to the base of an artillery projectile. It is filled with a slow burning powder cylinder that does not burn fast , but produces a large volume of hot gas. Upon firing it is ignited, burning during its flight. The base bleed does NOT act as a rocket motor (it does not generate any thrust), but it releases just enough hot gas to fill the vacuum behind the projectile, thereby streamlining the airflow passing over the base of the shell, reducing the base drag considerably.
It was first used on the 7,5cm anti shipping Sjomelsgranat M66 and the 12cm fixed coastal artillery Sjomalsgranat m/70.
As the 12cm shells were produced in the USA, the ‘secret’ classification was removed.
In 1971, the international patents were sold to Gerald Bull’s SRC company.
Shown on picture 02 are -for comparison-;
The 155mm ERFB-BT, the 155mm ERFB-BB and the 155mm M107 HE. It can be clearly observed that the ERFB shells are much better aerodynamically shaped, but also that the explosives volume is much larger and the amount of fragments is much larger.
In numbers it translates as follows:
M107-HE; weight 43kg (95 lb),Vo.: 675 mtrs/sec (2.120 ft/sec), range 17,8 km (11,1 miles). Projectile length (fuzed): 695mm.
ERFB-BT; weight 45,5kg (100,4 lb), Vo.: 897 mtrs/sec (2.940 ft/sec), range 29,9 km (18,6 miles). Projectile length (fuzed): 935mm.
ERFB-BB; weight 48kg (105,9 lb), Vo.: 897 mtrs/sec (2.940 ft/sec), range 39,6 km (24,6 miles). Projectile length (fuzed): 960mm.
The ERFB-BT has a range that is 1,6 times longer than the M107 HE
The ERFB-BB has a range that is 2,19 times longer than the M107 HE
The ERFB-BB has a range that is 1,34 times longer than the ERFB-BT
It must be noted that a 155/45 gun barrel is to be used.
The GC-45 –and ERFB ammo- is being used by the following countries;
China, Iran, Iraq, Israel, Kuwait, Thailand, Saudi Arabia, Singapore , South Africa.
One can see the difference between older and newer ERFB shells by looking at the ‘nubs’ on the outside of the projectile body: with older shells the nubs are welded to the body and machined to the correct diameter, with newer shells they are an integral part of the shell body, machined into shape.
When firing the projectile with the maximum charge, the acceleration force is so tremendous that the normal M557 PD fuze’s hollow nose piece will buckle. Therefore, the M557 PD was modified by filling the hollow nose cap with polyester resign, and so reinforce the nose cap. This fuze was renamed M572 PD (pict 03) and is modified to be used on high speed shells like the 175mm M437A1 and the 155mm type ERFB shells. The Booster assembly used below the fuze is the M125A1 which differs from the M125 in that it has no reduction gear train slowing down the rotation of the detonator rotor assembly. With the M125A1 , a spring loaded set back pin retracts upon firing, releasing the (spring loaded) radial safety pin, allowing it to move outward by the centrifugal force, releasing the detonator rotor assembly to rotate the detonator in line with the fuze and the booster charge.
The M107 shell , -which is much slower- uses the M557 PD fuze in combination with the M125 booster assembly.
Some internet info :
Gerald Bull:
https://www.youtube.com/watch?v=4lPwNMylYyE
or look for ; Gerald bull, Babylon project
Here one can see the ERFB-BT shells being loaded;
https://www.youtube.com/watch?v=b9SQhKFhUfM
or look for : Elbit ,155mm athos
An interesting fact I found on Wikipedia about the Israeli 155mm/52 Atmos Self -propelled artillery system;
“With a 155 mm/52 barrel, a 41 km maximum range can be achieved, using Extended Range Full-Bore - Base Bleed (ERFB-BB) projectile, 30 km firing the NATO L15 High Explosive (HE) projectile and 24.5 km firing the older M107 HE projectile. The ATMOS 2000 carries a total of 27 155 mm projectiles… “
It means that all projectiles shown in pict.02 can be fired by the same gun/howitzer.
Regards, DJH
Attachments
Last edited:
