Ten80 Student Racing Challenge

Ten80 Student Racing Challenge launch with NASCAR and Ryan Newman.

2011-03-01T12:41:00.001-08:00

More information coming soon!

It was sad

2010-10-22T15:39:00.000-07:00

It was sad,….

A lot more was lost this week than just a race team. In a time long, long ago, in a place that now seems far, far away, 1958, Richard Petty began his racing career.

Years ago a popular "gather-'round-the-campfire" song for children at summer camp was a tune which had a chorus of,…

It was sad (…oh, it was sad)

It was sad (…it was sad)

Oh, it was sad when the great ship went down,…

An oddly haunting refrain about the sinking of the Titanic.

A great ship went down this week, Richard Petty Motorsports, RPM. Only a couple of years more than a decade ago companies stood in line, literally, to pay (a lot) to have a little decal on the B pillar of the 43 car. But times change and somehow RPM didn't, they stayed in Level Cross when all the other teams set up shop in the Concord-Mooresville area. NASCAR entered the engineering era, driven in no small part by Hendrick who hired Gary Eaker from the GM wind tunnel to run their aerodynamics program--with Ray Evernham who obsessed about data for an up-start kid named Jeff Gordon; the age of specialization produced a string of championships.

The change was so dramatic that by 1994 Earnhardt Sr. remarked "there ain't gonna be no more Alan Kulwicki's." As prophetic as the grammar was bad, the age of the lone owner, builder, crew chief, driver was over.

Where RPM had been fast on the track they were now slow on the learning curve. By the time RPM did move to Concord it was too little too late. Like watching a Greek tragedy unfold, this day of final doom seemed inevitable when RPM merged with GEM, Gillett-Evernham Motorsports, the sorry remnants of what had been Evernham Racing. GEM was anything but a gem, as Gillett seems to have gone from junk bond scandal to hockey to football teams in England (otherwise called soccer) to NASCAR, each step along the way building a larger house of cards on ever larger amounts of debt.

The sad part is that by the time RPM tried to join the modern era the choices were so slim it made the GEM deal seem like a good idea, or the grasp of a drowning operation clutching at anything still afloat.

It is impossible to imagine that Jack Roush ever wanted to beat Richard Petty as a car owner this way--on the track, yes, every week--by scheming mortgage deals: never.

NASCAR has become a "product," fueled entirely by sponsor dollars, defined by marketing, the great ship of racing has slipped beneath the sea,…

It was sad (…oh, it was sad)

It was sad (…it was sad)

Oh, it was sad when the great ship went down

Deep Thought on Big Hits

2010-08-05T12:31:00.000-07:00

Deep Thought reflects on more than an 80 g acceleration, theta, and dt

For a very funny "Onion" sort of piece by Jeff Meyer go to http://www.frontstretch.com/jmeyer/30604/

And now the real Deep Thought
There are three parts to determining what effect an acceleration has on an object, including a human body: magnitude (how much acceleration); direction (an angle, theta); and the time duration of the acceleration, dt.

Numerous medical studies have shown that a human can withstand surprisingly high accelerations, more than 100 g's (one hundred times the acceleration of gravity) provided that the duration is very short (on the order of a millisecond, 0.001 seconds).

While NASCAR has indicated the magnitude of the acceleration sustained by the 19 car, they've said nothing about where the accelerometers were placed, the direction of the acceleration or the duration of the acceleration. But then, high g accelerations make for good headlines.

The 19 car was sliding down the track as well as heading for the Armco barrier.

Note the location of the TV camera and the extreme foreshortening of its images.

Looking at the event area in more detail, indicates the path and orientation of the 19 car as it slid and rotated, heading for the Armco barrier.

Acceleration is a change in direction and/or speed of an object. Mathematically if one looks at the velocity of the car going into the impact event and the velocity of the car leaving the impact event it is possible to construct a moment diagram of the event itself.

Momentum is shown in a flat plane, with two directions X (along the Armco barrier) and Y (perpendicular to the Armco barrier); the Z direction, straight up, is the angular momentum of the object (rotation). If one takes the sum of the momentum vectors, they must close, that is the sum of momentum going in minus momentum leaving must equal zero. The dV vector is the change in velocity during the impact event.

From what little information is available on You-Tube videos it would appear that the total acceleration for the center of gravity of the 19 car was on the order of 110 g's.

The duration was very short, video frame rate is 30 frames per second, the 19 car changes from going forward to going backward between two frames, i.e., 0.033 seconds. The peak acceleration probably lasted for less than 0.008 seconds.

The short of the whole story is that the track needs to be modified, the grass area between the track and the Armco barrier is less than 100 feet, not enough to slow a car while sliding through wet grass. One of the many people who have emailed me since my previous blog post suggested sand traps such as you see in F1 tracks, good idea but not enough room. The Pocono track back stretch is scary narrow for cars going 180 or 200 mph.

Now on to Watkins Glen and the fact that in the early days of auto racing, all courses were road courses.

Reconstructing the 19 car

2010-08-02T12:39:00.000-07:00

Mathematics gives you X-ray vision

Even better than the comic book version of Superman's X-ray vision mathematics makes it possible to "see" what is otherwise invisible.

The wreck of the 19 car at Pocono on Sunday was spectacular and perhaps an engineer's view might add a bit more insight beyond what was on television. For all the cameras the television networks bring to a race the wreck of the 19 car nearly escaped notice, until the aftermath became apparent. Search as they might it seems as if there were no images leading up to the impact of the 19 car with the inside wall (Armco barrier) on the back stretch of the Pocono track. However, mathematics allows one to look back in time and reconstruct the event with some degree of veracity.

There's an entire branch of engineering studies called "accident reconstruction" and having worked in that business this is a quick summary of what I saw on TV. Ordinarily a report on an accident would entail hundreds of hours of collecting data, detailed examination of the pieces of evidence (car parts, skid marks, measurement of impact points along the wall, etc.) followed by hundreds of hours of calculations. What follows is the result of a few calculations and measurements done from images gleaned from You-Tube postings on the internet.

After the parts stopped flying around, the 2 car and the 19 car were fairly well demolished, the 19 car showing much the worse of the bargain. This image is from Turn 2, the Tunnel Turn at Pocono which is patterned after one of the Indy 500 turns, in fact it is just about a perfect replica. The final skid marks of the 2 car are easily seen in this picture with the remnants of the 19 car sitting in the middle of the track some distance back.

A map of the track traced from a Google image provides some orientation of where this took place.

A more detailed sketch is shown here of the location of where the event with the 2 and 19 cars took place 19; again traced from a Google map and matched up with images from You-Tube postings.

Several images of the area were posted during the TV broadcast, some apparently taken from a helicopter.

A couple of salient features are immediately apparent; the skidding trail left by the 2 car, the engine block of the 19 car at the edge of the track, and the skid marks of the 19 car in the grass and on the track.

The scale of the track and camera angles were deceptive in the TV broadcast, things were not exactly what they seemed to be at first glance; particularly the impact angle of the 19 car. Translating the information in this photo to the traced map yields the following results.

The foreshortened view of the TV camera looking down the back stretch was particularly deceptive, not by intention but rather it provided the only images available. The 2 car in the middle left of the image is more than 400 yards from the camera, and the 19 car almost at its impact point in the lower right of the frame is 200 yard from the camera.

From the camera angle it appears as if the 19 car plows square, head on into the wall; the skid marks shown in photographs of the area indicate that the 19 skidded some distance from its impact point to its final resting point (FRP), and at a fairly shallow angle to the inside wall (Armco barrier) of the track.

The reflected angle of an impact is roughly equivalent to the incident angle, i.e., an object bounces off a wall, or fence, at about the same angle as it approached. You can conduct a simple experiment to verify this effect. The shallower, flatter, the angle is of the thrown ball with respect to the ground, the flatter the rebound is.

With a bit of trigonometry and a momentum diagram it is possible to reconstruct the approach of the 19 car to its impact point.

When this information is added to the TV image, the result is a bit different than first impressions. The 19 car appears to be driven straight into the Armco barrier of the inside wall of the track.

But it isn't.

The angle with the wall is actually about 20 degrees.

The 19 car rotates after its impact, although due to the low friction in the grass its center of gravity travels in nearly a straight line, like an Olympic racer on skates who falls in a corner, their body continues to slide on almost a straight line even though they're rotating as they skid.

The swirling skid marks in the helicopter view picture evidence the rotation of the 19 car as well as the fact that the front end damage is much greater on the right front than the left, and the engine didn't leave the car until about 200 ft after the impact point (when the 19 car went over the access road).

So while the 19 car took a huge hit, the perpendicular impact speed with the wall was probably on the order of 50 to 60 mph not 150 or 170 mph, the forward speed of the car.

While a 50 or 60 mph hit is huge, one should temper the comments on the structural integrity of the new NASCAR design a bit. Most new street cars with the latest air bag technology would have protected the driver in this impact just as well; the best of new cars also include crumple zones at the front of the car to dissipate energy in a collision. A passenger car is designed so that in a frontal impact the engine subducts under the vehicle, then front frame bends and crushes, leaving the passenger compartment intact. When I worked at Ford my office was next to the full-scale crash test facility (where the crash test dummies take one-way rides) and it was very instructive to examine the results of their tests.

