When packs of drivers jockey for position on the speedway at Sunday's Indianapolis 500, a select group of engineers will be thinking, not about engines and tires, but about the effects of laminar and turbulent airflow.
"It's one thing when you're riding around the track and there's no air disturbance," Mark Johnson, general manager of KV Racing Technology, told us. "But when you're in a three- or four-car pack driving through disturbed air, it's another matter. That's why the wind tunnel simulation is so important."
Indy's engineers spend hundreds of hours testing cars in wind tunnels. Along with on-track testing, KV Racing employs a "rolling road" at a wind tunnel to build an "aero map" of its vehicles. The rolling road, operated by Wind Shear Inc., measures 10.5 feet wide and 29.5 feet long. Its continuously turning steel belt can accelerate from 0 to 180mph in less than a minute and incorporates a measurement system that monitors the aerodynamic downforce under each tire.
Indy cars can use aerodynamic downforce to ride lower and get a better grip on the road. (Source: Littelfuse)
"Going to the wind tunnel is critical to our understanding," Johnson said. "The engineers learn what happens when they make a change on the rear or front of the car, and they find out what they have to do in order to make all the changes work in concert with each another."
Given the new rules at Indy, those changes won't be big, but they can still make the difference between victory and defeat. One of the key components not constrained by the rules is the wicker -- a little piece of angle iron on the car's front and rear wings. The wicker, measuring anywhere from one-sixteenth to one-half of an inch in cross-section, can run the full width of a wing (about 18 inches across). By altering the size and angle of the wickers, engineers can significantly change the aerodynamics of their vehicles. To find out how much change they've wrought, they bring the vehicles to the wind tunnel or to the actual track and take measurements.
At a track in Texas, for example, KV recently experimented with wickers to provide more aerodynamic downforce for a rookie driver. Starting with a flat rear wing and varying the size of the wickers on the front up to three-eighths of an inch and then down to one-fourth of an inch, they found they could produce amazing amounts of downforce. "We got to where he could drive around the track and never lift the throttle for five or six laps at a top speed of 205 miles per hour," Johnson said. "After he got more comfortable, we took a little bit of the wicker off."
Such adjustments are commonplace for Indy race teams, Johnson said. Through trial and error, they learn how to use aerodynamics to make their cars ride high or low, increasing or decreasing drag and thereby tweaking the downforce. "You can get the car to ride closer to the ground, which increases your grip, or you can let it ride higher and faster. It's a very fine balancing act."
You can learn more about the Indy 500 at Littelfuse's Speed2Design site.
I totally understand the criticality of analyzing airflow to make tweaks to the car that will deliver a competitive edge. But what about employing 3D simulation software as opposed to or in addition to physical wind tunnel testing. Wouldn't simulation testing be easier and less expensive than putting the cars through their paces in physical wind tunnels? Do they not have the technology or are there specific reasons why the physical world still has an edge in testing at this stage of game?
Beth, in my experience, and that of others I talk to, the setting up of a model is very difficult and time consuming. This is especially true of something like an Indy Car. Considering the time between races and the ability to simulate the track with a device, it might be quicker to do it this way. On the other hand, when designing a large complex machine or one that will be made in large volume, the time is worth it.
Perhaps after getting driving rights for their autonomous cars, Google might look at autonomous race car operation. Machine accurate, faster-than-human measurements in all directions and consistent operation, it might provide an interesting man-vs-machine contest. If nothing else, the machine operated car could remove human support systems along with the human. The vehicle could operate closer to the limits.
UAVs have already revolutionized military aviation. Almost every other week or so, UAV launched missles attack our enemies in Pakistan and Yeman. The robot warrior is becoming a fact, at least in the air.
That's a very good point, Bob. If all of the variables the driver faces could be identified, they could also be optimized. The lag time between an event and a response would be quicker with a computer. That coule make all the difference.
Some day, that could happen, Rob. The problem with autonomous driving right now is so-called "rogue vehicles," i.e., cars driven by humans. Autonomous cars have trouble predicting the crazy things that humans do. If we could get all the humans off the course, I think it could happen.
