This is a nozzle from the One-Stick Repulsor rocket of the German Society for Space Travel (the Verein für Raumschiffahrt or VfR). Formed in 1927, the VfR began experimenting with crude liquid-propellant rockets in 1930. By spring 1931, society members tested their "two-stick" Repulsor rockets, named after the vehicles in a famous German science-fiction novel. ("Sticks" referred to the rocket's two outside tanks.) In August 1931, tests began on a simplified Repulsor IV model, also known as the One-Stick Repulsor.
Although this nozzle was never fired and was a reject, it represents likely the only surviving example of a VfR motor, since the Society disbanded in 1933 and all of its rocket artifacts were lost or destroyed. Herbert Schaefer, one of the members of the VfR rocket group, brought this nozzle with him when he emigrated to the U.S. in 1935. In 1978, he gave it to the Smithsonian.
This is a rocket engine nozzle of the "Einstab," or One-Stick Repulsor rocket, of the Verein für Raumschiffahrt (the German Rocket Society). The German Rocket Society, one of the world's first space advocate groups, was formed in 1927 and began its first experimentation with crude liquid propellant rockets in 1930. Their first rocket motor was called the Mirak, for Minimum Rocket. By the Spring of 1931, they tested their "double-stick" Repulsor rockets. They were called Repulsors after the fictional Repulsor-powered Martian spacecraft in the 1897 novel Auf Zwei Planeten (On Two Planets) of 1897 by the German science fiction author Kurd Lasswitz who was very influential to the later German space flight movement. The term Repulsors for the rocket was named by Willy Ley, one of the VfR founders and the group's first Vice President who wanted to avoid the word "rocket" since that still meant a standard firework powder rocket at the time. The term "sticks" referred to the rocket's two outside tanks. One was for the gasoline fuel and the other for the nitrogen pressurant which forced in the oxidizer into the combustion chamber. The liquid oxygen oxidizer tank was situated above the motor, though there were several varied designs.
After some initial problems, a Two-Stick Repulsors flew as high as 1.5 kilometer (almost a mile) by 1932 but from August 1931, tests had already begun on a more simplified Repulsor IV model, also known as the One-Stick Repulsor. In this configuration, the experimenters consciously used the Congreve method of placing the tanks in line down in the center of the rocket. These types of rockets, some using liquid oxygen and alcohol as propellants, were tested over the space of a year and represented the VfR's last official rocket experiments. The motors were made of aluminum and hand-machined. They were usually water-cooled, using a water cooled jacket. Probably the partial grooves on this nozzle were meant to facilitate the flow of water around it. Although the nozzle shown here was a reject and never fired, it represents a rare surviving example of VfR hardware. The Society disbanded in 1933 due to internal political problems and so far as is known most all of their equipment, including rocket motors were lost or destroyed.
The nozzle was saved by VfR member Herbert Schaefer, a friend of Ley's, who, like Ley, emigrated to the U.S. in 1935 to escape the Nazi regime. He took the motor and some VfR photos and notes with him. Schaefer later came to use the experience he gained from the VfR's old Raketenflugplatz (Rocket Test Field) site in a Berlin suburb and became an engineer for the Expendable Launch Vehicles Office of the U.S.'s National Aeronautics and Space Administration (NASA). In 1978, Schaefer donated the nozzle to the nearby National Air and Space Museum.