The first flight of Airbus Helicopters’ DisruptiveLab flying test demonstrator on January 13 marked the latest milestone in the company's decade-long effort to accelerate improvements in rotorcraft performance and fuel efficiency. Now in the midst of testing a series of mainly sustainability advances, Airbus expects the DisruptiveLab to deliver technology that will slash carbon dioxide (CO2) emissions in half, thanks largely to a planned fully parallel hybrid propulsion system that allows for battery recharging in flight.
Other advances include a more compact rotor head for reduced drag, improved energy efficiency, and perceived noise, enabled through more efficient integration with its three blades. What Airbus Helicopters director of research and innovation Tomasz Krysinski called dynamic optimization of the rotors, in part using a new damper concept and blades with thinner tips, accounts for 15 percent of the 50 percent reduction in CO2 targeted for the DisruptiveLab. Speaking with AIN ahead of the Heli-Expo show, Krysinksi called the feature “really key because the future is really to reduce the energy need for flight.
“Optimizing the blade is really basic to our engineering,” he explained. “We did 40 wind tunnel campaigns to reduce the drag and the result is already 15 percent of the energy you don’t need for flight. I always say the best energy for flight is energy we don’t need.”
The clean-sheet design testbed aircraft is now flying each week with the DisruptiveLab team reviewing the data from each flight and then agreeing on the objectives for the next sortie. During a February 14 visit to the company's headquarters at Marignane in southern France, AIN witnessed the fifth weekly flight, which achieved maximum continuous power and confirmed the expectations of Krysinski's team that a five-kilogram reduction in weight would equate to a one kilowatt reduction in power requirements.
The reductions in drag Airbus is seeking to achieve from the new airframe and rotor architecture are a significant part of this equation. A new landing gear design with just three connection points to the fuselage is another factor in reducing drag and ground resonance.
Another 25 percent of the fuel burn reduction is expected to come from a new thermodynamic cycle in the powertrain and the final 10 percent from a planned move to a new hybrid-electric option that has yet to be fully defined, noted Krysinksi. Airbus is aiming to demonstrate a hybrid system that allows for use of both an as-yet-unspecified electric motor and the turbine engine simultaneously or separately to allow the pilot to switch between the power sources depending on what is most efficient at a particular stage in the flight. Beyond this technology, the manufacturer is eager to tap the potential for hydrogen propulsion for rotorcraft.
According to Krysinksi, the technology being pioneered on the DisruptiveLab is all scalable and could be applied to different sizes of helicopters. He said that his team is already fielding internal requests from different Airbus Helicopter programs to apply these innovations, and it is now focusing on how it could minimize any recurring costs for doing this.
Airbus aims to complete the "hybridization" of the DistruptiveLab aircraft in 2024, using a concept that Krysinski said is similar to that used for Toyota's Prius car. In around three months from now, it aims to start flight testing new simplified fly-by-wire systems.
As the latest of three Airbus Helicopters' current technology demonstrators, the DisruptiveLab complements the company’s FlightLab demonstrator, which uses an existing H130 platform and whose main mission involves enhancing autonomy and safety “technobricks.”
Flight tests of the FlightLab started in April 2021, when Airbus used the demonstrator to measure helicopter sound levels in urban areas and, in particular, to study how buildings might affect people’s perception. Tests showed that buildings play an important role in masking or amplifying sound levels. Airbus called the studies instrumental to sound modeling and regulation setting, especially for advanced air mobility initiatives. Airbus also used FlightLab to evaluate the Rotor Strike Alerting System (RSAS), which alerts crews about the imminent risk of collision with the main and tail rotors.
Last year’s trials included testing an image-detection system using cameras to enable low-altitude navigation, the viability of a dedicated health and usage monitoring system (HUMS) for light helicopters, and an engine backup system, which will provide emergency electric power in the event of a turbine failure. Testing on the FlightLab also evaluated a new ergonomic design of intuitive pilot flight controls intended to further reduce pilot workload in traditional helicopters and other VTOL “formulas” such as UAM.