How Boom Supersonic is reducing drag on their XB-1 using a sharkskin inspired material
BLOGS
3/28/20254 min read
Key Points
Research suggests sharkskin-inspired riblets reduce drag by smoothing turbulent airflow, potentially saving the aviation industry significant fuel costs.
It seems likely that these riblets, mimicking shark denticles, lower skin friction, enhancing aircraft efficiency across various speeds, including supersonic.
The evidence leans toward this technology being durable, with successful tests on Boom Supersonic's XB-1 aircraft showing no degradation.
Introduction to Sharkskin-Inspired Drag Reduction
Sharkskin has long fascinated scientists and engineers due to its ability to reduce drag as sharks glide through water. This natural efficiency is attributed to tiny, tooth-like scales called denticles, which minimize friction. Inspired by this, aerospace engineers have developed riblets—microscopic grooves applied to aircraft surfaces—to replicate these drag-reducing properties. This article explores how this sharkskin design reduces drag, based on insights from Boom Supersonic's exploration of the technology.
Development and Testing
MicroTau, founded by Henry Bilinsky, pioneered a scalable method in 2015 to print these riblet microstructures, aiming to improve fuel efficiency in aviation. Boom Supersonic tested this technology on their XB-1 demonstrator aircraft during flights 8 through 13, applying riblet patches to the aft underbelly, covering 0.5 square meters on both painted and unpainted titanium surfaces. The tests spanned subsonic, transonic (Mach 0.8 to 1.2), and supersonic speeds, with flights 12 and 13 achieving supersonic speeds over the Mojave.
Mechanism and Benefits
Riblets work by smoothing turbulent airflow, reducing skin friction and thus aerodynamic drag. This leads to lower fuel consumption, reduced carbon emissions, and decreased operating costs. Henry Bilinsky estimates that this technology could save the aviation industry up to $10 billion in fuel annually, with commercial aviation customers potentially seeing a 20% profit uplift. The successful tests, showing no degradation even at supersonic speeds, highlight the durability and potential of this approach.
Future Implications
The technology, researched for over 40 years since NASA's Langley Research Center studies in the 1970s, is being considered for both military and commercial applications, including potential use on Boom Supersonic's Overture aircraft. Collaborators like the Defense Innovation Unit and Air Force Operational Energy Office underscore its broad interest.
Detailed Analysis of Sharkskin-Inspired Drag Reduction
Background and Inspiration
Sharks have evolved over millions of years to optimize hydrodynamic efficiency, with their skin covered in denticles—tiny, tooth-like scales that point toward the tail. This structure reduces friction from surrounding water, enabling efficient gliding. The webpage from Boom Supersonic highlights this natural design as a model for aerodynamic improvements in aviation, noting, "Sharks have been perfecting their riblet design for millions of years. Their skin is covered in tiny, tooth-like scales, which help them glide through water with impressive efficiency."
Riblet Technology: Mechanism and Development
Riblets are microscopic grooves inspired by sharkskin, designed to reduce skin friction by smoothing turbulent airflow. The webpage explains, "On aircraft, riblets are microscopic grooves on the surface that reduce skin friction by smoothing turbulent airflow." This technology was developed by MicroTau, founded to enhance fuel efficiency in defense and commercial aviation. In 2015, Henry Bilinsky, the founder, invented a scalable method to print these drag-reducing sharkskin riblet microstructures, which have since flown thousands of flight hours globally.
Testing on XB-1: Methodology and Results
Boom Supersonic tested MicroTau's riblet material on their XB-1 demonstrator aircraft, focusing on the aft underbelly with patches covering 0.5 square meters (5.4 square feet) on both painted and unpainted (titanium) surfaces. The tests, conducted during flights 8 through 13, included subsonic, transonic (Mach 0.8 to 1.2), and supersonic (above Mach 1.0) speeds. Notably, flights 12 and 13 broke the sound barrier over the Mojave, providing a rigorous test environment.
The results, as detailed on the webpage, showed remarkable durability: "Patches survived subsonic and transonic speeds with no observable degradation. During Flights 12 and 13, patches broke the sound barrier with no macroscopic degradation or lifting, despite extreme conditions." This success de-risks the technology for potential applications on U.S. Air Force legacy aircraft like the C-17 Globemaster III and commercial platforms, including Overture.
Benefits and Economic Impact
The reduction in drag achieved by riblets translates to significant operational benefits. The webpage states, "Developed by MicroTau in Australia, the sharkskin-inspired riblet material reduces drag, which in turn can reduce fuel consumption, carbon emissions, and operating costs." Henry Bilinsky emphasized the economic potential, noting, “From a big picture perspective, our Riblet Package product can potentially save the aviation industry up to $10 billion in fuel annually,” with commercial aviation customers expecting a profit uplift of around 20 percent.
Historical Context and Collaborative Efforts
Riblet science has a long history, with research beginning over 40 years ago at NASA's Langley Research Center in the 1970s, pursued by both aerospace and maritime industries. The current efforts involve collaboration with the Defense Innovation Unit and Air Force Operational Energy Office, indicating interest from military and governmental sectors for applications on aircraft like the C-130 Hercules and KC-135 Stratotanker.
Unexpected Detail: Supersonic Durability
An interesting aspect is the technology's performance at supersonic speeds, which is not commonly associated with sharkskin-inspired designs. The successful tests at Mach 1.0 and above, with no degradation, suggest that riblets could be particularly valuable for high-speed aircraft, aligning with Boom Supersonic's goals for their Overture project.
Conclusion
The sharkskin-inspired riblet design offers a biomimetic solution to reduce drag in aviation, with proven durability across a wide range of speeds. By smoothing turbulent airflow, it lowers fuel consumption and operating costs, potentially transforming the industry. The successful testing on XB-1 and the involvement of major stakeholders highlight its readiness for broader adoption, promising a future of more efficient and sustainable air travel.
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