In 1945, preliminary design began on Allison's first turboprop engines. One was the T40 (Allison Model 500), which consisted of two T38 power sections driving co-axial contrarotating propellers ...

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Have you got a system worth treating to £10/metre speaker cables? If so, then QED thinks it's new XT40 cable is just the ticket - and that's why the company is laying down "The QED XT40 Challenge".