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By: David Rilley-Harris, Curator, DITSONG: National Museum of Military History (DNMMH)


Gerald Bull in 1964 (photograph: Wikipedia).


Gerald Bull was a Canadian gun engineer who is considered to be the most advanced large gun engineer the world has ever known. By the time of his death in 1990, Bull had produced experimental data which is still relied on today. The guns he produced are still the most advanced large guns ever made. Unfortunately, Bull’s work was often hindered by bureaucracy and funding issues, and so to fund his work, Bull began selling weapons and technology to any willing buyers. Weapons technology that Bull designed is still in use on current battlefields. His legacy would become one of unfinished work and association with some of the late twentieth century’s worst dictators.


Gerald Bull was born in 1928, one year before the Great Depression would destabilise his family life. His family had been financially comfortable but his father had been buying stocks on the margin and found himself drowning in bank debt after the stock market collapse. The family moved to Toronto for work where Gerald Bull would become a student with average school marks but with a passion for aircraft and rocket technology. At the University of Toronto Bull studied aeronautical engineering and although he graduated with average marks he would also become the youngest person to have ever received a PhD from the University of Toronto (twenty-three years old). At twenty years old in 1948, with his degree completed, Bull was hired into a drafting job at an aircraft manufacturing company called Avro Canada. In the year Bull joined Avro Canada, his university also opened its Institute of Aerodynamics (later the Institute of Aerospace Studies) which was funded by Canada’s Defence Research Board (DRB). Bull was one of twelve students chosen by the Institute and found himself working on the construction of a supersonic wind tunnel for the observation of wind flow over variously shaped surfaces. At the time, supersonic aircraft were yet to be developed but rockets, bullets, and artillery rounds moved at supersonic speeds.


In 1950, the DRB entrusted Gerald Bull to assist with aerodynamics work on the Velvet Glove Missile Project for the somewhat secretive Canadian Armament and Research Development Establishment (CARDE). The Velvet Glove Missile Project was developing a radar guided air-to-air short range missile that would be used with an aircraft called the Avro Arrow which was also being designed. Concerns about the ability of the missile to be fired while at supersonic speeds slowed down the project which was later abandoned with designs in the United States taking the lead. Bull had been hampered by financial constraints preventing him from building a supersonic wind tunnel, but this hurdle would launch Bull’s lifelong dream. In order to test the stability of the proposed missile at supersonic speeds Bull had to find an option more affordable than a wind tunnel. At a substantially lower cost, he built a large gun that would fire projectiles at supersonic speeds which would then be monitored through their flight for aerodynamic data. This method also provided an advantage in that the projectiles were being observed in real world conditions, including changes in the atmosphere at varying altitudes. By the end of the 1950s United States Army Research and Development had taken an interest in Gerald Bull and they built a 130 mm version of Bull’s gun in Maryland which began test firing over the Atlantic Ocean in 1961. Bull used the gun to fire scale models of aircraft and discovered stability problems in the shaping of the Avro Arrow, improving the aircraft. By this time Gerald Bull had developed a reputation of being difficult to work with especially in regard to his impatience with bureaucracy and funding issues. It was also in 1961 that he made an aggravated move to become a professor at McGill University in Montreal, Canada. Late in that same year Bull managed to draw interest from the governments of Canada, USA, and Britain for his idea of cost effective experimentation using large guns to test missile components for their efficacy during earth atmosphere re-entry. This led to the creation of a project that would provide the most productive work of Gerald Bull’s life. It was called Project HARP (High Altitude Research Project).


The Avro Arrow (photograph: Wikipedia).


Ground space for Project HARP was found in Barbados where work started in 1962. The US Navy provided a surplus 406mm battleship gun which was re-bored into a 417 mm smooth bore gun by the Office of Naval Research. The first uses of the gun brought irregular results which were caused by the use of old gunpowder and the problem of projectiles leaving the gun barrel too quickly and so failing to gain the full effect of the gunpowder’s burn. By the end of 1962, with the arrival of modernised gunpowder, the gun was firing 150 kg projectiles at over 3 km/s to altitudes of 66 000 m. Space itself begins at roughly 100 000 m and, although low earth orbit would require much greater altitude, Gerald Bull was becoming increasingly enticed by the idea of putting missiles or satellites into orbit using guns instead of more expensive time-consuming rockets. There was certainly potential in using guns for the launch of multi-stage rocket projectiles.


The abandoned Project HARP gun in Barbados (photograph: Wikipedia).


