Selig S3021
The airfoil that makes 100 km range possible.
Airfoil Characteristics
Wing Geometry
Why Selig S3021
The Selig S3021 was designed specifically for low-Reynolds-number flight — exactly the flight regime where the Stork operates. At Reynolds numbers between 100,000 and 300,000, most airfoils struggle with laminar separation bubbles and high drag. The S3021 is optimized for this range.
Its moderate camber (3.4%) and thin profile (9.8%) produce a favorable lift-to-drag ratio at the low airspeeds and small chord lengths typical of sub-3 kg aircraft. The result is less power required to maintain cruise — and more range per watt-hour.
Optimized for Cruise
The S3021 reaches its best lift-to-drag ratio at 2–3° angle of attack — precisely the AoA the Stork maintains during cruise. This isn't a coincidence. The entire aircraft geometry is designed around flying at this airfoil's sweet spot.
With a maximum CL of approximately 1.1–1.2, the wing generates sufficient lift at cruise speeds of 54–60 km/h to support the full all-up weight with comfortable margin. This keeps the aircraft well away from stall conditions during normal operations.
In Plain Language
Think of the airfoil as the wing's cross-section — its shape determines how efficiently the wing converts forward motion into upward lift. Most airfoils are designed for larger, faster aircraft. They perform poorly at the Stork's size and speed.
The S3021 is purpose-built for small, slow aircraft. It generates strong lift with minimal drag at exactly the speeds and altitudes the Stork flies — which means less energy wasted fighting the air, and more energy available for covering distance.
The practical result: 100+ km of autonomous range on a single battery charge.
Aerodynamics That Deliver
Every curve in the wing profile is optimized for one thing — getting your payload where it needs to go.
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