Kepler in 1590 Explains Darlington in 2010

2010-05-07T21:59:00.000-07:00

Kepler Explains Darlington

The mascot for Darlington is a revised Kepler with a little help from the Hubble telescope and a large inspirational contribution from Gerrit Dou.

Kepler, an astronomer of the late 1590's, made the observation that "all things happen for a reason, and those reasons are the fundamental forces of the universe. If you duplicate the reasons you replicate the results."

This simple statement by Kepler essentially started all of modern science and mathematics.
Although known as an astronomer Kepler never made any observations of his own, his eye-sight was terrible; he worked out the mathematics from other people's data; notably that of Tycho Brahe. Delightful book, Heavenly Intrigue by Anne-Lee Gilder and Joshua Gilder, which suggests that Kepler may have murdered, poisoned, Brahe in order to gain possession of the trove of celestial observation data collected by his employer, Brahe.

One of the interesting bits Kepler gets credit for discovering is the fact that the quantity of

(V ^2 ) r,.. this is velocity squared, i.e., velocity multiplied by velocity then multiplied by radius r,

is the same for all planets; V is the velocity of the planet orbiting the sun, squared, multiplied by the mean radius, r, of its orbit yields the same number for all the (then known) planets. Kepler couldn't explain why this might be true, it was just a fact of observed data. The explanation would have to wait for almost 100 years and Newton, Leibnitz and the Bernoulli's.

The planets are held in their orbit by gravity; a race car is able to navigate a turn due to the pull of the wheels keeping it on the track which provides the same function as gravity does for the planets. Race cars can navigate a corner faster if a track is banked, higher banking allows higher speeds; and larger radius turns also allow higher speeds. If we write these processes into an equation and call it the Kepler Index, KI, then

where QS is the qualifying speed of a track, the Greek letter Beta, B, is the banking angle of the turns and r is the radius of the turns.

The Kepler Index, KI, is essentially the same number for all tracks,... except the SMI trio of Atlanta, Charlotte and Texas (more on that in the next post).

Moreover, Qualifying Speed can be fairly well predicted from the banking angle and radius of the turns on a track.

Whereas the size of the track alone is not very useful in predicting qualifying speeds but it is informative; note the difference between the qualifying speed at Pocono with its three distinct corners compared to the symmetrical tracks of Indy, and Daytona, with all three tracks the same size, 2.5 miles around 1 lap.

TV does not convey the distinctive nature of the various tracks, the contrasting differences are astonishing. Darlington is shown outlined in Black and it is easy to see why it was called the first super speedway, it's nearly the size of Atlanta. But note it is not symmetrical, turns 1 and 2 are much larger in radius than 3 and 4, moreover, turns 1 and 2 are more steeply banked (by 2 degrees) and the straight-a-ways are nearly flat. Richmond, site of last week's race is shown in the infield of Darlington, and Martinsville, the week before just outside the Darlington and Atlanta outlines.

This whole configuration would fit inside of the Talladega infield,….twice.

The asymmetry of Darlington is what makes it so challenging, turns 1 and 2 can be driven at a much higher speed than 3 and 4, not only because of the radius but the flatter banking of 3 and 4 also contributes to lower cornering speeds. If Richmond was the test of brakes and gear choice, then Darlington is the consummate test for the vehicle dynamics engineers and people who run the 7 post rigs. This is ultimate and confounding set-up problem for weight balance, springs, shocks, anti-sway bar, roll center, camber, and polar moment of inertia,..this is math modeling nirvana.

The races are much more distinctive than what a viewer would imagine by watching the race on TV.

The original calculation by Kepler from the Brahe data would yield the following graph (augmented by modern data for the three planets discovered since 1600).

The real painting of the "Astronomer by Candle Light" is by Gerrit Dou (in 1665); this detail is from a photograph taken by the J Paul Getty Museum ©.

And, finally, we have a new use for old incandescent light bulbs: turn them into oil lamps.

Talladega pas de deux: why restrictor plates necessitate contact drafting

2010-04-27T09:42:00.000-07:00

The official Talladega mascot:

Pas de Deux (pronounced as "pah-day-due"), Part 2

Restrictor plates necessitate contact drafting

Engine horsepower is not a single number, but rather a function of speed (engine RPM) and typically has a humped shape; power output increases with engine speed up to a peak and then drops off.

The actual horse power numbers for any given engine and differential gear ratio are a closely guarded secret by each shop. Even though we've seen the actual numbers this is a confidentiality we're not about to breach here so we'll show hp qualitatively (no numbers) but accurately.

A car must be pushed to ram it through the air; the required push (a force) increases proportionally with the square of speed, that is: Force, F = n x (speed x speed).

This diagram shows the pressure on and around a car going 190 mph, high pressure on the front of the car, low pressure behind it.

Those pressures applied over the frontal area of the car determine the aerodynamic drag. (Red is high pressure, blue is low pressure)

It is often informative to also look at the pressures on the surface of the car as well.

The power consumption (force x speed) due to aero drag increases with the cube of speed, that is: (speed x speed x speed), so it increases dramatically with speed, and it just keeps on going up. At 190 mph the force required to ram a NASCAR Cup car through the air is on the order of 700 lbs or more.

The net power (engine less aero drag) describes what is left for accelerating the car.

A plot of the difference between the two curves illustrates the frustration of drivers with restrictor plate racing, when the two curves cross there is zero left to accelerate the car and when the net power gets to zero that's as fast as the car will go.

Note also as the car approaches its terminal speed, the available power for acceleration is also approaching zero, i.e., the car becomes more and more "sluggish," it has no "throttle response," you push the accelerator pedle farther down but the car doesn't go any faster.

The only way to go faster is to reduce aerodynamic drag, hence, the newly realized pas de deux of two cars running nose to tail, literally touching and both cars together ramming the combined block through the air. Notice that the high pressure area on the nose of the second car fills in the low pressure void behind the lead car.

The result is to reduce the overall drag of the two cars together.

Even though the two cars together are not a smooth shape as one can see with the turbulence over the back of the lead car and on the front of the second car, but the combination of two cars pushing together has twice the horse power of one.

Moreover, the two cars have much less drag than the sum of two individual cars, about 27% less drag as shown in these studies.

As a result of the lower aerodynamic drag the speed at which the net power for accelerating the car is zero has increased in the pas de deux, contact drafting. Thus, two cars together go motoring right by a single car or a long string of cars.

While one might think that if two are good, then three should be better, but the dynamics of getting three cars actually touching nose to tail doesn't work. It is physically impossible to keep the front and back contact forces on the middle car centered for any period of time as the cars do bounce around more than a little. Even though the Talladega track is one of the smoothest tracks on the NASCAR circuit, the cars are not on rails and they move relative to each other. As soon as the forces on the middle car are not centered it turns the middle car around. Thus, three cars trying to run as a trio ends up either being two in a pas de deux plus a third as a trailer, or all three do get together and it's called a wreck.

A surprisingly small gap between the cars is sufficient to mitigate the drag reduction compared to two cars in contact with each other. The pas de deux with a trailer just isn't as streamlined as two.

Don't expect to see too much of the pas de deux formation at the Daytona race in July because the Daytona track is much rougher than Talladega so it is much more difficult to keep two cars in actual contact,…but I bet they'll try. With the repaving at Daytona now scheduled to be completed for the 2011 races it may then make DIS the second pas de deux track, sort of a pas de deux of pas de deux racing.

Next week will be the opposite end of the spectrum of tracks, Richmond, where the turns are the tightest (365' radius), except for Martinsville (188' radius), and the banking at 14 degrees is less than half that of Talladega; the race at Richmond is all about brakes and the right gear to accelerate. This is the track where the race car engineers get to show their skills, it's all in the set-up.

Again, these CFD studies in SolidWorks by FastTrack Racing Challenges for participating junior high and high school teams are possible due to the generous support of SolidWorks (visit their web site and look at the full software package at SolidWorks.com) and in particular thanks to Marie Planchard, their director of worldwide education markets.

Talladega Pas de Deux: why two is the magic number at 'Dega

2010-04-26T07:56:00.000-07:00

The official Talladega mascot should be:

Pas de Deux (pronounced as "pah-day-due")

Merriam Webster dictionary defines "pas de deux" as

1. a dance or figure for two performers

2. an intricate relationship or activity involving two parties or things

A funny thing happened in Alabama on Sunday. Suddenly for the first time in memory two cars in a pas de deux outran an entire string of cars at "the big track." Until now a long string of cars-- 5, 10, 15 or more cars-- always had the advantage,…a huge advantage because a string of cars always had less overall drag than one or two alone. But on Sunday suddenly we saw two cars outrunning the freight train; how is that possible when it never worked before?

As many TV commentators remarked repeatedly, "the closing rate of the two cars over the rest of the field is incredible," as much as 15 mph or 22 ft per second, a car length per second. When you're only 3 feet away from another car, they're going 180 mph and you're doing 195, closing on them at 22 ft per second makes the slower car appear as if it is sitting still.

Several factors explain the two car run away: Talladega was repaved in 2006 and the surface is unusually smooth, allowing cars to get very close to each, nose to tail, and stay that way for long periods of time. The geometry of the CoT has the nose and tail of the car at essentially the same height so the trailing car can literally push up against the lead car and shove it. Previously with the car dubbed the Twisted Sister if the trailing car pushed this hard on the lead car they'd lift the rear wheels of the lead car off the ground and they'd both wreck.