Totally fascinating to me that this kind of ingeniousness and intelligence and creativity can be put forth for an entertainment venue.
But when it comes to something like perfecting the wind engine which could impact the lives of millions of people, no effort is put forth at all. Just a bunch of lemming stuff based upon a 1946 design found in the Bowels of the NASA drawing files.
When the magnificent Automotive Suspension Engineer, Bill Allison set out to see if he could hit the Betz limit, he did very methodically. And he became convinced that a confined flow wind tunnel produced supercharged, erroneous results so he created a non confined flow test environment. The results were amazing.
Yet idiocy persists, and the ethics of a profession are constantly called to question.
Not idiocy at all, Architect. Simulation is used as design shortcuts, not as final solutions. It works well to get to the finer tuning stage - then real life comes to play.
The wind engine is still a "pie in the sky" - it can't earn its own keep - even after the billions spent on research and pilot projects. It can't pass "real life". You can only "bang your head on the wall" for so long.
Don't be questiong the ethics of a noble profession because it cannot perform miracles.
I wrote that Allison hit the Betz limit. That is 59% efficient.
The current 3 bladed fans achieve less than 20% efficient.
From an engineering perspective, what kind of improvement is that?
From what I have witnessed, engineers will kill for a 3% increase in efficiency.
Those dufus 3 bladed flying fans were known by Bill to be bogus over 30 years ago. Yet the engineers persist on the wrong path without any sort of proper testing and development and no one has stopped to understand that it's not the principle of flying but the principle of resisting that extracts the greatest amount of energy from the wind.
Ever hear of a spinnaker, or a parachute, or a windmill? They resist to extract the energy.
So Buford, in saying that he lost $150,000,000 on his farm was destined to lose because he followed some of those engineers who were advocating the very poor design approach.
You mention all sorts of testing. Where? There virtually has been none. There really is no testing and development facility that is objectively examining this issue anywhere in the world. Was Bill lying? I don't believe that at all.
As a 73 year old Architect who co-oped at the Corporate Engineering Staff at the GM Tech center, while attending GMI, I am aware of what it takes to develop something properly. And I have witnessed many lying engineers in my life, particularly those wedded to the political world.
And I have witnessed similar things in the Architectural world
No profession is completely and inherently noble. To be sure there are magnificent efforts like those of Sam Williams and Bob Lutz and Burt and others but politics seems to muck things up very quickly.
Actually Robinson Helicopter could solve the issue. They know how to set up a non confined air flow wind "tunnel".
Seems lke we went to different engineering schools Frank.
The increse in efficiency from <20% up to 59% represents a 300% increase in my book.
Not worth looking at? Not one fine engineer capable of examining this in all of the world?? Not one creative and competent engineer willing to take another look?
Other issues?? What other issues? There always are other issues. Sure the wind doesn not blow constantly everywhere. But in some places it is very important.
Perhaps these men with their wonderful discoveries could push that limit. Maybe they could beat Bill.
Look at the beautiful Indy Cars with their all sorts of fins and scoops, they are examining and learning things that will benefit the broad section of humanity.
And I am curious now about that wind tunnel... how does it simulate the disruptive flow with 3 cars racing side by side? And what about crosswinds?
Air seems to be a fickle lady that seems to take the path of least resistance and it will compress in front of an obstructive object.
But I tend to think that one does have to be clear about their focus and intentions. Development forces that.
Yes Bil was either lying or just plain wrong. I design, build windgenerators among other things, presently doing 2 2kw designs for production.
And mine will hit 35-40% eff, not 20%
Facts are the best wind power collectors are 3 blade rotors like you see on most all cost effective WG's. As more blades are added they just interfer with the ones before it and add drag, lower tip speed needed to make real power. Basic physics, deal with it and stop making ill informed statement.
Do you know why there is a Belt's limit? Air flowing to a WG if too much energy is taken, the wind slows down in front of the WG rotor and goes around it instead.
I've done every type of WG including fast 20-30mph sailboats and physics holds well on all of them. Sadly means any WG with more than 5 blades just isn't going to be eff, cost effective.
