Propulsion Programs For A Greener Future In Aviation

CFM, the General Electric and Safran joint venture, caused a sensation earlier this year by unveiling plans to develop an open fan demonstrator engine. Known as RISE (Revolutionary Innovation for Sustainable Engines), the program is targeting a 20% reduction in fuel consumption and CO2 emissions compared to current engines and is squarely aimed at a successor to the current Leap-1 turbofan in the 20,000 lb. to 35,000 lb. thrust class. The demonstrator program expects to culminate in 2024-2025 with flight tests of a single-stage, gear driven fan paired with active stators in a tractor configuration – a design never previously tested at full scale.
 

Beyond tests of a gear-driven rotor more than 12 ft. in diameter, RISE will also include a suite of disruptive technologies all supporting CFM’s long term sustainability goals for powering next generation single aisle airliners. These include multiple new combustor designs to ensure future compatibility with both sustainable aviation fuels (SAF) as well as liquid hydrogen. Other technologies also include motors and starter-generators for hybrid-electric adaptation, a compact high-pressure core, and a recuperating system to preheat combustion air with waste heat from the exhaust. 

Eager to protect its growing presence in the single-aisle market Pratt is studying upgrades for the PW1100G version which will provide the option of additional thrust for heavier weight applications such as the Airbus A321XLR, whilst maintaining time-on-wing. The focus is on delivering additional power and reliability for the same reduced fuel burn as the baseline engine.

Further off, Pratt is also evaluating further improvements including short duct inlets which would help reduce the weight and drag of the nacelle. These efforts would build on earlier tests of advanced inlets conducted as part of the FAA’s CLEEN environmental program. 

Despite lengthy supply chain hold-ups due to the COVID-19 pandemic, Rolls-Royce says components for the first UltraFan demonstrator are finally beginning to arrive in quantity at the company’s Derby, England, facility for final assembly. The 80,000 lb-class thrust demonstrator, which is expected to run in early 2022, is designed to prove out a new geared architecture which will burn around 25% less fuel than the Trent 700.