This would be like an airboat-a car with a large propeller in the back, which drives the car forward, without an engine geared to the wheels.
I suppose that at highway speeds, such a vehicle could be quite efficient, as there is no frictional losses in a drivetrain. Plus, you would not need a transmission (you could alter the pitch of the propeller).
Reversing such a car would be a bit of a challenge, though.
I’d expect that frictional losses in the drivetrain are negligible compared to the inefficiencies you’d have in the airflows. The technique is only used on boats when there aren’t any alternatives, because there’s too much vegetation in the water to use a water propeller.
The helicron, though the propeller is in the front.
If you’re going to use a prop with controllable pitch, reverse is easy - just allow the pitch to be set to negative.
Yep, same way you reverse an aeroplane.
I see a lot of people in my neck of the woods experimenting with these things. They’re souless things that trade style, power, excitement for efficiency and safety. I’m afraid they’ll someday be the only things on the road and it will be illegal to drive a “real” car. Screw that. I bought some deserted farmland a while back, a nice place that no one knows about. I’m going to buy a classic car, restore it, and keep it for my nephew. I’m thinking something in the red family, but not sure what to buy…
Are you sure you’re talking about the same thing we are, here? So far as I can figure, style and excitement are the only reason to build a car like the OP describes.
Some of them, maybe. But IMHO most are just a Rush to some environmental dystopia, where these slow-going, sanitized whooshmobiles are the only things allowed on the road.
I’d take some convincing that they offer any meaningful safety or efficiency benefits. A first look says the efficiency of a propeller compares poorly to that of a simple drivetrain, and whirling blades are definitely something of a hazard. Noise is another safety-related issue.
Wait, Hold Your Fire! Yes, now they are like that. But technology doesn’t stay like that. Doesn’t anyone remember, say, Moving Pictures? Loud, raucous, high-energy. Then, Presto!, things change for the mellower. I guess no one else is picking up on the Signals here, these things are going to be the bane to the driving experience–in their quest for efficiency they probably won’t even have Power Windows…
Not only that, the damn things are often two-lanes wide…
I’ve heard that they will be gleaming alloy air-cars that shoot towards you two lanes wide.
(ETA: Dammit, I type too slow)
Propellers are dreadfully noisy, huge spinning metal things. Like a blender except bigger, and not hidden in a glass jar. For even limited safety they would have to be ducted and screened to prevent soft fleshy things from being … blended. The screen would reduce efficiency. Prop wash tends to kick up a lot of dust and pebbles. I hate my neighbour’s Harley, but I am glad hasn’t put a prop on it.
Low speed acceleration and responsiveness seems to be pretty poor with aircraft. This could be helped by engineering the performance envelope of the prop to be better at ground transport / parking lot speeds. I suspect however, the major issue is that thrust based propulsion systems rely on moving mass, air is low density, and there is just a lot more mass available to move at higher speeds.
Ekranoplans and Ice Boats are interesting variations on the concept.
Might I suggest a Barchetta? Classic lines. Elegant styling. Really just an all around definition of awesome on four wheels.
But don’t rush to a decision. Give it some thought by the fireside.
And how do aircars compare to drivetrains in stopping distance?
Rhythmdvl, if there are people who think that propeller cars will somehow eventually become more green, and are therefore fooling around with them to give themselves eco-cred, those people are what is commonly referred to as “idiots”. Much more likely, the people fooling around with them are doing so because it “looks cool”, and feel very annoyed by people like you who would like to stop them and see to it that the only cars on the road are styleless, soul-crushing drivetrain vehicles.
Place your orders.
http://www.terrafugia.com/
See! As noted by others above, those are clearly gleaming, made from some alloy, and with their wings expanded at least two lanes wide. And that’s no Fly by Night operation, either.
Well, since this is GQ and all, I present the following for people who are baffled by the turn the discussion has taken:
[spoiler]Rhythmdvl and the people responding to him in kind are making reference to the music of Rush, especially “Red Barchetta,” which includes the line about how the hero is being chased by “a gleaming alloy air-car, two lanes wide” while driving an old car his uncle built for him, in some dystopian future where automobiles have apparently been outlawed.
But also the other capitalized phrases Rhythmdvl used, like “Moving Pictures,” “Presto,” “Power Windows,” “Signals,” “Fly By Night,” etc. All Rush music.
[/spoiler]
Thanks, I was too embarrassed to ask.:o