Also the CoT with a spoiler on it has a very different wake than with the wing (red is highest speed air flow down to blue which is the lowest speed air flow).

There's a very distinctly larger area of low speed wake behind the race car with the spoiler compared to the race car with the wing. The result is that the two cars can actually touch and stay in contact which reduces the overall drag of the two car duet, considerably, by perhaps as much as 30%.

Power consumption increases with the cube of speed (speed x speed x speed) so the observed difference of two cars together at 195 mph vs one car or a string of cars at 180 mph should have required (7.415/5.832) 27% more power to go that much faster, but actually what happens is that the two cars linked together in a pas de deux have 27% less drag as shown in these studies.

While the two cars have a huge speed advantage there is very little air flow reaching the front of the trailing car, which means that the engine of the trailing car will quickly overheat because cool fresh air is not getting into the radiator. This limits how long the two cars can continue their pas de deux, and from watching the race one would deduce that a couple of minutes is about as long as two cars can stay in contact (NASCAR Cup cars can run 2.2 laps at Talladega in two minutes).

Harvick played the final lap pas de deux perfectly, and then at the last possible moment swung around his dance partner (McMurray) to win the race by a mere 0.011 seconds.

After the race Jamie McMurray was quoted, saying, "it's hard to explain to you guys that aren't in cars, but when there's someone directly behind you and they pull their car out of line really fast, it's like you pull a parachute in your car. It literally feels like you lose 3 or 5 mph immediately, and when that happens, the car that's doing the passing just has the momentum."

It doesn't just feel like the car slows down, it actually does slow down. The aerodynamic drag on a car is the difference in pressure on the front of the car, minus the pressure on the back of the car, and that difference of pressure applied over the frontal area of the car is the drag force (pressure multiplied by area equals force), perhaps 700 lbs or so on a car going 190 mph.

When the cars are nose to tail the low pressure area behind the lead car is filled in by the high pressure area on the front of the second car.

But when the trailing car gets out of line to go around the lead car, suddenly there's a low pressure area behind the lead car and the drag force on the front car suddenly increases by as much as 400 lbs. This has the same effect as throwing an anchor out, it slows the lead car by as much as 5 mph almost instantly.

These CFD studies in SolidWorks by FastTrack Racing Challenges for participating junior high and high school teams are possible due to the generous support of SolidWorks (visit their web site and look at the full software package at SolidWorks dot com) and in particular thanks to Marie Planchard, their director of worldwide education markets.

Sun, Sand and HORSE POWER = Daytona

2009-07-03T15:24:00.000-07:00

1956 and Big Bill (France) started planning the BIG Track, and oh, what a time it was.

In 1956 we (the US of A) were on a roll, we’d won the war (the BIG one, WW II), we made more steel, cars, airplanes, TV’s, telephones, movies, radios, OIL, and just about every thing else than any other country in the world. And, we’d just launched the world’s first nuclear submarine.

The 1953 Buick Road Master—the name alone, Road Master, symbolized the era; at two and a half tons with a huge V-8 engine and an ultra smooth hydro-slush transmission it made a Greyhound bus seem like a nimble sporty drive by comparison. The car was so heavy and the ride was so smooth you could run over a concrete mixer and not notice it. We couldn’t make cars big enough, and we didn’t grasp the idea that there were limits to much of anything.
We had gasoline price wars, where filling stations would lower the price of gasoline to lure customers. In 1956, when Big Bill was planning the Big Track, during a price war in Cedar Rapids, Iowa, I filled up my ’47 Ford with gasoline, and took my date to Dairy Queen for malts, all on $2.35; gasoline was $0.09 a gallon.

And if gasoline was inexpensive, nuclear power was going to make electricity so cheap it wouldn’t pay the utilities to even meter it; in fact, we started designing nuclear powered everything: including cars.

The Daytona International Speedway mascot drawing is of a Ford Nucleon concept car circa 1956, and that thing which looks like a glorified spare tire cover on the back is actually the vent for a nuclear reactor. If you thought Ford had a problem with Pinto gas tanks, imagine a few million cars running around each with an unregulated nuclear reactor in the trunk. To understand the USA in the 1950’s you must realize that at the time we thought this was a good idea. A friend of mine worked at Westinghouse Nuclear, the company that built the reactor for the Nautilus, the first nuclear sub, they really were working on designing nuclear powered cars, trucks and trains. We were totally convinced that technology could solve all of our problems; we’d move to Florida or California and go surfing at least four days a week. Surfers were the icon of a carefree life; and the seemingly unlimited power of a nuclear engine symbolized our belief that we could run roughshod over everyone and everything. The term “ugly American” wasn't entirely undeserved.

As big and outlandish as the Daytona International Speedway now seems, and totally over whelmed by technology, it was a perfectly reasonable idea in 1956.

Build a track where race cars could go as fast as the engineers could invent motors to propel them, and the drivers had the nerve to keep their foot down. Same track length as the Indy 500 (2.5 miles per lap), but with two sweeping turns, and banked as steeply as could be paved with the technology of the day (31 degrees). If you’ve visited Charlotte, Atlanta and/or Texas, the tracks at 1.5 miles per lap seem incredibly huge, but they’re dwarfed by Daytona.

Talk about contrasts: from last week at New Hampshire a 1 mile track, and nearly flat (2 to 7 degree banking) to Daytona, 2.5 miles and about as steep as a mixing bowl (31 degrees). It is as far around the perimeter of Lake Lloyd in the Daytona infield as it is around the New Hampshire track.

And Daytona was indeed off to the races: faster and faster every year, until 1970, when NASCAR realized things (in fact the engineers and engine builders) were getting out of hand.

Detroit was producing engines with more than 400 cubic inch displacements, some were approaching 500, and at 195 mph the race cars were not staying on the ground. Old adage in engineering: given enough power you can make a lead brick fly.

Bobby Isaac won the NASCAR Cup Championship in 1970 and earned less than I did as a junior project engineer in a not very big steel company. A “well funded” NASCAR team had a sponsor, as in ONE, and a car, as in ONE. Isaac’s car still had windshield wipers on it, these were stock cars, even if Smokey Yunick did make a seven-eighths scale Chevy one year; sure had a lot less drag than everyone else had.

After a couple years of experimenting, NASCAR settled on the 358 cubic inch rule for engines in 1974, and there it has remained for 35 years.
Daytona International Speedway is completely out of the park in terms of size and banking (only other track in this league is Talladega); it dwarfs even the Michigan track, DIS is simply off the charts.

In 1956 no one thought the engineers could ever build a car fast enough that a driver would have to lift off the throttle, or that the cars would need to be limited in speed so as to not have them hurtling into the grandstands.

There's a "neutral" speed for a car on any turn of a banked oval track, the speed at which there is no side force on the car, neither up-hill or down, the rides around the turn only being pushed down squarely on all four tires.

The centripetal force tending to make the car slide uphill to the outside of the turn is just equal to the down-hill force (the pull of gravity) that is would make the car slide into the infield. Bigger tracks with a larger radius at any given banking angle allow for higher speeds. This graph illustrates the effect of turn radius on neutral speed as a function of banking angle.

Even at 31 degree banking the neutral speed at Daytona is less than 100 mph. At any speed faster than the neutral speed, the tire friction must hold the car and prevent it from sliding up-hill and off the track, or into the outside wall. If the tire-track coefficient of friction is 0.8 then one can calculate the maximum speed a car can go around any turn, if you know the radius and the banking.

The coefficient of friction is approximately the ratio of the force required to pull a car sideways divided by the weight of the car.

Coefficient of friction ordinarily varies between 0 and 1; good, new clean tires on a smooth asphalt highway and a passenger car tire might have a coefficient of friction of 0.6, on wet, smooth ice the coefficient of friction is less than 0.05, nearly 0. Hot, new, race tires on smooth asphalt may be 0.8 or 0.9.

The graph illustrates that the maximum sustainable speed through the turns at Daytona are on the order of 200 mph with optimal tire traction, somewhat above the speeds now encountered with restrictor plates. But as the tires wear and friction decreases (lower friction values in the graph) the cars are capable of going at the very limit of the tires, and beyond, which is where the driver skill part of the equation comes into play.
Adhesion of the car to the track is improved by adding down force, in the form of aerodynamics, the shape of the car and its attitude (pitch of the car, nose down), which acts to push down on the car.

An airplane wing is designed to lift the craft off the ground, race cars are intended to be inverted airplanes where the aerodynamic shape is intended to add down force to the car and push it down and increase the load on the wheels—making the tires stick better to the track.

The keys to running well at Daytona can be distilled down to two elements: (1) the right set-up so that all four tires work almost equally, thus minimizing the rate at which the tire adhesion decays with laps.

How far down the purple line, at 31 degree banking, does your car degrade as the laps build up? The car with the best combination of springs, shocks and sway bar will have the best tires and the driver can maneuver the car where they want, following the draft at will.

(2) The second key element for Dayton is "The draft," several cars in line have less drag than the same number of cars running individually.

To a large extent the closer the cars are together the better, aerodynamically at least; up to the point where they touch and then it’s not such a great idea.

