Wind turbine on the front of a car.
 

Tell me all the reasons why putting a wind turbine on the front of a car is a stupid idea.
And no I don't want to do it. I think its a stupid idea.
I think this idea ranks up there with putting an alternator in an electric vehicle to charge the batteries as you drive. :rolleyes:

Smokey Yunick did it on a race car but that was only because it had a problem throwing belts.

It seems to me that such a set-up would increase aero drag thus cancelling or more than cancelling out any gains. I had that "brilliant" idea as a kid but my engineer uncle explained why it probably wouldn't work. For sure it would fail bolted on the roof, for example.

Someone recently suggested putting one in the engine compartment, an already draggy place with lots of airflow(?). I think it would either still increase aero drag but maybe not enough to notice. And/or it might not spin enough, enough of the time to keep the battery charged.

Maybe the answer isn't simple? :confused:

Not actually that dumb of an idea. It actually works if you happen to have a nice, windy dry lake to play on: https://en.wikipedia.org/wiki/Blackbird_(land_yacht)

But for an ordinary vehicle, I think the biggest drawbacks are 1) carrying around all that excess weight when the wind's not blowing; and 2) chopping up other vehicles, pedestrians, and so on with the propellor :-)

A sail would look better.

FYI:

Ram air turbine
https://en.wikipedia.org/wiki/Ram_air_turbine
https://upload.wikimedia.org/wikiped...-F-105_RAT.jpg

From the same link:
https://upload.wikimedia.org/wikiped..._%28Can%29.jpg
Again the same link as sourced:
https://www.flickr.com/photos/bernd2011/7759518858
http://forums.pelicanparts.com/uploa...1446497270.jpg

Airbus A380
http://a380flightdeck.tumblr.com/pos...am-air-turbine
http://forums.pelicanparts.com/uploa...1446497289.jpg
http://forums.pelicanparts.com/uploa...1446497311.jpg
An engineer would have to do the math for me, but I suspect for cars direct to the engine is going to be most efficient.

However, maybe if you are far from the main power source as with a train car or a caboose, and have a power requirement while underway, then it might make sense. Then again, train cars have wheels and axles, which could be mechanically/parasitically drawn upon for generator power, right?

I don't think it's a stupid idea. Expecting it to work anywhere but parked facing into a headwind is stupid.

Lots of ways to recover energy normally lost in braking. The best is to not brake in the first place.

regards
mech

Underway, or not underway, this 4x4 RV has roof mounted solar panels.

EarthCruiser FAQS- Questions we want you to ask….. | Earth Cruiser
http://earthcruiser.com/wp-content/u...d-Oregon-7.jpg

The RAT will give way to solar panels in most automotive use applications I suspect.

Around 2000, Popular Science / Mechanics had a small write up on an electric van with a fan on the roof. ( It was mounted horizontally. )
The blades were designed in such a way that they would fold flat as they turned, thereby reducing drag.
They claimed that even in a parking garage, the wind would turn the blades.

So agreed - not such a stupid idea after all. I wonder what became of the prototype though.

wind turbine
 

*The mechanical efficiency of the turbine would around 80%.
*The mechanical efficiency of the generator might be 98%.
*Combined,for every 746-Watts of power extracted,you'd have to overcome 964-Watts of drag for the turbine alone,then add in the drag of the nacelle,supporting strut,interference drag at the attachment interface,plus you'd be driving in the turbulent wake of the turbine; of which it's kinetic energy could never be converted back to useful pressure,disturbing local body airflow,increasing the car's overall aerodynamic drag.
*Think of a side-view mirror the size of the rotating disc of the turbine!
*It could be the poster child for Entropy.:p

Under the hood might show some promise. To some degree it will act like a like a grill block.

If you want to seriously look at this its being done you are looking at the wrong end of the vehicle.

C-pillar vortices are the scourge of car aero dynamics. Not only could you recover energy from them but in doing so you could reduce drag as well. Nasa did a study on generating power from wing tip vortices and showed they could also reduce drag.

Also of note I remember reading of a study done on adding a horizontal rotating drum like structure behind a car to generate power and improve aerodynamics.

