Slip angle and car control
 

http://www.motoiq.com/MagazineArticl...r-Control.aspx

Great piece by Billy.

Note that it's five pages and it's worth reading the entire article. It's an excellent intro to car control and why it matters.

good read!

very good article ;)

That is a fantastic article and very well timed for me as I've been playing with slip angles on my last couple of track days! Among the things that hadn't occurred to me was that the traction at slip angles would decrease with speed. Also it hadn't occurred to me that the tread goes straight with some slip angle from deflection.

Really worth the read!

Good refresher before a race weekend.

billy johnson is a pretty big reason i stick around trackhq. especially considering how dead that forum is.

On point, this is.

It's only dead if you don't have a Miata/S2000/Corvette :D

Very good.

I must add that what he writes is very much supported by science. Having been a researcher studying cognition this all rings true. I especially like the part where he reflects on how good drivers don't really have lightning quick reflexes. The variance in group of given drivers is probably pretty low. What the good drivers do is digest what is unfolding in front of them with greater ease and earlier.

This reminds me of learning to surf. I'm pretty crap at it and a lot of it has to do with timing and recognizing that a wave is "good." People who have done since they were kids (I grew up away from waves, but always near the coast) recognize a good wave way before I do.

This is related to that: http://en.wikipedia.org/wiki/Chunking_(psychology)

I think most of the inputs to a driver who is trying to recognize the tipping point of traction to slipping comes from the inner ear. I know some of it is visual but I bet most of the input to the system is vestibular. Some is probably also a feedback loop containing steering input and vestibular system feedback.

For the really nerdy: back in the day I did work around people who worked with the ACT-R system (http://en.wikipedia.org/wiki/ACT-R). We spent many days trying to use experimental data and put it into models that would perform much like people do on very basic perception and attention tasks.

Also of pertinence to this discussion is the so-called 10 year rule. http://mindsandmodels.blogspot.com/2...year-rule.html
TL:DR More seat time + get a good nights sleep before a "driving practice" event.

i wonder if that is funny to anybody but us two. also, im kinda glad i have a miata despite what the sheriff thinks about them.

Great post. Thanks Mike!

From B. Johnson's piece:

"It is often said that really good drivers don’t inherently have great reflexes, but rather can anticipate what the car is going to do and adjust their inputs as an unwanted event is occurring, not in reaction to it."

This is frequently referred to as being 'ahead of the car'. 'Anticipate', to some, may imply a thought process; it's not, and as BJ makes clear elsewhere in the piece, it's a muscle memory/automatic response borne out of practice that enables a driver to be able to perform at that level. BJ forgot to mention talent, that separator of the stars from the rest of us (speaking for myself :-).

FWIW, this clip will show you what being ahead of the car looks like at high speed in a downpour:


[ame="http://vimeo.com/6818237"]Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo" target="_blank">Aaron Povoledo at Watkins Glen 9-27-09 Sideways out of the esses on Vimeo[/ame]



The driver in this video is a pro and will tell you that, generally, it's his vision that enables him to stay ahead of the car when at speed it wants to head off-line against his will. That's the conscious part (i.e., don't forget, keep your eyes up at all times). His kinesthetic sense is involved as well; that's automatic, and that does indeed involve lightning reflexes - without them, he'd have been in the Armco in no time flat.

BTW, that amount of movement visible in a car at speed in a video with this perspective is well on its way to a tank-slapper - in the rain. Additionally, and as the owner showed me after the race, the car ran on hard, years-old BFGoodrich g-Force T/A KDWs. Compared to fresh dry rubber or Hoosier wets, they were hockey pucks. Rules dictated the tire, but not the age.

FWIW, the car in the video has twins power and in this major season-ending Northeast BMW club race vanquished a ton of cars that in the dry would have been 5-10 seconds/lap quicker- all because of the pro driver's car control skills and rain line expertise.

I've coached 100% visual drivers. 100% visual drivers are NOT outliers in this day and age... Gran Turismo drivers are all 100% visual. One of these visual drivers I coached was a GT Academy finalist.