If you think Bill's WG is so good build them and make a fortune. Until you build and prove your points it's just misinformed vaporware or just a plain scam.
Well Jerry, Bill was a very highly respected engineer in the automotive industry working for Hudson, Packard and Ford. He held over 80 patents which I suspect is more than you ever will. Bill grew up as a farm boy in Western New York State and knew the difference between horsesense and horsedukie. And yes, they had an aermotor. And after a huge wind storm coming in off of Lake Erie when the rotor blew off, he learned about the tremendous power in the wind when he hoisted the baby back on the axle on a summer vacation from Michigan while studying with some preeminent engineers, some of whom you may have heard of.
Ever hear of the Packard Torsion Ride? Sir Clive Moulton was aware of his work and inspired by it as a young boy.
Bill was a classic American of that era, believe me he didn't lie ever. In fact he recorded the lift off of the Challenger and had it completely analysed within several days and sent NASA his analysis. He showed me the graphite streaks. It took them over a year of analysis to come to the same conclusion. And he knew who caused the disaster and began to worry about government agents. You know who caused the disaster don't you? His analysis of the crash of flight 255 revealed that he knew a lot more than the Judge.
Bill knew enough to stick with the problem until he solved it. That is why he was so very successful. Lie? Outrageous conclusion. If you look at the succession of articles in Popular Science you will notice that every time he added more blades the efficiency went up in the next article.
In your third paragraph You purport to have all the facts. You don't. Your mind is closed and dead. You mention sail boats. So you probably have heard of the spinnaker. Tell me about it. Does it operate on the same principle as the mainsail? If you say yes, we know that your education and experience has led you to some very erroneous conclusions which you hold as the precious truth. It's not and you are the one who is wrong.
Those 3 bladed fans try and fly in the wind. Bill's didn't. They resisted the wind. The greater the number of blades, the more energy he got.
So you are one of the flyers that he was so scornful 30 of years ago.
You are one of those, so convinced in your "truth" that you go down the same path over and over again hoping to see a huge change. You won't. Psychologists have a word for that.
So your words... lie, just plain wrong, "facts", isn't going to be, misinformed, vaporware, scam... are more than rash.
Show us how you determined your efficiency, show us that you understand the different physical principles of dealing with the wind, show us your calculations, and show us that you are open to other lines of logic and physics, othewise those words that you are trying to stick on a very noble enginer really apply to you.
The flyers have lost according to Buford. Did you miss that?
Architect, Just because one is good in one area doesn't mean they are good in others.
Yes I know exactly the difference between a spinnaker and a mainsail. One is eff and the other isn't. Guess which one isn't? PS I design, build 25knot cruising sailboats, live on, race and cruise them. And on them a classic spinnaker isn't useful because they go faster downwind by tacking from one broad reach to the others allowing a high apparent wind going so much faster even with the extra distance.
The only reason a spinnaker works on a monhull well is it's so slow. My Cats, Tri's are 4x's as fast so only special lift, not drag spinnakers are used.
As an illistration I once sailed a Mega 30 monhull but fast though a racing fleet like I had my own private wind. How is the wind was about .5mph out of the aft quater/broad reach. I caught it, not easy and slowly pulled in the sails tighter which increased over the deck windspeed/apparent wind. As the boat went faster, about 1mph added to the wind speed made it go faster. I got it going about 2mph that way while all the other boats sails just flopped around from the waves. Guess which ones had spinnakers up?
Fact is drag is just that. At low blade speed of a drag based fan just can't extract much power because it resists!!! Because of this resistance you are so proud of the wind mostly just goes around the rotor.
Vs a low blade/area ratio/2-5blades, allows the wind to go through easily, more of it and faster. Without all the air friction and blade interference drag of a many bladed rotor the blade can go many x's the windspeed at the outside end allowing it to work in 100=300mph winds to extract power. Vs just the windspeed for the drag style.
Please put up the specs, more info but basic physics, what I use to judge everything, it doesn't look good for Bill.
