New Tire Model Debuts on New Impala B

[VELOCIPEDE]

The wait is over. After 18 months of crunching numbers and pounding computer keyboards into submission, Dave Kaemmer and his guys have pronounced their new, state-of-the-art tire model ready for prime time. The product of their labor of love may well be the most significant development in the iRacing service since the company opened its virtual doors for business in the summer of 2008.

“Previous tire models for race simulations have been based on measuring real tires and fitting performance curves to data generated on test machines,” says Kaemmer. “But without understanding why tires generate the forces they do, it’s hard to predict what’s going to happen outside of the performance envelope where tires are tested. It also is very time consuming to determine the many numbers needed to describe a tire using a fitted model like that.

“So we went back to first principles to figure out how to model a tire from basic measurements we can do without putting them on a tire test machine. How does the patch of rubber in contact with the road generate grip? How does that patch of rubber move across the road? How does it distort when you climb a curb or when the tire starts to slide?

“The theoretical model we’ve come up with does the right things. When a car slides to a stop it takes the right amount of time; burn-outs look and feel right . . . all kinds of behaviors we used to struggle to reproduce by fitting numbers now happen almost automatically. There are comparatively few numbers involved in describing a tire now, all of which are much more easily measured. That means we’re more accurately reproducing the ways in which tires behave, which, in turn, enables us to make a car’s performance extremely authentic.”

A new tire model deserves a new car: the new Impala Class B. The new Impala incorporates all the chassis and aerodynamic modifications NASCAR mandated for its Nationwide Series cars including a longer wheelbase together with a wider nose and non-adjustable “splitter,” taller rear deck and fixed rear spoiler.

Everyone who already owns a 2009 Impala SS will automatically receive the “upgrade,” complete with the new tire model. Those who don’t already own the 2009 Impala can purchase both the new Class B Impala and 2009 Impala SS together for $11.95 - and get their hands on iRacing’s new virtual tires in the bargain. We think you’ll be amazed by the performance of the new tires and remind you that every car on the iRacing service will be equipped with the new tires by later this year.

2011 Impala B

- The new B class Impala (Nascar Nationwide COT car) is now available as an update to the older Nationwide car. They are distributed together as a single package, so if you own the current Nationwide car you will automatically get the new one in this update. If not, simply purchase the Nationwide car and you will get both. The new car has an updated aerodynamic model which more accurately reproduces the high speed response to setup changes. The suspension geometry and some suspension elements are also updated, giving more accurate response when running coil-bind setups as well as conventional setups.

- The new Impala B car also has a new, more accurate tire model. This is a preview version of the iRacing 2.0 tire model; there are a few known issues (lack of tire smoke being the most visible), but the tires' response is very close to what you will experience when the model is complete. The heavy, high-speed Nascar oval cars work the tires very hard, so be aware that overdriving the car, or pushing too hard, will be costly in terms of laptime and tire life. That said, we think you will enjoy them!

Cars

- We have revised all cars for race ending suspension damage. Previously every car would not be allowed to continue a race if it suffered 100% damage to any corner's suspension, which could be very frustrating because you could destroy your suspension and not realize it and your race is over. Now, just about every car can always have it's suspension repaired effectively enough to keep driving. The exceptions that can still have a race ended for excessive suspension damage are the Dallara IndyCar and Lotus 79, but these cars can also have a small amount of damage repaired, while the Williams FW31 can't have any suspension damage repaired at all.

Old Impala B

- Updated some fixed setups.

Tracks

- The new tire model is very susceptible to sustaining mysterious unexpected amounts of damage from wall corners and seams. We have made some improvements to many tracks to reduce the chance of having these weird invisible collisions against certain spots in the walls at many tracks, but there may still be spots against walls where you may find the 2011 Impala B blowing a wheel out unexpectedly. We'll be working on improving this by the time we do a full release of the new tire model.

Charlotte

- Removed Lowes logos.

Okayama

- Add gained time checkpoints at Okayama to prevent cutting of pit entrance apex.

Bug Fixes

- Don't do any further tech inspections on a car once it has started a race.

- Fix bug where tech inspection could lock you out of your car if you were in the garage when the warmup ends and the race begins

- Corrected a bug in fixed setup races where you could cause the sim to load the last used non-fixed setup.

- Make the fixed setup button show properly in garage.

- Only lock a car that is too damaged to continue in the pits if it isn't moving while it passes through the pit stall.

- Must let pitstop begin when car is unrepairable if there is a fast repair available.

- Fixed a bug where the pit speed limiter would keep the throttle cut and cause a stalled motor if locking up the drive wheels from braking hard.

- Fix bug involving selecting cars to view which have leading zeroes in their number.

Edited June 22, 2011 by VELOCIPEDE

[VELOCIPEDE]

video confronto fra vecchia e nuova Impala