Axial Flux vs Radial Flux: Why We Chose Axial for the Cyclotis
Every electric car on the market uses radial flux motors. Tesla, Lucid, Porsche, Hyundai — all of them. Schubert Motors doesn't. The Cyclotis uses twin axial flux motors producing a combined 2,000 horsepower. Here's why that matters.
Radial Flux: The Industry Standard
In a radial flux motor, the magnetic field flows radially outward from the rotor — like spokes on a wheel. The rotor spins inside a stator, and the air gap between them is cylindrical. This design has been refined for decades. It's well-understood. It works. It's also fundamentally limited.
The problem: in a radial flux design, only the outer circumference of the rotor actively participates in torque generation. The interior volume — the space inside the rotor — is mostly structural. You're carrying weight that doesn't produce power.
Axial Flux: The Higher-Density Alternative
In an axial flux motor, the magnetic field flows parallel to the rotor shaft — through the face of the rotor disc, not around its edge. The entire disc surface generates torque simultaneously. This means 3-4x the power density of an equivalent radial flux motor, in a package that's one-third the weight.
The tradeoff: axial flux motors are harder to manufacture. The air gap between rotor and stator must be precisely controlled across the entire disc surface. Thermal management is more challenging because the heat-generating windings are concentrated in a smaller volume. And the power electronics must switch at higher frequencies to handle the different magnetic circuit characteristics.
Schubox Axial Flux Hybrid System — Key Specs:
• Twin motor configuration (one per axle)
• Combined 2,000 HP output
• Direct oil cooling via microchannel stator housing
• Custom SiC inverter controller ASIC (BAMF Semiconductor)
• 4 patents pending
• Weight: 43 kg per motor (vs 90+ kg equivalent radial flux)
The Manufacturing Challenge We Solved
The reason axial flux motors aren't in production cars isn't because the theory doesn't work — Michael Faraday demonstrated the principles in 1821. It's because manufacturing them at tolerances tight enough for automotive use is genuinely difficult. The stator windings must be laid with sub-millimeter precision across the entire disc. The rotor must spin true within microns at 20,000 RPM. And the whole assembly must survive 15 years of thermal cycling, vibration, and road salt.
We solved this by designing for low-volume production from day one. Our stator windings are laid on CNC-guided fixtures by a precision motor shop in Warren, Michigan. Our rotors are machined from billet aluminum and balanced to 0.1g at operating speed. The assembly is hand-fitted in our Detroit workshop by technicians who stay with each motor from winding to dyno certification.
The Hybrid Advantage
Pure electric hypercars (Rimac, Pininfarina Battista) are devastatingly quick but emotionally sterile. They make no sound. They have no power band — just instant torque and then nothing. Pure combustion hypercars (Koenigsegg, Pagani) are theatrical but inefficient. The hybrid configuration gives us both: instant electric torque off the line, with a 5.2L twin-turbo V8 that screams to 9,000 RPM. The axial flux motors fill the torque gaps during shifts. The V8 provides the soundtrack.
This is Schubox — not just a motor, but an integrated hybrid control system. The motors, inverter, battery, and engine ECU communicate over a deterministic CAN bus at 500 Hz. The torque split between front and rear axles is recalculated every 2 milliseconds. The result is 1,200 lb-ft of torque available from 0 RPM, with a 9,000 RPM V8 howl layered on top.