Research and Development of Riblet Technology for Practical Use

As part of global efforts toward carbon neutrality and the Sustainable Development Goals (SDGs), the JAXA Aviation Technology Directorate is accelerating its efforts to reduce environmental impact, with a focus not only on environmental sustainability but also on economic efficiency. In particular, fuel consumption reduction technology is vital, both in terms of improving fuel efficiency and reducing CO₂ emissions. Acquiring such technology is critical for Japan’s aviation industry to remain competitive in the global arena.

Looking ahead, technologies that can control the various components of aerodynamic drag will be essential for future passenger aircraft. Among the different types of drag, skin-friction drag accounts for more than 40% of the total aerodynamic drag on passenger aircraft. Therefore, one of the most effective ways to reduce overall drag is to minimize skin-friction drag.

Our solution is riblet technology. By applying fine, groove-like structures to aircraft surfaces, riblet technology can significantly reduce skin friction drag.

What Are Riblets?

Riblets are an aerodynamic technology used to reduce skin friction drag by fine grooves of about 0.1 mm in width on the surface of the airframe, thereby improving fuel efficiency and reducing CO₂ emissions. This riblet technology is especially valuable in that it can be retrofitted to existing aircraft, offering high potential for widespread adoption.

For example, if riblets are ideally applied to the entire airframe surface of a passenger aircraft, and assuming skin friction drag accounts for 40% of total drag, even a 5% reduction in skin friction drag could lead to an overall drag reduction of approximately 2%. In aviation, even a 1% drag reduction is considered highly significant.

JAXA's Challenge: Key R&D Areas

JAXA's riblet technology is designed for high durability, and employes unique methods to form fine riblet structures directly within the aircraft’s surface coating. To enable practical implementation of this technology on passenger aircraft, JAXA is working closely with airlines and industry partners to address three key challenges:
1. Evaluating changes in riblet shape caused by deterioration over time during actual flight operations,
2. Applying riblet coatings to large area with fuselage lengths of 30 to 60 meters, and
3. Developing advanced riblet shape designs to further reduce surface friction drag.

1. Durability Testing in Actual Flight Conditions

The durability of riblets is being demonstrated using a Japan Airlines Boeing 737 in regular commercial operation. Riblet coatings that meet airline requirements (such as adhesion strength) have accumulated over 2,000 flight hours, including approximately six flight cycles per day with routine cleaning, confirming their high durability in actual operational environments.

Additionally, JAXA is developing wind tunnel testing methods to evaluate changes in surface friction drag reduction performance caused by slight aging-related deterioration of riblet shape.

2. Large-Scale Riblet Application Techniques

JAXA and its partner manufacturers jointly hold patents for riblet application technologies. In collaboration with airlines, we are refining these techniques to enable rapid, large-scale implementation on commercial aircraft. Wind tunnel testing has also been conducted to evaluate how the presence of areas where riblets cannot be applied due to maintenance constraints impacts the overall drag-reduction performance.

• 
• 
• 

Figure 3: Riblet coating applied to the lower fuselage of JAL’s Boeing 737 for flight testing (JAL/O-WELL/JAXA)

3. Development of Advanced Riblet Designs

Based on aerodynamic insights and manufacturing constraints identified through this research project, JAXA is developing new riblet designs that achieve both ease of application and high aerodynamic performance. One such innovation is a single bevel riblet (patent pending), which has demonstrated improved surface friction drag reduction compared to conventional shape, as verified through numerical simulations and wind tunnel testing. This technology has the potential to offer a distinct competitive advantage as global competition in green aviation intensifies.

• 
• 

Figure 4: In pursuit of higher-performance riblets; Left – Flow simulation of JAXA’s single bevel riblet (flow direction is perpendicular to the page); Right – Set up for wind tunnel test

Collaborative Framework

To develop practical surface treatment technology for applying riblet structures as aircraft coatings, JAXA is working closely with coating manufacturers O-WELL Corporation and Nikon Corporation, and airline partner Japan Airlines Co., Ltd. (JAL), under the Refresh (RiblEt Flight RESearcH for Carbon Neutral) program. This collaboration enables technology demonstration using passenger aircraft with riblet coatings in actual operational environments, advancing the concept from laboratory research to practical implementation.

Short video: Riblet coating technology to improve aircraft fuel efficiency

Aug 28, 2025