Fuel Spike Revives Open Rotor Jet Tests
GE and NASA, with help from Snecma of France, have teamed to continue evaluation of counter-rotating fan blade systems for open rotor jet designs. Back in the '80s, GE successfully flew an open-rotor jet engine. The GE36, with two rows of counter-rotating blades, was mounted on Boeing 727 and MD-80 aircraft and demonstrated fuel savings of more than 30 percent over similar-sized jet engines running with their front fans conventionally ducted. That efficiency was soon confronted with falling fuel prices and countered by the design's greatest challenge -- noise -- which together (likely along with development costs) effectively shelved the product's development. But GE says it has now "dramatically advanced its data acquisition systems and computational tools to better understand and improve open-rotor systems."
That and wildly volatile fuel costs have led to the company's joint research with NASA as part of a longer term technology evaluation that focuses on advances for next-generation engines GE/Snecma CFM56 engines. Current tests do not involve full engines, but component tests of subscale fan systems. Snecma, a longtime GE partner is participating in the project by contributing fan blade designs.