United Technologies CEO Louis Chenevert took the biggest gamble of his career on something called a geared turbofan. In a modern jet airliner there are really just two ways to increase fuel economy, the most critical selling point in an era of tiny margins and volatile costs for carriers. One way is to increase combustion temperatures so fuel is burned more efficiently. But engines are already operating at levels above 2,500 degrees Fahrenheit, the melting point of the turbine blades that propel the plane, forcing engineers to dream up exotic cooling systems and turn to special coatings and unwieldy materials like ceramics.
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