With restrictor plates limiting the power and hence speed of the cars, the aerodynamic down-force on the cars is actually secondary to the banking of the track. In order to keep the cars on the ground and out of the grandstands it is necessary to reduce or limit the power, consequently speed, that can now be produced by a 358 cubic inch engine, albeit an archaic design at that.
By 1970 the engineers and engine builders had trumped the concept of big high banked track designs, just eleven years after the first race at Daytona. A 358 cubic inch engine is equal to 5.87 liters, nearly twice what is allowed in F1 (3.0 liters) and yet the F1 cars go faster because they develop nearly twice the power of a NASCAR Cup engine. But F1 cars have a huge down-force from their wings, more than three times the weight of the car, compared to a down-force of less than one-fourth the weight of a NACSCAR Cup racer. With NASCAR Cup cars in their current configuration, DIS is a dinosaur: run over by technology.

We’re not going back to 1956 in any sense of the word.

Can NASCAR re-invent racing, and make tracks such as Daytona and Talladega relevant again?

Land of the Damn Yankees

2009-06-25T18:23:00.000-07:00

NASCAR racing in its essential form has been preserved in New Hampshire, ironically in the land of the damn Yankees.
In early colonial times New York City was called New Amsterdam because it was owned by the Dutch, but it was a hotly contested area with the British.
The derisive Dutch term for Englishmen of the day was “John Cheese,”—due to their affinity for the food of the same name— the intended slur if pronounced with a Dutch accent sounds like “yan kees,” that became "Yankees." New England colonists of the British persuasion actually liked the term and adopted it.
The mascot for New Hampshire International Speedway is the "Quarter Minute Man," the pit crew that can at the drop of a yellow flag consistently turn fifteen second, one quarter of a minute, pit stops all day.
There are several “Minute Man” statues, but the pit crew “Quarter minute man” is patterned after the statue by Daniel Chester French (the real Minute Man is on display at Concord, MA, not New Hampshire, but it’s only 40 miles from NHIS)—French is better known for his statue of Lincoln which resides in the Memorial in Washington DC.

New Hampshire is yet another 1960’s track, originally built as Bryar Speedway, a sports car road course replete with a lake in the middle of it. Too bad the lake’s been filled in, as it would make for an interesting challenge; if you are speeding leaving pit road you could end up in the lake. A new sign would have to be added inside the cars: “In case of a water landing your seat cushion may be used as a flotation device.”

Rebuilt in 1989 by a new owner and changed into an oval which incorporates one turn of the old track, New Hampshire is among the slowest (average speed) tracks on the NASCAR Cup circuit; Dover and Rockingham (before it was cut from the schedule) also 1 mile tracks, are both much faster.
However, New Hampshire preserves the essence of racing: finding the elusive optimal combination of driver, set-up, engineering (gear ratio in particular), and racing smarts. This track is oval racing at its finest, purest form. And it is due to the geometry of the track.

New Hampshire is among the flattest (2 to 7 degree progressive banking) of the 1 mile tracks and it also has the smallest turn radius, hence the lowest record qualifying speed (Phoenix, also a 1 mile track is much steeper —11 degree banking—and also has a larger radius turns, hence, qualifying speeds are about 2 mph faster than at New Hampshire). The relatively long drag race straights make up, to some extent, for the tight, flat turns.

To understand New Hampshire it is necessary to look at the detail of the corners.
Due to the laws of physics it is actually rather easy to predict fastest qualifying speed based on the geometry of a race track. If Michigan is big and steep compared to a general trend line of track designs, then New Hampshire is way off the trend line in the other direction--way, way off the trend line: small radius turns and flat.

An index that describes a track by a combination of size (distance around one lap) and banking angle is a good indication of maximum average speed a racecar obtain. There are a couple of notable exceptions, Pocono being much slower than the track geometry would suggest (because it is three different turns defying all attempts to optimize a car set-up for all three). The other is New Hampshire, also much slower than the geometry of overall track length would suggest. Physics of turning, described in the previous graph on banking and turn radius explain this outcome.

Since next week is back to Daytona, juxtaposed to New Hampshire, it illustrates the extreme contrasts in track design philosophy. New Hampshire speeds, from its road course antecedents, are limited by technology: adhesion of the tires to the track, requiring that the driver slow down for the turns thus lap times are a mixture of driver, machine, and engineering.

Daytona, like Indy, was designed with the idea of having a track where race car drivers could just wind it up and blow it out, no limit other than engine building and driver nerve: run wide freakin’ open the whole way around the track. In the fifty years between designing Indy (1908) and Daytona (1958) it was necessary to increase the banking of the track dramatically in order to run wide open.

Somehow, track developers don’t seem to bother looking at trend lines which are a consequence of engineering and technology. Engineers are forever trying to find a way to improve things, in the case of race cars, go faster, more reliably, using less and less fuel. It should have been evident from looking at the trend of qualifying speeds at the Indy 500.

The sudden jump in qualifying speeds in 1971 and onward can be explained in a single word: aerodynamics, and wings in particular. From this point forward the essential problem with racing is going to be to limit racing speeds to keep the cars out of the grandstands.

The problem of going fast, with a reliable machine had been solved; and it overwhelmed all then extant track designs.

In just a year more than a decade of racing Daytona was faced with the same problem, slowing the cars down in the interest of safety: for both drivers and spectators. The first attempt at this was to limit engine size, but NASCAR doesn’t seem to understand how engineers think and this was simply a delay not a change.

The engineers quickly found ways of increasing power even in a reduced engine block (the 358 cubic inch displacement rule still in place today). Finally, in 1988 restrictor plates were introduced and now cars are limited by a rules committee; engineering and driving have been marginalized.

Engineering and technology overwhelmed the track design,...20 years ago.

But real racing lives on, go to New Hampshire and see it; on the way there stop in Philadelphia, Boston, and Concord (both of them) and walk the trail of American history, it’s a fascinating tour.

And look for other Daniel Chester French (1850-1931) statues along the way, he was the preeminent sculptor of the day.

Driving Mr. Kahne

2009-06-24T17:29:00.000-07:00

It was uphill the whole race.
Road Trip …to Sonoma and back (Part 2)

Hopefully everyone watching the race noted that Kasey cemented his race win on the restarts, pulling ahead of the 14 car going uphill through turns 2 to 4; there’s a reason why that worked, and he did it in California where you are your car.
The automobile, specifically American iron from the Detroit Big Three, was the quintessential icon of the USA at its uncontested zenith, the two decades from 1950 to 1970. And California was the epicenter of the car era.
In the 1960’s new state of the art road courses were built at Riverside, and Sears Point (Sonoma). But acting as a true bellwether for the direction that our country was headed, Riverside Raceway closed in the 1980’s and is now the site of a shopping center.
When the streets were ruled by American iron and the heart of every youngster captivated by Annette and Frankie, we all longed to be in California; trouble is too many of us actually went there.

The mascot for Sonoma, Infineon Raceway, should be the
Indy-NASCAR-American LeMans Series woodie, with a motorcycle tied to the back of it.
In the '60's racing was still the test ground of the automotive industry with series such as CAN-AM which allowed almost anything with 4 wheels and an internal combustion engine to be raced, resulting in some truly ingenious machines (unfortunately, some fatally dangerous ones, too). Going fast for long distances was still a technical challenge and the machinery had not yet overwhelmed the track designs. Road racing was the consummate test of driver, machine and technology, a few laps of racing was more informative than months or even years of running production cars at street legal speeds.
In the 1960’s Henry Ford II (Henry’s son) wanted to include one more jewel in the company crown, a testament to the most successful car brand in history, to own Ferrari and dominate racing. Enzo Ferrari didn’t just say “no,” he said “hell, no,” in such an unpleasant manner that a rebuffed Ford II returned to Detroit still stinging from his rude rejection and ordered the Ford engineers to bury Ferrari at their most prestigious event: the 24 Hours of LeMans.

And they did; not just winning the race, but in 1967 finishing 1—2—3, several laps ahead of the nearest Ferrari in 4th.

Road racing had originated in Europe, partly for want of real estate; land was very expensive and it was much simpler to commandeer a few city streets for a race than building a track. The idea caught on in the US, and from 1908 through 1911 the world driving championship was decided in Savannah, Georgia, on a road course that used several city streets (fascinating book for history buffs, The Savannah Races by Dr. Julian K. Quattlebaum).

Oval racing was the singular province of America, starting in the 1890’s with horses running on simple dirt tracks at just about every county fair ground in the country. Bicycle companies then took advantage of the facilities and brought touring companies of riders and board tracks (assembled over the fair ground horse track) to stage races and market their product—the first iteration of “race on Sunday, sell on Monday.”
Car companies took up the idea and oval dirt track racing (along with board tracks) became a main stay of the American scene. It quickly became evident that speed was limited by a combination of the size (radius) of the turns and the banking of the track. Because the basic physics haven’t changed, this is still evident in a plot of record qualifying speed as a function of track length (as a general rule, larger tracks have bigger radius turns).

