Toyota Investigating Hovercars

cartechboy writes: Remember back in the day when we all thought we'd be driving flying cars in the future? Well that clearly didn't happen, though it still might in the future. But somewhere inside Toyota there's a team of engineers who think hover cars might be a thing, and apparently there's a project underway at one of Toyota's "most advanced" research and development areas. We aren't talking Jetson's flying car, more like a car that merely hovers "a little bit away" from the road. Probably a few inches, with the aim to reduce road friction. With no wings or ridiculous speed, this is probably no simple process. No one really knows how long Toyota has been working on the idea, or how far along it is. Basically, don't expect flying Priuses any time soon...

Comments

aka

[GoddersUK]

small hovercraft.

this is probably no simple process

Surely the underlying technology required is essentially what's already been developed for hovercraft, which already come in car sized variants. Don't get me wrong, I'm not saying it would be easy to stick a car body on them, develop intuitive controls and stick them on public roads; I'm just not sure the technology is as novel and underdeveloped as the summary makes out.

Re: aka

[Rei]

That's not true. It varies from vehicle to vehicle and between driving profiles, but it's usually 50-75% of the resistance at highway speed coming from aero drag - not 95%. Rolling drag remains a significant loss factor at all speeds.

That said, this doesn't sound to me like the most logical approach to tackle rolling drag - wheels are more efficient than hover as-is in most general-use cases, and I can easily envision a lot more that could be done. For example, you could use very high pressure (120+ psi) tires with a hard, thin central tread, relying on automatic camber to a thick, sticky side tread during accel, braking, cornering, or when traction control kicks in (the additional vibrational load from cruising on high PSI tires could be canceled with, for example, a cable vibration isolation system or active vibration cancellation). Such a system should be able to approach the rolling coefficients of hard steel wheels (a tenth that of traditional car pneumatic tires - effectively rendering rolling losses irrelevant). Heck, if you're going to that extent, it's not much further to go all the way to completely solid wheels (though you'd want foam-core carbon fiber or similar to keep the weight and in particular unsprung mass down, not solid steel) and not even have to deal with tire inflation or puncture risk. So long as you have a way to automatically shift to a thick, sticky tread as needed based on current traction conditions and have a mechanism to soak up the higher vibrational loads to maintain ride quality, you're fine.

Is that a pretty huge deviation from standard practice? Yeah, by no small amount, it's literally reinventing the wheel. But you know what, it's also a pretty huge deviation to have cars outright hover on the highway. ;)

But yeah, you're right in that rolling losses aren't the *primary* loss mechanism on the highway. A lot more has to be done to tackle aero drag, and that's trickier - not least of which because the optimal shape varies based on speed and things like crosswinds (and the more you optimize your shape, the bigger of an issue this becomes). One of the more clever ideas I've seen - I don't know how it'd play out in the real world, mind you - was Aptera's plan to take a page from Gerald Bull's playbook and fill in the low pressure wake with air ducted in through the cabin. There's also a fair bit of research designed for aircraft (where aero drag is an even bigger issue) that could translate to cars, for example, skin textures or microstructures designed to maintain laminar flow or reduce surface drag. One of the more exotic variants of that which I've seen is a taut film outer-layer over a microscopic layer. The film vibrates in the wind between its ridges, setting up standing waves which separate the laminar flow from the surface, reducing the flow speed in contact with the surface and thus reducing direct surface drag. There've been peer-reviewed papers on it, and one of the researchers founded a company that now makes kits to reskin a variety of small aircraft (not very many thusfar, the skin has to be custom designed for each model). That's of course just one example among many, it's a very active field of research, as even a fraction of a percent reduced aero drag on a commercial airplane results in massive fuel savings.

Honestly, I'll be happy if we can just get people's style preferences to shift away from naturally high-drag forms like those ridiculous oversized front-end things where you can barely see over the hood. I know I'm out of the mainstream, but I love the look of aerodyamics. Real aerodynamics, not counterproductive curvy features that a lot of people think are "aerodynamic" but actually raise your drag. I want my car to look like a wingless plane, a car that cuts through the air like a knife rather than a clobbering oaf shoving it all around as it drives by ("Excuse me air, coming through, excuse me, sorry there!"). I want a rounded front end and a rear end that tapers vertically down with as long of a t