[Illustration: 47. _The Bombardment of Algiers_, 1816. Congreve
rockets in use.]
The rebirth of European interest in military rocketry can be traced to
the English conquest of India during the late 18th century. William
Congreve, an artillery expert, was intrigued by the tactical success of
the Indian war rockets. He began a research program in 1804 that led to
the development of a metal-cased, stick-guided artillery rocket that
could be fired in barrages against enemy troops. The rocket carried
incendiary or explosive warheads.
The 14.5-kilogram (32-pound) Congreve war rocket models on display show
the early side-mounting of the stabilizing guide stick and the later
(1815) design in which the guide stick was center-mounted to give
greater accuracy. Congreve rockets played an important role during the
Napoleonic Wars and the War of 1812.
The experimental 45.4-kilogram (100-pound) Congreve incendiary rocket
was developed as a siege weapon for use against fortresses or entrenched
enemy positions, although it is not known to have been used in combat.
The 6.7-meter (22-foot) guide stick screwed together and fitted to the
side of the projectile before firing. Like the smaller Congreve rockets,
it could be launched from a frame or earthen embankment.
William Hale was an English engineer and ordnance expert who made
cumbersome guide sticks obsolete with the introduction of spin
stabilization to rocketry. Hale’s first design of a stickless, or
rotary, rocket was patented in 1844. Although the 5.4-kilogram
(12-pound) rocket was used during the Mexican War (1846-1847) and the
Civil War, Hale subsequently refined it because the rocket had a
tendency to oscillate in the air following exhaustion of the propellant.
Hale’s intermediate pattern rocket of 1862—on display—was never
produced, giving way in 1865 to a rocket weighing 11 kilograms (24
pounds) with a maximum range of 2012 meters (2200 yards) when fired from
a 4.6-meter (15-foot) elevation. The propellant burned for 5 to 10
seconds, producing an estimated maximum thrust of 136 kilograms (300
pounds).
The American version of the Hale rocket has two sets of gas nozzles. The
major aperture on the base of the case allowed the propellant gases to
escape. The smaller holes above the rocket’s midpoint are angled; the
exhaust gases spin the projectile, stabilizing it during flight. Hale
rocket designs were employed by both sides during the Civil War.
[Illustration: 48. Hale rocket with canted nozzles for
spin-stabilization.]
The Congreve 14.5-kilogram (32-pound) war rocket model was copied from
the original at the Royal Artillery Institution; the experimental
Congreve incendiary rocket on display is a gift of that Institution.
Hale’s 1844 design rocket, his 1862 experimental rocket, and the 1865
rocket are on loan from the Science Museum, London. The American Hale
rocket is on loan from F. C. Durant III.