I don’t know anything about Halbach arrays, but my impression is that it increases the efficiency of the magnetic field and thus the motor. Perhaps someone more familiar with other brushless motors could weigh in on how the specs (below) of this one.
Design files available for $25 under “makeSEA Halbach Array Brushless Motor Non-Commercial Use” license. Can’t find text of license on their site. No details about commercial licenses.
Detailed instructions and photographs are available publicly over at makesea.com/makesea/1gt. Maybe possible to mod an off-the-shelf 3-phase brushless motor instead of totally DIYing it.
“This is a very powerful, 3d-printed brushless motor. The main components like rotor and stator can be printed with a common FDM-printer. Magnets, copper wire, and ball-bearings are ordinary components can be sourced from the links below. The motor is a redesign based on the learnings from the makeSEA Motor. It has 600 Watts, and performs with more than 80% efficiency. The magnets of the rotor are arranged as Halbach Array. The motor runs with a standard ESC widely used in different RC-applications (plane, drone, car).” - makeSEA.
Max. Power (tested) 600 W Nominal Voltage 30 V Nominal Current 20 A Kv 255 rpm / V Efficiency (at nominal power) 80 % Total Weight 900 g Diameter 105 mm Length (without shaft) 85 mm Shaft Diameter 8 mm
Fabrication overview video: (damn you new user link/photo restriction policy!)