Donuts with Incredible Power and Torque

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Out of Stealth Mode

Donut Lab, according to Green Car Reports, is a Finnish firm and outgrowth of Verge Motorcycles.  The Lab came out of “stealth mode”  with a surprise announcement at the annual Consumer Electronics Show in Las Vegas.  Here, CEO and co-founder of the lab, Marko Lehtimaki discusses the significance of his company’s electric donuts.

It’s a bit hard describing this type of motor.  It’s not radial or axial flux, but maybe toroidal flux.  Wikipedia goes into a short, but challenging description of a toroid, which is, in short, “The torus is an example of a toroid, which is the surface of a doughnut. Doughnuts are an example of a solid torus created by rotating a disk, and are not toroids.”

On a more practical level, motors created in this shape have the advantage of having the active elements at a distance from the geometric center of the motor.  On the large automotive and truck motors, this distance is 21 inches, sufficient to provide a great deal of torque.  Indeed, for a weight of 40 kilograms (88 pounds) the motor delivers 630 kilowatts (844 horsepower) and an astonishing 4,300 Newton-meters (3,171 pound-feet) of torque.  A friend noted that would make it not only possible to “pop wheelies,” but to flip the vehicle over.

Some have commented on what they feel is the heft of this particular motor, 88 pounds being a lot of “unsprung weight” on a single wheel.  With the added weight of an actual road wheel, mounting hardware and a tire, this is a significant load.  Part of that could be offset by the lack of need for a power transmission system, according to Donut Lab.

HyperQ’s drone uses Donut Motors on co-axial hubs. Illustration: UrDesign.  Could swarms of these overwhelm incipient wildfires such as those ravaging Los Angeles?  Each drone could carry up to 1,000 pounds of water (166 gallons), and present no risk to its operator.

Because it’s an open center wheel with no central hub, the motor must be cantilevered from the frame in some manner to drive a vehicle.  For an aircraft, how will one mount a propeller?  Perhaps a spinner serving aerodynamic and structural purposes could be employed.  An Australian firm proposes a remotely-operated co-axial helicopter using paired Donut motors.  Hyper Q Aerospace’s has designs could lift up to 1,000 pounds and be used in applications ranging from agriculture to fire-fighting and search and rescue work.  It is but one possible application, with uses including motorcycles, drones,

But Wait.  There’s More

Donut Lab isn’t content to make only motors.  Its products include integrated battery packs, an automotive controller called “The Brain,” and software to run it all.  Details are somewhat scant on Donut Lab’s web site, but we will probably be able to fill those in soon.  In any event, linked controls for window winders and windshield wipers probably won’t be essential for aircraft use, and whatever capacities the Brain will have for flight will be of interest.

An Earlier, Mechanical Approach

Franco Sbarro, Italian-born designer, was a fixture at European auto shows for over 40 years.  One of his more revolutionary ideas, the Orbital Wheel, was a feature on many of his cars and motorcycles.

Franco Sbarro with dual Orbital Wheel motorcycle, 1989.  One can understand the complexity of cantilevering the wheel off the frame and mechanically driving it.

Despite the mechanical complexity, Sbarro said his wheel was lighter, and would provide better handling and acceleration.  The same promise applies to the Donut Lab electric version.  Like the Sbarro wheel, theirs is available for motorcycles, bicycles, cars, busses and trucks.  It’s also capable of driving propellers, and may show up on a flight line soon.

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