28/32cm Wurfrahmen auf Infanterieschlepper UE; source: Flickr.com, published with the permission of the original contributor, edited

Among the equipment captured in France, the Germans seized several hundred small Renault UE tracked cargo tractors. These vehicles had served the French army primarily as ammunition carriers. Despite their compact size, each machine could carry 400 kg of cargo in its own rear load compartment, plus an additional 500 kg in a towed trailer. The running gear on each side consisted of six small road wheels, suspended and sprung in pairs. The wheels were separated by a flat beam, which connected at the rear to the last spoked idler wheel. At the very front sat the drive sprocket, also spoked. The track was supported from above by two return rollers.

The engine was located at the very front of the hull, with the two-man crew compartment immediately behind it. Above the crew positions, hemispherical hatch covers protruded through the roof — necessary because the hull itself was too low for the crew to sit inside with their heads below the roofline. These dome-shaped covers featured a narrow vision slit at the front. Armour thickness reached 7 mm at the front and sides, and only 4 mm at the rear. Power came from a four-cylinder engine of 2.1 litres displacement, producing a maximum output of 38 horsepower.

The Germans put the captured tractors to a wide variety of uses. In addition to their original role, they also served as the basis for an improvised tank destroyer (covered separately in the Tank Destroyers section) and a self-propelled rocket launcher.

28/32cm Wurfrahmen auf Infanterieschlepper UE captured by American forces in France; source: internet, Public domain, edited

The rocket launcher existed in two variants. In the first, the rocket frame was installed directly above the original rear cargo compartment. This frame, welded from steel tubing, held four rockets — either 280 mm high-explosive or 320 mm incendiary. The second variant carried the rocket frames on the sides of the vehicle. The individual rocket cages were hung on a tubular structure similar to the one used on the half-tracked Sd.Kfz. 251. This variant also carried four rockets.

The conversion of the French tractors took place in the second half of 1943. The exact number of rocket launchers produced is not known.