Fully Electric car with wind generators

[gearhead]

I'm pretty sure someone somewhere has already built one, I've gone over the concepts involved and it does seem both practical and possible. The idea is this: electric-powered car that is recharged by several wind-generators(essentially fans on the roof) that recharge the batteries once the car is driven up to speed. Yes i do realize that any energy that is being used for recharging the batteries by the generators is how much extra the motor will have to work to overcome the drag(and consequently using battery power), but as long as the generators are generating enough power to equal what the motor is using to sustain constant speed, then the car could in theory run almost forever, right? The only situations where you would be draining the battery and not recovering the charge are: accelerating and going up hills, and of course, any power lost through heat given off through the wires(no electrical system is 100% efficient). Yes the batteries would eventually die, but you could always recharge them and you'd probably get at least hundreds of miles before you ran out. Any ideas why these kinds of cars aren't being marketed?

 

[mgb_phys]

Any ideas why these kinds of cars aren't being marketed?

The 2nd law of thermodynamics?

(in before the lock!)

 

[negitron]

Because it won't work, that's why. The only energy the generators will produce is entirely offset by the drag on the fan plus systemic losses, such as friction and generator electromagnetic losses. It's a net loss, overall.

 

[gearhead]

yes i realize that it's a net loss, but you'd still probably get at least 40 miles or so on it before batteries died, right?

 

[negitron]

You don't understand. You will ultimately get FEWER miles out of your batteries with your fan/generator than you would without it, all else being equal.

 

[gearhead]

allright, thanks for clearing that up for me, another question: could a similar system work in a hybrid? For example, let's say that you have a generator that produces 5hp at highway speeds to recharge the batteries. 5hp to a 100hp engine is not that much extra power for it to output and therefore doesn't consume too much more gas. Would this be practical or is it subject to the same impracticality?

 

[negitron]

Same problem. Ultimately, all the vehicle's forward motion comes from it's engine/motor and anything you do to try to recover that energy, be it a fifth wheel driving a generator or a wind turbine, places an additional drag on the vehicle and results in a net loss due to conversion losses

 

[Danger]

Given the malicious perversity of mechanical systems, I suspect that any actual losses would be even greater than those which would be calculated mathematically. Machines are out to screw us any way they can think of.

 

[berkeman]

I'm pretty sure someone somewhere has already built one, I've gone over the concepts involved and it does seem both practical and possible. The idea is this: electric-powered car that is recharged by several wind-generators(essentially fans on the roof) that recharge the batteries once the car is driven up to speed. Yes i do realize that any energy that is being used for recharging the batteries by the generators is how much extra the motor will have to work to overcome the drag(and consequently using battery power), but as long as the generators are generating enough power to equal what the motor is using to sustain constant speed, then the car could in theory run almost forever, right? The only situations where you would be draining the battery and not recovering the charge are: accelerating and going up hills, and of course, any power lost through heat given off through the wires(no electrical system is 100% efficient). Yes the batteries would eventually die, but you could always recharge them and you'd probably get at least hundreds of miles before you ran out. Any ideas why these kinds of cars aren't being marketed?

When I was about 11 years old, my dad found me cutting the bottom off of a coffee can for a project. He asked what I was doing, and I explained how I was going to mount two propellers on a shaft in the can, with the top propeller at one opening, and the bottom propeller at the bottom opening. I was going to put a harness on it so I could wear it like a backpack, and then when I spun up the propellers, the top one would provide the thrust, and the bottom one would recover the thrust and keep the top propeller spinning. I was looking forward to flying around like the jet-pack guy I'd seen on TV (dating myself here).

My dad sat me down and patiently explained why perpetual motion machines don't work, and how real jet engines do work, etc. I was disappointed, but it sure helped me understand the world better.

Does that help to answer your questions?

 

[gearhead]

yeah, thanks. funny story.

