The Himmelstürmer (Literal translation: "Sky Trooper") Flightpack, or Einpersonenfluggerät, was a flightpack invented by Nazi Germany late in the war. Its intention was not to achieve flight for the user, but to jump over obstacles and waterways that would otherwise be difficult to traverse on foot. The jetpack, or flightpack consisted of a larger rocket on the back for propulsion, and a smaller one on the front for steering. The propulsion was achieved by the use of a Schmidt pulse jet, developed originally in 1931 by Paul Schmidt (inventor). Though he didn't invent the pulse engine, engineer Paul Schmidt (inventor), pioneered a more efficient design based on modification of the intake valves (or flaps), earning him government support from the German Air Ministry in 1933. The same pulse technology was utilised in V1 rockets, albeit in larger form.
Because the flight time was so short the soldier wore no special flight gear, each simply wore the standard Feldbluse, and were armed with standard infantry weapons and two Stielhandgranates for deploying though the open tops of enemy vehicles or other opportune targets while in flight above them. The unit consumed fuel rapidly, so had to be turned off by the operator as soon as landing. Both rockets had to be operated simultaneously to work, the smaller rocket in front having controls for piloting. Schmidt paired the two pulse jets so the thrust from the larger pulsejet, worn on the back, created a thrust vector that thrusted its force through the centre of the mass of the whole "vehicle". This prevented it from "tumbling" and kept the vehicle stable and on its intended trajectory. The smaller pulsejet utilised enough force only to control direction.
The devices were tested by the Wehrmacht, late in 1944, but the war ended before they could be utilised.