Note that at 2.5 miles, there is a group of tracks in a vertical line with Talladega and Daytona at the top, then Indy, Pocono, Watkins Glen and Sonoma at lower qualifying speeds: it’s in the banking. Daytona is steepest at 31 degrees, then Indy at 8, Pocono with three different turns (defying all attempts at finding a set-up that is optimal for all three curves), then Watkins Glen a road course with flat corners, and slowest of all, Sonoma with flat corners and a big elevation change—160 vertical feet—equal to a 16 story building (cars can’t go up and downhill as fast as on a flat course).
Elevation changes aren’t captured well on TV and so Sonoma is not fully appreciated by a viewing audience that hasn’t visited the venue in person, or been to some other road course track has significant elevation changes (Road Atlanta, Lanier, Georgia, being an interesting example).
It is amusing to follow the racing articles and blogs that complain about “the cookie-cutter” (somewhat similar 1.5 mile) tracks on the NASCAR circuit and then deride the tracks which really are different: Pocono and the road courses.
Shifting gears while turning left and right and also racing at the same time is an integral part of every NASCAR race, on oval courses they’re called pit stops. The majority of lead changes on oval courses now occur during pit stops, so this much maligned aspect of racing has become the best way to advance your track position on every NASCAR track. Think of road racing as very long winding pit roads with no arbitrary speed limit, just the speed limit imposed by the physics of the track and car set-up.
That Kasey Kahne secured his win by being able to pull ahead of the 14 car while going uphill is a testament to engine design and gear selection: the right engineering makes winning possible every time. Lifting a 3400 lbs car a height of 160 feet requires work, a lot of it, namely 3400 lbs x 160 ft = 544,000 ft*lbs (equal to lifting a 100 lbs weight from sea level to Denver, one vertical mile). The time in which this work is done is power (work divided by time equals power). But most significantly, the work done in lifting the 9 car ahead of the 14 isn’t done at a constant speed; the cars are accelerating. This is in racing jargon the essence of “power curve” or “power band” for an engine, the rate of work done by an engine at various speeds.

The new engine in the 9 car developed with the help of Dodge engineers has a broader power band and can provide close to maximum work over a wider speed range; this is what engine builders are paid to design and calculate. The maximum or peak power, what NASCAR measures, is still the same as before, but the power band is greatly improved.
Next week, New Hampshire, will be an entirely different problem, look back at the graph of qualifying speeds as a function of track size: New Hampshire is one of the flattest (12 degree banking) of the 1 mile tracks with the smallest turn radius, hence the lowest record qualifying speed (Phoenix, also a 1 mile track is actually flatter—11 degree banking—but has a larger radius turns, hence, qualifying speeds are about 2 mph faster than at New Hampshire

Road Trip: Driving to Sonoma (part 1)

2009-06-21T10:01:00.000-07:00

To Sonoma and back, an American Saga

Most of the larger NASCAR teams get their Infineon Raceway road course racecars to Sonoma via Michigan in a “double,” a transporter that can haul 4 cars compared to the usual two. First leg is Charlotte to Detroit then turn left to Michigan International Speedway where the cars for MIS are dropped off while the two remaining cars destined for California continue on to the coast.
The track now known as Michigan International Speedway was dreamed up in the mid-1960’s when America was best described by the song lyric,…”we are the champions,…of the world” (written 25 years later by Queen, 1991).
Construction on the Michigan track was started in 1967, and the first race season began in October of 1968 with a USAC Indy car race. The track at Sears Point (Sonoma) was also started in 1967 and its first race was a SCCA Enduro, held on Dec. 1, 1968; twins separated at birth?
In 1967 we were the biggest, wealthiest, most powerful industrial society the world had ever seen. We produced the most, the best of nearly everything, from steel, to cars to movies, to telephones, and oil, too. In 1967 we were also one of the world’s largest oil exporters. We had it all.
The Michigan track measures a full 2 miles around one lap, and banked at 18 degrees in the turns.

Our cars in 1968 were great land yachts made of steel and iron, and there seemed to be no end to the engine size race from Detroit; comics of the day lampooned the Big Three for producing cars such as the Behemoth 11, with room for your entire football team (along with the cheerleaders), powered by the new V32 BelchFire 9000 engine (available only in Texas because you needed a private oil well to fuel the thing). It was funny because it was almost true.
The mascot for the Michigan International Speedway should be the Big Block.

The Big Block, 8 cylinders, 3072 cubic feet of displacement, made of solid American—by god—Iron.

MIS is an interesting track, 75 feet wide (equal to 5 standard Interstate lanes), huge sweeping turns and banked at 18 degrees which is steep by Indy car standards, although by NASCAR measure rather flat (Atlanta and Charlotte are 24 degrees, Daytona is 32 degrees, and Bristol is banked at 36 degrees).

There’s a trend line of banking and turn radius for the vast majority of tracks in the USA, shown here as a red fuzzy line, from Bristol to Milwaukee, nearly every track fits this pattern, with a few exceptions, Michigan being one and it is way off the trend: much steeper banking for tracks with a comparable turn radius.

As a result, the world’s record for a car on a closed course was set by a CART racecar (234 mph) on the Michigan track.
“C'mon and turn it on, wind it up, blow it out—GTO” (1966, Ronnie & the Daytonas); we were all going to California on Route 66 with the Beach Boys playing on the radio.

But 1969 was also the year of Woodstock, the hippies in Haight-Ashbury (San Francisco), and my father bought a VW beetle.

Only the morning sun rising in the west would have been more shocking, as Bob Dylan would sing, “the times are a-changing.”

Indeed, and today General Motors is bankrupt.
I grew up in a household where the idea that “what’s good for General Motors is good for the USA,” was a gospel fact; the universe revolved around Detroit and its center was built of American iron.

In 1968 the top 50 GM executives made more (including stock options) than the President of the USA, the Vice-President, the military Joint Chiefs of Staff, 9 Supreme Court Justices, 435 members of the House of Representatives, 100 Senators, and the Governors of all 50 states—combined.

The year is now 2009, not 1969, and it was great fun to watch Mark Martin win another race, but he’s fifty years old. And my personal hero for aging interestingly if not quietly, Paul Newman, drove racecars until he was in his 80’s.

The recollections, however, just made Michigan a poignant and profoundly sad weekend. The story of what America once was, and unfortunately Mark Martin is the image of racing past, not racing future.

Detroit now has half the population it did in the 1970’s; vast areas of the city look like pictures of Berlin in 1947, and the 11th largest city in the country (almost 800,000 people) doesn’t have a single brand name grocery store. Wayne County (Detroit) is the poorest county in the country, it is a veritable wasteland.
The half hearted attempt by the Detroit Three to pretend they were still in the race seemed more like a wheezing 70 year-old trying for his last hurrah by playing street hockey against a bunch of teenagers. It isn’t a pretty picture.

After Michigan it is on to California; the trip feels like the American saga as told by the NASCAR schedule, we left the cold winters of Michigan to move to the sunny west coast, allowed our essential manufacturing capability to rust away while we dreamed that we’d all build computers in Silicon Valley, write clever software, go surfing everyday and get dot-com rich. Instead we find ourselves hedge-fund screwed
America, which is to say California, in the 1960’s and ‘70’s was the zenith of the car age: TV shows such as Sunset Strip, and the movie American Graffiti captured the era with Norman Rockwell clarity and pathos. Your car defined your station in life, and your car came from Detroit.

Part 2 after the checkers wave at Infineon.

Doin' the Pocono Pretzel

2009-06-03T20:31:00.000-07:00

Pocono 500

The mind bender track for crew chiefs and racecar engineers

Stroll back in history to 1971, when suddenly one day a successful, busy, wealthy Philadelphia dentist decided he’d had enough of the daily grind—seven days a week for eight years—he just packed it all in and went on holiday. The Pocono Mountains were the east coast getaway place; Dr Mattioli bought into some property for its land value and somewhat to his chagrin found himself also in the race track business. Long Pond, Pennsylvania, a little village less than 75 miles from Times Square in New York City, and less than 100 miles from Constitution Hall in downtown Philadelphia, it was a perfect market to attract the big city crowds.

What must have seemed like an incredibly clever idea: pattern your new race track after the most famous tracks in the country. Trenton Speedway, in Trenton, New Jersey, then the premier track on the east coast; the Indy 500; and the Milwaukee Mile, then the most famous track in the Midwest (less than 100 miles from Chicago). Use only proven designs and you don’t have to pay an architect to in an attempt to create something better than what was already considered the best race tracks in the world.

The Mind Bending Pocono Pretzel

Dover has Miles the Monster, Atlanta and Lowe’s have Lug Nut, Pocono needs the Pretzel, mind twistingly difficult to set-up a car for all three turns.
Opened for racing in 1974 the Pocono Speedway is unique in that it has three distinct turns, each one duplicating a turn of the most famous tracks of the day, and the track is huge: 2.5 miles for one lap, same as the distance around the Indy 500 track.

Turn 1 is the Trenton turn, 14 degree banking, radius is 500 feet a virtual copy of what was really an unusual track. The Trenton Speedway built on the grounds of the New Jersey State Fair property started automobile racing in 1900.

Trenton was a mile and a half course considered to be a 5 turn track, a kidney shape with a right hand turn in the middle of the back straight-away.

After eight decades of motorsports, the Trenton Speedway closed in 1980, and the New Jersey State Fair Grounds became the sculpture garden of an art gallery.

A drawing shows the comparison of Pocono, Trenton and Darlington.

Once around Pocono Turn 1 (the Trenton Turn) the cars race down the Long Pond straight-away (named for the stream that parallels the track) and into Turn 2, now usually called the Tunnel Turn, but its real name is the Indy turn. Again an accurate duplicate of a turn at a famous track, this one is Indianapolis. It’s a full left hand, 90 degree turn on a radius of 860 feet, with 9 degree banking in the corner, a carbon copy of the Indy track.