For referece eff for 2 blades about 48%, 3blades, 56%, 4 blades 42%, 5 blades 38% IIRC and eff drops off from there. The Fan type used for pumping water is less than 10% eff. They do it on purpose so it survives high winds better and just need torque to pump a little water so eff doesn't matter much as ruggedness.
If it's so good why don't you build it and make a fortune? Put your money up like I'm doing.
You must not have watched the last America's cup race. If you had you would have noticed the mad scramble to get the spinnakers up. Gee, I wonder why?
Speed picked up didn't it.
You completely missed what I was saying about Bill's discovery that he pulled more power when he removed two blades from a 12 blade configuration. The wind quite clearly stopped avoiding the fan disc and flew on through. That is when he hit the Betz limit which you will never do. This was completely visible to the naked eye with the "steam" from the dry ice.
Bill built a dynamometer to determine the efficiencies of his laborious efforts.
I doubt that you could do that as much as I completely doubt your notions of efficiencies. You are stating values that no major wind turbine maker would ever assert. They simply don't achieve those numbers. I've had manufacturers admit that their efficiencies are about less than half of what you are quoting, and only under ideal conditions.
So you will have to prove it and show us the test setup, the dynamometer, and the wind generating facility, the test data.
Bearuford Pickens got on Ted not too long ago and said that he lost $150,000,000 because the wind turbines are too inefficient.
So there is something very specious about the numbers that you are quoting. Clearly your reference data is false.
Were you also trying to reference the Venerable old Aermotor? Wow! You don't understand it's operation at all.
Cut the crap big talk about money, get on to the truth.
The US needs a proper testing and development facility where different designs can be tested in unconfined flow situations. That is the real point. And it doesn't exist.
Then you can relax and look at all those U-Tube presentations of 3 bladed fans exploding and catching on fire all over the world.
You actually are quoting efficiencies that are close to the Honewell multibladed design. No way with 3 blades. Complete and utter falsehoods.
56%? You are a hoot at wild exaggerations. Maybe you should go talk with Beauford Pickens and straighten him out.
You talk big money so you two might have lots in common.
Or better yet, build the world's finest development and test facility and open it up to explorations rather than the lemming instinct.
Since you do not have the demeanor of a seasoned, methodical, reasoning engineer I no longer believe that you are one.
You persist in aspersions and threats and challenges and that causes me to become even more suspicious of your assertions. Clearly your efficiency ratings are false and you have shown no data or tests, nor the dynamometer to prove your wild assertions.
Flying 3 bladed fans are very inefficient.
I asked you to put up your proof and you never once did.
I asked you to show us your test setup and you never did.
I asked you to build a test facility since you imply that you are a high roller.
You didn't
You ignore T Boone and his very public statements that wind turbines are too inefficient and he lost $150,000,000 in creating a useless 3 bladed wind farm.
The fact almost all windgens are 3blade is my proof.
Most of your statements show a lack of understanding basic science and you put up not even pics of your supposed great windgen. Windtunnel? I never mentioned one.
I'm just starting my new design so don't have pics. But Mine doesn't matter as what you described can't complete with any decent 2-5 blade WG.
It's you making wild claims so show us the data. I've put up mine, the industry 3 blade standard because they work best for ROI. Where is your data other than spurious claims?
So no more from me on this, good luck as you'll need it.
That fact is proof of the lemming instinct and nothing else.
You apparently have no understanding of science which includes explorations and careful testing. Design without proper development testing is pie high in the sky.
You have shown no verifiable data at all yet make outrageous statements.
Are you incapable of listening? What is Boon's ROI?
You can read about Bill Allison in my article in AltEnergy.com:
Clearly you are no match to that man, either educationally, experientally, or ontologically.
An article on a friend who perfected the wind engine:
Finally real info. I remember it from when he did it and yes it's an improvement on full fan turbines but still isn't as anywhere near good as a standard 3 blade unit.
2 things stand out he used a windtunnel which is known for giving false readings like this from wall interference preventing the aiir from going around the turbine with so many blades. Yes when he removed blades it went better because they let more air through.
