improvement on solar-powered cars?

I haven't been paying much attention to the research being done in the field of solar-powered cars, and know nothing about auto mechanics, electrical engineering and the like, but for some odd reason a few days ago I got to thinking about that solar-car competition held annually by a number of big engineering schools across the country. Results tended to be lackluster, from what I recall, and I got to thinking about something:

Would it be helpful to add a small wind turbine?

The way I see it, you're always going to get wind resistance while driving, so why not take advantage of it? The windmill could go behind a grille under the hood (sizable port in front required, I know) and follow current auto-body aesthetics. Making it more marketable if the mechanics are viable.

Of course, I'm sure that someone else out there more qualified to think about these things practically has already come up with the idea, tested it, found it doesn't work, and put it behind him/herself like so many other bad ideas. I just had to get it off my mind. what do you guys think about my idea?

I like it!!!

Problems:

Adds weight. Especially with the generator.
To produce enough power to be worth anything, you're going to cause a lot of extra drag. Meaning that you'll be using power to create power.

Turbines/Props create a LOT of drag. In aircraft, if and engine dies the prop has to be feathered (the blades are turned so the "sharp" edge is into the wind- minimal drag), otherwise performance takes a drastic hit.

Solar cars could probably make good use of the braking systems like hybrid cars have, though.

Originally posted by Speedo
To produce enough power to be worth anything, you're going to cause a lot of extra drag. Meaning that you'll be using power to create power.

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It's worse than that. By the second law of thermodynamics (no perpetual motion machines) you would be losing energy if you tried this. Assuming there is no head wind, the motion of the car is what is causing air to move past the blades. That kinetic energy is converted into electrical energy, that is sent to the wheels' motors to create more kinetic energy that is transferred back to the blades, ad infinitum. In each energy transfer you lose efficiency, so you would actually lose energy in this circular process.

Wind generators work because they are stationary, so the kinetic energy is supplied by an outside source - the wind.

why not just put a sail on the car. it would proly be a more efficient way to use the wind anyway and you could make the car lighter by getting rid of all that solar power stuff.
maybe leave a small panel to power your radio and headlights

1. Power lines
2. Trees
3. No wind = no go.
4. Weight. Even a small, one person car (not just a seat with wheels, mind you) using all possible composite materials would probably weigh at least 4-500 lbs after you add the driver. It'll take a lot of wind to move that up a hill.

Originally posted by RoddyVR
why not just put a sail on the car. it would proly be a more efficient way to use the wind anyway and you could make the car lighter by getting rid of all that solar power stuff.

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Can you imagine rush hour with 3 million sailboats on the road?? The economy takes a terrible hit when theres no wind for a few days and nobody can get to work

Originally posted by Dumb pothead

Can you imagine rush hour with 3 million sailboats on the road?? The economy takes a terrible hit when theres no wind for a few days and nobody can get to work

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This isn't a problem. We can cut out the bottom of the cars and use foot power, like the Flintstones.

or just put big turbines on the roads to MAKE the wind. then there would actualy be a LEGITIMATE USE for road tax and tolls.

Originally posted by Speedo
1. Power lines
2. Trees
3. No wind = no go.
4. Weight. Even a small, one person car (not just a seat with wheels, mind you) using all possible composite materials would probably weigh at least 4-500 lbs after you add the driver. It'll take a lot of wind to move that up a hill.

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Don't forget about overpass clearance.

Yeah, I was wondering how much a windmill would weigh if you could fit it into a car. I figured it would weigh about the same, perhaps only a little more than an average V-12 engine, which I understand weighs quite a bit (like I said, I know next to nothing about cars, electrical engineering and the like). Not to mention I was also forgetting that you would be losing power with such a system, as Pirate pointed out. Of course, I had meant it to be supplementary to the solar panels, not replacing them totally. Though I imagine that would just add even more weight, and be a bit redundant to boot now that I think about it.

Originally posted by Martacus

...Not to mention I was also forgetting that you would be losing power with such a system, as Pirate pointed out. Of course, I had meant it to be supplementary to the solar panels, not replacing them totally. Though I imagine that would just add even more weight, and be a bit redundant to boot now that I think about it.

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I didn't mean replace them either. They would still sap power instead of supplementing. You would be taking power from the wheels to move the car to drive the turbine to power the wheels. It's a losing cycle. Just leave the power in the wheels in the first place.

Regenerative braking is a good idea, however.

I'm the current president of the team that won the Stock class in that solar race Martacus mentioned, and we've considered most of the stuff you guys listed. It's a great engineering achievement, but face it, solar cars will never be practical. The area needed to hold enough cells to provide equivalent power to a gasoline engine is far too massive. Current tech gives at most ~15 hp in 8 sq meters.

Regenerative braking is used extensively, and is actually quite easy to implement. I know at some of the commercial electric cars use it.

While onboard power generation probably won't go to far, battery technology is advancing to the point where we can plug in a car overnight and then drive all day. They're still expensive, but that's the way things should go.

If you want to learn more:
www.sunsetters.org my team
www.americansolarchallenge.org cross country race
www.formulasun.org closed course race

Wind resistance means.... er... wind resistance

If you put that on a car, it won't be able to go 35 miles over the speed limit. No one will want to buy it