3. Pay attention to vehicle dynamics. Although race engineers cite dampers as a critical way to gain a competitive edge, they acknowledge that other aspects of vehicle dynamics are only slightly less important to the performance of the car. "Springs, anti-roll bars, and suspension geometries all play a big role," said Eddie Jones, a race engineer for KV Racing. "The rules give us just enough room to tune the vehicle dynamics the way we want them. The rules also give us enough room so that, if we do it wrong, we can get ourselves into trouble."
4. Study the vehicle's aerodynamics. On an oval course such as the Indianapolis Motor Speedway, aerodynamics can make a huge difference. By increasing the downforce on the vehicle's wings, engineers can make it ride higher or lower, faster or slower. They adjust the vehicle's drag in two ways. First, they place so-called wickers -- pieces of angle iron -- on the vehicle's wings. Second, they test the wickers of varying sizes and angles in wind tunnels. The wind tunnels enable the race team to create an "aero bit map," which, when used with computational fluid dynamics (CFD) software, provides a full understanding of how the car will behave on straightaways and in turns. "Our job is to find each one of those bits and know how it will be affected under every condition," Johnson said.
5. Make liberal use of simulation. These days, simulation is the best way for an IndyCar team to understand its vehicle. Simulations offer more data at a lower cost. "It's so much more economical to simulate than to take your car out on the track," Johnson said. "You get more accomplished through simulation, whether you do it through shakers, wind tunnels, or CFD."
[Learn more about IndyCar at Littelfuse's Speed2Design site.]
Nice job Chuck, on translating the thrill of racing into engineering challenges that other engineers, even if they don't work on the race car circuit, can relate to and are grappling with every day for their own types of products. Those minor design tweaks and keen attention to simulation outcome are what can set one company's offering apart from another--whether it's a highly competitive IndyCar race or components for commercial cars.
Good point, Beth. It's amazing to learn that IndyCar's number one engineering challenge -- vehicle reliability -- is the same as for production cars. It's true they only need to go 500 miles at the Indy 500, but it doesn't mean that reliability is any less important. In fact, a simple failure -- like the one on Parnelli Jones' vehicle in 1967 -- can be devastating.
Absolutely, there is far less room for error (likely no room in fact) for those 500 miles since at those speeds, lives are at stake. One teensy, little glitch in something as small as a misplaced fastener, and you could be primed for disaster.
The comment about the aerodynamic vacuum under these cars at speed reminded me of the Chaparral 2J car from the Can-Am series in the 70's. The car has side skirts and an on-board "vacuum cleaner' powered by a snowmobile engine which generated a downforce which exceeded the weight of the car. It was so much faster than the competition that it was banned under a questionable rule interpretation. Unfortunately, engineering brilliance in car racing can be overruled by the need to put on a good race for the fans (unfortunate) or by the need to hold down top speeds for safety reasons (probably a good idea).
I fully agree with the reliability and handling of racecars. What good is a racecar if it breaks (fails) before the end of the race? I've seen many interviews from top competitive drivers sorely disappointed in their provided equipment that broke just before the race ended. Racecars that can't handle well look slow on the race tracks compared to the better handling cars, and that very much includes NASCAR. Tires and suspension adjustments are critical to success (tires can be adjusted by air pressure).
Architect is right about the IndyCar race this past weekend. Because all the cars need to be "spec" machines, they all look alike except for the paint. Now I believe next year other manufacturers can offer "aero kits" which supposedly will make the cars a little different but how much is anyone's guess.
Roger Penske himself said the cars are essentially giant vacuum cleaners and literally sucked up the temporary asphalt. One could argue that using asphalt to patch a concrete surface was just asking for it, but I will focus instead on the huge amount of downforce these cars create.
The reason why the teams spend so much time on shock absorbers, suspension tuning, and CFD is to make sure the car stays firmly planted to road surface so the aerodynamics can work. There is way too much attention being given to making sure the attitude angle and ride height don't vary much. Springs are incredibly stiff. Shocks are close to be overdamped. All in the name of aero.