 

[falinx]

hmmmm this guy seems to have filed a patent stating you're all wrong :)

http://www.freepatentsonline.com/5920127.html

burn hiiiiiiiiiiiiiim
ha ha

however that one looks good but the one from the 70's will really help you pull chicks:

http://www.freepatentsonline.com/3876925.html

 

[Buckethead]

Interestingly enough, I saw an picture in Sci-Am of a proposed ship that had 2 giant wind turbines mounted where sails normally would be, and these would supposedly power a motor directly that turned a propeller, but once the math was worked out it turned out that just using sails would make a much faster ship.

 

[RonL]

Until just a few years after 1492 it was a well known fact that the Earth was flat.

At some time in the near future, someone that doesn't know any better will likely have an idea that makes use of that mean old friction and law of motion. Behind some brick wall is a better idea.

I wonder what Columbus would think of the fancy sail boats moving around the ocean today.

 

[mgb_phys]

a proposed ship that had 2 giant wind turbines mounted where sails normally would be, and these would supposedly power a motor directly that turned a propeller, but once the math was worked out it turned out that just using sails would make a much faster ship.

Sails are very efficent - assuming the wind was in the right direction.
The wind turbine ship doesn't have to tack to maintain a course, tacking a 400m container ship through the English channel would be interesting.

There is an intermediate solution that has been tried - a giant parafoil kite deployed in front of the ship.

 

[mgb_phys]

Until just a few years after 1492 it was a well known fact that the Earth was flat.

No it wasn't, nobody thought the Earth was flat since they stopped hitting each other with rocks. The diameter of the spherical Earth was measured 2000 years before columbus.
The "they thought the Earth was flat" thing was made up by Washington Irvine to show how primitive and superstitious Europeans were compared to educated high tech scientific Americans (how times have changed).

 

[RonL]

No it wasn't, nobody thought the Earth was flat since they stopped hitting each other with rocks. The diameter of the spherical Earth was measured 2000 years before columbus.
The "they thought the Earth was flat" thing was made up by Washington Irvine to show how primitive and superstitious Europeans were compared to educated high tech scientific Americans (how times have changed).

Thanks, you might have saved my day, learned something not nascar related.

 

[MacLaddy]

When I was about 11 years old, my dad found me cutting the bottom off of a coffee can for a project. He asked what I was doing, and I explained how I was going to mount two propellers on a shaft in the can, with the top propeller at one opening, and the bottom propeller at the bottom opening. I was going to put a harness on it so I could wear it like a backpack, and then when I spun up the propellers, the top one would provide the thrust, and the bottom one would recover the thrust and keep the top propeller spinning. I was looking forward to flying around like the jet-pack guy I'd seen on TV (dating myself here).

My dad sat me down and patiently explained why perpetual motion machines don't work, and how real jet engines do work, etc. I was disappointed, but it sure helped me understand the world better.

Does that help to answer your questions?

11 years old and you thought of that? Plus you could understand the concepts of energy that your dad was telling you?

I could barely tie my shoes at eleven years old!

 

[vanesch]

I was disappointed, but it sure helped me understand the world better.

What a terrible experience ! Did you become a terrorist ?

 

[sophiecentaur]

Until just a few years after 1492 it was a well known fact that the Earth was flat.

At some time in the near future, someone that doesn't know any better will likely have an idea that makes use of that mean old friction and law of motion. Behind some brick wall is a better idea.

I wonder what Columbus would think of the fancy sail boats moving around the ocean today.

Nearly two thousand years before 1492, the Greeks measured the radius of the Earth to within something like 16km.
(http://en.wikipedia.org/wiki/Spherical_Earth)

There have been plenty of "idea"s that ignore friction but have there been any proper theories or working inventions?

 

[Buckethead]

Sails are very efficent - assuming the wind was in the right direction.
The wind turbine ship doesn't have to tack to maintain a course, tacking a 400m container ship through the English channel would be interesting.

There is an intermediate solution that has been tried - a giant parafoil kite deployed in front of the ship.

