Key Takeaways
- NASA has successfully completed a high-speed taxi test of a scale model of a design that could make future aircraft more efficient by improving air flow across a wing’s surface
- The Crossflow Attenuated Natural Laminar Flow (CATNLF) concept aims to increase laminar flow and reduce wind resistance, potentially achieving annual fuel savings of up to 10% for large, long-range aircraft
- The technology has the potential to save millions of dollars per aircraft per year and reduce emissions
- The CATNLF design has been tested in a wind tunnel and has shown promising results, with flight testing expected to begin soon
- The technology could have a significant impact on commercial aviation, with potential applications in supersonic flight in the future
Introduction to CATNLF
NASA researchers have successfully completed a high-speed taxi test of a scale model of a design that could make future aircraft more efficient by improving how air flows across a wing’s surface, saving fuel and money. The Crossflow Attenuated Natural Laminar Flow (CATNLF) test article reached speeds of approximately 144 mph, marking its first major milestone. The 3-foot-tall scale model looks like a fin mounted under the belly of one of the agency’s research F-15B testbed jets, but it’s a scale model of a wing, mounted vertically instead of horizontally. This setup allows NASA to flight-test the wing design using an existing aircraft.
The Concept of CATNLF
The CATNLF concept aims to increase a phenomenon known as laminar flow and reduce wind resistance, also known as drag. A NASA computational study conducted between 2014 and 2017 estimated that applying a CATNLF wing design to a large, long-range aircraft like the Boeing 777 could achieve annual fuel savings of up to 10%. Although quantifying the exact savings this technology could achieve is difficult, the study indicates it could approach millions of dollars per aircraft each year. Reducing drag is key to improving efficiency, and the CATNLF design achieves this by increasing laminar flow, or the smooth motion of air, within the boundary layer.
The Science Behind CATNLF
During flight, a thin cover of air known as the boundary layer forms very near an aircraft’s surface. In this area, most aircraft experience increasing friction, also known as turbulent flow, where air abruptly changes direction. These abrupt changes increase drag and fuel consumption. CATNLF increases laminar flow within the boundary layer, resulting in more efficient aerodynamics, reduced friction, and less fuel burn. The CATNLF testing falls under NASA’s Flight Demonstrations and Capabilities project, a part of the agency’s Integrated Aviation Systems Program under the Aeronautics Research Mission Directorate.
Development and Testing of CATNLF
The concept of CATNLF was first developed by NASA’s Advanced Air Transport Technology project, and in 2019, NASA Armstrong researchers developed the initial shape and parameters of the model. The design was later refined for efficiency at NASA’s Langley Research Center in Hampton, Virginia. In a 2018 wind tunnel test at Langley, researchers confirmed that the CATNLF design successfully achieved prolonged laminar flow. "After the positive results in the wind tunnel test, NASA saw enough promise in the technology to progress to flight testing," said Michelle Banchy, Langley principal investigator for CATNLF. The NASA Armstrong’s F-15B testbed aircraft provides the necessary flight environment for laminar flow testing, enabling researchers to address fundamental questions about the technology while keeping costs lower than alternatives.
Applications and Future Directions
CATNLF currently focuses on commercial aviation, which has steadily increased over the past 20 years, with passenger numbers expected to double in the next 20, according to the International Civil Aviation Organization. Commercial passenger aircraft fly at subsonic speeds, or slower than the speed of sound. "Most of us fly subsonic, so that’s where this technology would have the greatest impact right now," said Mike Frederick, principal investigator for CATNLF at NASA’s Armstrong Flight Research Center in Edwards, California. NASA’s previous computational studies also confirmed that technology like CATNLF could be adapted for supersonic application. In the coming weeks, CATNLF is expected to begin its first flight, kicking off a series of test flights designed to evaluate the design’s performance and capabilities in flight.
Conclusion and Future Implications
Looking ahead, NASA’s work on CATNLF could lay the groundwork for more efficient commercial air travel and might one day extend similar capabilities to supersonic flight, improving fuel efficiency at even higher speeds. "The CATNLF flight test at NASA Armstrong will bring laminar technology one step closer to being implemented on next-generation aircraft," said Banchy. The potential impact of CATNLF on the aviation industry is significant, with the potential to save millions of dollars per year and reduce emissions. As the technology continues to be developed and tested, it will be exciting to see the potential benefits it could bring to the industry and the environment.