While certainly some downforce is necessary to keep the cars from flying off the road, the huge amount now generated is clearly excessive. It is said that the current IndyCars generate 2 - 4 times the car weight in downforce. That seems absurdly high. It makes marginal drivers the equal of really good ones. To me, racing is about car control, not having the guts (or stupidity) to plant your right foot firmly to the floor and hang on.
There are an incredible number of variables that need attention when setting up a race car. Engines are not the same, close maybe but not identical. When maximum torque occurs and how fast it climbs, greatly affect handling, same with horsepower. Two 750 HP engines with the same displacement may have entirely different performance maps depending on the driver and track. Front/rear down-force, tire pressure and pressure build rate are significant. Not every driver is comfortable at driving ten tenths for 100 laps, let alone 500 miles. A driver who can drive 20 laps within 1/10th of a second difference per lap while adjusting for wind, temperature, tire pressure, engine variables is a far better calculating machine than the finest computer ever made. The difference between "push hard" and "not so hard" may end up only changing the lap time by 2 or 3 tenths of a second but may extend the life of a component by a hundred miles. The rules package has made Indy racing somewhat less fun for the casual race fan who sees a 500 mile parade of identical looking cars interrupted by occasional crashes. It in no way diminishes the remarkable success achieved by the winning team.
bob from maine...nice post! You did a good job of summarizing many of the basics about racing seemingly identical cars. Yes, race conditions constantly change, and each car has a different driver...adjustments are needed that most casual race fans are not aware.
At Detroit's Belle Isle Gran Prix last weekend, Dario Franchitti improved from a 15th start to 2nd place finish. ...that's good racing by Dario and team!
After reiability, which relates to "If you can't finish the race you can't win the race", handling is vitally important. And keeping the tires on the pavement is an important part of handling, a MOST important part. So now areodynamics is one very good way to hold the car to the road, even moreso since the rules don't allow the cars to carry gravity intensifiers or inertia absorbing systems. Presently the cars are l9imited to holding onto the track by means of down force, which is provided by aerodynamics.
The result is that with the limitations on horsepower, which is limited by engine rules, all of the cars are underpowered, at least by the explanation that I got from one driver years ago, " If you can make it all the way around the track without having to back off, you don't have enough power". I have observed that to be totally correct, and I have used that relationship to win some races. But my point is that with all of the cars being a bit underpowered, the only areas left are handling and reliability. And reliability is not exciting to watch.
As a racing enthusiast, the state of Indycar racing saddens me greatly. The Indianapolis 500 began as a race that encouraged innovation with a minmal set of rules [like a max engine size of 600 CID] and has evolved in the opposite direction. Many of the rule changes are for safety - like smaller engines. The most disappointing thing today is that as the rules continue to narrow, they support the status quo with whatever teams can squeeze out of it. The most blatant reaction was in 1967 when Parnelli Jones looked like he was going to win with 10 miles left and then had a bearing failure [oops - reliability problem]. Jones had qualified his turbine powered car in the top 10 and had shown that he could run ahead of everyone - the reaction of the rules committe could have been to 'tweak the rules' to equalize the turbine, but their reaction was to reduce the turbine intake area by 33% - effectively saying 'we do not want them turbines running here!'. They have been gradually moving to an "everyone races the same car" model ever since. They even want to restrict firmware updates.
OK, got that off of my chest.
With all of the restrictions, teams still have to tune the overall system. Although the cars 'all look alike' just like a casual observer might comment about the compact cars on a rental lot, there is more than one distinct body shape in the Indy photos [at least for this year]. Outside of the aero and mechanical reliability, it looks like evrything else is electronic - lots of opportunity for a tiny edge on the competition.
One thing that I envy about the guys that support these cars - REQUIREMENTS - the marketeers and chrome hangers aren't coming in every week asking for a new feature!!
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