The parafoil kite is a cool idea, especially since winds tend to be stronger at higher altitudes, but it seems one is limited to the direction of wind travel, or at least close to it. With sails, one can sail in any direction except for about 70 degrees into the wind. Yes, you have to tack to go in certain directions, but not all. A broad reach or a run don't require tacking. With the wind turbine, it doesn't seem likely one could move directly into the wind, as the wind resistance would be stronger than the propeller force so some kind of tacking even with a wind turbine would require tacking.

 

[sophiecentaur]

"With the wind turbine, it doesn't seem likely one could move directly into the wind, as the wind resistance would be stronger than the propeller force"
That doesn't follow. It is true that you couldn't go forward faster than the wind is blowing towards you but there is no reason why you couldn't make forward progress to windward, albeit at a low speed. It's not a matter of force, it's a matter of power. As long as forward speed times water propeller / turbine thrust is designed to be less than wind speed times normal force on turbine you are ok. The design factors would be the areas and pitch of the two turbines (air and water).
There would, of course, be a component of drift backwards (as there is always leeway when a boat is close hauled) but the overall movement could be forwards.

"When the wind wouldn't blow and the wind wouldn't blow, we got carter the ****** to start 'er."

 

[RonL]

Nearly two thousand years before 1492, the Greeks measured the radius of the Earth to within something like 16km.
(http://en.wikipedia.org/wiki/Spherical_Earth)

There have been plenty of "idea"s that ignore friction but have there been any proper theories or working inventions?

Might not be a proper theory, but consider how a boat gets on plane in the lake, it glides on top of the water much easier than plowing through it.
Think of a vehicle that moves forward at some velocity and forces most air under it and with side fairings the air is pretty well encapsulated. You have forward velocity and gravity applying a force to the volume of air as the vehicle in essence slides over it and if directed through some conversion mechanism that uses both frictional and thermal properties the air mass (or volume?) is reduced and dumped into the low pressure backdraft area of the forward moving vehicle.

Lots of physics and mechanics in what is described, lots of potential energy to move back into the power supply.

Someone in thermal engineering should have a good time with all of it.

Ron

 

[sophiecentaur]

"Someone in thermal engineering" would know that certain 'Laws' Apply throughout our physical lives.
Your rather vague suggestions about "sliding over" a volume of air have been tried and used, successfully by hovercraft to reduce contact friction with the ground but there are still many losses from the fan and from turbulence. You may have noticed that hovercraft are no longer used as serious commercial carriers except over swamps and other odd surfaces. They are not used commercially (much: I may be proved wrong in some obscure example), even over the sea because boats and hydrofoils work better.
The "potential energy" to which you refer is only the equivalent of raising the vehicle by a meter or so and that, as well as being very hard to recover, is only the same as you'd get by rolling down a 1m high hill.
In all these issues of Energy, you have to do the actual SUMS before seriously proposing any novel system - which is why so few novel systems don't actually work. It's not a matter of ultra conservativism in the Scientific community.

 

[RonL]

"Someone in thermal engineering" would know that certain 'Laws' Apply throughout our physical lives.
Your rather vague suggestions about "sliding over" a volume of air have been tried and used, successfully by hovercraft to reduce contact friction with the ground but there are still many losses from the fan and from turbulence. You may have noticed that hovercraft are no longer used as serious commercial carriers except over swamps and other odd surfaces. They are not used commercially (much: I may be proved wrong in some obscure example), even over the sea because boats and hydrofoils work better.
The "potential energy" to which you refer is only the equivalent of raising the vehicle by a meter or so and that, as well as being very hard to recover, is only the same as you'd get by rolling down a 1m high hill.
In all these issues of Energy, you have to do the actual SUMS before seriously proposing any novel system - which is why so few novel systems don't actually work. It's not a matter of ultra conservativism in the Scientific community.