Then the cars race down a “short chute” (just like Indy) before entering the next turn, but this one is a corner from the Milwaukee Mile.
Racing started in Milwaukee on what was a one mile dirt oval in 1903, with races every year until 1953 when it was paved. Racing has been uninterrupted, now on a paved Milwaukee Mile making it the oldest continuously operated race track in the world; hosting races for every major racing series for more than a century. The winners at the Milwaukee Mile is a list of the most famous in the world from the ancients such as Barney Oldfield, Ralph DePalma, to A.J. Foyt, Mario Andretti, Bobby Rahal, Jim Clark, Alan Kulwicki and now Jeff Gordon, Dale Jarrett, as well as Dale Earnhardt, Jr.
After the Pocono Turn 3 (the Milwaukee Mile turn) the NASCAR Sprint Cup cars run down the front straight, 3780 feet, nearly three-quarters of a mile in length. Until very recently stock cars shifted gears on the front straight because it was so long and the engines would reach such high RPM’s that without shifting the engines would expire long before the 500 miles did. Now, better engine technology and NASCAR rules about gear ratios have eliminated the gear shift.

When racecars did shift gears many drivers called Pocono a “roval,” a cross between a road course and an oval, or a three turn road course connected by very long straights.

TV commentators make a great puffery about Darlington because the two ends of the track are somewhat different compared to all other ovals which are at least intended to be symmetrical. But the difference from one end to the other at Darlington pales in comparison to the differences in the three turns of the Pocono Speedway.

There are two critical elements to a turn, the radius of the corner and its banking, the illustration below shows those parameters for a few tracks.

Notice that the Darlington parameters for the two ends of the track are relatively close together and not all that far off those of Atlanta (which is also similar to Charlotte, and Texas). But the Pocono turns are WAY OFF, and each corner is vastly different from the others. It is simply impossible to find an ideal set-up for all three Pocono turns because they are from three completely different tracks.

But instead of mind bending the crew chiefs to set up just one common NASCAR Sprint Cup car to run all three turns, what if you could bring a car that was designed along the lines of the Pocono track concept; three different kinds of race cars bolted together to make a single vehicle.

What would that look like?

We invite you to send us your version for solving this puzzle; and enjoy the race at Pocono.

Dover Monster tamed by math

2009-05-28T17:15:00.000-07:00

Dover Monster Mile

The track that grabs cars as they exit the turns 2 and 4, and chews them up (crashing the cars against the outside wall)

In an interview Elliott Sadler described driving the Dover track as feeling like an amusement park roller coaster ride, however, he didn’t seem to realize he'd explained the car crushing feature of the Dover “Monster.”

It’s all about transitions, from the banking in the turns to the banking along the straight-aways. The track is 1 mile around (measured 30’ inside the outside wall, NASCAR rule), and has 24 degree banking in the turns (same as Atlanta and Charlotte—Lowe’s—) and 9 degrees on the straights; but as the track is only two-thirds size of the other two, the radius of the turns is smaller.

This photo (taken in the stands from Turn 1) shows how the track looks in person, along with section lines drawn into the picture to illustrate important points in the turn.

This cartoon sketch exaggerates the track but shows the idea, at section 1 the track is still banked at 24 degrees, by the time one gets to section 5, the banking is down to 9 degrees, as a result the runs uphill from the apex to line 1, over a crest (line 3) and then it is literally a down-hill run at the end of the turn exit (line 5).

In the traditional car chase scene over the hilly streets of San Francisco the hills are so steep that the cars literally are flying after they crest the hill. This is because the car drops at the acceleration of gravity, 32.2 ft per second per second; but if the road is dropping away more quickly relative to the forward speed of the car, then it goes air borne.

One can imagine in this sketch that if the car is moving slowly it stays on the ground, but at high speeds it does not. If one knows the curve of the hill it is easy to calculate the maximum speed that will still have the car on the ground, or conversely, the minimum speed to get it air borne (this is the essential calculation for stunt teams in doing ramp jumps).
Relative to the track at Dover, the crest of the hill for the drive path of most race cars occurs at about section line 3. Now if we look at the vertical profile of the drive path of the race car around the turn, it becomes more apparent what the effect is.
The car doesn’t need to actually become air borne to significantly change the handling of the car.If the car is still turning, the driver hasn’t straightened out yet, and the tires are pushing at their maximum side thrust to keep the car from sliding sideways, then unloading the car just a little bit, due to the road dropping away too quickly, results in the car seeming to “jump” sideways (and often into the wall).
The spring rates in a NASCAR Sprint race car are on the order of 300 lbs per inch, so if the racetrack drops away just 1 inch too much (the car continues on its arc as in the San Francisco car flight illustration, but the wheels follow the road) then the frictional load on the tires is decreased by 1200 lbs (300 lbs per inch of spring x 1 inch elongation of the spring x 4 wheels = 1200 lbs reduction in wheel load on the ground).

The teams which have 7 post rigs can predict the wheel loads for any given drive path on any track for which they have an accurate survey. It then requires a crew chief and driver to talk to the race car engineers to understand the relationship between drive path and ability of the car to turn at any given speed.

Consider an entire turn.

At point A the driver is at maximum speed from accelerating down the straight-away, and this is their lift point, the spot where they get off the throttle and onto the brakes to slow the car. As the car turns in, point B, the car is slowing and the driver is turning more to the left. By point D the car is at it slowest and the driver has turned the wheel to the maximum for this curve. From point A to D the car has been literally going down-hill due to the banking. At point D the car starts going up-hill, the driver starts accelerating and decreasing the turn of the steering wheel. As the race car exits the turn, through points E, F, and G, it is accelerating and going up hill, all the while decreasing the amount of turn in the steering wheel, the car is straightening out for the run down the next straight.

However, if by point G the car is still turning, and running as fast as the tires will allow without sliding, then as the car crests the hill at G and starts down towards section line 4, the wheels will partially unload and the car will suddenly slide sideways towards the wall: it actually appears to “jump” sideways.
Watch for TV views from the vantage point of looking down the straight-away towards a turn and see how often a car “jumps” sideways to get crunched by the Dover Monster.

Some drivers can learn intuitively what the drive path is that will allow them to defeat theDover Monster, but it’s a slow process; much easier and quicker if you have a good engineer.

All the big teams with 7 post rigs and race car engineers can calculate the path and show the driver where it is and at what speeds (engine RPM) they can negotiate the turn. The 7 post rig also allows the team to evaluate different set-up combinations, springs and shocks, for a given track, before they ever leave their race shop. This is in part why the well funded teams are the only ones that win, with the exception of a weather fluke as last week in Charlotte (Lowe’s).

Just having sophisticated equipment such as a 7 post rig is in itself not sufficient to win races, the crew chief must be technically astute enough to understand and utilize the information which engineers can provide; this is the essential skill of some one such as Chad Knaus (for the 48 car), Steve Letarte (for the 24 car) and Alan Gustafson (for the 5 car) in the Hendrick operations.

Carl 2 Long

2009-05-22T19:32:00.000-07:00

Carl 2 Long
Or is NASCAR too short, again?

So, Carl 2 Long was found to have had an oversize engine, 358.17 cubic inches, over the allowed 358.000 as per the NASCAR rule book.
Not to be insulting but Carl Long is a back marker, something like 63rd in points the last time I checked; the 46 car wouldn’t be a threat to pull an upset win if you spotted them 17 cubic inches, much less 0.17 cubes.
It’s math time, students. First of all 0.17 above a limit of 358.000 is 0.04748 %, or less than half of one-tenth of one percent. If you weigh 180 lbs and take two quarters in change out of your pocket, you will weigh less (about 0.047 %), but it doesn’t mean you’ll suddenly be running the wheels off of Lance Armstrong in a bicycle race.
And how would you measure this difference?

The number we want is the total displacement of the pistons in the engine (the volume that is swept by the pistons moving up and down inside round tubes called cylinders), which are inside the engine block.

The idea is simple: measure the distance a piston moves, called the stroke, and multiply it by the area of the cylinder, remember that algebra thing?

However, since we measure diameter, we use

and area becomes

The area is pi times the square of the diameter of the cylinder all divided by 4; easy enough. But the level of precision required is not so easy.

A standard piece of notebook paper is approximately 0.0025” to 0.0035” thick, depending on the quality of the paper, the humidity and temperature of the room and if you’ve touched the paper. The make or break measurement for Carl 2 Long is on the order of 0.0005”, or one-fifth the thickness of one sheet of paper.

Now think of measuring out a ribbon that is to be three and a half feet long, 42,” and cutting it precisely to 42.000” in length, 41.999” is too short, 41.001” is too long. What does that look like? If you’ve measured out a length that is precisely 42.000” in length, see the arrow in the picture.

You must now cut it to precisely that length, and a line is drawn where the cut is to be made. If you cut to the left of that line, it’s too short, if you cut to the right it’s too long, you must cut right down the middle of that pencil line, the line itself is too wide to help, it is 0.0197” in width. You must measure to a level of precision that is one-sixteenth the width or thickness of this line.

In machine shops there are tools, called dial calipers, which have a precision of 0.001” (a tape measure at best has a precision of 0.0625”, too crude by a factor of 62).

Shown here we’re measuring the diameter of a piston from an RC car.

