Reading American engineers want to build a hypersonic aircraft that could travel between any two locations on the globe in less than two hours For the daily journey to work, many Germans need at least three quarters of an hour. In this time one will be able to travel from Frankfurt to New York in the future according to American scientists. The aircraft is already on the drawing boards of the engineers from the Lawrence Livermore National Laboratory in California: The "HyperSoar", in German "Hypergleiter" would jet at 11, 000 kilometers per hour through the air - that's ten times the speed of sound (Mach 10), He could carry twice as much freight and passengers as a comparable in size and weight Boeing 747. Father of this idea is aircraft engineer Preston Carter. His concept combines new engine technology with the design of supersonic aircraft, some of which were discussed in the 1940s. At that time, the plans failed due to the two biggest problems in the super fast air traffic: heat and too high engine weight. When a machine at supersonic speed of Mach 5 or faster flies through the atmosphere, an enormous heat develops around the missile, causing even the hardest materials to melt. This problem flies around the HyperSoar: He is in his air travel largely outside the atmosphere. With a rocket engine, the machine climbs to a height of 60 kilometers, six times the usual altitude. When this maximum is reached, the passengers experience - or suffer - two minutes of weightlessness. Without drive, the HyperSoar falls back towards the Earth's atmosphere. As soon as the machine hits tighter layers of air in 35 kilometers, the plane bounces off and hops back into space. "The HyperSoar is subject to the same forces as a flat stone that is slanted over a water surface and then jumps three, four times over the surface, " explains Carter. During each haul, which brings the machine 450 kilometers forward, the passengers are exposed to 1.5 times the gravitational acceleration. Despite this, traveling with the HyperSoar is convenient, say the American scientists. However, many experts are skeptical of their plans. Rolf Radespiel, head of department for high-speed aircraft at the German Aerospace Center (DLR): "Even if it were technologically possible to build such a hypersonic aircraft - flights with it would be far too expensive." This was mainly a result of high fuel consumption. and manufacturing costs. Carter, on the other hand, makes another calculation: Although the hypersonic aircraft costs twice as much to maintain as a conventional machine. But the HyperSoar can handle the tenfold "flight turnover" compared to the Boeing 747 every day. HyperSoar will fly with hydrogen, which has a positive impact on the environment: "As it looks, the HyperSoar behaves ecologically neutral, " says Carter with an eye to ongoing climate studies and computer simulations. However, DLR expert Radespiel sees another problem: A rocket engine, as provided by Carter, makes a hell of a noise. "At traditional airports, HyperSoar can not therefore start." The engineers at the Lawrence Livermore National Laboratory are convinced that the HyperSoar can be built with today's technologies, with the exception of the engines already developed by NASA. But some time will pass before travelers can blow up the hyperglyph. "We need three to five years for a prototype, " estimates Carter.

=== Désirée Karge

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