A New Era for Aircraft Aviation experts expect that today's aircraft will begin to be re-placed with some new form of supersonic transport in a few years'time. A 21st century hypersonic aircraft may open a new age of air-craft design.154The designers of this country displayed the project of such a su-personic passenger liner among the prospective models at one ofthe latest Aerospace Salon held on the old Le Bourget airfield inParis. An elongated fuselage with a sharp nose and without a hori-zontal stabilizer makes it look more like rocket. The speedmatches the looks. This plane will fly at a speed five to six timesabove the speed of sound, e.g., it will cover the distance betweenTokyo and Moscow in less than two hours. The diameter of the fu-selage will be 4 meters and the overall length 100 meters, with thecabin accomodating 300 passengers. The future superplanes of sucha class will have no windows, but passengers can enjoy watch-ing the panorama of the Earth on the TV monitor at the front ofcabin. They will fly so fast that ordinary aircraft windows wouldmake the structure too weak to withstand the stresses such aspeed. At high velocities the air resistance in the lower atmosphereis so great that the skin is heated to very high temperature. The onlyway out is to fly higher. Therefore, airliners' routes will mainly liein the stratosphere.In general, to build a reliable hypersonic plane one has to over-come a whole set of technological and scientific difficulties. Apartfrom creating highly economical combined engines and heat-insulating materials, designers have to make such an amount ofthermodynamic computations that can't be performed withoutusing supercomputers. One of the ways to make planes as economi-cal as possible is lightening the aircraft by substituting new com-posite materials for conventional metal alloys. Accounting for lessthan 5 per cent of the overall aircraft weight now, the percentage ofcomposite material parts will exceed 25 per cent in new generationmodels. An extensive use of new materials combined with betteraerodynamics and engines will allow increasing fuel efficiency byone-thirdBecause of the extreme temperatures generated by the atmo-sphere friction, a hypersonic craft will also require complicatedcooling measures. One possibilityis using cryogenic fuels, such asliquid hydrogen, as both coolants and propellants. The fuel flow-ing through the aircraft's skin would cool the surfaces as it vapor-izes before being injected into combustion chamber.In addition, specialists in many countries are currently workingon new propeller engines considered much more economical andnoisy than jets. The only disadvantage that propeller planesfly slower than jet planes. However, it has recently been announcedthat specialists succeeded in solving this problem. As result aventilator engine with a propeller of ten fibre-glass blades has beenbuilt, each being five meters long. It will be mounted in the experi-mental passenger plane.1. What is this text about? 2. What aircraft was displayed inParis? 3. What are the characteristics of the new liner? 4. What arethe difficulties in building a hypersonic plane?​