The principle has been known since Hero of Alexandria. His simple toy was a hollow sphere having four jets which could be filled with water and heated over a flame. When his aeolipile began to eject steam through its jets, it rotated about its axis. Nothing apparently came of this early practical demonstration of jet propulsion.
In 1275, Marco Polo brought back from China stories of rolled cylinders filled with a black substance. When attached to long sticks and ignited, the whole apparatus rose into the air spewing sound and a trail of foul smoke. These gunpowder rockets or “fire arrows” were said to cause bewilderment among men and panic among horses. During this same time period, the art of artillery was beginning in Europe while the Mongols brought rocketry with them in the penetrations of Eastern Europe. A century after Marco Polo’s accounts, gunpowder rockets were used in battle at Chiozza by the Paduans, and again a year later (1380) by the Venetians. Writings on gunpowder rocketry were numerous in Europe during the 16th and 17th centuries.
Late in the 18th century came the challenge, a response to which was to spark the development of a high point in solid-propellant rocketry.
In 1760, British colonial troops in India were defeated in a battle at Seringapatam by the rocket forces of the Prince of Mysore, Haidar Ali. His rockets had metal tubes, in contrast to European festival fireworks, and were stabilized in flight by long bamboo sticks. Ali’s rocket battalions numbered 1,200 men. Ali’s son, Tippoo, later increased the size of his rocket-firing units to a corps of 5,000 troops. British cavalry forces again suffered defeats in attacks at Seringapatam in 1792 and 1799. This was also the moment when England was in the midst of a series of wars triggered by Napoleon Bonaparte.
It was in these circumstances that a member of Parliament, William Congreve, began to undertake the development of improved gunpowder rockets. He was to develop a practical rocket weapon that found its way into the armies of most European nations and even the United States. To William Congreve, as is not often appreciated, goes the credit for the reintroduction of the age-old gunpowder rocket into Western military technology.
In 1804, Congreve started his investigation of the powers of the rocket. He said he was first interested in the reaction motor principle because: “As the force of the rocket is exerted without any reaction upon the point from which it is discharged, it might be successfully applied, both afloat and ashore, as a military engine in cases where, from the violent recoil produced by exploding gunpowder, the use of artillery according to ordinary modes, is either entirely impossible or at best very limited.”
He knew Haidar Ali and son’s rockets had a range of under 1,000 yards, and were of small size. Congreve’s first experiments consisted of having made, at his own expense, the largest rockets possible in London according to the contemporary method of fabrication. With these he experimented and modified the design until he succeeded in increasing their range to 1,500 yards. These rockets were constructed of stiff paper, probably much like present-day cardboard, and used for their propulsion a form of gunpowder dried in a paste form and stuffed into the paper cylinder. Their weight was roughly five pounds.
The results from these experiments were promising enough to allow him to obtain permission to move his experiments to the Royal Laboratory facilities at Woolwich, England, where he was to carry out the remainder of his experiments in the next 20 years. The fact that William Congreve’s father was the director at Woolwich at this time perhaps had some small weight in the decision.
Shortly after his arrival at Woolwich, Congreve succeeded both in increasing the weight of these simple paper rockets to six pounds and in extending their range to 2,000 yards. At this point, he laid before William Pitt, the Prime Minister, a plan for the bombardment of Boulogne by his “fire rockets.” After Pitt had witnessed a demonstration of these small rockets, he approved the construction of a total of ten launches fitted to fire the rockets, and appointed Sir Sidney Smith to their command.
Delays of construction caused the postponement of the scheduled attack to the mid' die of November, 1805. The attack was finally set for the night of the 21st of that month. On the afternoon of the day of the attack, however, a storm blew up with such strong winds that the Royal Navy vessels were recalled before a single rocket was fired. Five of the firing launches were swamped. This ended the possibility of attacking that winter, and sent Congreve back to the laboratory for another year.
Congreve spent the year developing a new rocket, the 32-pounder, which was to prove to be his most successful model. It was essentially this rocket that was to be employed with such devastating results in the bombardment of Boulogne in October of 1806, and of Copenhagen the following year.
