The jetpacks were yet another one of the technologies explored by the Germans during World War Two. The “Himmelstürmer” (Sky Stormer - but literally Heaven Stormer) flight pack was an experimental project that would allow German combat engineers and infantry to cross and to jump over enemy defenses like bridgeless waters, minefields, barbed wire, trenches, and other obstacles without hindrance. Fortunately, like all their secret super-weapons, it arrived late in the war.

As such, the device had to be for short duration “jumps” of ranges up to 50-70 meters. This was not meant to be a individual flying machine to achieve any sort of altitude or long flight journey, so emphasis was placed on finding a suitable type of propulsion to accomplish the limited jump range.

Illustration of German infantry crossing a minefield 
with the Himmelstürmer packs [Via discaircraft.greyfalcon.us]

The Schmidt pulse jet seemed ideal for this, but since a pulse jet cannot operate without forward airspeed, the units involved were adapted and force-fed oxygen by a separate oxygen tank. Paul Schmidt patented his pulse jet design in 1931 but the unit involved here should not be confused with the V-1 flying bomb Argus-Schmidt pulse jet. These Schmidt pulse jets were small pulse tubes able to be carried by one man.

The Himmelstürmer used a pulse jet engine, like the one that powered the Fieseler Fi 103 flying bomb. The Fi 103 was the official name of the the infamous V-1 Buzz Bomb.

The apparatus involved strapping on two Schmidt pulse tubes - one on the back for forward flight, the main pulse engine, and a smaller, less powerful unit carried ventrally for simple control with hand grips for steering.

Both pulse tubes had to be ignited at the same time to enable proper jumps. The units consumed 100 grams of fuel per second. Flight duration was minimal and both units had to be turned off immediately upon landing. The engineer throttled the back engine to make him jump over greater or shorter distances. It consumed very little fuel, never ran hot, and didn't require special clothing because it wasn't designed to run for long period of times. All while achieving 180 feet jumps at an altitude of 50 feet.

These devices were tested with a Heer unit in late 1944 but were still in the experimental phase once the war ended. 

While no photos of the Himmelstürmer remain, only recreations. It is said that Americans captured the technology along with some other secret weapons and brought some of the devices back to America. Bell Aerosystems got the devices at the end of the war, but changed its design thinking they could turn every soldier into Superman, instead of just super-jumpers. Their version, however, wasn't reliable enough for real action, and was canned after a few years