Boeing ecoDemonstrator tests recycled carbon fiber sidewalls, acoustic upgrades for aeroengines and more

Boeing (Chicago, Ill., U.S.) created the ecoDemonstrator program in 2010 to advance new developments for improved safety and efficiency and to minimize its environmental footprint. Since then, Boeing and its industry partners have accelerated innovation by taking promising technologies out of the lab and testing them in the air. The program has expanded to assess new features, services and approaches that can improve the entire aviation ecosystem, including technologies that reduce fuel use, emissions and noise, and incorporate more sustainable materials. Newly delivered Boeing airplanes and those already flying in commercial aviation’s global fleet include a number of technologies that were evaluated and proven on the ecoDemonstrator program, such as more aerodynamically efficient winglets on the 737 MAX.

Eight airplanes have served as flying test beds for the ecoDemonstrator program. These have included a NextGeneration Boeing 737, 757, 777-200, 777 Freighter, 787 Dreamliners and an Embraer E170. A 737-9 in partnership with Alaska Airlines is serving as the test platform for 2021.

Sustainable aviation fuel (SAF) is another focus area, with potential to reduce life-cycle CO₂ emissions by up to 80% — depending on the source used to make it. Each test bed airplane flies on a blend of sustainable and regular jet fuel. These flights demonstrate the viability of SAF and provide data for the industry. The 2018 program made history by conducting the world’s first commercial airliner flight flown on 100% SAF.

The 2019 ecoDemonstrator 777-200 tested new vortex generators, which are small, vertical vanes on the wing that improve an airplane’s aerodynamic efficiency during takeoff and landing. Shape memory alloys developed in collaboration with NASA enable the vortex generators to retract into the wing during cruise when they’re not needed, improving fuel efficiency and reducing carbon emissions.

The 2021 program on an Alaska Airlines 737-9 is testing about 20technologies. Boeing and Alaska are working with the National Oceanic and Atmospheric Administration to expand its measurements of greenhouse gas emissions, which will help improve climate modeling and long-term forecasting. An acoustic lining inside the engine nacelle is being evaluated for its ability to reduce noise on current jet engines and inform designs for next generation ultra-high bypass models.

Guy Norris gives additional images and details in an Oct 2021 article for Aviation Week:

“The program has also tested acoustic lining concepts in the aft fan duct of one of the aircraft’s CFM Leap 1B engines, to evaluate potential noise reductions on current engines as well as inform designs for next-generation models. Conducted in conjunction with the FAA’s Continuous Lower Energy, Emissions and Noise (Cleen) program, the tests focused on treated thrust reverser blocker doors as well as specially developed acoustic gloves between the centerbody of the aft fan bifurcation duct and the inner walls of the thrust reverser.”

Another initiative is testing cabin interior sidewalls made from recycled carbon composite fiber, which can reduce noise and waste going to landfills. Again, Guy Norris adds additional insights:

“As part of the drive to reduce life-cycle environmental impact, the cabin interior is partially configured with sidewall panels made from recycled carbon-composite material salvaged from the 777X wing production site in Everett, Washington. Testing has focused on the acoustic properties of the panels, which are considered rare examples of recycling for high-value aerospace components. Previous ecoDemonstrators have tested both advanced ‘acoustically tuned’ sidewall designs to minimize vibration as well as other cabin features made from recycled materials.”

Recycled carbon fiber composite material was also used in Boeing’s self-disinfecting lavatory, one of 53 projects tested in the 2019 ecoDemonstrator on a Boeing-owned 777-200. The lavatory uses ultraviolet light to kill 99.9% of germs in about three seconds after every use, and used the recycled carbon fiber composite in a moisture-absorbing floor.

Another recycling initiative was tested as one of 37 projects on the 2018 ecoDemonstrator, a 777 Freighter owned by FedEx Express. Manufacturing byproducts were reused as high-value materials for fittings, replacing titanium alloy (Ti64) with over 75% recycled content. In 2015, active flow control was demonstrated on a 757. The aim was to improve airflow over the rudder to potentially improve its aerodynamic efficiency by more than 15% and allow for a smaller vertical tail design in the future (in cooperation with NASA). Notably, in 2012, Boeing tested a regenerative hydrogen fuel cell for aircraft electrical power in a 737-800 delivered to American Airlines.

More information about the 2021 ecoDemonstrator program and previous flying test-bed airplanes can be found at boeing.com/ecodemonstrator