This 32-pounder rocket was simple in design, easy to use, and very effective. The body of the rocket was a cylinder of sheet iron wrapped with wire of about the same gauge as the iron of the case. The rocket was 3 feet 6 inches in length, and 4 inches in diameter. To ensure even burning, the propellant was Pressed in a separate mold, with an air gap in the center extending from the end plate to about two feet into the rocket. When ignited, combustion of the propellant took place very rapidly, due to the large burning surface, producing a high velocity during the first part of the flight. The composition used was very similar to gunpowder; it was consumed before the projectile had proceeded 400 yards in flight. The stick, originally 20 feet long, and 1½ inches in diameter, was gradually reduced to a length of 15 feet by the time of the bombardment of Boulogne in 1806; it was attached to the side of the rocket by three encircling clamps. The construction of the rockets was, of course, done entirely by hand by the craftsmen at Woolwich.
In addition to developing the 32-pounder in the year preceding the bombardment of Boulogne, Congreve was busy in another closely related field. He had a weapon which he was convinced would revolutionize the art of warfare if properly used. But how to employ it properly? Throughout history each new weapon has necessitated the development of a new set of tactics to answer that question, and Congreve’s “rocket system” was no exception. He did the bulk of his postulating on this subject in the period from about 1805 to 1810, supporting his theories on the basis of the successful attacks at Boulogne in 1806 and Copenhagen the following year.
Congreve realized that his weapon was mainly useful in producing a conflagration, and in creating confusion and fright among enemy troops and citizenry. He therefore stated that his weapon could be used to best advantage in the case of bombardment of a fortified town or lightly constructed fortress. In the former instances, the rocket would cause such terror on the part of the inhabitants that they would force their defending garrison to capitulate, and in the latter, the rocket could easily penetrate the light fortifications.
An interesting fact in this connection is that until this time troops were considered safe from artillery shells behind an earthwork 12 feet thick. Congreve rockets, however, due to their shape, very often penetrated to depths of 21 feet before exploding. In the case of a heavily fortified position defended by regular troops alone, however, he conceded that conventional mortar fire would be most effective. This fact was borne out in 1814 by the attack on Fort McHenry at Baltimore, in which the rockets used produced no great effect other than the red glare observed by Francis Scott Key.
But shore bombardment was by no means the only use which Congreve proposed for his rockets. The simplicity of the firing apparatus and light weight of the rocket were made to order for cavalry and light infantry Units. Loaded with an exploding head, the 32-pounder rocket had roughly the same effect upon enemy troops as did a 10-inch spherical shell, with the tremendous advantage that it did not require a 600-pound cannon to fire it. Anywhere a single horse could travel, a rocket launch tube could go. Moreover, if massed fire was needed, even the launch tube could be dispensed with. A slanting earthwork could be constructed, scored with small trenches directed toward the enemy, and the rockets could be laid in and fired from these trenches in a broadside. When the rockets were used in this way at the battle of Leipzig in 1813, they were instrumental in winning the day for the British forces.
In later campaigns, however, the sloop-of-war was developed as the primary type of rocket firing ship. It was fitted with 21 rocket scuttles in a broadside.
The rockets could be launched from the sloop’s launchers “ ... At the highest angles, for bombardment, or used at low angles, as an additional means of offense or defense against other shipping.” The method of construction used left the spar deck free for the use of the traditional gun batteries. They could be used at the same time “without the one interfering in the smallest degree with the other, or without the least risk to the ship.” Thus, the small sloop-of-war could deliver as much ordnance, on the target, as could a 74-gun man-of-war. The combination was, moreover, a very effective one. The rockets would be loaded primarily with carcasses filled with burning material, which would set fire to anything in which they lodged, and an occasional broadside from the gun batteries prevented the enemy from coming out from cover to fight the fires.
The use of rockets on fire ships was another tactic proposed by Congreve. He suggested placing about 1,000 rockets in various positions, aimed at random, to be set off by the fires which consumed the ship. This would have the double effect of being very damaging to the morale of any enemy rowboats attempting to tow the vessel away, and of greatly extending the damage potential of the fireship.
The second attempt to bombard Boulogne proved the validity of Congreve’s reasoning, and the value of his weapons system. On 8 October 1806, a squadron consisting of 18 rocket launches under the command of Commodore Owen were once again off Boulogne. Congreve observed: “The attack was made with as much order as could be expected in so new a service. In about half an hour above 200 rockets were discharged. The dismay and astonishment of the enemy were complete—not a shot was returned—and in less than ten minutes after the first discharge, the town was discovered to be on fire. . . . The fire . . . lasted from two o’clock in the morning to the next evening.”