Imagine yourself to be a dutiful NASCAR inspector: does this piston have a diameter of 0.735” or 0.736”? The dial indicator is in between. If your call is 0.735” then Carl 2 Long must be renamed as Carl The Legal; and if your call is 0.736” then Carl 2 Long is a cheat and a liar. Notice the indicator doesn’t have another level of precision, so we can’t say precisely if it is 0.735” or 0.736.” The precise number is something between those two values. Now you the honest, diligent inspector, must make a judgment call.

To be really thorough, the inspector should measure each of the eight cylinder diameters and strokes (not just one and then multiply by 8). The dial in our one example seems slightly over the rule limit of 0.735”. But the next one might be slightly under, and the total of all 8 cylinder measurements would still meet the rule.
Just for laughs say that the engine which Carl 2 Long ran had a stroke length of precisely 3.250000000” allowing a piston diameter of 4.187066887” inches to meet the 358.000 cubic inch limit (never mind that this level of precision is down to counting individual molecules and there’s no way to do so).
But, just as in the example above, when you measure the piston diameter, it seems to be between 4.187” and 4.188”. Look at the dial in the picture above, if you say you’re going to “round up” and call that dimension 0.736” or, 4.188” in our example, then Carl 2 Long gets shorted 200 Large (street slang for fined $200,000). If you think the dial is slightly less than half way between the two lines and you round down to 0.735” (or 4.187” in this example), then Carl The Honest has been unfairly taken to the cleaners.

On the one-hand, NASCAR publishes a finding which purports to have found an overly large engine, but without any supporting data. What measurements were taken, by whom, using what piece of equipment? The NASCAR rule is 358.000 cubic inches but they only report 358.17 cubic inches, this alone is too crude a measure by a factor of 10. To put this in perspective it is the difference between 1/10th scale RC cars and real, full size cars.
Measurements at this level are very demanding, and now the consequences have been made very painful ($200,000 in fines and parked for 12 races), but so far the published reports don’t support the charges against Carl Long.
There are other micrometer calipers which can measure precisely down to 0.0001” but there’s no published supporting paper indicating that this was done.

In the world of technical experts who testify in liability trials, the case NASCAR has made public seems particularly weak and ill-founded at this point. Perhaps they have better data. For the sake of credibility this would be an excellent time to produce the numbers.

Acceleration

2008-03-13T21:45:00.000-07:00

Acceleration, in the world of engineering and science, is a change in speed or direction; the rate as which change takes place. For all the sudden interest, rather belatedly one might add, in the price of oil the price is actually just following the trend of the last 7 years: it's right on track. The data for the graph is from EIA (US government), the trend line (a second order regression) is by prof pi.

The price of oil is increasing for several reasons, speculation by investors (to some extent) but most importantly, world production is flat and has been for the last three years while oil consumption by China is increasing at nearly 20% per year and India is not far behind. Very simply, more people want their part of a what is a limited supply.

Gasoline at $4 per gallon by the summer of '08 and nearly $6 by the summer of '09; unless there is a major US recession the rest of the world will buy what we don't use.

Prior to the year 2001, the price of oil had been nearly constant for almost 30 years, an entire generation.

The world has been pumping oil out of the ground for more than a century, and many of the largest, and oldest, oil fields are now in decline (as the mathematical model by M. King Hubbert would predict).

The continental US is now down to about half the rate of our best year (1970), and our production continues to decline. Cantarell in Mexico, the Alaskan North Slope, the North Sea, etc., are all in decline. For the next four years there are enough new major fields coming online to off set the decline of existing production.

After 2012, the rate at which the price of oil is increasing is going to jump dramatically. There won't be any new fields to offset the depletion of the existing fields.

The demand for oil in the years beyond 2012 will greatly exceed the supply capability of the existing oil industry, both OPEC and non-OPEC combined.

Big oil producing operations are huge engineering projects, requiring years from concept to funding and construction. Anything due to come on line in the 2013 to 2015 time frame needs to be well underway now; there simply aren't any such projects.

One of the strangest after effects of the Spitzer stupidity is that his replacement seems to be (a) aware of the peak oil problem, and (b) willing to articulate it. Difficult to imagine but some public benefit may actually arise from such folly as the last week has seen.

In the words of H. L. Mencken, "politics is the only thing that exceeds sex in which the pursuit is more costly, the pleasure is more fleeting and the position is more embarrassing." It's not clear that even one as cynical as Mencken had imagined what combining sex, politics and relentless TV coverage could wreck.

Thanks for taking a lap around the track with me, see you on the next pit stop.

Creative Failures

2008-03-08T08:14:00.000-08:00

The world of NASCAR is an interesting sand box in which to play; it is its own little set of rules. As with most everything from the classroom world of school administrations playing in the "No Child Left Behind" sand box to auto racing playing to sponsors' marketing efforts: rules shape the entire program.

Oil Tank Box Covers

The Oil Tank in a NASCAR race vehicle is located in a fabricated metal box behind the driver's seat, as indicated in this photo taken of a model Cup car.

NASCAR appears to want a "racertainment" series based on a cult of driver fame and corporate marketing, while trying to minimize the science and engineering development of the machine, i.e., the car. "Racertainment" is a word combining "racer" and "entertainment" coined by Peter DeLorenzo, author of the most excellent website http://www.autoextremist.com/; it is highly recommended reading for anyone interested in all things about the automotive industry.

The latest NASCAR flap, oil tank box lids, typifies the result of trying to control ingenuity in a world where a better machine gathers up all of the rewards of the whole system. A faster car gets the driver to the front of the pack, more television coverage, and ultimate measure of success: more visibility for the sponsor. If there is any way to gain an advantage it will be pursued, relentlessly. Whether it is in better training and practice for pit crews, driver skills, or mechanical bits of the car itself, if there's an advantage to be gained, and the sponsor will foot the bill to pursue it, racers and engineers will work tirelessly to exploit whatever advantage is possible.

NASCAR race vehicles are strange anachronisms, the engine package used in the race cars today hasn't been used in a production car since the mid 1970's; the suspension system design largely dates back to the 1950's and the aerodynamic concept simply defies logic (any reasonably bright 12 year old could improve the under-car air flow, but improvements aren't allowed, it's the rules).

The underside of a NASCAR race vehicle is more than lumpy, it is an aerodynamic nightmare; if "aerodynamic" means making it smooth to minimize drag, the underside of a NASCAR Cup racer is a very un-aerodynamic mess.

You can approximate this by making a box with a lumpy bottom, including an indented (closed on top) pocket (the now infamous oil tank box) and holding your pretend racer out the window of your car while a friend drives along a highway.

Some considerable force is required to hold the box steady at speeds above 45 mph or so.

There's a high pressure area at the front of your wedge car, and also under the car. The pocket for the oil tank helps stall (low speed) the air under the car, creating a high pressure and diminishing the downforce on the race car.

These CFD diagrams are from the FloWorks component of SolidWorks, a software CAD program included in the FastTrack Racing Challenge kit; thanks to Marie Planchard and the SolidWorks company in supporting student design projects.

The air speed along the bottom of the car and in the Oil Tank Box is very low (this increases the local pressure, a result now commonly called the Bernoulli effect).

A simple modification, poking the indented pocket open so air can escape into the box representing the main car body, then cutting a hole in the back of your pretend racer, and surprise! it takes much less force to hold your racer steady as you're driven along the highway.

Air is vented from the high pressure area under the car to the low pressure area behind the car. This accomplishes two things, it increases the downforce on the car (giving it better traction in the corners) and secondly, it reduces the drag (air resistance) thus allowing the car to run faster with a given amount of power.

Poking the hole to open the indented cavity is the same as taking the lid off the box inside the race car which contains the oil tank.

Air is able to flow up through the Oil Tank Box into the main body of the car and out the back.

This has two effects: it reduces the drag (air resistance) of the vehicle, hence less power is required to push it through the air; and, secondly, it reduces the pressure under the car, thereby generating more downforce and improving the grip of the car on the track.

From the numbers generated here in FloWorks it sounds as if some of the numbers now circulating on various blogs and news stories about the improvement gained by the 99 car in having the lid to the Oil Tank Box "fall off" during racing are entirely credible. The 99 car may have realized as much as an additional 100 lbs of downforce (Cup cars generate about 700 lbs of downforce at race speeds), so perhaps as much as a 12% increase, with a similar reduction in drag, about 100 lbs. At the speeds of the cars in Las Vegas this would amount to a reduction of perhaps 40 hp needed to push the car, or conversely it would allow the car to run faster with the same hp.

As more than one driver has observed, very seldom do you see parts falling off of a race car where the loss of the part would diminish its performance. The loss of parts which enhance the performance of the race car is entirely a different matter.

Engineering science is now very good at analyzing parts and assemblies of parts to determine the conditions under which they will fail. Designing a couple of bolts to fail after some period of rather severe vibration (a race car going 185 mph) is not that difficult. In defense of Roush Racing the complete loss of the lid on the Oil Tank Box was most likely a real accident, it wasn't supposed to fall off entirely.
Because of the rules NASCAR has written to limit engineering creativity in large areas (changing the shape of the car, or the under-body), even more eningeering is now required to find an ever diminishing advantage in an ever smaller field of play; all of this requires still more technology and engineering dollars, not less.

Working on a race car that has hit the wall or another car during a race is an integral part of NASCAR racing.

