Behind The BST Hypertek Electric Motorcycle

The really interesting stuff is not always in the brochure.

The major masses: simple carbon frame, in-unit fork tubes and upper/lower crowns, “tank” housing power supply and control electronics, metallic-orange radiator, below it the main battery section, and under the seat, the electric motor.BST/

As the wraps are whisked off the fab prototype, almost invisible in the center of the crowd here at the big glitzy international show, hold your phone high, maybe even hop for added height, trying to be first to get an image to your publication. Damn! Overloaded the local cell tower again! Too many of us, all trying to blow big graphics files through. A millisecond too late means clicks that could have been yours fly to a competitor’s site, and lost clicks mean you’re deleted.

For the information seeker, gee whiz may be the only response. Rad. Seriously futurismo. Reminds me of the Death Star. Wonder what any of it means. Wanna get something to eat? For me, the first impact of the BST Hypertek electric motorcycle is names: designer Pierre Terblanche and engineer Gary Turner. Turner’s BlackStone Tek outfit in South Africa has sold 30,000 carbon-fiber motorcycle wheels. That means serious money, like $50 million. These are people of great accomplishment, not science-fair entrants ordering parts from the Grainger catalog to be fastened together with Dexion.

Streamlining for a motorcycle is mainly achieving the lowest possible frontal area. If it can be small, why make it big?

This is minimalism, like the Sachs “Beast” of 2000 from Target Design: two wheels, an engine, and a place to sit. Why no plastic? Two reasons. One, this is surely an urban project, and two, remember what the late John Britten said: Streamlining for a motorcycle is mainly achieving the lowest possible frontal area. If it can be small, why make it big? This electric motorcycle actually explores new possibilities presented by electric powertrains.

The usual approaches to electric-bike design are two:

  1. A shapeless suitcase of batteries slung between two wheels. Why so ugly? Well, we had to let the public know we aren’t, you know, motorcycle enthusiasts. We’re more like, uh, Prius people.
  2. A conformist faired sportbike with the combustion engine lifted out and 350 pounds of batteries and electrical machinery stuffed in its place. Weight is 589 pounds.

Weight is clearly a central issue. How can we be rid of it? Can’t do much about the battery because the scheduled breakthroughs are behind schedule, so let’s start with vehicle structure.Boeing 787 designers knew that every pound of structure requires a pound of fuel to carry it, so the lighter the structure the less fuel needs to be carried. Aluminum is traditional, but carbon fiber (CFRP) offers a 15 times greater specific stiffness (ratio of stiffness to weight). Practical designs can’t realize all of that; there has to be an adhesive to bind the ultra-strong fibers into a solid structure, and methods of fastening CFRP to metal components weigh something as well.

Zoltan the Annihilator
Minimalism! If you don’t need it, it’s not here. The green unit below the main battery case has room for a range-extending third battery group. Zoltan the Annihilator rides again!BST/

Motorcyclists have long thought of carbon fiber as something light and expensive, but mainly for making glossy but functionally boring bits like fenders and seats. They look good in the Ducati accessory catalog. But now that carbon swingarms have found a specific purpose, who knows what may come next?

In the case of BST Hypertek, both the abbreviated chassis and the integrated unit consisting of upper fork tubes and both fork crowns are carbon. Carbon structure saves serious weight.A conversation with Terblanche at a European show where the Ducati 999 was present revealed that he has interests other than styling, namely simplicity and manufacturability. Manmade creations accumulate parts and complexity, so someone must from time to time “simplify and add lightness.” Terblanche showed us examples on the machine itself. Reduced parts counts cut costs and simplify assembly and service.

Now consider this bike’s DHX Hawk 60 permanent magnet synchronous electric motor, which is unusually small and light. Its producer, DHX Machines, is in—surprise!—Braselton, Georgia. Traditional electric motors are large and heavy because they are limited by the heat they generate. The danger of overheating is that the insulating enamel on the motor’s wire windings will be destroyed by high temperature, rendering the motor useless. If that heat could somehow be extracted, they could be made much smaller and lighter. The important innovation here is compact, 3D-printed hollow heat exchangers (each like a thin, narrow card), small enough to be fitted, one in each of the motor’s many stator winding slots and in contact with the heat-generating windings themselves, to carry away their heat via circulating fluid.

DHX Hawk 60 motor
Oops, something is missing. Could it be the front belt sprocket? The DHX Hawk 60 motor drives forward to a shaft below, plus bevel gears to the sprocket. Air shock (lower right) lives between the swingarm beams.BST/

With active liquid-cooling of every wire bundle, more electric current can safely be pushed through the motor, allowing great power to be produced from small, light packages. Instead of weighing the nearly 600 pounds of many electric motorcycles, Hypertek is claimed to “only” weigh 450 pounds. Yes, that’s still substantial, but it’s a change in the right direction. This is design, working toward desired goals.

Terblanche shared some details with us on his way home from Milan: “The suspension is similar to the Horst Leitner-designed suspension on the ATK motocrossers.” What you see between the upper and lower beams of the single-sided swingarm “is a K-Tech air shock actuated by a linkage that runs under the swingarm. I put it there because there is no other ‘there.’ ”

BlackStone Tek carbon-fiber
A well-known and respected player in the exotic wheel game: South Africa-based BlackStone Tek produces flawless carbon-fiber work, with mirror-like surfaces.BST/

“There are three battery packs containing 2170 cells from Panasonic [as in Tesla Model 3]. We are looking at 4.75 kWh for both top packs [symmetrical]. These are mounted horizontally to lower the center of gravity and to aid cooling. An auxiliary pack can be mounted below these to add range.

“The motor drives forward to a clutch, which has a bevel-drive shaft to the output sprocket. It uses a 20mm Gates belt. Above the top batteries is the electronic module [power supply, controller, etc.]. A clutch is fitted to enable easier wheelies and burnouts.”

Successful weight reduction. Distinguished design that departs from the expected. Actual electric powertrain innovation, not just more mix and match from the usual suppliers. Structural uniqueness.