You might have helped make my point. The hovercraft is almost the exact reverse of what I mentioned, a total waste of energy to lift a vehicle and make it move.

We are talking "energy recovery" and with the proper engineering to maintain operator control, you can have a method of making a 6,000 pound vehicle (electric) feel to it's power system as if it only weighs 1,500 pounds.

 

[mgb_phys]

The parafoil kite is a cool idea, ...but it seems one is limited to the direction of wind travel, or at least close to it. With sails, one can sail in any direction except for about 70 degrees into the wind.

The makers (kiteship) claim that the winds work for a lot of trade routes.
The big advantage is that you don't need any changes to the ship, no masts and rigging to make loading difficult. And you don't need the crew to manage the sails
It's just a computer controlled winch at the pointy end where the current anchor winch is.

 

[sophiecentaur]

You might have helped make my point. The hovercraft is almost the exact reverse of what I mentioned, a total waste of energy to lift a vehicle and make it move.

We are talking "energy recovery" and with the porper engineering to maintain operator control, you can have a method of making a 6,000 pound vehicle (electric) feel to it's power system as if it only weighs 1,500 pounds.

How does its mass appear to be less? Are you suggesting that it becomes easier to accelerate? How is its mass relevant?
Also, where does all this returned energy come from? If it is suspended above ground you can't even use regenerative braking.
The nearest thing that I can think of to what you seem to be describing may a 'ground effect' air transport - old news. It requires less energy to fly it but has the disadvantage that it will bump into trees and buildings because it is only a metre or two, max, above ground. Again, there is no "energy recovery" - just relatively low friction / drag forces.

 

[RonL]

How does its mass appear to be less? Are you suggesting that it becomes easier to accelerate? How is its mass relevant?
Also, where does all this returned energy come from? If it is suspended above ground you can't even use regenerative braking.
The nearest thing that I can think of to what you seem to be describing may a 'ground effect' air transport - old news. It requires less energy to fly it but has the disadvantage that it will bump into trees and buildings because it is only a metre or two, max, above ground. Again, there is no "energy recovery" - just relatively low friction / drag forces.

Sorry to be so long giving an answer, what I'm suggesting is a weight being semi supported on a wedge of air, the reason for 1500 pounds of weight being in contact with the ground through 4 wheels, is for control purposes. In a real emergency the entire weight can be transferred to the wheels for braking and steering.

I would think anyone that understands scoops on race cars, should be able to form a little bit of a picture in their mind of what I'm suggesting.

The mechanical transfer of airflow into work or electrical power can go in many directions, that is why such a general and simple statement.

Ron

 

[mgb_phys]

Sorry to be so long giving an answer, what I'm suggesting is a weight being semi supported on a wedge of air, the reason for 1500 pounds of weight being in contact with the ground through 4 wheels, is for control purposes. In a real emergency the entire weight can be transferred to the wheels for braking and steering.

Can be done, and often is for moving very very large objects
But you are using a lot of power to run the air compressors to generate the air pressure, a lot more than you use in overcoming friction of the wheels/tires.

 

[sophiecentaur]

Roni
You are confusing force with energy. The weight is always the weight (unless you go to a different planet) and the time it counts is only when going up / down hill. Mass is involved when gaining or losing speed. Efficiency in vehicles can be affected by reducing contact friction and drag. Railway trains do a very job of keeping friction to a reasonable value by using steel wheels and rails.
You haven't commented on my earlier mention of good old fashioned ground effect. You are only, in effect, introducing that in your suggestion.
You need to appreciate that there is no "energy return" involved in your idea.

 

[Buckleymanor]

No it wasn't, nobody thought the Earth was flat since they stopped hitting each other with rocks. The diameter of the spherical Earth was measured 2000 years before columbus.
The "they thought the Earth was flat" thing was made up by Washington Irvine to show how primitive and superstitious Europeans were compared to educated high tech scientific Americans (how times have changed).