After the bombardment of Boulogne, Congreve again set to work to improve his product. He wanted:
• To make the case a perfect cylinder, with the exterior and interior surfaces absolutely concentric;
• To form the vents and female screw for the stick so that the resultant motive force shall act in the same line as the axis of the cylinder, and that the stick when attached should have its axis in this line.
• To increase considerably the thickness of the case and strength of composition;
• To reduce the lengths of the firing tube and stick;
• To allow little windage—air gap—in the launch tubes.
As Congreve stated: “From Boulogne to the time of Copenhagen, continual improvements have been made in the weapon, in construction, . . . the apparatus used to project it, . . . and the mode of fixing the stick, . . . the proper strength and texture of the iron plate, . . . and the sort of seam best adapted.”
The bombardment of Copenhagen was carried out in November of 1807 in much the same manner as was the action at Boulogne the preceding year. In addition to the rocket launches, the sloop-of-war described above was also employed; it was estimated that roughly 2,500 rockets were fired. An insight as to the effect of this attack can be obtained by the following letter, sent by one Baron Eben to the Prince of Wales following the action.
I was in Copenhagen for some time after the capitulation . . . not being an Englishman, I have perhaps had some opportunities which your countrymen had not.
The Danes were very much afraid of the rockets, and said they had burnt a great many houses, and besides, warehouses . . . I saw a house myself, which was struck by a rocket which went through the roof and three of the floors, and struck into the side of the wall.
As Sir William Congreve believed, the attack on Copenhagen established “the certainty of [the rocket’s] ability to produce a conflagration and . . . their powers of penetration which many doubt. . . . There never was such an instance of conflagration known to have been produced in so short a time.”
Following Copenhagen, Congreve returned to work at Woolwich, attempting to refine and further develop his rocket. In 1815, he tested the first rocket having its stick mounted in the center, by means of a screw and socket arrangement, instead of on the side. His rockets appeared at Waterloo and were also used to destroy a pirate fleet at Algiers in 1816. Rocket technology was so advanced, however, that the version used at Copenhagen was never significantly improved upon by Congreve, although their use spread to Russia, Austria, Spain, Prussia, and Sweden.
Sir William’s 32-pounder rocket contained about 7 pounds of carcass composition, making it equal in this respect to the 10-inch spherical carcass. The improved rocket would range about 3,000 yards, 1,000 further than the comparable spherical shell, and it was lightweight and mobile. The 10-inch shell could range 3,000 yards if its shell were built up to withstand the increased powder charge necessary to attain that range; but this made the shell even less effective. The 10-inch spherical carcass, due to its weight, would penetrate all the way through a house, and lodge in the floor of the cellar. The 32-pounder rocket, on the other hand, due to its shape and lesser weight, would penetrate the roof and several floors, but not all the way to the cellar, lodging in the center of the building for maximum damage, like a nail driven through a board in a ceiling, for instance. Since the iron plate in the head of the rocket was thin, it was more effective, as a carcass, for it “soon became red hot, burned away, and gave free issue to the fire,” while the spherical carcass, being made to withstand the shock of being fired from a mortar, “greedily devoured the caloric of its internal fire . . . suffering a comparatively feeble and lambent flame to issue through a few confined apertures.”
In answer to critics who contended that the 1 stick of the rocket would act as a lever with which to extract the burning rocket, Congreve replied, “The stick shatters on impact
into pieces . . . which I have seen fly a considerable distance . . . and penetrate a foot into the ground; in effect, instead of assisting to disarm the rocket, as has been supposed, the stock adds greatly to its destructive powers.”
From an economic viewpoint as well, the 32-pounder rocket was superior to the comparable spherical shell. The 32-pounder rocket cost less than the 10-inch, and half as much as the 13-inch spherical carcass, although it was likely to be a more effective instrument of conflagration than either. Moreover, the shell expenses were exclusive of the charge needed and the cannon required to fire it.
In yet another way the Congreve rocket was superior to the gun—stability and resistance to deterioration in storage. It is a well-known fact that in that era gunpowder could not be preserved in a fresh state for long periods of time, especially in a damp climate. There were instances on record, however, of tests conducted using Congreve 32-pounder rockets 17 years old and covered with mold and rust, which, when fired, performed as if they were fresh from Woolwich. Congreve commented: “. . . There can be little danger in having rockets in store, secured as the rocket carcass is—in fact, the case is alike impervious to fir and water. I have accordingly fired rockets after they had been under water for several hours.”
