General Electric (GE.N) and France"s Safran (SAF.PA) on Monday unveiled plans to test-build an open-bladed jet engine able to reduce fuel use and emissions by 20% as they prolonged their historic CFM International joint venture by a decade to 2050. The "RISE" engine, positioned as a possible successor to the "LEAP" model used on the Boeing 737 MAX and some Airbus A320neo, will feature a design with visible fan blades known as open-rotor and could enter service by the mid-2030s. The system will also contain hybrid-electric propulsion. CFM is the world"s largest jet engine maker by the number of units sold. It is the sole engine supplier for the Boeing 737 MAX and competes with Raytheon Technologies (RTX.N) unit Pratt & Whitney for airline engine selections on the Airbus A320neo. The technology demonstrator project comes as the industry prepares to battle over the next generation of single-aisle planes like the MAX and A320neo in the busiest part of the airplane market while facing mounting environmental pressure. Industry sources have said Boeing is considering launching a replacement for its slightly larger and long-range single-aisle 757 that could pave the way for a replacement of the MAX. But it has deferred a decision on whether to move relatively quickly - a step that would require an available conventional engine - or wait for the arrival of technology like open-rotor with hybrid propulsion, Reuters reported recently. read more GE Aviation Chief Executive John Slattery said CFM would be ready to compete for whatever jet might be launched. "If Boeing or any airframer launches a platform and the business case makes sense for us, then we will present our best aggregate technologies that we have at that moment in time," he told a news conference. SUMMIT BIRTH The open-rotor engine concept places previously hidden whirring parts on the outside of the engine to capture more air and reduce the burden on the engine"s fuel-burning core. Previous attempts since the 1980s to develop such engines have had to contend with concerns including noise. Safran Chief Executive Olivier Andries said a prototype tested in 2017 had produced no more noise than the LEAP. "I am very confident we will meet the most stringent noise regulations ... and safety requirements," he told Reuters. All eyes are now on rivals led by Pratt & Whitney, which is expected to give updates on its geared turbofan later this year. "We are committed to continued investment in evolving propulsion systems to power the next generation of commercial aircraft," Pratt & Whitney said. Founded in 1974, CFM dodged bankruptcy to become a titan with 35,000 deliveries and a CFM-powered jet taking off every two seconds. GE and Safran extended the CFM accord on Monday. It was the brainchild of two industrialists with colourful war records: a German-born fighter engineer who fought for the allies and was made a U.S. citizen by an act of Congress, Gerhard Neumann, and a French resistance hero called Rene Ravaud who lost an arm when the British bombed Brest in western France. The low-key French-American tie-up skirted transatlantic battles raging in other parts of the industry: a trade dispute between Airbus and Boeing and a bitter contest to supply American tankers to the U.S. Air Force, whose existing fleet had quietly run on partially French-designed CFM engines for years. CFM only saw the light of day after a summit deal by U.S. President Richard Nixon and French counterpart Georges Pompidou, following attempts by the Pentagon to block it on the grounds that its new engine was related to a design for the B-1 bomber. Under a compromise, French engineers were banned at first from looking inside the sealed casing of the original CFM core. Although such restrictions vanished long ago, GE and Safran still maintain an unusual Chinese Wall between them over costs on the world’s most-sold jet engines to avoid disputes. "One of the ingredients of CFM"s success is that we share the revenues; we don"t share the costs. If one of us is not competitive, it doesn"t reflect on the (other) partner. Everyone is fully responsible," Andries said.