In his work with Project HARP Bull had produced advances in modernised gunpowder which had developed into less of a powder and more of a rubbery solid fuel. In 1963, these developments led Bull to work with a more conventional bored-out 175 mm gun from the United States Marines M107 self-propelled artillery piece. He used the gun to fire multi-stage rockets to altitudes of 249 000 m which sufficed as proof-of-concept for firing projectiles into earth orbit. Aside from multi-stage rockets, at the US Army Yuma Proving Grounds, Bull managed to fire a projectile to an altitude of 180 000 m, a record from 1966 that has never been broken. Despite his successes, Bull’s projects ran out of funding. The Cold War, especially the Vietnam War, had brought on a public distaste for military funding. In the late 1960s, searching for ways to continue his work, Gerald Bull set up his own company, the Space Research Corporation (SRC), to gain funding through international consultancy for artillery technology. Through the SRC Bull started a space programme at Norwich University in Northfield, Vermont, where he improved the range, versatility, and accuracy of conventional guns with a new rifling technic and a design for a new type of shell which he named the Extended Range Full Bore shell (ERFB). During the 1970s, Bull was gaining funds through the international sale of artillery shells which included 50 000 shells sold to Israel in 1973. In the late 1970s, Bull designed a new gun for a weapon that would become known as the GC-45 howitzer (Gun Canadian – 45 calibre). Included in this new weapon was the use of base-bleed shell technology whereby the base of a fired shell expels gas. The expelled gas negates a pocket of turbulence behind the shell reducing drag and substantially increasing the gun’s range. The base-bleed technology had been researched in Sweden and was further developed by Gerald Bull. A GC-45 firing ERFB rounds could strike within a 10 m radius 30 km away making the new technology internationally desirable.


1977 was a pivotal year for Apartheid South Africa and its relationship with the USA. As a facet of the Cold War the USA had been supporting South Africa as a measure to resist the global spread of communism. President Jimmy Carter’s election in 1977 moved some USA focus away from the Cold War creating space for the United States government to become more actively supportive of arms embargos against South Africa. In the same year, South African arms company, Armscor, secretly bought a 20% stake in Gerald Bull’s SRC. South Africa had been looking for weaponry which could compete with Soviet artillery in Angola and the GC-45 was an excellent option. Plans for the production of the GC-45’s gun were illegally received by South Africa from Gerald Bull along with at least 30 000 155 mm shells. South Africa may have received as many as 55 000 shells and two GC-45 gun barrels. South Africa developed a new artillery piece calling it the G5 howitzer (Gun 5). A self-propelled version was developed called the G6 howitzer known in the twenty-first century as the Rhino.


The G6 Howitzer (Armoured Fighting Vehicles Collection: DITSONG: National Museum of Military History (DNMMH)).


Gerald Bull had begun to trade weapons, ammunition, and technology with competing countries all around the world. His illegal sales to South Africa found Bull arrested, fined, and imprisoned in a USA prison for six months in 1980. He was also fined for selling 155 mm shell technology to China without a permit. Facing this new type of financial constraint, Bull moved his offices to Belgium from where he continued to associate with various countries, including China and South Africa, and he also began working with Saddam Hussein’s Iraq where he developed an upgraded G5/GC-45 gun. South Africa produced some of Iraq’s G5 gun barrels to help with Iraq’s high demand for 200 GC-45s in 1985, during the Iran-Iraq War (1980-88). South Africa would later sell 100 G5s to Iraq. During the Iran-Iraq War Iran also obtained 140 GC-45s. In the same period, Iran was a threat to the state of Israel to whom Bull had sold ammunition in the 1970s.


Despite Bull’s international trading, he still did not have enough funding to pursue his goal of developing a gun for the launch of projectiles into earth orbit and so he turned to Saddam Hussein. Iraq funded Bull’s supergun project in exchange for his assistance in the development of Iraqi Scud missiles which were later used against Israel during the Gulf War. Iraq could also look to the prospect of using superguns as long range weapons to partially negate enemy air superiority. Enemy air superiority or other air defences would likely be unable to intercept shells fired from a gun. As was the case during the Second World War, an unresolved weakness of a supergun is that it is large, difficult to manoeuver, and makes for an easy target. Bull’s Iraq-based supergun development began as Project Babylon in 1988. Meanwhile, G5 howitzers were in use in southern Africa and Bull’s technology was still being traded around the world, which included trade between Bull and Iran, China, and Taiwan. The United Arab Emirates bought 70 G6 howitzers from South Africa in 1990. By this time, it might be fair to say that Gerald Bull was playing with fire and was making himself a potential target for assassination, by any number of possible assailants. Bull focused on Project Babylon. Built for testing purposes, his first large gun in Iraq was called Baby Babylon and was 45 m long with a 350 mm barrel. He then began work on Big Babylon. It was going to be 156 m long with a 1 m barrel bore and would be able to fire multi-stage rocket-assisted shells over a distance of 8000 km, or fire 200–540 kg satellites into earth’s orbit. It would be so large that the gun would have to be elevated by being built against a mountainside. Big Babylon was referred to as the PC-2 machine (petrochemical complex two) in order to disguise the purpose of orders of large metal pipes. Some of the barrel/pipe was ordered from a company in Britain which alerted authorities to the specification request that the pipe be able to withstand strangely high volumes of pressure that would be unnecessary for a petrochemical pipeline.


A barrel section of Big Babylon (photograph: Wikipedia)



While working on Big Babylon, Bull received threatening telephone calls warning him to stop working with Iraq. As another apparent warning, his apartment in Brussels was broken into several times without anything being stolen. At 62 years old, on 22 March 1990, he was arriving home opening the door of his apartment and holding a briefcase which had $20 000 cash inside when he was shot five times at close range in his back and head. The cash was not taken.  Nobody has ever been charged with the murder but Israel’s National Intelligence Agency, Mossad, is considered to be the most likely of several possible assailants. Gerald Bull never managed to build a gun for launching satellites into space but the concept is still one of interest. The data he collected during Project HARP still accounts for half of all the upper-atmospheric ballistic data available today.

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