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A typical early Congreve rocket, showing the attachment of the guide stick. The casing for the warhead (A) and rocket body (B) was made of iron. When the rocket was assembled for use, the stick (D) would be slid through three soft iron bands (C), which were then crimped tightly around it with special pincers. Congreve rockets made for the British army, like the one shown here, used guide sticks that were divided into 4-foot sections for ease of transport, and then assembled in the field using soft iron ferrules (E) to join the sections.
Black powder rockets were used sporadically on the battlefields of the seventeenth and eighteenth centuries. Where they were used, however, they tended to be used in large numbers—possibly as a way of magnifying their psychological effect and getting around their lack of accuracy. The Chinese text Wu Pei Chih, written in the 1620s, describes rockets with explosive warheads being fired from wooden boxes divided into cells and capable of holding 100 projectiles each. The rulers of the kingdom of Mysore, in southern India, began to equip their armies with rockets in the 1750s. Haider Ali and his son and successor, Tippoo Sahib, ultimately attached a company of rocketeers to each of their army’s brigades—a total of 5,000 rocket-carrying troops by the 1790s. Their rockets, built in two standardized sizes, had tubes of cast iron rather than the then-standard bamboo or pasteboard. The use of iron added weight but also lent strength, allowing designers to make the rockets more powerful without fear that the added pressure from the expanding exhaust gasses would burst them. The extra thrust that iron tubes allowed more than compensated for the extra weight. According to Indian sources, Tippoo Sahib’s rocket troops could bombard targets as much as a mile and a half away.
The military value of Indian rockets became apparent when Haider Ali and Tippoo Sahib led their troops into battle against the British army in the 1780s and 1790s. Haider Ali’s victory at the Battle of Pollilur (1780), during the Second Mysore War, was due in part to rockets setting a British ammunition wagon afire. Tippoo Sahib, who ascended to the throne when his father was killed in 1782, made effective use of rockets again in his attack on the city of Travancore, which started the Third Mysore War in 1790. The final act of the Fourth Mysore War was played out in 1799 when British troops cornered Tippoo Sahib in his capital city, Seringapatam. A British force under Colonel Arthur Wellesley (later the Duke of Wellington) approached the city, but turned and fled when the Mysoreans unleashed a rocket barrage and a hail of musket fire. Ultimately, however, the British regrouped and brought their artillery to bear on the city walls. An early, lucky shot touched off a storeroom filled with rockets, and the resulting explosion opened a breach in the wall that later shots expanded. The British charged, and Tippoo Sahib died, ironically, fighting to hold a gap in his walls accidentally made by his own secret weapon.
Tippoo Sahib’s secret weapon did not remain secret for long. Word of his success with rockets reached Europe while the Mysore Wars were still going on, spurring research on military rockets in England, France, Ireland, and elsewhere. After the capture of Seringapatam and the death of Tippoo Sahib, the British shipped hundreds of rockets home to the Royal Arsenal as spoils of war. The point of the shipment was less to equip British troops with Indian rockets than to “reverse engineer” them: take them apart, study how they were made, and learn how to build rockets that were as good or better.
The comptroller of the Royal Arsenal was an old soldier named William Congreve who was also a senior officer in the Royal Artillery. His oldest son, also William, was twenty-seven when Tippoo Sahib died—a recent graduate of the University of Cambridge who practiced law, edited newspapers, and lived the high life among wealthy and titled friends in London. The younger Congreve had connections to the Royal Arsenal through his father and connections to some of the most powerful men in Britain through his friends. He also had a deep fascination with machines, and in mid-1804 he gave up both publishing and the law to pursue it. Congreve eventually received patents for things ranging from steam engines and canal locks to a new printing technique that made paper money more difficult to counterfeit. His first project, however, was to devise a weapon that could destroy the fleet of troop-carrying barges that Napoleon was assembling along the coast of France in preparation for an invasion of England. Congreve began with captured Indian war rockets and, improving on them, single-handedly brought on a revolution in rocket design.
Congreve’s revolution was part of the larger Industrial Revolution that was transforming Britain in the early nineteenth century. One of the central elements of the Industrial Revolution was the standardization and mechanization of manufacturing. Products that had been made one at a time by individual workers in separate workshops were increasingly mass-produced in centralized factories. Workers who once shaped raw materials directly, using hand tools and muscle power, increasingly tended steam powered machine tools that shaped the materials for them. Factory-made products were cheaper and more abundant than the workshop-made products that they replaced, and they were also more uniform. Even the most skilled and attentive hand worker turned out products that varied slightly from one another. A well-tended machine would, in contrast, always cut a strip of fabric to the same width, plane a block of wood to the same thickness, or bore a hole to the same depth. Congreve applied this principle to rocket design. To be truly effective weapons, he concluded, rockets had to be rigidly standardized.