The other is flat blades. Sorry but just not going to cut it aerodynamically.
Some people are easy to fool it seems. Like I say just put physics to work if you want to know what is fact or fiction or in many cases like this, not quite knowing how to do wind tunnel testing. This problem has come up recently in serveral cases. The windtunnel needs to be 4x's the size of the windgen and even then there are effects.
Finally real info. I remember it from when he did it and yes it's an improvement on full fan turbines but still isn't as anywhere near good as a standard 3 blade unit.
2 things stand out he used a windtunnel which is known for giving false readings like this from wall interference preventing the aiir from going around the turbine with so many blades. Yes when he removed blades it went better because they let more air through.
The other is flat blades. Sorry but just not going to cut it aerodynamically.
Some people are easy to fool it seems. Like I say just put physics to work if you want to know what is fact or fiction or in many cases like this, not quite knowing how to do wind tunnel testing. This problem has come up recently in serveral cases. The windtunnel needs to be 4x's the size of the windgen and even then there are effects.
Wow, you are really having a tough time understanding this Jerry!!
I. Vastly superior to flying 3 bladed fans. 59% Efficiency, 3 bladed flying fans are lucky to hit 20% efficiency. Don't forget Beauford's conclusion.
II. He was absolutely adamant that a confined flow wind tunnel NOT be used for the very reasons that he pointed our and you have reiterated. How many times do I have to repeat that? Your statement is completely contrary to what he did and what he advocated
III. He found through meticulous and careful testing that the flat blades "pulled the most Power" and that the higher the polish, the more energy you absorbed. He advocated broken sheet metal, stainless steel. You know why don't you?
Bill was anything but a fool, and he didn't fool me either.
After all, he did identify the cause of the crash of the Challenger and flight 255 simply by watching television.
You know who caused the disposal of the teachers don't you?
I bummed because I can see about 40 of these windmills on the horizon and just the other morning when it was very windy they were all sitting there not spinning. The fact is there was plenty of energy there. But the inferstructure to be able to store and use this energy is just not in place.
I can't wait until engineers are able to find the way to store and continue to make this technology more efficient and more profitable. I know it will be a while before engineers are able to conquer some of the larger problems with the system. But I can't wait.
Chaschas you sould do a little research as windgenerators do earn their keep and profits nicely.
Please don't confuse the finacial vehicles known as wind farms with whether wind is viable. Facts are in many places wind is the low cost energy source and those using it are paying lower costs. A recent utility study forcast that wind in the mid to west will keep the cost of electricity down. Afterall it only takes 2kw of wind generator to power an eff home and tetail they are going for $2k/kw in larger sizes.
Facts are now solar PV, Solar CSP/CHP, wind are all now under $2k/kw or will be soon. At that pricepoint it's less costly than retail coal.
As for Indy Aerodynamics it's mostly used for downforce and using hp to overcome the large aero drag it causes. It's a very hard thing to design because things like paint lines have brought down airplanes and air coming out sideways from the racecar, etc create all kinds of problems.
I depend on weight, low CG to keep me stuck to the earth and just use aero to lower drag to increase range.
Bill (Architect), I won't disagree that "the way we've always done it" often wins out over creativity and methodology and I'm also no aerodynamic expert, but I would argue that such an exhibition like that of Watson could help fund research that would potentially benefit millions of people...
I agree. Going away from the human element would decrease crowd size as well as make things too automated. Part of the fun of racing is watching someone take a risk that a computer wouldn't take and succeed causing them to win the race.
In quite a few races the difference between winning and losing is knowing how much gas is left in the tank and often that is a little bit more than an educated guess. But not much more.
A field of only autonomous cars may happen some day, Chuck. That would certainly showcase the quality of the inidividual vehicles. Remote control might be an option as well.
