I want them to succeed, but it will be difficult. Looks like they're following Tesla's model of starting with the top-of-market so they can "fundraise" via early adopter sales. Will they ever be able to hit mass production? Not sure.
In-wheel motors are interesting. That changes the dynamics of the vehicle by adding what we mech-e's call "unsprung mass". Vehicle handling takes a huge hit. There's a reason there are no cars on the market with in-wheel motors at present. Additionally, you're putting expensive components in a place where they can be more easily damaged. There's also the fact that in-wheel motors can be very dangerous if there's a failure of the control system. Since there are no cars on the road like this, I'm wondering if the team truly has the expertise to tackle these issues.
But I'm not trying to be a cynic. I spent 8 years as a mechanical engineer designing hybrid and electric cars; these are simply challenges that need to be engineered around. This is a cool car, and I hope it makes it to market. We need more of this.
I would bet that there's more unsprung mass in this configuration, but it's hard to say without knowing the details of the motors themselves. If each motor is, say, 80 pounds or heavier, then this configuration would likely increase the unsprung mass.
Note a distinction between "control" and "handling". Four in-wheel motors will have better control but worse handling. Traction control can be applied to each individual motor, improving control in some cases, but on bumpy or rough roads the car will experience worse handling, as the wheels will "hop" off the surface more.
Imagine a car driving over a speed bump a little too fast. In a standard suspension, the wheels are light enough that the suspension pushes them back down to the road surface very quickly at the far end of the bump. If there is more unsprung mass, however, the wheels have more inertia, and so the suspension is not able to push the wheels down to the surface as quickly. Now imagine that same car taking a fast turn on an uneven road surface. If the wheels aren't pressed down to the surface after coming up off a bump, that wheel will lose traction, and traction is required for sticking the turn. In that case, no amount of traction control can make up for the loss of friction.
> If each motor is, say, 80 pounds or heavier, then this configuration would likely increase the unsprung mass.
Apparently, the motor on the Tesla Model S is 70 lbs ( https://chargedevs.com/newswire/elon-musk-cooling-not-power-... ). With individualized motors, each would likely be less than this. Combined with the battery weight attached to the car's chassis, I would expect this to result in a lower ratio of unsprung mass to sprung, and thus better handling than typical on a non-battery car.
I mean that if it's better than what is typical, then it shouldn't be inadequate, and that helps justify this trade-off in favour of efficiency / range.
> Traction control can be applied to each individual motor
This is not a feature of in-wheel motors, but individual motors. And not even much of that, because you can apply the brakes to shift power through the differential to the other wheel (a technique modern all-wheel drive cars including Teslas use for traction control). Is having a motor for each wheel really a huge improvement over that? Maybe latency can be improved a little?
In-wheel motors are interesting. That changes the dynamics of the vehicle by adding what we mech-e's call "unsprung mass". Vehicle handling takes a huge hit. There's a reason there are no cars on the market with in-wheel motors at present. Additionally, you're putting expensive components in a place where they can be more easily damaged. There's also the fact that in-wheel motors can be very dangerous if there's a failure of the control system. Since there are no cars on the road like this, I'm wondering if the team truly has the expertise to tackle these issues.
But I'm not trying to be a cynic. I spent 8 years as a mechanical engineer designing hybrid and electric cars; these are simply challenges that need to be engineered around. This is a cool car, and I hope it makes it to market. We need more of this.