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Nazi Germany’s Space Bomber

Mr. R. Colon
PO Box 29754
Rio Piedras, Puerto Rico 00929

When Germany unveiled its Sanger II space ship, a low-orbit, two stage shuttle vehicle capable of taking off and landing on conventional runways, at the 1986 Farnborough Air Show; it was a tribute to the work of the late German engineer Dr. Eugen Albert Sanger and his pioneering research in Germany into ram jet engines and advance rocketry. Work that provided the basis to one of the most advanced designs ever: the Space Bomber. Sanger was born in Bohemia in 1905. Since his early years, Sanger was fascinated by the words of Hermann Oberth, a famous space exploration writer. Oberth envisioned humans reaching low earth orbit utilizing a multi-stage missile system. It would be Oberth’s book, Rocket to the Planets, first published in 1923, that would lead Sanger to this strange new and developing field: rocketry. Sanger assimilated Oberth’s ideas and went further. He believed early on that if humans were to explore the universe, they did not necessarily need a multistage rocket to reach orbit, he championed the idea of using what he called an “stratospheric aircraft” to reach earth low orbit. In the summer of 1933, Sanger published a book titled Rocket Flight Technique in which he detailed his ideas for the development of an orbiting, manned space station.

The feedback from the still-infant aerospace community in Germany and the rest of the world was impressive. The success of Rocket lead Sanger to write, between 1934 and 1936, several major papers for the influential aviation magazine Flug, an Austrian publication well regarded in the aviation community. These papers caught the eyes of Luftwaffe officials who immediately realized the potential of rocket engines in the development of advance fighters and bombers. He was recruited in the fall of 1936 to work at the Hermann Goring Institute. There, Sanger was assigned the task of developing functional ram jet engines for fighters. He focused his attention on the development of an air-breathing engine. He started his research gathering all the information he could from a 1905 patent filed by French aviation pioneer Rene Lorin. Lorin’s original research data proved that air compressed inside an aluminium tube and expanded by a combustion reaction would generate an enormous amount of thrust.

By November 1941, Sanger’s team was producing concrete results. In one experiment, he mounted a sewer pipe atop an Opel truck. The truck was driven at 55mph, forcing air into the pipe, at the same time; gasoline was injected into the centre of the pipe and ignited. The result was nothing short of spectacular. The combustion was successfully maintained as long as the truck keep going at the same speed and the gasoline kept igniting. The results were so successful, that Sanger’s team commenced the development of an operational ram jet the following spring. In mid 1942, a newly design ram jet was fitted in the top of the fuselage of a Dornier 217E bomber. The engine performed flawlessly. It sustained its thrust as long as the fuel lasted. In fact, the experiment would have been even more impressive if the aircraft selected, the above mentioned Dornier 217E, could had handled the speeds the engine was capable of. The ram jet engine installed on this particular sample 217E was capable of speeds around 600mph while the aircraft’s fuselage could only sustain pressures at speeds of 350mph.

While performing his duties to the Luftwaffe, Sanger never lost track of his ultimate goal. The development of an aircraft capable of reaching low orbit. By early 1944, Sanger must have been aware of the ultra secret work being performed on Germany’s planned long range bomber, the A9 or America Bomber. Originally conceived in 1929; the Sanger concept of a bomber calling for a winged rocket design. He performed calculations on the design and, along with his wife, mathematician Irene Bredt; came up with the idea of an atmosphere re-entry platform. This vehicle would offer high payload and almost unlimited range since the aircraft would be “flying” in space, using small fuel cells, the low earth orbit and gravity would act as the aircraft’s main propulsion system. He proceeded to write a report titled On a rocket Propulsion Engine for Long Distance Bombers, in an attempt to gain government financial support for the development, and eventual production of what he called the Rocket Bomber. But by this time the tide of war had changed for Nazi Germany. Fighting for its survival, Nazi leaders needed weapon systems now, not another long term developing program. Sanger never got the financial resources he requested.

Nevertheless, Sanger and Bredt worked around the clock on his idea of a rocket bomber and in the spring of 1944, they produced a major paper on the benefits of his design, He distributed it to all the major players in Germany’s aerospace industry. Wernher von Braun, Werner Heisenberg, Dr. Ernst Heinkel, Willy Messerschmitt and Professor Dornier got copies of the paper. The paper explained in extraordinary detail, Sanger’s idea of a bomber capable of bombing cities in the United States from bases in Germany. He changed the name of the aircraft; it was now called the Silverbird Bomber. The Silverbird was designed to be a 100-ton monster, of the 100 tons, 90 would be use to store fuel.

The bomber would have been launched into the air by a sled fitted with a rocket engine capable of producing 610 tons of thrust for eleven violent seconds. After which the plane would be propelled to around 5,500ft in the air. Once airborne, the bomber power plant would ignite and the aircraft would climb steadily to an altitude of 130,000ft, slightly above the twenty five mile level of the denser atmosphere. It would then proceed to dive into thicker air where its wings would make the bomber ricochet back into a long and steep climb. This “ricochet” along with the remainder of the bomber’s fuel, would enable the aircraft to reach attitudes of around 160 to 175 miles above the earth surface. The bomber would then maintain its heading until it reaches its main target. The Silverbird would continued its flight until it reached Japanese controlled South Western Asia where it would deploy its tricycle undercarriage to perform the landing manoeuvre.

The German government was so impressed with the report, that it deemed it a State Secret. It was labelled with instructions intended to forbid copying or photographic it. It was placed in a steel safe and guarded twenty four-seven. When Germany collapsed in May 1945, Sanger and his wife, as well as many top ram jet engine engineers, went to work for the French Air Ministry.

In 1952, ‘Rocket’ was translated into English and became widely circulated among the Western Democracies’ air force research facilities. In the summer of 1954, Sanger and Bredt returned to Germany. They immediately began working for the West Germany government in the research of aircraft propulsion systems. Over the years, historians and pundits had given many different names to the Silverbird Bomber. Names such as the Orbital Bomber or the Atmosphere Skipper to name a few, were used to describe Sanger’s aircraft concept. But maybe the name that more resonates with the public is that of the Antipolar Bomber. Numerous articles and televisions documentaries have described the concept as the Antipolar Bomber.

As impressive as the Silverbird concept was, it never went beyond the design stages. Several test mock-ups were built and tested in wind tunnels during the 1950s, but with advances in conventional jet engines, mainly fuel consumption, the designs mock-ups never made it to the drawing board. But the idea never went fully away. Today, the United States utilize Sanger’s concepts in its impressive Shuttle Re-entry Vehicle.

Top Secret Tales of World War II, New York, John Wiley & Sons 2000
German Secret Weapons: Blueprint for Mars, New York, Ballantine Books 1969
German Heavy Bombers, Atglen PA, Schiffer Publishing Ltd 1994