This article just underscores how much aerodynamics have created parades rather than races. With the incredible emphasis of creating a car that can be driven flat out all the way around Indy, driver skill is secondary. If you look at an Indy or F1 car there are all sorts of wickers, splitters, trim tabs, diffusers, flaps, etc. designed to keep the car glued to the road with minimal drag. Unfortunately this creates unpredictable handling when running close to other cars so there is no way to pass unless one car is a lot faster (i.e., less drag) than another. I would really like to see substantial limits on aerodynamics, including an outright ban on wind tunnel testing, so that driver skill and the ability to pass are brought back into racing.
I agree that some of the aerodynamics improvements have made racing less exciting. However, I think technology has also made racing more exciting. I disagree a little bit with this article because it focuses so much on aerodynamics. There is so much more to racing. I am in awe that taking 1/2 pound of air out of the left front tire can really make that much of a difference in how the car drives. But it does. Absolutely awesome.
Bill Allison discovered that his best configuration was with 10 blades, dead flat, highly polished, 8deg, in a 12 blade configuration was best.
He would talk about a cone of resistance which you couldn't see until he got a hunk of dry ice in a baking pan with water. Then you would see this nacelle like a P-51 nose cone show up with the 12 blade config. He would point out that to be an area of high pressure and that the oncoming wind would circumvent and avoid it hence losing efficiency. When he removed two blades directly opposite of each other the cone would instantly disappear and he said that the condition was in place to pull the most power.
So something similar must happen when 3 cars are abreast. The air in front must copress to some degree and a car lagging a little behind would suffer from having to battle the compressed oncoming stream.
The issue then would be how to insure that the air directly in front of one car would becontained and related to that car rather than shunting it off and making it much more difficult to the competitor. That almost insinuates flat fins on eather side of the vehicle forcing the air over the top rather than trying to buffet your neighbor.
Charles—Fascinating article!OK, the first time I have heard the word "wickers" in my life—first time.You mention in your write -up that KV spends considerable time with trial and error before settling upon a suitable design that gives optimum performance.I recently published an article on the Sim Center located within the University of Tennessee at Chattanooga facilities.This center performs computational engineering analysis on air flow ( and other things )around the "big rigs"; eighteen wheelers fully loaded and going coast to coast.This is a remarkable technology and certainly one not existing when I was in engineering school.Maybe the folks at KV could gain additional insights and reduce the time tolaunch with this approach.Again—great article.
Thanks, bonjengr. It's surprising how important those wickers have become. IndyCar's rules are so confining that teams now spend thousands of hours working on details -- such as wickers -- to distinguish themselves.
Steamlining, or reducing the airflow drag, is certainly the best way to get "free horsepower" for racecars. IT^ does get complex when there are multiple cars close together, though. Drafting is a bit different, it works for most cars on the road. We proved that back in 1967, using vacuum gauges to measure "effective engine load", which was a lot cheaper than an air tunnel or dynamometer. The problem with doing experiments on the local interstate is the way other folks get so upset at seeing two cars six inches apart. But it is safer than you might think, because if the front car slows quickly the second car catches up quickly and so the impact is quite small.
The number of blades on the big wind turbines is the result of a compromise that includes cost and weight, rather than being based just on maximum energy recovery. Otherwise they would have more blades.
Reducing the drag on "big trucks" is a very valuable effort because of the large number of them around. I am waiting for somebody to try air dams on the trailers and some sort of means to avoid the high-vacuum turbulence that I see behind the trailers. I have thought for some time that lowering the box three feet could do a lot to reduce the drag, but there are a lot of other considerations, it turns out. BUt I have seen a lowered tanker truck and it did look a lot more stable than the standard ones. IT would be very educational to hear what the research folks have come up with relative to steamlining trucks. After all, even a 1% reduction in fuel consumption would save a whole lot of money.
UK-based Plastic Logic and French company ISORG have created what the pair tout as a first in flexible printed electronics: a large area, conformable, organic image sensor printed on plastic.
For 3D printing to make the jump from rapid prototyping to manufacturing, engineers will need to find easier ways to move products from their CAD screens to their printers.
Gigabit and PoE are two networking technologies moving ahead in tandem as industrial users power remote Ethernet devices such as IP security cameras at 1,000 Mbps over existing CAT5 cable.
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