Glorious rocket launcher will crush fascists! The BM-13, or Katyusha, was concieved in 1938 as a prototype by the Jet Propulsion Research Institute (RNII). It was completed in 1939. It featured modified 132mm M-132 rockets on a platform based on the ZIS-5 truck.
It proved to be a valuable asset for the Red Army, and bombarded the Germans until 1945. To control the truck, use left shift to increase throttle and left CTRL to decrease throttle, but you will also need to use the W, A , S and D keys to drive it.
6 and the VTOL control raises the launcher, 7 + the VTOL control turns it.
1, 2, 3, and 4 for the rockets. Don't fire first without moving the rocket launcher, or you will explode. Have fun comrade!

Credit goes to IntexAF, I just modified it so it looks more realistic.

Modifications include lowering the top, putting actual wheels on, and adjusting the lights and pieces of the hull + repainting the truck and it's rockets.