Congreve made three critical innovations in rocket design. The first, borrowed straight from the rocketeers of Mysore, was to use metal rather than pasteboard (or any other organic material) for the tube. The second was to use a mass-produced black powder mixed according to a standardized formula and prepared with mechanical grinding mills that produced particles of uniform size. The third was to use a device like a small pile driver—a heavy weight, lifted by ropes and pulleys and then dropped—to pack the powder into the tube. Congreve’s machine-ground powder burned more smoothly than the hand-ground powders it replaced, and mechanical packing eliminated the empty or loosely packed pockets that hand packing sometimes left. His rockets developed a consistently high thrust, and their metal bodies ensured that they could withstand the increased gas pressures that produced it.
Congreve rockets thus offered not only better performance than earlier types, but more consistent performance as well. Access to the firing ranges of the Royal Arsenal allowed him to conduct extensive tests, which led to further fine tuning of both rockets and their launching apparatus. He was thus able, in 1805, to offer the Royal Army and Navy what would now be called a “weapon system”: an array of rockets in various sizes, each with an appropriate launching apparatus and most with a choice of explosive or incendiary warheads.
British cannon were named, in the early nineteenth century, for the weight of the iron balls that they fired: a “9-pounder” was a relatively small gun, a “32-pounder” a relatively large one. Congreve rockets were also designated as “___-pounders,” but in their case the weight was that of the largest lead ball that would fit inside the rocket tube. Those in active use ranged from 6-, 9-, 12-, and 18-pounder “light” rockets through 24- and 32-pounder “medium” rockets to 42-pounder “heavy” rockets. Tiny 3- pounders and massive 100- and 300-pounders were also developed, but the former was too small to do significant damage and the latter were too cumbersome to handle in the field.
British forces first used Congreve rockets in battle in 1805, and continued to use them throughout the wars against the French (1805–1812, 1815) and the Americans (1812–1814). A massive barrage of Congreve rockets— as many as 25,000 according to some accounts—set the city of Copenhagen, Denmark, afire in 1807, and the 150-man Royal Artillery Rocket Brigade played a critical role at the battle of Leipzig in 1813. Led by Captain Richard Bogue, it laid down a barrage that caused 2,500 French troops to break ranks and flee at a decisive moment. British rockets were also decisive at the 1814 Battle of Bladensburg in the War of 1812, which set the stage for their capture and burning of the city of Washington.
The most famous use of rockets in this war, which the British called the “Second American War,” was, ironically, a failure. For nearly twenty-four hours on September 12–13, 1814, British ships anchored off Baltimore bombarded Fort McHenry with cannon and 32-pounder Congreves in an effort to force its surrender. The fort survived, but Francis Scott Key— an American envoy being held temporarily on one of the British ships— immortalized “the rockets’ red glare” in his poem “The Star-Spangled Banner.”
The use of Congreve rockets eventually spread well beyond Britain. They were, by the middle of the nineteenth century, in the arsenals of every major European power as well as the arsenals of the United States and a number of Middle Eastern and Latin American nations. The reasons for this wide popularity are easy to understand. Congreve rockets were a new kind of artillery that were, in many ways, superior to cannon.
Even a “light” 12-pounder Congreve had a range of a 1.25 miles— double that of contemporary light artillery. A 32-pounder could, at a range of nearly 2 miles, punch through the walls of buildings or penetrate 9 feet of earth. Rockets generated no recoil (the force that slams a cannon back when it is fired), and so could be launched from lightweight wooden frames. The frames for light rockets could be carried by individual soldiers or mounted in small oared boats; those for heavy rockets could be mounted on horse-drawn wagons and the decks of modest-sized ships. Reloading the muzzle-loading cannons used in the early nineteenth century was a complex, multistep process. Reloading a rocket frame involved little more than lifting a new rocket into position. Trained rocketeers could, as a result, fire four rounds in a minute—a pace that even the best gun crews could not match. Freed of the need to move a heavy bronze or iron cannon and its carriage, rocketeers were also more mobile than traditional artillery units. A hundred men on foot could hand-carry 10 frames and 300 light rockets to the front lines and discharge all 300 rockets in less than 10 minutes. Four horses—barely enough to pull a medium-sized cannon—could carry 4 frames and 72 rounds on their backs. Rocket troops could move fast and hit hard, a combination that endeared them to forward-looking army and navy officers alike.
For all their advantages, the Congreve rockets had drawbacks. The most important was a well-deserved reputation for erratic flight, which sometimes made them wildly inaccurate. Part of the accuracy problem was the rocket’s center of gravity, which shifted steadily forward as the fuel burned away. Part of it was the shape of the rocket body and the position of the exhaust nozzles, which were seldom perfectly symmetrical. The largest part of the problem, however, was the stick. Like the Indian rockets on which they were based (and virtually all other rockets that came before them), Congreve rockets used a long wooden guide stick to keep them stable in flight. The stick, up to 15 feet long in heavy rockets, made Congreve’s weapons cumbersome to handle and vulnerable to air currents while in flight. It also, because it was mounted off-center, tended to throw the rocket off course even when the air was still. Congreve reduced the balance problem in 1815 by mounting the stick in the center of the rocket’s base plate and directing the exhaust through a ring of small nozzles around the edge of the plate. Even when centered, however, the stick was never perfectly centered, perfectly stiff, or perfectly straight, and the rockets continued to have a reputation for erratic flight.
From:war and game