As an engineer it would seem that one of the most fruitful areas of investigation with the new car would be to explore "creative failures:" parts of the car that can be modified under the guise of "repairs" or "fixing the car" after incidental contact with the wall or another car. The "repairs" are actually modifications, but done carefully to improve aerodynamics. Venting air from under the car is so beneficial that it's easy to suggest that this latest "lid flap" will be just the tip of the iceberg, the start of really inventive engineering: parts that bend and/or fail during racing, along with pit road "repairs," as very clever ways to improve vehicle performance.

Inspite of every effort by NASCAR to the contrary, the team with the best (and most inventive) eingeering staff will always be at the front.

Thanks for a lap around the track with me; I'll see you on the next pit stop.

2008-01-22T21:13:00.000-08:00

Confessions of an addicted machiniac

Machiniac: one who is fascinated by the beauty of machines

and my addiction is to graphite, as it is propelled from a 0.5mm mechanical pencil

A sketch (self portrait) I did of a drawing session, sharing graphite with my youngest grandson, Cameron

As with any task, the proper tools are essential; here are a few of mine, ones that I made myself (machined on a lathe from solid pieces of aluminum bar stock).

While those pictured are my "home made" examples, my collection of mechanical pencils started with a drafting career in the late 1950's and I've been at it ever since. My collection numbers in the hundreds; many rare pencils bought on business trips to Japan and Germany, wonderful pieces of this art form that went out of production 25 years ago.

My first attempt in the art business was making hand-drawn comic books in the first grade, and selling them to my fellow students (for their lunch money); enterprise aside, my efforts were not applauded by the school, or the parents of my customers (the other 1st grade students).

My father was an engineer and when the firm he worked for bought all new drafting tables he pulled a discarded drafting table from the company dumpster and brought it home for me, so from the age of 5 on I had my own "drawing studio:" the drafting table in a corner of the basement. Math was a game I played with my dad; he gave me his old math books and a slide rule as toys. It just never dawned on me that solving square roots and Pythagorean triangles wasn't how all second graders spent Saturday afternoons with their dad.

By the sixth grade I was in serious risk of failing math; while everyone else was figuring out how to do simple division, I'd "invented" a base 36 number system (10 digits and 26 letters), made a slide rule (in my father's machine shop) that used this system and was busy doing trig problems with logarithms in my new numbering scheme. My math teacher thought I was just playing, and I most assuredly was not doing my long division homework,...let's see, 2 pages every night of problems like 18 divided by 6, etc., just wasn't holding my attention. Can't imagine why.

After a big conference at school, parents, teacher, principal, math prof from the local college, I was allowed to study math at the local college with sophomores taking trigonometry; in part because the 6th grade math teacher wouldn't allow me back in her class (I was viewed as being too disrespectful,...I suspect it was probably a fair assessment of my attitude).

Machines fascinated me; any machine, old lawnmowers, washing machines, radios, clocks, anything that had a motor of some sort and gears. My father encouraged (or indulged, depending on one's point of view) my passion by stopping along the road on the way home from work whenever he saw an old machine of any sort being discarded and would bring it home for me to "play" with it. Whatever I didn't have in reality I drew pictures of, cars especially, and cars of the 1920's and 30's seemed like the most perfect sculptures in metal, and glass that I'd ever seen.

By the 8th grade I was "fixing" lawnmower engines, "improving" them with a few modifications done in the machine shop where my dad was plant superintendent.

Mostly I "improved" them a little too much and they'd disintegrate at high speeds, running at least twice as fast as they were ever intended to operate; but the failures were spectacular: fire, and oil, and pieces of metal parts flying every where.

In retrospect, it's the stuff that makes scientists and engineers; and it's also a wonder I didn't kill either myself or any of my friends who came to watch my "experiments."

By the 10th grade I'd taught myself drafting and the rudiments of calculus because I actually wanted things to work, not just produce amusing displays when my inventions went a little off course.

Engineering was the path of least resistance for me; the math was fun, the science was fascinating. I went to what was then Carnegie Tech, in Pittsburgh, and worked in the steel mills.

There are three kinds of humans: men, women, and hot metal workers. Being around a blast furnace when it's "drilled in" is a show that overwhelms even the most eloquent and dramatic descriptions; there are few things in life that are actually beyond words, but a working blast furnace is one.

This is a small laboratory furnace, it only makes 20 tons of steel in a single heat, about 30 minutes. I'm standing on the stairs on the right side of the picture.

With insurance rules what they are now I can't take students into a steel plant and have them stand next to a blast furnace, where they suddenly realize that math and science are the ultimate pursuits of the human intellect.

But I can have them racing 1/10th scale RC cars with 90% of the thrills and excitement and very little threat of serious injury. Real problem solving holds the same enchantment no matter what the field or size of the machinery.

In the words of Richard Feynman, "it is the pleasure of finding things out."

Perhaps the greatest pleasure that life holds.

Thanks for taking a lap around the track with me; and I'll see you on the next pit stop

2008-01-22T12:27:00.000-08:00

Why electric cars?

FastTrack Racing Challenges
and Green Volts

Producing electricity to charge a battery is the great integrating effect; there are a myriad of methods and energy sources for producing electricity. Any of them can be combined in any mix because they have a common output: DC current to charge a battery.

All bio-fuels intended for internal combustion engines (ICE’s) start with an almost insurmountable difficulty: the ICE technology developed symbiotically with the technology for refining oil. Consequently one is trying to force bio-fuels to conform to the behavior of refined crude oil (gasoline or diesel oil). Bio-fuels shoe-horned into an ICE developed for gasoline and diesel, fuels derived from crude oil, will always be at a disadvantage, they are fundamentally different compounds than gasoline and diesel fuel, and bio-fuels won’t work as well as the fuel for which the engine was designed.

A hundred years ago (1907) electric and steam cars were much preferred and outnumbered the production of gasoline powered cars. However, as roads improved and people started making longer trips the energy density of gasoline over that of batteries resulted in the first demise of the electric car. In just 30 years electric cars went from being the dominant product to non-existent.

1931 Detroit Electric

The United States and Western Europe have for a century built our entire societal structures based on the dual assumptions of individually owned vehicles run on relatively inexpensive and available gasoline or diesel fuel.
Products derived from crude oil are going to be progressively neither inexpensive nor readily available. The age of cheap oil is over.
The 2008 Detroit Car Show was a seminal event: Rick Wagoner, the chairman of General Motors acknowledged that “for some years now, the consumption of oil has outstripped supply.” Peak oil has arrived.

There are various scenarios for when “Peak Oil” arrives: the time at which we’ve extracted half of the available oil.
The Hubbert model, written in 1955 very accurately predicted the peak of oil production in the continental US (1970), predicts that world oil will peak in the 2005-2010 time frame.

The discovery of new reserves of oil, worldwide, peaked in 1960 and has declined inexorably ever since. However, explorations looking for new oil have increased every decade since 1960. Thus, the ratio of new oil discovered per exploration well drilled over the same time frame is a dramatically bleaker scenario than is shown here.

The real price (constant $) of gasoline has declined steadily from 1920 to the year 2000 (except for the Iran-Iraq war of the early 1980’s); since the year 2000 the price of gasoline has increased dramatically. At just a little over $3.00 per gallon, gasoline is now more expensive than it has ever been since the age of Model T began in 1908. This projection done in 2006 underestimated the price of gasoline in 2007 by more than 10%.

There are now two new players in the world oil drama: China and India. In 2003 China consumed one-third as much oil as the US, by 2007 it was half, at the present growth rate China will by 2012 consume as much oil as the US.
The projected price of oil based on a 30 year model (1970 to 2005) predicts an average of $90 oil by 2008, $120 by 2010 and $180 by 2015 (results in gasoline at more than $10 per gallon).

China has ten times the population of the US and they’ve just discovered that they like cars; currently less than 3% of the families in China own a car, but ownership is growing at almost 15% per year.

The demand for gasoline and diesel fuel is now growing at a rate the world has never seen before.

We cannot rebuild our cities overnight; city streets and houses on average last for more than 100 years if well maintained.
But we can change our vehicle mix; cars presently last an average about 10 years. We can start a sensible program to convert our fleet of commuter (and neighborhood errand) vehicles to smaller, more efficient, electric power.
In the US we currently average about 22 mpg for all the cars on the road (in 1925 the venerable Model T got 25 mpg); in Europe the current average is more than 35 mpg. At an average of 29 mpg the US could shut off all oil imports from OPEC countries. The most cost effective weapon we have against terrorism is to stop buying the oil that funds them.

Two technologies are now changing very rapidly; solar cells that convert sun light directly (PHV) to electricity (in terms of $/kW), and the energy density of batteries (in terms of kWhr/kg).
While utilities claim that solar power COSTS more than conventionally generated power, what matters to the consumer is the PRICE of power. Current technology solar panels installed on the roof of your home (i.e., off-grid, private, distributed power), along with a solar umbrella over your parking space at work would power a commuter car back and forth from home to work. The price would be less than half of what you’re now paying for gasoline.

A new paradigm in transportation requires marketing the concept to a new generation with a new approach: hands-on racing at the engineering model scale, so that by the time these students are adults (just 5 years) they’ll be looking for electric cars.

Thanks for taking a lap around the track with me; see you on the next pit stop.