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WHEN WE last visited the German aviation industry (in 1922; see www.wp.me/p2ETap-W8), the Inter-Allied Commission had demanded—and got—destruction of the Zeppelin-Staaken E-4/20. This passenger liner was simply too advanced, potentially too easily turned into a bomber.
Instead, the Commission limited German aeronauts to investigations with gliders—and eventually with space travel.
At least this was the professed line of the Verein für Raumschiffahrt, literally, the Club for Space Ship Travel, founded in 1927. The VfR grew eventually to 500 members, many attracted to the hobby by a 1923 book, Die Rakete zu den Planetenräumen, By Rocket into Planetary Space. Others credited Fritz Lang’s 1929 science fiction flick, Frau im Mond (Woman on the Moon). In retrospect, still others—the suspicious types—say the VfR was an imaginative ploy to power German glider research, if you get the drift of their meaning.
Friedrich Sander was a pyrotechnics engineer and manufacturer. Fritz von Opel was a grandson of Adam Opel, founder of the automobile company of the family name. One of Fritz’s responsibilities in the business was vehicle testing; another was publicity.
Opel combined the two by seeking the technical help of Sander in producing a series of Rak vehicles, race cars, rail cars and airplanes, each with a battery of rockets attached to its rear.
This can’t help but bring to mind that hapless guy on ice skates with rockets strapped to his back; see http://goo.gl/dBfjM. But Opel, his colleagues and other members of the VfR were rather more methodical—and a lot more successful.
In 1928, Opel’s RAK.1 rocket car went 47 mph, its power supplied by a battery of 12 solid-fuel rockets. The same year, 24 of them powered his RAK.2 to 143 mph at Berlin’s AVUS race circuit.
Not all of their tests were successful. The RAK.3, an unpiloted rocket sled, went 158 mph—or possibly 180 mph—on rails. On its second run, it jumped the track and destroyed itself. The RAK IV rocket train had one of its rockets explode, igniting the rest of them and destroying it. Railway authorities said enough already and banned further tests.
At the same time, Opel was fooling around with rocket-powered airplanes. He bought an earlier VfR effort designed by Alexander Lippisch, the Ente (German: Duck). This was a canard aircraft that proved unstable; fortunately it was destroyed by an explosion before it hurt anyone.
Then Opel commissioned Julius Hatry to build a more stable aircraft, a parasol-wing design with a boom-mounted tail structure set high to avoid the rocket thrust.
Archival film footage (see http://goo.gl/R5Atc) shows an interview with Hatry and the flight of the RAK.1 rocket aircraft. It also has footage of other Opel efforts, including the RAK.2 car’s AVUS drive (with some scary looseness evident in one sequence!).
The Rak.1 aircraft had a battery of 16 solid-fuel rockets. On September 30, 1929, Opel piloted this aircraft on 75-second flight covering almost a mile. Its top speed was estimated at 93 mph; its altitude never exceeded 30 ft.
A less than smooth landing damaged the Rak.1 beyond repair. There were plans for a second rocket plane, but Opel apparently lost interest before its completion.
Not that others didn’t keep the VfR going (until 1933). Among its members were Willy Ley and Wernher von Braun. (See www.wp.me/p2ETap-uh for their post-World War II space exploits on our side.)
And not that the Rak series is forgotten. At the 2011 Frankfurt Motor Show, Opel exhibited its RAK e experimental vehicle. The RAK e is a battery electric vehicle that “can reach 120 km/h (75 mph) in less than 13 seconds.”
It’s an interesting little BEV, but not nearly as exciting as the RAK.1—nor as imaginative as the Verein für Raumschiffahrt. ds
© Dennis Simanaitis, SimanaitisSays.com, 2013