RE: Fisker Surf reservations
There has been talk about wheel motors for years and I have yet to see anyone do any more than a conversion prototype with them (like the Mini QED, if you remember that). And even then you'll hardly see them do much more than creep along in a straight line.
Lightning originally planned to use PML Flightlink's wheel motors for the Lightning GT, but eventually abandoned them for a more conventional setup. PML Flightlink went bankrupt and then restructured to form Protean (to focus on automotive applications) and another company (I forget the name) to focus on other applications for thin motor technology that were more practical/profitable (like small drive motors and joysticks). Protean, however, is still trying to get some traction (so to speak), but it's not really looking that promising.
So what's wrong with wheel motors? Well one issue is the unsprung weight which gives unfavorable driving dynamics. Another is that you can typically get more power per unit mass by simply designing a larger single motor rather than multiple smaller motors.
Then there are the normal regulatory concerns. This was from back in 2006 when the Tesla Roadster was first unveiled:
http://www.worldchanging.com/archives/005118.html
I say what Tesla is doing with their liquid cooled motor and inverter (mated to a single speed diff/transaxel) is the best I've seen so far.
Heh... no.kabalah70 said:
There has been talk about wheel motors for years and I have yet to see anyone do any more than a conversion prototype with them (like the Mini QED, if you remember that). And even then you'll hardly see them do much more than creep along in a straight line.
Lightning originally planned to use PML Flightlink's wheel motors for the Lightning GT, but eventually abandoned them for a more conventional setup. PML Flightlink went bankrupt and then restructured to form Protean (to focus on automotive applications) and another company (I forget the name) to focus on other applications for thin motor technology that were more practical/profitable (like small drive motors and joysticks). Protean, however, is still trying to get some traction (so to speak), but it's not really looking that promising.
So what's wrong with wheel motors? Well one issue is the unsprung weight which gives unfavorable driving dynamics. Another is that you can typically get more power per unit mass by simply designing a larger single motor rather than multiple smaller motors.
Then there are the normal regulatory concerns. This was from back in 2006 when the Tesla Roadster was first unveiled:
http://www.worldchanging.com/archives/005118.html
So basically no serious manufacturer is considering wheel motors for the near future. I suppose they could help the Surf get more trunk space, but it would be at the expense of performance.
I say what Tesla is doing with their liquid cooled motor and inverter (mated to a single speed diff/transaxel) is the best I've seen so far.