Following several months refurbishing a special NASA test rig, GE Aviation and NASA this summer will begin a wind-tunnel test program to evaluate counter-rotating fan-blade systems for so-called “open rotor” jet engine designs.


Double vision: The image on the left is a basic rendering of an open rotor engine. On the right is the refurbished NASA test rig, which will be installed in the NASA wind tunnel for acoustic testing. GE’s subscale composite blades on the rig are “baseline” designs, harkening back to the days of GE’s UDF (Unducted Fan) engine.

In the 1980s, GE successfully ground-tested and flew an open-rotor jet engine that demonstrated fuel savings of more than 30 percent compared with similar-sized, jet engines with conventional fan systems. But as fuel prices fell sharply in the late 1980s and early 1990s, GE never launched its engine commercially, though it was recognized worldwide as a technology breakthrough.

“The tests mark a new journey for GE and NASA in the world of open rotor technology,” said David Joyce, president of GE Aviation. “These tests will help to tell us how confident we are in meeting the technical challenges of an open-rotor architecture. It’s a journey driven by a need to sharply reduce fuel consumption in future aircraft.”

For the NASA tests, GE will run two rows of counter-rotating fan blades — which are 1/5 subscale in size — with 12 blades in the front row and 10 blades in the back row. They’ll be tested in simulated flight conditions in a low-speed wind tunnel to simulate low-altitude aircraft speeds for acoustic evaluation, and also in a high-speed wind tunnel to simulate high-altitude cruise conditions in order to evaluate blade efficiency and performance.

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The video below shows how the carbon fiber composites technology developed during the UDF project in the 1980s is now at work in GE’s breakthrough GEnx engine, which was developed for Boeing’s new 787 Dreamliner and 747-8 long-range jets.


Meanwhile, the GEnx team is busy preparing for the Paris Air Show — the world’s largest aviation industry event. It takes place at Le Bourget Airport near Paris, France, which was where Charles Lindbergh landed his famous single engine flight across the Atlantic in the Spirit of St. Louis.

In preparation for this historic event, which runs from June 15-21, a GE engineer will be blogging from the show. You can see his flip cam video of the early preparations below — with more updates provided throughout the Paris Air Show next week on GE Reports.