Not so - see the link I posted. Under the right conditions, you can extract more energy from the wind that it takes to propel the vehicle. Of course that's actual wind, not relative, so it doesn't work in calm conditions. Otherwise, how's it logically different than powering a car hooked to a stationary wind turbine?

Put it in the exhaust, its called a turbo.
New F1 cars use their turbos not just for power but they also generate electric power that is stored for later use.
These F1 cars are amazing hyper-hybirds.

Vertical axis FTW.

http://www.tuvie.com/wp-content/uploads/flow1.jpg
Flow – Wind Solar Energy System | Tuvie

Variable pitch blades made from compound curved photo-voltaic panels. If this isn't happening, it should.

A wind turbine on its own is a silly idea, certainly.

But if you connected it via a propshaft to a propellor at the rear of the vehicle, then I think you'd be on to something.
You could put a gearbox in between and drive the rear propellor at a suitable speed for conditions. You could put it in reverse and get a braking effect!

One time I was researching Prius battery replacement and I found some comment that regenerative braking was only the beginning, they needed solar panels, wind turbines, and some other bit of perpetual motion. As I recall, Toyota said "Solar panels are not cost-effective on a car."

"Shut up and take my money!"

"Toyota is pleased to announce rooftop solar panels!"

Someone told me that solar cars were as feasible as wind-powered ones, although didn't the A Team make one of those? :)

As always, it seems the pick up truck is always the best starting point t for wholesale improvements.

One idea would be a pop up turbine that charges the battery overnight (ie when solar won't work), and folds flat in transit.

Another idea is to harness the swirling air motion behind the trucks cab- the separation bubble- to power a water wheel like device. Might even improve drag.

Sky Stream used to sell a 30 tall tower, they said "it spins" but it wasn't high enough to produce a usable amount of energy.
A tilt up tower on the vehicle is going to be heavy and near useless as most vehicles are not heavy enough to keep a useful sized tower from tipping over.

There are several models of motor glider whose engines for takeoff tuck away very neatly into the fuselage. You could potentially hide away the turbine very neatly.

One problem with the idea is liability. It only takes one fool with incautious fingers to hit you with a lawsuit for getting their hands all blenderized in the parking lot.

I looked up the inventors name and got additional images.

Flow intends to flood your dens with alternative energies | Designbuzz : Design ideas and concepts
http://www.designbuzz.com/wp-content...PLW9d_5784.jpg
http://i0.wp.com/www.designbuzz.com/...5784.jpg?w=474
This is not the low profile top of a van style generator I first thought it to be, in fact the workhorse of the design is what's underneath once projected up into an air-stream.

Bring tent stakes/weights for the guy wires.

The bottom line is the same as with solar panels: if you have $X to invest in wind turbines, solar panels, or whatever, it's much more cost-effective to put them in a good location where they can generate whenever the wind's blowing or the sun's shining, than to put them on top of a vehicle where they have much less than optimum exposure to their power source, plus you have to burn energy to haul around the extra weight.

I was trying to find more info on that EV with a fan on the roof.
Google didn't help much :
http://archive.delawareonline.com/blogs/fan.jpg

Thanks. That's interesting in a different way. I was thinking the top part rotates and it could have cyclic pitch for the solar and collective pitch for the wind.

But this is more like Bucky Fuller's call for indoor windmills. If the PV vanes were pitched cyclically [following wind direction] and it sucked air up through the unshrouded bottom half, it would substitute for the conical rotating vent [as*] used on the 1947 Dymaxion house.

I think I like it better.

Edit:
*An indoor windmill wouldn't be appropriate for a house, it would be a little breezy. But a greenhouse could benefit from a strong breeze. A low arch dome would maximize both planting area and the lift from wind load that would translate into harvestable power.

Not a good idea to have a rotating mass on the end of a pole. Better to mount it tangent to the surface of a geodesic. The concentric rings resist the vibration.

