RADICAL

vs FCS M-5

Direct comparison against the market reference fin. Same simulation conditions, same mesh, same solver. Consistent advantage of +53–56% in lift across the entire range.

Metric	RADICAL	FCS M-5	Improvement
Avg lift	200.1 N	129.3 N	+55%
Avg L/D	5.01	4.48	+12%
Max L/D	9.09	8.06	+13%

Specifications

Geometry and materials

Height (L) 150.0 mm

Base (L) 152.9 mm

Max thickness (L) 25.67 mm

Rake 15°

Sweep 5°

Twist tip 2.0°

NACA profile 0012

Weight (L, laminated) 130 g

Biomimetics tubercles + serrations + channels

Material PA-CF + 3K Twill

System FCS II

Available sizes

Size	Height	Base	Area	Weight
S	125 mm	138.3 mm	231.3 cm²	88 g
M	140 mm	152.6 mm	288.7 cm²	122 g
L	150 mm	152.9 mm	305.1 cm²	130 g
XL	170 mm	182.8 mm	397.6 cm²	193 g
XXL	185 mm	200.4 mm	473.3 cm²	248 g

Final measurements and weights with epoxy coating + carbon fiber.

Biomimetic features

3 layers of natural design

No other manufacturer combines all 3 features in a single fin. Not decoration — each one is parameterized, simulated, and optimized.

RADICAL — biomimetic diagram: tubercles, serrations, and microchannels

The 3 layers of biomimetic design visible in the final geometry: leading-edge tubercles (Megaptera), trailing-edge serrations (Bubo), and surface microchannels (Carcharodon).

1

Tubercles

Megaptera novaeangliae

Amplitude 4 mm, 5 cycles on leading edge. Delay stall, improve control at high angles of attack. Delayed: +2.5° of stall before separation.

2

Serrations

Bubo virginianus

Amplitude 6 mm, 6 cycles on trailing edge. Reduce hydrodynamic noise and improve wake flow efficiency. Improved L/D across the entire curve.

3

Microchannels

Carcharodon carcharias

Amplitude 0.5 mm, 8 channels per side. Reduce surface friction. Flow stays more attached to the surface — less parasitic drag.

CFD

Numerical performance

RANS k-ω SST simulation, fine mesh (~3M cells), 4 angles of attack. Fluid: real seawater at 7.5 m/s.

RADICAL CFD animation — flow around the fin

Angle	Lift (N)	Drag (N)	L/D
5°	99.12	11.01	9.00
10°	199.38	21.24	9.39
15°	300.42	49.45	6.08
20°	401.66	248.44	1.62

RADICAL CFD — pressure distribution and streamlines

Target

Radical surfer

Extreme maneuverability. Instant rail response. For the surfer who demands maximum grip in tight turns and demanding conditions.

Maximum grip

152.9 mm height and thick NACA 0012 profile for maximum lift in aggressive turns. The fin won't let go.

Total control

Tubercles that delay stall — the fin responds linearly even at extreme angles where others have already separated.

Aggressive

For powerful waves, vertical maneuvers, and surfers who push the rail to the limit. Not for cruising.

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QS RADICAL