Rocket design work by German engineers persisted throughout the 1920s and 1930s, leading to adoption of several rocket-projecting weapon systems by the Army. One such development was the "15cm Nebelwerfer 41" (15cm NbW 41) which began delivery in 1940 and was in formal service from 1941 to the end of World War 2 in 1945. The NbW 41 allowed for a tremendously lethal effect (both physical and psychological) on enemy troops where a target area could be saturated by large-caliber, exploding rockets through indirect fire. While use of this sort of weapon during World War 2 is primarily detailed in the various Soviet advances of the war, all major players fielded some sort of rocket projector in the conflict. Indeed, the Germans themselves fielded several versions of their Nebelwerfer, varying in caliber and in delivery method (as some were vehicle-mounted projectors). In the German, "Nebelwerfer" translates to "smoke thrower" or "smoke projector" which is not a far-off descriptor for the weapon system.
At its core, the Nebelwerfer 41 was a 150mm, towable rocket projector showcasing six large launch tubes - the rockets actuated by way of a remote control arrangement. For simplicity, the launch tubes and their mounting hardware were sat upon a slightly modified form of the existing two-wheeled artillery carriage used in the 3.7cm PaK 36 series towed anti-tank gun (detailed elsewhere on this site). The carriage featured solid wheel rims, rubber road wheels , and split-trail arms. The arms were brought together for towing the weapon (via mover vehicle) or split apart and lowered into the earth to be used as a recoil absorbing measure. The six launch tubes were arranged in a hexagonal pattern and no gun shield was afforded the operating crew - the assumption being that, as an indirect weapon, the NbW 41 was fired well-behind the dangerous frontline. The design held the capability to empty all six of its tubes in just 90 seconds. A resupply vehicle would allow for reloading though this action was nearly always a time-consuming process - making a "first-strike" utterly important.
Nebelwerfer 41 series rocket projectors were operated in the field by the "Nebeltruppen", a specialist group within the German Army charged with operation and delivery of unconventional weapons including gas and smoke screens through unconventional means. This also included high-explosive warhead rockets which were frequently used to "soften up" enemy positions prior to an advance by friendlies. The concept was well-adopted by the Soviets and, to a lesser degree, the British and the Americans. The NbW 41 rockets could carry just about any useful combat-minded payload available though explosives were largely the call-of-the-day. A spinning action stabilized the rocket along its arced flight-path.
The launch tube's mounting hardware allowed operators an elevation span of +45 degrees with traverse a full 360-degrees if the system were merely spun about its road wheels into the direction of the target area. Each rocket exited its tube at approximately 1,575 feet per second and firing ranges reached out to over 2,100 yards - giving the crew a fairly good "reach" on the battlefield. While their anti-infantry capability was well-documented, the large rockets could also render certain combat tanks useless by injuring exposed crew, damaging hulls, and disabling track systems - dual-purpose weapon to an extent but hardly a dedicated anti-tank measure. Top-facing surfaces of most all armored vehicles were generally their weakest panels.
NbW 41 rockets held a unique design element about them - the rocket propulsion system was installed within the forward section of its length, exhausting through an aft venting arrangement which allowed the bulk of the HE payload to be exposed above the surface of the ground when the rocket detonated upon impacting - this was intended to maximize the lethal effects of the exploding rocket. However, this also had the undesirable effect of slowing mass production efforts of individual rockets which ended up numbering about 550,000 rockets by war's end. To this was added the manufacture of some 5,283 launcher units.
American forces nicknamed the Nebelwerfer 41 as the "Moaning Minnie" due to the sound generated by its incoming rockets.