Some superstitous primative Europeans still think it is flat .

http://en.wikipedia.org/wiki/Flat_Earth_Society
I nowtice there is the odd American in there too.

 

[A.T.]

With the wind turbine, it doesn't seem likely one could move directly into the wind, as the wind resistance would be stronger than the propeller force

It can be done.

On water:
http://www.youtube.com/watch?v=NNbNNSDljGI&NR=1

On land (currently record about 64% windspeed, directly upwind):

It is true that you couldn't go forward faster than the wind is blowing towards you

No, there is no hard theoretical limit on your speed. Neither for directly upwind, nor for directly downwind. The only limit is efficiency.

This lecture talks about both directions:
http://www.youtube.com/watch?v=JUwZmUjjgn4#t=3m10s

And here a simple mechanical analogy:

 

[RonL]

Can be done, and often is for moving very very large objects
But you are using a lot of power to run the air compressors to generate the air pressure, a lot more than you use in overcoming friction of the wheels/tires.

I'm not suggesting a compressor to blow air under a car, the velocity and weight of the car as it moves forward represents energy that has been applied in a productive way. If the air that is being pushed aside in all directions is (as much as practicle) directed under the car, with controlable fairings, you then are sitting inside a moving linear air compressor.

The proper air motor type device built into the car can take advantage of this large mass of airflow, will produce some amount of work and dump it's discharge into the draft area in back of the forward moving vehicle.

Reducing the effect of low pressure vacuum in back of the car, would in it's own right, be a positive action as good as regen.

 

[RonL]

Roni
You are confusing force with energy. The weight is always the weight (unless you go to a different planet) and the time it counts is only when going up / down hill. Mass is involved when gaining or losing speed. Efficiency in vehicles can be affected by reducing contact friction and drag. Railway trains do a very job of keeping friction to a reasonable value by using steel wheels and rails.
You haven't commented on my earlier mention of good old fashioned ground effect. You are only, in effect, introducing that in your suggestion.
You need to appreciate that there is no "energy return" involved in your idea.

I'm not sure what to say.
Anything set in motion offers a potential of "energy return".

Flying in ground effect involves (in general) fast speed and extensive flat and open areas.
Driving in ground effect will involve much slower speed and contact with the ground, for reasons of operator control.

Any work performed with any compression of air will produce a change of temperature. Making use of pressure changes around a moving object can produce big returns in how much overall energy is needed to keep the object in motion.

 

[magpies]

Ya know if the wind was strong enough on the given day a car powered by wind power could work... NOT.

 

[sophiecentaur]

You don't seemed to have grasped the fact that taking erergy from the air you're traveling through merely increases the energy required to drive you forward. No free lunch.

 

[A.T.]

Ya know if the wind was strong enough on the given day a car powered by wind power could work... NOT.

Why NOT?

 

[OmCheeto]

You don't seemed to have grasped the fact that taking erergy from the air you're traveling through merely increases the energy required to drive you forward. No free lunch.

Not only that, but vehicles optimized to utilize this effect(for speed) have to reach significant speeds to take advantage of it. Not to mention they are incredibly light for their footprint.

http://boatdesign.net/articles/tunnel-hull-design/index.htm

50 mph yields 110 lbf of lift
100 mph yields 340 lbf of lift

This is with a 2 degree angle of attack which yields a lift coefficient of about 0.2
Increasing the angle to about 9 degrees(optimizing for lift) yields a unity lift factor which gives the following:

50 mph yields 550 lbf of lift
100 mph yields 1700 lbf of lift

Since most land vehicles achieve maximum fuel efficiencies between http://www.speedvsmpg.com/wp-content/uploads/2008/07/speedvsmpg.jpg" , due to a combination of aerodynamic drag and ICE characteristics, it is my opinion that it's pointless to try and reduce the rolling resistance of the vehicle through lift, since power required to push a vehicle is related to the cube of the wind speed and only proportionally to that of the rolling speed.

It would be fun to run the numbers, but I've a hole in my roof and have to go patch it.