These advantages kept Congreve rockets as a standard of European arms until the improvement of the rifle and hand-loading guns in the 19th century. After the battle of Copenhagen Congreve continued to advance the sciences of rocketry. He had found that the power of his rockets seemed to increase in a certain ratio to their size. He constructed several 42-pounder rockets which ranged even further than his most advanced 32-pounder model; he hoped that he could succeed in extending its range to 4,000-5,000 yards. Although today we consider that there is a practical limit, he saw, in his words, “No reason why the greatest weight necessary in bombardment may not be projected by the extension of the weapon.” It is little wonder that he was never able to succeed in his efforts in this direction against the gun, for even today, 160 years later, this problem of fire support by missiles versus fire support by heavy guns still confounds the best minds of military strategy.
Some of his proposals were to be incorporated in modern weaponry. For instance, Congreve proposed: “In the future ... to carry the body of the rocket separate from the head, so that as occasion requires, I may be able to add with the same rapidity as the stick is now fixed, either a carcass, a shell, or a case, containing a large quantity of bursting powder, with the powers of regulating the fuze at the time of firing.” This was essentially a prediction of the variable time fuzer incorporated into later artillery shells.
Another Congreve proposal was directly related to the modern-day hand grenade; the idea for a rocket with a shortened stick containing a 5½-pound shell that could be tossed onto the deck of an enemy ship about to be boarded. To Congreve, “The smoke, fire, and dreadful violence with which it would scour the deck, followed by the explosion of a 5½-inch shell . . . completed a picture too terrifying to doubt for a moment an easy victory over the ship’s crew.” Finally in a direct prediction of the modern guided missile, he contemplated with great confidence of success, being able to get rid of the stick altogether ... by substituting some more convenient means of guiding the rocket.
If Sir William Congreve were alive today, he would surely be most gratified, and might not be too astonished at the progress of the reaction motor.
At the time of his death in 1828, however, the improvements which he sought were not within the capability of contemporary technology. Most of his fellow experimenters were beginning to enjoy some success in their attempts to improve the conventional weapon, the gun. Science was advancing to the point where it could extend to these men new techniques of metallurgy and mechanics, making possible advances in gunnery that were unattainable before 1815: the screw gun, the rifled barrel, breech loading, and gun turrets. The Congreve rocket went as far as it could within this limited technology. The bulk of the sciences on which its improvement depended were for the most part not even contemplated for the next 75 years.
Perhaps the major shortcoming of Congreve’s rocket was its lack of precise guidance. In a light to moderate wind blowing in any direction, other than 180 degrees from the direction of fire, the force of gusts of wind on the long stick caused the rocket to weathercock—turn into the wind. It was more common than not for the rocket under these conditions to turn far from its target, and sometimes it even made a complete turn, coming back to fall among the persons firing the rockets. This was most disconcerting and discouraging to say the least.
There was an even greater hazard to the user. Metal expands and contracts as the temperature varies. Sometimes the composition in contact with the sides and the portion of it in contact with the end plates would become cracked and loosened in the rocket by this phenomenon, especially in climates which experienced large temperature variations daily. When ignition of rockets in this condition was attempted, the weapon would burst like a barrel of gunpowder. Needless to say, this also tended to cause great dismay on the part of the artillerymen concerned.
The greatest cause for the relative decline of the rocket in the late 19th century was undoubtedly the quantum jumps that were made between 1840 and 1865 in the development of gunnery. Had the effort expended in this development been diverted instead to advancing the sciences on which the rocket depended, it is probable that many of the problems associated with the rocket’s further development would have been surmounted earlier, and the war rocket would have taken a place at least equal to and probably superior to that enjoyed by conventional artillery, as it has today.
Today, as man plans to rocket himself to the moon, the early pioneers who provided the first impetus to the journey must not be forgotten. Sir William Congreve is certainly one of them.
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A graduate of the U. S. Naval Academy with the Class of 1966, Lieutenant (j.g.) Hobbs has been serving as Damage Control Assistant in the USS Richard E. Byrd (DDG-23) since September 1966. This essay was selected as the Robert H. Goddard Historical Essay for 1966, in the annual contest sponsored by the National Space Club of Washington, D. C.