Flywheels come up every once in a while (I remember seeing them for the first time about 20 years ago).... but I wager they'll never become mainstream. The problem is the more energy they store, the more explosive they become.
Same kind of thing with the Dymaxion car (1930) - a 3 wheeled car that could transport 11 passengers @ 30mpg, reach speeds of 120mph and do a U-turn in it's own length. Sounds brilliant.. except what happens when something happens to one of the tires.
Why do you state that when the article linked clearly says: "The cause of the accident was not determined, although Buckminster Fuller reported that the accident was due to the actions of another vehicle that had been following the Dymaxion closely.".
It's a pity investors bailed on the project, it seems like it was well ahead of its time, prototype failures are usually experienced behind the scenes, not in front of an audience that large and I think that they investors probably were on the money pulling out because of public perception, even if they blamed the tech, it was not the wheels that had anything to do with this, but more likely a lack of reinforcement of the main structure of the car.
As for flywheels: http://afstrinity.com/ that company (a merger of American Flywheels and Trinity Power) is probably right at the cutting edge.
Anything storing a significant amount of energy is prone to accidents, from batteries to rocks on the tops of mountains.
Flywheels are one of the few technologies that can store signficant amounts of energy and can be engineered to fail with relative grace, as opposed to say a fuel tank blowing up. Another strategy is to use many relatively small flywheels in parallel, each in their own containment vessel.
This also helps with some other engineering difficulties involving flywheels. Flywheels are ancient tech, at least 50 years old but probably much older, and if you count them as storage devices in a purely mechanical context as well then you can go back in to history quite a bit, about a thousand years.
> Why do you state that when the article linked clearly says:
> "The cause of the accident was not determined, although
> Buckminster Fuller reported that the accident was due to
> the actions of another vehicle that had been following the
> Dymaxion closely.".
For the obvious reason why 3 wheel vehicles have never become mainstream.... If you work with computers you should know about Single Point of Failure. If you are cruising on the highway and get a flat with 1 of your 4 tires it's no Big Deal. How do you think that would figure with only 3.
Or another example. Why so many wheels on an 18-wheeler. Wouldn't it be awesome if a truck could do a u-turn in it's own length? Those things blow out tires all the time. But it doesn't matter because they have 18. SPOF. 3 wheel vehicles will never catch on in the mainstream. They'll only ever be the equivalent of glorified motorcycles - the ultralights on the road.
You could get all the advantages of a tadpole configuration and mitigate the risk of blow-out considerably by using two wheels at each spot side-by-side, that's fairly simple engineering and this is used on plenty of lightweight fly-over trailers.
The tadpole configuration has stability issues though, rolling it over is fairly easy if the vehicle has a high center of gravity.
The Reliant Robin solved that for the most part by reversing the arrangement putting the single wheel in front, but they still tend to overturn quit easily.
The accident mentioned above during the demonstration probably really was caused by that other car, but the ease with which a three wheeled configuration turns over most likely contributed to the severity, and in the long run would have had to be solved using tricky engineering such as a single wheel for low speed maneuvering and two wheels for higher speeds.
the AFS Trinity website only mentions their car with ultracapacitors. Know of a link where they're working with flywheels?
And I feel I should point out that the accident of the Dymaxion was in a prototype with a canvas roof. The death of the driver is probably the main reason it was abandoned at the time, that's pretty bad PR-mojo.