The 21 cm Nebelwerfer 42 (21 cm NbW 42) was a German multiple rocket launcher used in the Second World War. It served with units of the Nebeltruppen, the German equivalent of the American Chemical Corps. Just as the Chemical Corps had responsibility for poison gas and smoke weapons that were used instead to deliver high-explosives during the war so did the Nebeltruppen. The name "Nebelwerfer" is best translated as "Smoke Mortar". It saw service from 1942–45 in all theaters except Norway. It was adapted for aerial combat by the Luftwaffe in 1943. Description The 21 cm NbW 42 was a five-barreled multiple rocket launcher mounted on the towed carriage derived from that of the 3.7 cm PaK 36 anti-tank gun. A pivoting stabilising jack was added to the front of the carriage to steady the launcher when firing. The 21 cm Wurfgranate (thrower-shell) 42 rockets were spin-stabilized, electrically-fired and had only high-explosive warheads. The rocket nozzle assembly contained 22 orifices evenly spaced around the rim of the nozzle with the orifices set an angle of 16° from the axis of the rocket to give the rocket clockwise rotation. The rockets had a prominent exhaust trail that kicked up a substantial amount of dust and debris, so the crew had to seek shelter before firing. This meant that they were easily located and had to relocate quickly to avoid counter-battery fire. The rockets were fired one at a time, in a timed ripple, but the launcher had no capability to fire single rockets. The rockets could be fitted with either impact or delay fuses as necessary. Liner rails could be fitted to allow the launcher to use 15 cm Wurfgranate 41 rockets with their HE, smoke and poison gas warheads. The individual rockets were long and weighed . Their high-explosive warhead weighed . They had a muzzle velocity of which gave them a range of . Despite the improved aerodynamics of the Wgr. 42 rocket over the 15 cm Wgr. 41 it proved to have similar dispersion problems; notably an area long and wide because of uneven burning of its propellant. Army use The 21 cm NbW 42s were organized into batteries of six launchers with three batteries per battalion. These battalions were concentrated in independent Werfer-Regiments and Brigades. They saw service on the Eastern Front, North Africa, Italian Campaign and the defence of France and Germany from 1942—45. American