The 21 cm Nebelwerfer consists of a five-barrel assembly and a mounting. The barrels, which are disposed equally about a central channel, are 4 feet, 3 1/2 inches long, have an internal diameter of 9 1/4 inches, and are fitted at the breech end with 3/8 inch angle-iron guides, giving a clear diameter of 8 1/2 inches. Starting with the top barrel, they are numbered 1, 3, 5, 2, 4, probably indicating the order in which they are to be fired. Three spring levers at the base of each barrel prevent the projectile from sliding to the rear. The barrel assembly is strengthened and retained by two steel plates which are fitted around the circumference of the assembly at the breech end and half way between the breech and the muzzle respectively.
A junction box situated at the top of the barrel assembly suggests an electrical firing system similar to that of the 15 cm Nebelwerfer 41. The sight had been removed from the captured weapon, but instructions inside the lid of the sight box indicate that ranges of from 500 to 2,000 meters can be obtained. This, however, is not the extreme range of the weapon.
The mounting is a two-wheeled, pneumatic-tired type with a split trail at the rear and an adjustable leg at the front. The latter is raised when the weapon is being towed, and lowered to give stability when firing.
The Nebelwerfer 42 fires the 21 cm Wgr. 42 Spr. mit Hbgr. Z. 35K.
There appears to be a six-barrel version of the 21 cm Nebelwerfer 42 in addition to the one described above. However, the five-barrel type is believed to afford better balance and greater stability.
SPECIFICATIONS
| Caliber | 210 mm (8.27 ins.) | |
| Length of barrels | 4 ft., 3 1/2 ins. | |
| Range | ||
| 45° | 9,734 yds. | |
| 30° | 8,538 yds. | |
| Ammunition | 21 cm Wgr. 42 Spr. mit Hbgr. Z. 35K |
German: p. 351