2nd Edit: http://www.yigang-design.com/ is nothing but an inducement to install Flash™. As if.

more
 

The article I looked at was about a turbine-propulsed vehicle running downwind,which would not be germane to a discussion about a turbine generator on the front of an I.C.-powered car.
*Turbines cannot have over-unity efficiencies when extracting work from a working fluid.
*Generators cannot have over-unity efficiencies when converting shaft work to electrical power.
*The theoretical maximum mechanical efficiency for a turbine is in the 80% range.
*The turbine nacelle will add drag
*The support structure which holds the turbine unit in the airstream will add drag.
*The amount of energy harvested from the turbine will always be less than the energy entering the system,or you're violating the 2nd-Law of Thermodynamics and into unicorn territory.

What if you were driving into a headwind? Theoretically couldn't you add more power then it cost from weight and drag?
Then of course you would need a big spinnaker for the other direction. We need wider roads so we can tack as well.

Actually I just watched a different blackbird video that shows the physics. I may need to eat my sarcasm
http://www.wired.com/2011/02/ff_fasterthanwind/

Certainly it's germane. It is a working demonstration (and of the most extreme case) of the fact that you can extract energy from absolute wind, even in instances where "common sense" suggests you shouldn't be able to. Thus a car with a turbine generator (and it's irrelevant whether it's on the front, back, or in the middle) could in principle extract energy in excess of the drag it adds, as long as you're driving in windy conditions.

One of the world’s four largest sustainability races – Een van de vier grootste duurzaamheidsraces ter wereld | Every august at the Sea Dyke in Den Helder, (inter) national student teams race against the wind. The world record is 96,91%,

Not very practical for everyday use, but it seems to be possible.

in excess
 

I went into my fluid mechanics text.I was wrong about the numbers I shared.The theoretical maximum efficiency of a wind turbine is 59.3%.
The text reported that in actual practice,the efficiency rarely exceeds 40%.
Wind is free,so there's an engineering 'disconnect' with respect to 'fuel cost',and fuel economy'.
When the automobile's engine must create all the 'wind energy' for the turbine to extract it's portion ,we run smack dab into the 2nd Law of Thermo.
There are sail effects associated with automobiles,given certain relative wind spectra.It's been known about since around the 1920s.But it occurs at very low driving speeds.Lower than motorists would put up with.And we have no control over wind speed and direction.
And as far as I know,contemporary wind turbines simply orient their turbine blades into the wind.
Reaction turbines have exotic,streamlined stator turning vanes to guide the flow onto the turbine blades.
The larger the turbine,the more efficient,due to the relative leakage proportion around the blades.A small,ducted,'internal' turbo-generator would suffer this inefficiency.
If you've got some peer-reviewed scientific paper which illustrates how we go from 59.3%,to 100+% efficiency with a turbine electric generator 'd love to see that.:)

practical
 

If the Montreal team's Chinook ETS was racing into a 5.5 m/s wind,we're talking 11.7 mph for the car.

Why do you need to get 100% efficiency? (Let alone more than 100% :-)) You just need to extract more energy than is needed to overcome the extra drag. And as the examples show, it IS possible to do that, just not practical for daily driving. Rather like the solar cars racing across the Australian Outback.

Perhaps it would help you to abstract this a bit.

Remember in school all of those math problem solving exercises?

The ones where there was a bunch of stuff on the left side, and bunch of stuff on the right side, and an "equal sign" in the middle.

That equal sign was pretty important wasn't it?

Why was that darn thing there anyway you probably asked yourself over and over and yet nobody could give you a satisfactory answer.

What I think aerohead is saying, is that to solve for this problem, both sides of your equation have to equal each other, or complement each other in some way. You cannot have an unequal equation, gotta account for everything or you missed something.

Inequalities ppt revised
http://image.slidesharecdn.com/inequ...?cb=1358931329

Perhaps if someone wrote out an equation showing the energy into the system (power generated), energy out of the system (power used; air drag, rolling resistance) which included the wind turbine as a factor we could all visualize this in a simplified manner and know which category to put things in.

Often defining the problem leads to solving the problem.

In other words, if you cannot define your problem, then you have little hope of solving it.

Identifying the problem is key to it's solution.

You cannot hit what you cannot see, so stop squinting so hard.

