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SCAR retrospective

SCAR—internally “Saber Crown AirBike”—was a self-funded prototype exploring single-rider flight on a large ducted-fan drone platform. It remained an experiment, never reached a safe or practical level, and is recorded here as a failed project.

SCAR maiden flight test.

What we attempted

The concept was a personal eVTOL: an eight-rotor, ducted-fan airframe sized to lift one rider in a tightly constrained setup, with a motorcycle-style seat and handlebars. Design work—done with an external aerospace partner for sizing and FEA—covered frame stability, propulsion sizing, duct selection, and control-response experiments.

  • Eight MAD M30 (~100 kV) motors with MAD AMPX 200A ESCs.
  • Eight FLUXER 40×13.1 in propellers (4 CW + 4 CCW).
  • Welded aluminium 6061-T6 truss airframe with CNC-machined motor mounts.
  • Carbon-fiber ducts and booms using ~80 mm circular carbon tube.
  • Three duct concepts evaluated: Hex Duct, Bumper Frame, and Circular Duct.
  • ~1025 mm inner-diameter 3D-printed duct with honeycomb support and mesh for thrust and pilot protection.

Preliminary analysis put bare-airframe drag at ~15.5 kg at 50 km/h, with ~3.7 mm carbon-fiber boom tip deflection under a 117 kg motor-mount load case (factor of safety 1.3). Carbon-fiber and metal parts were sourced through fabricators across Slovakia and the EU.

Outcome

The safety margin never arrived.

Technical and risk constraints outweighed progress, and a paid funding line dried up. Development stopped before any meaningful operational milestone. The physical prototype was offered for sale to recoup some of the cost.

Why keep the failed project?

These notes are a retrospective, not a launch announcement. The work still captures real decisions about structural design, propulsion, fabrication, controls, and knowing when a prototype path should end.