Anyone with spare time on their hands can try this spot:

http://ecomodder.com/forum/tool-aero-rolling-resistance.php

Plug in the numbers for your vehicle and replace the "Rolling HP" with a value corresponding to the lift generated at different speeds. Also change your frontal area to correspond with the duct-work required to port said winds underneath the vehicle. Get back to us with the speed required to make your vehicle more efficient.

hmmm... You'll need a couple more equations:
Coefficient of Lift = 2 * pi * a ('a' being the angle of attack)(only good between 0 and 15 degrees)
Lift = L = 1/2 rho v^2 Sref Cl (rho = 1.2, Sref is your lifting area, and Cl is your Coefficient of lift)

 

[sophiecentaur]

I'm not sure what to say.
Anything set in motion offers a potential of "energy return".

Flying in ground effect involves (in general) fast speed and extensive flat and open areas.
Driving in ground effect will involve much slower speed and contact with the ground, for reasons of operator control.

Any work performed with any compression of air will produce a change of temperature. Making use of pressure changes around a moving object can produce big returns in how much overall energy is needed to keep the object in motion.

You write as if you think there's some magical extra energy available. The best you can do , when you are running steadily, is to minimise your losses. Putting energy into producing a change in temperature (from which you seem to think you can get some useful energy) will involve more energy input than you get out (pretty much the most fundamental law you can think of).
Regeneration of energy has nothing to do with what you are talking about - it's about reducing your overall losses (a bit) when you need to slow down or stop. You minimise the wasted Kinetic Energy that you would have wasted, that's all. What are "big returns", in your context?

 

[OmCheeto]

You write as if you think there's some magical extra energy available. The best you can do , when you are running steadily, is to minimize your losses.

Exactly!

But like Ron, you have to change all parameters of an experiment, regardless of whether or not you think they will come close improving the system.

I thumbed through an insanely long 200 page pdf yesterday describing improvements in the aerodynamics of light trucks. (I own a light truck, so I was mildly interested.)

The last thing in the world I would have believed was that a cowl air dam across the front of the vehicle would contribute the greatest improvement of the 250 variations to the aerodynamics of the vehicle.(I actually still don't believe it)

http://www.tercelreference.com/downloads/gettrdoc.pdf (8 megabytes!)

They of course tried ducting, to no avail...

 

[sophiecentaur]

I remember reading Colin Chapman (Lotus designer) in his classic book of the 60s. He wrote that you cannot approach aerodynamics intuitively. 'Go faster' ideas usually don't.

It seems to be mostly a matter of reducing / shedding vortices rather than have them hanging around your back end. Those turned-up wing tips on all the big jets have more than paid for themselves.

 

[RonL]

Exactly!

But like Ron, you have to change all parameters of an experiment, regardless of whether or not you think they will come close improving the system.

I thumbed through an insanely long 200 page pdf yesterday describing improvements in the aerodynamics of light trucks. (I own a light truck, so I was mildly interested.)

The last thing in the world I would have believed was that a cowl air dam across the front of the vehicle would contribute the greatest improvement of the 250 variations to the aerodynamics of the vehicle.(I actually still don't believe it)

http://www.tercelreference.com/downloads/gettrdoc.pdf (8 megabytes!)

They of course tried ducting, to no avail...

You have to start the thought process as though everything is possible, then when something will not or cannot work, try to see if something will change the outcome.
For almost any application of energy recovery on ground based vehicles, they will involve suction and discharge conditions that make the process impractical.

One example for me to think of, is my loader bucket has a bottom area of around 60 sq. ft. If it is positioned where the front is about 24" up and the back is about 6" above the ground. A movement of only 1 or 2 MPH will cause an airflow to curl up behind the bucket, with such force as to lift massive amounts of dust, grass and weed fragments to the point of having to stop or raise the bucket higher. There is power in volume!