BS in Math & Physics, graduate degrees in computer engineering, so yes, I think I have some notion of what an equation is :-)

I think what you're overlooking here is that the (100 - 59.3 = 40.7)% (see, there's an equation for you!) isn't all, or even mostly, going into drag. It's just passing through, uncaptured. Which, when you think of it, is pretty much common sense, since if a turbine captured all the energy from wind, the air would stop moving, and it would be perfectly calm directly behind the turbine.

you just need
 

*The wind-powered race cars are traveling at 11.5-mph.
*At this velocity,the car is at sub-critical Reynolds number.
*A 'real' automobile cannot operate at a sub-critical Reynolds number due to the turbulent boundary layer of Earth in which it is traveling.
*'Sail' effects are the reason the wind-powered race cars can move into the wind.
*The turbines on the race cars are gimballed for yawing,to take advantage of relative wind - induced lift/thrust.
*On the front of an automobile,at the forward stagnation point,embedded within the grille area (?),the Prandtl lines of discontinuity in the streamlines would preclude the turbine from relative wind affects,required to produce the thrust present in the race cars.
*We'd be limited to a standard,garden-variety mechanical efficiency for the turbine.
*In traffic,it would be virtually impossible to produce any power,and you'd be relying on battery-alone,which would have to made made up when back underway.
*A conventional belt-driven,shaft-driven,or flywheel-mounted alternator is electrically as efficient as a wind-powered generator,minus drive losses where applicable.
*The mechanical efficiency of a V-belt,cog-belt,serpentine-belt,etc. exceeds the efficiency of a wind turbines ability to harvest energy from the passing air mass.
*On a calm day,the engine in the car would have to produce all the 'wind' for the turbine,and even with a Diesel TDI,we're talking 43% thermal efficiency,to make wind for a turbine which is 59.3% efficient.
*Now we're down to 25.5% efficiency for the electricity,about as efficient as a trash incinerator.
*I'm uncertain as to the minimum velocity of the air column necessary to even begin power generation with a turbine of such small diameter.
*The turbine sections of turbochargers in a 2016 Ford Shelby Super Snake Mustang might be looking at 280-hp worth of hot gases at their inlet.
*The accomplishment of the students,racing into the wind must be taken in view of a very contextual operational environment.

Pretty much true (though some of it is beyond my expertise), but it all seems to add up to just what I said: It is technically possible to do this, just as it is possible to have solar-powered cars. It's just not practical.

PS: FWIW, the current (AFAIK) record speed for a wind-powered car is 126 mph, though with an airfoil "wing", not a turbine. Land record challenge

Considering the above, me thinks it's time you put all that education to use and show some mad math skills.;)

Some thing along these lines?

Calculating the Coefficient of Drag - Urbee Example | Sustainability Workshop
http://sustainabilityworkshop.autode...g-Equation.JPG
The formula would need to be added to and modified a bit, right?

Prove to us that you can make this (compact turbine generator) mathematically work.

Maybe this is why such things are called "proofs".:cool:

You know, you have things exactly backwards. There are, in the posted links, working physical examples. (Although, as I keep saying, not in practical daily-driver conditions.) So if your equations say they can't work, then either your theory or your math is wrong. "Eppur si muove."

possible
 

Brent Singleton,of Ogden,Utah has a 'Quadbrid' Ford Escort (hybrid,solar,and wind-powered) that he pulls a hybrid LSR racer to Bonneville with.
He uses two wind turbines to help charge with.They're not mounted on the vehicle,and they're not duct-augmented,but he is harvesting power with as modern a technology wind plant as is commercially available and will fit in a car.
He's been at it since age 14,racing for public awareness:International Alternative Fuels Racing Association,International Alternative Fuels Racing Association.
Brent's is enjoying some of the fruit the race teams in the Netherlands have been sampling.:)

Think about this: a "feathered" propeller doesn't rotate, but with added pitch, that same propeller then "wind-mills" and starts its engine...non-aero AIR flow has power. Thus, hanging a wind-powered generator is little more than an "useful" aero-drag device, an electricity producing "brick".

I agree! I wonder if they read this link. I know it is long but it shows they proved the physics 99% of people thought was impossible was in fact possible.
One Man's Quest to Outrace Wind | WIRED
In a 15 mph wind he went 46 mph directly downwind! It seems like a magical energy machine but read the whole article and watch that CGI video in the middle. It really blew my mind.