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Rolls-Royce has accused Pratt and Whitney’s parent company of infringing the patented design of its swept fan blades in two engines.
A complaint filed by Rolls-Royce alleges that the fan stages on the GP7200, which is used to power the Airbus A380 and was part-developed by Pratt and Whitney, and Pratt and Whitney’’s PW1000G, which is to be used in the Bombardier C-Series, infringe one of its patents. The lawsuit, which seeks damages and injunctions, will be heard in the US by next summer.
The dispute dates back more than a decade and began when Pratt and Whitney’s parent company, UTC, applied to the US Patent Office to have the Rolls-Royce swept fan blade patent struck out. According to Rolls-Royce the efforts were unsuccessful so the patent stands in the US.
Pratt and Whitney said: “The named engines do not infringe the Rolls-Royce patent and the patent is invalid and unforceable. The lawsuit lacks merit and the company will vigorously defend itself.”
Geared turbofans are widely seen as the next generation of aero engine, because they offer greater fuel efficiency and reduced noise.
In a conventional turbofan, the fan and the turbine that drives it are connected by a shaft that runs through the centre of the engine. As the fan grows larger to increase bypass ratio, the turbine must also grow to create more power to drive the larger fan.
A geared turbofan uses a reduction gearbox to disconnect the fan from the turbine so that each component can turn at optimum speed. The engine turns a small turbine very fast, which allows it to drive a much larger fan slowly. Fast turbines are extremely efficient while slower fans are efficient and quieter than those on today’s engines.
Rolls-Royce is also involved in CFM, a joint venture between Snecma of France and General Electric, to develop another environmentally friendlier engine – the open-rotor engine. It offers the speed and performance of a turbofan with the fuel economy of a turboprop.