Video.
I've been wondering for a while why we've been stuck for so long with such vulnerable wheels. Probably because those flexible spokes (and hub) requires some pretty dang advanced materials if they are to be durable and keep their strength. I wonder what they're made of.
I also wonder why they think it will take 10-15 years before they are available for high-speed vehicles like personal cars. That seems to be unusually pessimistic. I'd have thought that prediction is no better than you'd get either "perhaps impossible" or "within five years".
Update: thinking about it, I think it's a little disingenuous that they start the demo/video with a high-speed car, when the product is not likely to be viable for such cars for many years yet.
This guy says he has the solution, with spokes that stretch too.
17 comments:
I was looking at something similar in "Off Highway" magazine a few months ago, but for construction vehicles. Looking around it probably was a Tweel.
I had heard about these a few months ago but hadn't seen any until this Saturday. They are kind of weird looking but won't seem so when there are more people out there. Like you I wonder what took so long.
What did you see them on, and where?
"I also wonder why they think it will take 10-15 years before they are available for high-speed vehicles like personal cars."
Let me ask you a question: how long do you think it would take before some inept driver trashes his car and ends up in court blaming it on some design flaw of the Tweel?
The matter is incredibly complex when you look at it from a safety & legal standpoint. In fact, this is true for any change envisioned to any one of a car's sub-systems that can potentially affect safety.
For example, power assisted brakes rarely fail, yet all braking assistance systems are add-ons to a conventional braking system. Not because it would be impossible to do otherwise, but because this is the accepted way of doing things. The logic behind this add-on philosophy is that, should the engine fail, you have to be able to brake anyway. The thing is, cars are now driven routinely at speeds and performance levels that far outperform the unassisted braking power provided. Also, this does not protect you in any way from a primary brake system failure, which is way more common than assistance system failure. But should one dare to remove the conventional "safety" feature, he would then be exposed to claims from anyone, justified or not.
It takes very strong motivation, usually of the economic kind, before anyone will challenge such thinking. For example, a few years back Airbus shocked the world when it announced that it was designing a fly-by-wire aircraft, the A320. Boeing & the like all shouted that nobody in his right mind would dare to fly an aircraft in which the yoke wasn't linked directly to the control surfaces (ailerons). Look at today's picture: they all build fly-by-wire aircraft. Why? The safety case was made for them by Airbus. Plus, today's flying leviathans would be impossible to control via human force anyway. The engineers at Airbus simply showed that they had a clear vision and understanding of their field, but they still had to carry the burden of demonstrating that their approach was just as safe, if not safer than the old way of doing things.
The same applies here with the Tweel. Before putting this in the hands of the general public, Michelin (or anyone else for that matter) will have to build a strong case to support their safety claims. This is best done in limited markets where the evaluation and perfecting of the technology can be done in a somewhat controlled fashion.
Even if you were ready to sign a discharge to Michelin waiving your rights to ulterior recourse (which waiver just about any court of law would invalidate anyway), it could not work because you would be endangering the safety of other public road users.
There is also a more subtle problem here. Nowadays, almost everybody is convinced that he/she is a good driver, certainly capable of handling any regular automobile. Cars have become so easy to drive that this claim is almost true, indeed. But this holds only within a fairly restricted range of operational parameters. In other words, sure we can drive any car, but the car is expected to behave in a certain predictable way under a variety of road and climatic conditions.
For example, when front-wheel drive cars were widely introduced in the early 1970's, numerous fender-benders were caused by the fact that the front of the car unexpectedly started skidding sideways under icy road conditions. In fact, I have never really gotten used myself to the idea of stepping on the gas (instead of letting go) when I start to lose control (on ice). It is plainly unnatural... but a few generations of drivers have since learned to drive with those cars (in fact, most new drivers have never known anything else), and these accidents are now fairly rare.
The transition to front-wheel drive took place nearly 40 years ago. Nowadays, with the American justice system being more and more confused with a lottery scheme, such a change would be far more perilous for the adventurous auto manufacturer. And btw, the shift was not motivated by performance reasons. In 1975, a front-wheel drive car was estimated to cost around 400$ less to build than a traditional rear-wheel drive. And yet the auto makers were successful in convincing many people that the new system was superior, and therefore was worth some extra money... To those who still buy into that load of BS, I'll simply ask why all (real) luxury cars still have rear-wheel drive power trains?
Back to the tires. My first impression, just by looking at a few images and videos, is that the road handling of the Tweel must be significantly different from a radial tire in extreme driving conditions, and perhaps even not-so-extreme ones. For the better or the worse remains to be seen, but that's besides my point here. It suffices that it be different to make it dangerous to introduce such a device in a market where the typical macho driver (and I include many young women in this group ;) won't care to admit that caution may be warranted while "learning" new tires...
Ten to fifteen years? Minimum. Progressive acceptance is key here, and unless the tires can be made to handle exactly as radial tires do, the introduction into the general market must take place in a progressive and controlled fashion, in order to allow for the public to be properly educated. I am positive that bean counters would like this to be a lot quicker, but I wonder how many beans they are willing to lose in the process?
As for the Super-Tweel, well, it sure looks like you should be ready to bounce around a lot. For tall drivers like me, a helmet probably wouldn't be a bad idea. And busty gals might consider reinforcement in strategic areas... ;-)
Thank you very much. Many interesting points.
