There is another way to build a greener jet engine: by bypassing the turbine to an even greater extent, with an open rotor.

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In addition, thousands of firms and entrepreneurs own single- and multi-engine aircraft powered by Intermittent Combustion (non-turbine) engines.

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The difference between turbocharging and supercharging is simple: a turbocharger boosts engine air pressure by using exhaust gas to power a turbine that pushes more air into the combustion chamber.

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Despite signs of a weakening U.S. economy, aerospace component manufacturers are working flat out, machining turbine compressor blades, high-speed bearings and other parts for jet-engine and aircraftmakers.

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This engine uses a gearbox to allow the fan at the front and the turbine at the back to run at different, but optimal speeds.

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