Nebel |
Born: 1894-03-21. Died: 1978-09-18. Birth Place: Weissenburg, Bavaria.
Rudolf Nebel played a key role in promoting early rocketry efforts in Germany. As part of publicity for the film Frau im Mond, director Fritz Lang retained rocket pioneer Hermann Oberth as technical consultant. Lang provided Oberth with funds to build and launch a liquid-propellant rocket to publicize the film. One of the assistants hired by Oberth to fabricate the rocket was Rudolph Nebel, a World War I fighter pilot with (unfortunately) little actual engineering experience. Oberth's project did not produce a rocket in time for the film opening, but Nebel had gotten the spaceflight 'bug'. He was looked down upon by his fellow space enthusiasts due to a perceived lack of technical ability. But it was Nebel that played a key role in organizing the VfR; in leasing the Raketenflugplatz rocket test ground in Berlin; in making the practical decisions that finally led to the society testing the Mirak 'Minimum Rocket'; in obtaining funding for the testing of the large-scale Magdeburg rocket; and finally in arranging for the German Army to back further rocketry development. This paradoxically led to Von Braun and most of Nebel's compatriots being hired away by the German Army. Nebel continued with private experiments until shut down by a German government prohibition on further private rocket development in 1934. His colleagues, in recognition of his key role, arranged for him to receive royalties from a key rocket patent from 1937.
After the second world war, the old German enthusiasm for rocketry was stirring. Nebel was one of the few German rocket pioneers who did not leave the country to work for one of the conquering powers. Despite the allied prohibition on aerospace research, Nebel, together with engineers Karl Poggensee and Albert Puellenberg, began renewed German work on rockets for peaceful purposes. They participated in the first meetings of the new International Astronautical Federation in Paris in 1950 and London in 1951. Nebel gave a lecture on rocketry and space travel in Cuxhaven on 6 April 1951. This eventually led to the establishment of 'Spaceport Cuxhaven' and a series of launches from 1958-1964 that reached into outer space. Then, once again, further private German space launches were prohibited.
The film, directed by Fritz Lang, with Hermann Oberth as technical consultant, provided a realistic portrayal of the rollout and launch of a liquid-propellant booster sending a manned expedition to the moon. Lang provided Oberth with funds to build and launch a liquid-propellant rocket to publicise the film. Oberth's rocket, using a conical combustion chamber to mix liquid oxygen and gasoline, was 1.8 m tall and was to have been launched to an altitude of 64 km over the Baltic Sea from Greifswalder Oie. One of the assistants hired by Oberth to fabricate the rocket was Rudolph Nebel, a World War I fighter pilot with (unfortunately) little actual engineering experience. Oberth also had no practical engineering or organizational ability, and was unable to produce the liquid rocket in the four months allotted. He then turned to an 11-m tall hybrid rocket that was to burn a to-be-determined carbon compound with liquid oxygen. This also proved impossible, and Oberth simply gave up and left town - returning, however, for the film's premiere. Ufa studios took ownership of the unfinished rockets.
Winkler had resigned as president. Oberth is back in Berlin, and a meeting is held, with Nebel, Wurm, Oberth, Klaus Riedel, Winkler, and Willy Ley in attendance. It was decided to try and get the Oberth rocket materials back from Ufa and press on to demonstrate flight of a liquid propellant rocket. For this purpose the Oberth rocket was much too ambitious and probably wouldn't work anyway. Nebel proposes building a new 'Minimum Rakete' or 'Mirak' to demonstrate that it could be done. Work begins to obtain funds to ground test and perfect Oberth's 'Kegelduese' conical rocket motor.
The VfR fires its 'Kegelduese' liquid oxygen and gasoline-fueled rocket motor in a demonstration for the Director of the Chemisch-Technische Reichsanstalt in an attempt to secure financial support. Nebel had arranged the demonstration and runs the Kegelduese for 90 seconds. It generates 7 kgf and consumes 6 kg of liquid oxygen and 1 kg of gasoline in that time (specific impulse 90 seconds). Participating are Oberth, Nebel, Riedel, Ley, and Von Braun. Nebel's Mirak is not yet ready to test.
Nebel and Riedel conduct a series of tests of the Mirak rocket at the farm of Riedel's grandparents near Bernstadt, Saxony. They slowly perfect the motor, finally achieving significant net thrust by September, when the motor explodes, ending the test series.
Nebel and the other designers realise that using liquid oxygen to cool the combustion chamber simply would not work - it turned to gas, and the excessive pressure eventually burst the oxygen tank. They turn to a water-cooled combustion chamber. The end result was an aluminium pressure-fed engine that weighed 85 g but produced 32 kgf while burning 160 g of liquid oxygen and gasoline per second - a specific impulse of 200 seconds. The new design proves reliable and is demonstrated to visitors from the American Rocket Society in April 1931.
Mengering, an engineer working for the city of Magdeburg, is entranced by the theories of Peter Bender, who proposes that the people of the earth are in fact living on the inside surface of a hollow sphere. He believes that this can be proven. A rocket fired vertically from Magdeburg should impact south of New Zealand. Mengering convinces the city authorities to fund experiments leading to this objective. Nebel, now a member of the Nazi Party, obtains a contract of 25,000 Marks for the first step. He will build a rocket that will carry a man to an altitude of one kilometre, from where the pilot will bail out and return to earth by parachute. The rocket is to be fired on 11 June 1933 in a huge event publicizing the city. The Pilot Rocket would be in the form of the VfR Repulsors, with the passenger in a bullet-shaped fairing over the engine compartment, and the propellants being stored in two long cylindrical tanks trailing the engine. It was to be 7.6 m tall and powered by an engine of 600 kgf. A prototype was to be built first, 4.6 m tall, powered by a 200 kgf motor. This would not be capable of carrying a pilot, but would have a parachute for recovery.
Nebel is presented with a water bill of 1600 Marks for 1930-1933. He and the VfR are unable to pay, so the government cancels the lease and takes the property back. Klaus Riedel manages to arrange employment for himself and several of the VfR technicians with Siemens, which also agrees to allow them to store the Raketenflugplatz rockets and technical materials in a company warehouse. After Riedel and the others are recruited by the Army and leave for Peenemuende, Nebel allegedly sells of these materials. In any case they disappear.