"a few years back Airbus shocked the world when it announced that it was designing a fly-by-wire aircraft, the A320. [...] Plus, today's flying leviathans would be impossible to control via human force anyway."
I'm confused, the Boeing 747 is nigh 20 years older than the A320, and it's huge. So it must have worked well with mechanical/hydraulic controls, somehow. Not better than fly by wire, for sure, but not impossible.
The Boeing 747 is a good example of what I was saying, actually. The flight controls are built like a car's braking system. You have a traditional direct (hydraulic) linkage between the yoke and the control surface actuators, but an assistance system is provided to ease the effort required to fly the plane.
There however have been many discussions as to the usefulness of this scheme in the case of the 747. Apparently, in at least some configurations of the aircraft, it would be impossible to control the plane well enough to perform a safe landing without power assistance.
The A320's emergency backup system might look ridiculous at first sight, but has proven to be effective. It is composed simply of a small turbine that pops down under the plane in the event of total engine failure. This generator provides enough electrical power to maintain control of the aircraft, as well as basic navigational capabilities.
Simple, lightweight, effective, and way better than the old system in the end. But that had to be demonstrated, and I'm sure it was no easy feat to do so.
What did you see them on, and where?
I'm afraid I'm not very good at identifying cars, knowing little about them. I had just pulled into a 7-11 and turned and saw one going down the street. I got a good enough look so I'm certain it was the real deal. I was very surprised because to be honest I had not expected to see any at least not for quite some time. This was in Toronto, Canada.
Maybe I should carry around a little digital camera on the off chance that I see it again. The person might live in my area.
Get one with image stabilization. The new Ixus (Elph) Canons are amazing.
Bert, I like the turbine solution. Brilliant.
Man, it looks primitive and fragile though!
http://en.wikipedia.org/wiki/Ram_air_turbine
"Man, it looks primitive and fragile though!"
Well, it's a safety system, not a showroom component. On most aircraft built, it will never be used, so there's little point in making it rugged and capable or withstanding thousands of hours of operation.
A guaranteed 10-hour lifespan would be a more likely design spec. It is also likely that the turbine is periodically replaced or rebuilt (every time it is deployed anyway), but that's chump change compared to the alternative amounting to loss of the aircraft with all hands on board...
Oh yeah, I was just giving my emotional reaction for the joke of it. I'm sure it's more than capable.
Aren't bigger cars RWD because of issues with stress on the transaxle? Compact cars benefit from the transverse mount engine with FWD as you can get more into the engine compartment, and less intrusion into the small passenger compartment. Heck even vans like the ford transit are benefitting from space saving of FWD, especially in specialty vehicles where a lower floor is needed.
The handling ability of FWD vs RWD was very apparent in auto racing. No serious rally contenders were RWD, and FWD dominated until 4WD appeared in some Mitsubishi then Subaru.
Again power in performance cars, rather than rice rockets and hot hatches, is still delivered through RWD. You can put more wheel back there, can't steer with those fatter rear tyres, and more power can be delivered through a heavier build prop shaft to a non steering axle.
The other class of racing which has a different need is hill trials, this was dominated by Hillman Imps and VW Bugs as they were good climbers, rear engine/RWD.
One example of speed, elegance and performance in a FWD is the Citroen Avant (15TA etc). These cars soon found a place with both the villains and Gendarme because of their superior handling and performance.
Alex,
Using most race cars series as a reference is biased at best, for racing classes are usually established based on available production cars. In other words, if there were no or only few FWD on the market, all racing cars would be RWD, and there would be just as many advocates for the advantages of RWD.
It is true that FWD technology has greatly improved since its introduction, and today's vehicles do exploit every possible advantage of FWD to it fullest extent. This has indeed brought along some very welcome changes in car design.
Yet, we both know that the mass transfer on the rear axle upon acceleration is very real, and that it is required to exploit this if you are to build heavier vehicles exhibiting decent performance. A FWD Mercedes 500 would be ridiculous, as it would spin its front wheels on any and every occasion.
But I guess that the bottom line would be, given a car equipped with only two integral electric motors (i.e. no drive axle), what would you choose? I definitely would go for a RWD, for the sheer pleasure of the resulting road handling.
P.S. Blogger does it again! I'm not sure I agree, but it claims that "cgiyuck"...
Kool.
CGIYUM.
Like the movies The Golden Compass or Ghostrider, or Stardust, the CGI was clearly the best part about them.
People made a big deal of The Golden Compass for the wrong reasons.
I imagine so. I heard it's sort of anti-religious. (Not that I care.)
I read part of the book, but it didn't keep my interest. I didn't find the characters very interesting.
I haven't read the book or seen the movie. I had just read some of the press and it seemed that a lot of people were making a big deal of it because it was supposedly anti-religious or more specifically anti-Catholic. I don't see what that really had to do with it since it was a fantasy novel and that people were not required to believe that our universe worked the same way. He is an atheist but I don't see how that has anything to do with it. What bothers me about the guy is his criticisms of C.S. Lewis, which included accusations of racism (totally unjustified). It's not because of that that I haven't read his books. Partly it's that I haven't got around to it and partly they do come across to me as being overrated.
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