Editing Congreve rocket (section)

==Design==
[[File:Congreve rockets.gif|thumb|Congreve rockets from Congreve's original work]]

The initial rocket cases were constructed of cardboard, but by 1806 they were made from sheet iron. The propulsion was of the same ingredients as gunpowder, the mixture of which varied with the different sizes of rocket. The warheads had side-mounted brackets which were used to attach wooden sticks of differing lengths, according to the sizes of rocket.

Rocket sizes were designated by the calibre of the tube, using the then-standard British method of using weight in [[Caliber#Pounds as a measure of cannon bore|pounds as a measure of cannon bore]]. Larger diameter rockets also had correspondingly longer tubes.<ref name="vanriper">{{cite book|title=Rockets and Missiles: The Life Story of a Technology|author=A. Bowdoin Van Riper|publisher=JHU Press|page=16}}</ref>

By 1813, the rockets were made available in three classes:
* '''Heavy''' – carcass/explosive rockets, 100- and 300-pounders; between five and six feet in length, with a stick length of 25–27 feet. Considered too cumbersome to use effectively in the field.<ref name="vanriper"/>
* '''Medium''' – 24- to 42-pounders; two to four feet in length, with a stick length of 15–20 feet
* '''Light''' – 6- to 18-pounders; 16–25 inches in length, with a stick length of 8–14 feet
The medium and light rockets could be case shot, shell, or explosive.

The 32-pounder was generally used for longer range bombardment, while a 12–pounder case shot was generally used for support of infantry and cavalry, with an extreme range of some 2,000 yards. The rockets could be fired from a wheeled bombarding frame, from a portable tripod, or even from a shallow trench or sloping bank. One in three horse artillerymen carried a launching trough for ground firing.

In December 1815, Congreve demonstrated a new design of rocket that had the rocket stick screwing centrally into the base of the case. This remained in service from 1817 until 1867, when it was replaced by the [[William Hale (British inventor)#Rocketry|Hale rocket]] which required no stick and used clockwise rotation to impart stability in flight.

Contrary to popular belief, rockets could not out-range the equivalent smooth bore guns of the period. In real terms, the maximum effective range for the 12-pounder rockets and for the six-pounder gun was some 1,400 yards or about 1,280 meters. However, the rate of fire with rockets could be higher than the equivalent muzzle loading ordnance.  The absence of weighty ordnance meant that fewer horses were required. Captain [[Richard Bogue]] needed just 105 horses for his troop, compared with the 220 of Captain [[Cavalié Mercer]]'s troop.

Rockets could be easily carried and readily deployed, particularly over difficult terrain or in small boats. This was amply demonstrated by the Royal Marine Artillery. The 12-pounder deployed at very close range was a fearsome weapon, as was seen at the battles of [[Battle of the Göhrde|Göhrde]] and [[Battle of Leipzig|Leipzig]] in 1813, as well as the crossing of the [[Adour]] and the [[Battle of Toulouse (1814)|Battle of Toulouse]] in 1814.

[[File:Leipzig, 32-pounder Congreve rocket.jpg|thumb|upright|32-pounder rocket {{circa}}1813]]

The lack of specific accuracy with the larger rockets at long range was not a problem if the purpose was to set fire to a town or a number of moored ships; this was shown with the attack on the French Fleet in Aix and Basque roads and at the [[Battle of Copenhagen (1807)|bombardment of Copenhagen]]. As Congreve himself had warned, however, they were of little use against fortified places, such as against [[Fort McHenry]], because of the lack of combustible structures.

Accuracy at medium range remained a problem. This is illustrated by Mercer's description of [[Mercer's Troop|G Troop Royal Horse Artillery]] during the retreat from [[Battle of Quatre Bras|Quatre Bras]] on 17 June 1815:

{{blockquote |text=The rocketeers had placed a little iron triangle in the road with a rocket lying on it. The order to fire is given – port-fire applied – the fidgety missile begins to sputter out sparks and wriggle its tail for a second or so, and then darts forth straight up the chaussée. A gun stands right in its way, between the wheels of which the shell in the head of the rocket bursts, the gunners fall right and left… our rocketeers kept shooting off rockets, none of which ever followed the course of the first; most of them, on arriving about the middle of the ascent, took a vertical direction, whilst some actually turned back upon ourselves – and one of these, following me like a squib until its shell exploded, actually put me in more danger than all the fire of the enemy throughout the day.<ref>[[Cavalié Mercer|Mercer, Cavalié]], ''Journal of the Waterloo Campaign kept throughout the campaign of 1815'', first published 1870, Da Capo Press 1995, {{ISBN|0-306-80651-7}}, p. 153</ref>}}