The Germans and US also had simular rocket launchers, although the Germans had the greatest variety, most based on the 150mm Nebelwerfer. A particularly deadly rocket contained a naplam-material that could be used from either the trailer launchers or the SPW-HT launchers.
The US used two widely used mobile launcher, that were fixed on the turrents of Shermans. The 4.6 inch rocket launcher was called the Calliope, and the larger (and considered more effect when available) 7.2 inch rocket rails was called the Whizbang.
Also, the US had a near identical rocket truck to the Katyusha, that mounted either the 7.2 or 4.6 inch rockets (on a GMC 1 ton chassis) although the 7.2 rocket was fairly rare.
