Airbus Starts Testing Airplane Wing That Changes Shape In-Flight
UpNext, an Airbus subsidiary "technology incubator," has completed the first flight of a modified Cessna Citation VII business jet that is flight testing components and systems for a wing that can change shape and form during flight to maximize its aerodynamic efficiency. If the concept is successful and integrated into new aircraft, it has the potential to significantly reduce fuel consumption.
The modified Citation VII is serving as a technology demonstrator for Airbus as part of the “eXtra Performance Wing” project that aims to use biologically inspired engineering (biomimicry) to develop the new type of wing. Initial flight testing of the demonstrator will not feature the new type of shape changing wing, which Airbus expects to have ready for flight testing by 2025.
However, the November first flight was an important milestone for the project because the demonstrator is fitted with the exact systems that it will have when the eXtra Performance Wings are installed for flight testing. The data gleaned from this and subsequent flight tests will allow Airbus engineers to measure important baseline performance metrics that will be used to determine the impact of the new wing design, such as reductions in CO2 emissions and fuel consumption.
Airbus selected the Citation VII because of its wing length relative to what a future in-flight shape changing wing would measure. As the targeted wingspan of the eXtra Performance Wing is more than 50 meters (an A320 wingspan is 35.8 meters), the Cessna’s 16 meter wingspan represents an approximately one-third scale model of the final design.
“Things are evidently simpler at a smaller scale,” says Sebastien Blanc, eXtra Performance Wing Technical Director. “But we chose the Cessna specifically because it constituted the best trade off between project complexity and representativeness of the final design.”
Launched in September 2021 the eXtra Performance Wing project is part of Airbus' wing research portfolio. This project explores some of the many technologies that could one day be integrated into the next-generation of Airbus aircraft, and complements the “Wing of Tomorrow” program. Airbus UpNext seeks to fast-track future technologies by developing radical technological breakthroughs in an agile environment.
The overall goal of the eXtra Performance Wing project is to provide multiple wing configurations that dynamically adapt to flight conditions. The design incorporates innovative active control technologies as well as physical changes to the wing structure. Gust sensors on the front of the aircraft will register changes in turbulence, triggering relevant adjustments to the control surfaces of the wing. “This system is designed to be entirely automatic,” says Blanc. “The eXtra Performance Wing technologies, which change the shape of the wing by mimicking a bird's feathers, will adjust automatically to maximize aerodynamic flow.”
There are also the hinged wingtips, which have a dual purpose. On the ground they prevent the aircraft from exceeding the maximum wingspan length that can be accommodated at airport gates (36 meters), and in the air they are flexible, able to change shape to avoid putting too much pressure on the wing. The wingtips also allow for a longer span to be achieved, increasing lift and reducing drag.
Once the initial flight testing has harvested enough baseline data, the demonstrator will be flown to Cazaux, France, where it will be based for the remainder of the project. A remote operation system will be integrated into the aircraft, followed by flights to test the communication between the 20 antennas on the aircraft and the control center on the ground. Then, in 2024, the eXtra Performance Wings will be attached to the Cessna and undergo ground testing before the first flights begin in 2025.
The demonstrator will be remotely piloted during flight testing to enable UpNext's engineers to push the technologies onboard to their limits. As the Cessna is only a demonstrator and will not be put into production, the decision to have a pilot test the plane from a ground center instead of onboard also alleviates the need to certify the demonstrator for human flight. “We want the flight testing to expose the eXtra Performance Wing to as many realistic flying situations as possible. This will give the different technologies the best possible chance of proving themselves, and of one day being integrated into the wings of tomorrow,” explains Blanc.