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Fritz von Opel is best known for his cars and trucks, but in the 1920’s he experimented on new forms of vehicular power, most notably the rocket. Opel’s first attempt at rocket power was with a car in 1928. Max Valier, Fritz von Opel and some others tested the rocket car in Berlin. Impressed by the speed, Opel started designing a rocket-powered glider, the RAK.1. This wasn’t the first glider to fly under rocket power, as Friedrich Staner flew one in June of 1928 for a distance of about one mile. Opel’s glider, though, easily doubled this distance, even though some of the rockets failed to fire.

The design of the RAK.1 was a basic one, featuring a high upper wing and a twin tail arrangement attached by twin booms. The pilot and rockets were housed in a small fuselage slung underneath the wing. For landing a skid was placed underneath the fuselage. Sixteen rockets were used, measuring 400 millimeters long and 90 millimeters in diameter. These rockets were designed to fire in pairs, with only two rockets firing at once. This prolonged the flight time and also reduced the initial G-forces that would result from all sixteen rockets firing at once.

The first attempts at flying the RAK.1 met with failure as the rockets did not ignite. After looking at the problem, it was determined that the battery was too weak to ignite the rockets, and the igniter was bent. After these problems were fixed, another flight was attempted. This time everything worked according to plan. On September 30, 1929, the RAK.1 became airborne, with the first two rockets firing for 25 seconds and lifting the glider into the air. When those rockets cut out, a further two were fired. To keep the plane within the confines of the airfield, a right-hand turn was performed, bringing it into a downwind leg. Another two rockets were fired, but only one actually burned, reducing the speed of the glider and bringing it down. The rough landing due to the tailwind damaged the RAK.1 to a point where much of it had to be rebuilt. Upon examining the plane, it was discovered that a total of 5 rockets failed to fire.

Nonetheless, the RAK.1 was a success, and just a couple weeks later the movie "Frau im Mond" was released, which brought rocket technology to the forefront of German public opinion. Opel’s RAK.1 was rebuilt and capitalized on the popularity of this movie, making a couple more flights, each one more successful than the last. Unfortunately financial concerns brought Opel’s involvement with the rocket glider to an end, but the concept remained in the German mind, with the result of such things as the V2 missile and Me163 rocket fighter becoming operational during the Second World War.
Type Single seat experimental rocket plane
Engine
Dimensions Length  , height  ,  span  , wing area   ,
Weights Empty , loaded  , max. take off weight  
Performance Max.. speed 150 km/h , cruising speed  , range 1,5 km, endurance  , service ceiling   , climb