Maximum efficiency

QS SPEED

The fastest fin in the catalog. Clean NACA 0008 profile, no biomimetic features. Max L/D 10.01 — the best hydrodynamic efficiency in the QuillaSurf line.

SPEED

vs FCS M-5

Less absolute lift, but the best efficiency in the line. The SPEED compensates for lower lift with much less drag. L/D +20% over the reference.

Metric	SPEED	FCS M-5	Improvement
Avg lift	162.3 N	129.3 N	+26%
Avg L/D	5.36	4.48	+20%
Max L/D	10.01	8.06	+24%

Specifications

Geometry and materials

Height (L) 150.0 mm

Base (L) 152.9 mm

Max thickness (L) 19.70 mm

Rake 13°

Sweep 4°

Twist tip 0.0°

NACA profile 0008

Weight (L, laminated) 99 g

Biomimetics no features

Material PA-CF + 3K Twill

System FCS II

Available sizes

Size	Height	Base	Area	Weight
S	120 mm	126.0 mm	208.1 cm²	59 g
M	135 mm	137.0 mm	256.4 cm²	79 g
L	150 mm	152.9 mm	304.5 cm²	99 g
XL	165 mm	166.4 mm	357.6 cm²	124 g
XXL	180 mm	183.2 mm	414.9 cm²	152 g

Final measurements and weights with epoxy coating + carbon fiber.

Design

Less is more speed

No tubercles, no serrations, no microchannels. Just a pure NACA 0008 profile, 0.050 relative thickness, and 4° sweep. Efficiency as a philosophy.

Pure NACA 0008

Unmodified profile

No additions that generate drag. The NACA 0008 profile is the aeronautical standard for minimum drag. It works just as well underwater.

Thickness 0.050

Thinnest in the catalog

17% thinner than the NACA 0012. Less thickness = less displaced volume = less drag. Made in PA-CF with 3K Twill reinforcement to maintain stiffness.

Pure efficiency

Best L/D in the line

Maximum L/D of 10.01 — the best efficiency of the three QS fins. Designed for top speed and maximum projection in every bottom turn.

CFD

Numerical performance

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

SPEED CFD animation — flow around the fin

Angle	Lift (N)	Drag (N)	L/D
5°	81.14	8.10	10.01
10°	162.28	16.30	9.96
15°	243.42	37.49	6.49
20°	324.56	147.49	2.20

SPEED CFD — pressure distribution and streamlines

Target

Speed surfer

For the one who lives on the line. Long waves, point breaks, downwind. Top speed, paddling efficiency, and maximum projection in every bottom turn.

Minimal drag

Just 4 mm thickness and pure NACA 0008. The SPEED cuts through water like a knife. The lowest drag in the entire QS catalog.

Projection

28° sweep for maximum projection in a straight line. Less induced drag = more speed maintained over long sections.

Minimalist

For the surfer who doesn't want the fin to get in the way. It responds, but you don't notice it. The SPEED does its job silently.

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