I remember reading Colin Chapman (Lotus designer) in his classic book of the 60s. He wrote that you cannot approach aerodynamics intuitively. 'Go faster' ideas usually don't.

It seems to be mostly a matter of reducing / shedding vortices rather than have them hanging around your back end. Those turned-up wing tips on all the big jets have more than paid for themselves.

Go faster ideas, is the heart of our problems, just my thinking.

The vortices are the product of the energy that has already been spent, the control of how smoothly these vortices are recombined with the hole just punched in the air is the key to "energy recovery".

Reducing friction drag on the skin of the vehicle will be the biggest area of inovation. We might start with something as non-se*y as a bus and work down.
Start with some amount of suction in the frontal area (the more the better) and move a very large volume of low pressure air flow into a hollow double wall shell, the inner wall is solid and the outer wall is perforated with tiny holes that allow an air ejection (low pressure) much the same as an air hockey table, this air will help to reduce the grip of the air that has been pushed aside.
Might sound crazy but ideas are the start of any type research, that makes use of old principles being applied in new ways.

 

[OmCheeto]

Reducing friction drag on the skin of the vehicle will be the biggest area of innovation. We might start with something as non-se*y as a bus and work down.

You're not an ex-NASA scientist are you?

from page 28 of the http://www.tercelreference.com/downloads/gettrdoc.pdf" I mentioned yesterday:

The test vehicle that NASA used is shown below:

Figure 7. NASA Dryden Research Vehicle – Box Shape​

NASA’s interest was primarily directed at improving semi trailer
performance but these results are even more appropriate for light trucks. They
found that a practical drag coefficient (Cd) of .25 was possible when a rounded
front was implemented along with a truncated “boattail” shaped back.

I was all like; "That's a NASA designed vehicle?" on Sunday. But seeing your bus comment today made me realize that science isn't always pretty, nor as sophie.c pointed out, intuitively logical.

 

[RonL]

You're not an ex-NASA scientist are you?

from page 28 of the http://www.tercelreference.com/downloads/gettrdoc.pdf" I mentioned yesterday:


I was all like; "That's a NASA designed vehicle?" on Sunday. But seeing your bus comment today made me realize that science isn't always pretty, nor as sophie.c pointed out, intuitively logical.

LOL, Om I thought you had read more of my posts, I can't even get much attention in the overunity crowds.

I didn't have time to go further when I made the post, but my thinking was to have the front like they said, but with suction intake in the center, then round the back into a taper circle and have two counter rotating, 7' diameter Tesla style turbines exhausting in the center.

Have you ever driven a few car links behind a trailer rig and felt the rough air gusts that are shed? If you move up too close, you ride in the draft area and it is pretty smooth.

No I did not know of their test design, but it makes me feel better about my thinking.
Sooo much room for design work.

Ron

 

[RonL]

Hey Om,
I just downloaded the pdf you posted, thanks!

I once made mention of the perforated skin surface, for reduction of surface drag, and the aviation crowds went silent, I just seem to have that affect on people.

Something you might be interested in, if you don't already know of these. Might be the seeds of a lot of my thoughts.

http://books.google.com/books/serial/ISSN:01617370?rview=1&source=gbs_navlinks_s

http://books.google.com/books/serial/ISSN:00324558?rview=1&rview=1&source=gbs_navlinks_s

 

[tropicalvikin]

Detractors of the idea seem to live in a flat world.
Where I live we have thousands on non flat roads, you can have vanes which close the ducts when going flat or uphill and open them downhill.
Downhill. You definitely can generate energy while making brake pads last longer.

I had a Pick Up truck, with a high (much taller that the cabin) canvas cover which was used on rainy days, the sail effect was amazing, and helped braking on downhills (it kept top speed very restricted also).

 

[sophiecentaur]

So, what are you saying, apart from the fact that regen braking is a good idea? Is this new? All the other stuff about flaps and stuff is either irrellevant or implies a bit if P.M.. (or yachting)