Now, it's bringing them back with the CFM Rise, promising 20% fuel savings. Unducted fans (UDFs), also known as propfans or open rotor engines, first popped up in the 1970s. They look a little odd ...

CFM International’s new push to develop an ... Meanwhile, GE designed a competing engine called an “Unducted Fan” – a “gear-less, counter-rotating pusher system” designed to be mounted ...

Credit: CFM CFM International joint venture partners ... to pave the way for a new generation of fuel-efficient unducted—or open fan—engines to enter service around the mid-2030s.

ultra-high bypass unducted fan engine to cut fuel burn by 25% in about 2025. Momentum increased in 2008 when CFM decided to "put a stake in the ground" by committing to develop a ducted Leap X ...

Some called it a propfan, others an unducted fan or open rotor ... engine meet current and anticipated noise regulations, says CFM. There has been concern about what would happen if a propfan ...

unducted fan blades are much noisier than ducted fan blades. The CFM RISE engine, however, takes a totally new approach to open fan design. Instead of the established concept of each open fan ...

Open fan and the CFM RISE programme If you ask GE’s chief engineer Chris Lorence, the time for open fan is now. Why? Since GE first flew an unducted fan in the 1980s, the open fan engine design ...

Promising 60% fuel savings and faster boarding, the 7J7 aimed to revolutionize short-haul flying with advanced materials, fly-by-wire controls, and a unique unducted fan engine. However ...

The Open Fan architecture is the major innovation of our CFM RISE technology demonstration program with ... such as whirl flutter, unducted FAN, propeller and vanes, high speed booster, high speed low ...

CFM believes the move to an open rotor will ... RISE builds on earlier unducted fan development work by GE and Safran that dates back to the 1980s, as well as more recent work with research ...