Every detail has a purpose.
The BoxWing allows us to use two wings with the drag of one. This gave us the opportunity to optimize each wing and section for a specific behavior instead of accepting a compromise to fit everything into one.
The outer wing increases power, line tension, and upwind angle. Two main parameters are tuned for this behavior:
STEEP WING ANGLE
As lift forces act perpendicular to the wing and the board is canted while edging, the wing must be angled outward, toward the edge, to maximize efficiency. Other board and fin manufacturers also use this principle, but they are restricted by the internal threads of the mounting system and the loss of straight-line grip due to spanwise flow when the angle increases. They are limited to angles below 10°, while we have angled the outer wing at 25° for optimal performance.
ASYMMETRIC AEROFOIL
Since the main function is performed by the wing next to the engaged edge, the aerofoil is optimized to generate lift in one direction. At only 4mm thin, this wing has less than half the thickness of a normal fin, like splitting it lengthwise and using only the effective part. The aerofoil is designed for good lift and a high maximum angle of attack. Since it is close to the edge, ventilation resistance was also considered. Like all aerofoils on this fin, its leading and trailing edges are designed to withstand harsh operating conditions.
The inner wing provides grip and control during landings, maneuvers, and high-speed riding. It delivers the familiar feel of a conventional fin. Two main parameters are tuned for this behavior:
STRAIGHT WING ANGLE
The forces generated by this wing prevent lateral slippage when the board is on edge and enhance directional stability when the board is flat. The distinct end reduces tip overflow, increasing utilization.
SYMMETRIC AEROFOIL
The inner wing’s aerofoil is designed to maximize the glide ratio. Since stalling is prevented by the overlap of both wings, as shown here, an extremely thin symmetric aerofoil was chosen. Similar profiles are used in fighter jets and America's Cup boats but are typically unusable in conventional fin design due to their early and abrupt stall. Just the stagger and overlap of our design allow these low-drag aerofoils to function without their usual drawbacks.
The strut is the lower surface that connects the wingtips of the inner and outer wings. It prevents pressure compensation around the wingtips and reduces vorticity. Its shape and profile influence the drag and lift of the entire system, optimizing the glide ratio.
The hollow profile enabled us to implement all these benefits. Its structural stability allowed us to create 4mm wings without the risk of breaking or unwanted flexing. It also made our innovative bottom-up mounting system possible granting full dimensional and angular freedom to form and position each wing as needed.
By flipping the screws upside down, we moved the thread from inside the fin to the top of the board. This not only gave us complete design freedom but also allowed for an extremely secure mounting system. The topmount houses two A4 marine-grade stainless steel nuts to ensure a corrosion-free, secure attachment,no matter how often you mount and dismount the fins. The nuts are hidden under a sleek cover that also provides additional grip for board-off tricks.
We use M5 stainless steel screws for our fins. This ensures compatibility with every mounting standard on the market while reducing weight and allowing for a smaller screw head. Since there are no bending loads on the screws, they do not break or bend like those in regular fins. If your previous fins used M6 screws, use the included spacer to eliminate any play.
Without the spacer, angular deviation may alter the riding experience:
TURNING THE TIPS INWARD:
increases playfulness and reduces grip.
TURNING THE TIPS OUTWARD:
increases grip and reduces playfulness.
Feel free to experiment and let us know which setting works best for your board!
Riding an F-One board? We’ve got you covered. Just let us know when ordering, and we’ll include the F-ONE spacers for free.