Spun It!

[Tony-Bones]

Yeh because Traffic Police know everything........ Some of the most hypocrytical drivers on our roads today. Because there always safe and never Speed!

Must admit apart from the bickering this has been a really interesting read!!

And gald Vyker and his car are ok!

Tom.

If we are honest though the Police can drive at very high speeds due to their training and they don't have the benefits of highly modified suspension to-boot.

We could debate areas like polar moment of inertia, lift off over-steer, or simply speed, "who knows" but in my opinion most times the king pin is the humans adaptive ability.

This is not intended to belittle Vyker, more to explain our constructed technology promotes a sense of apathy and denies most drivers to experience the saturation limits until it's to late.

If in this example the Yaw did exceed design then i say "well done Lexus" since by design the car performed exemplary by preserving the driver.

[Dave-Ellen]

Interesting post.

Facts are with any car if you are going too fast for a given situation then you will loose control.

Same if you are on a push bike,skis etc

Vyker posted up his experience not with any bravado (IMHO) but in a matter of fact way..............bet he will learn from that and no one was hurt or car/property damaged.

[TigerFish]

The problem with the modern car is that it drives you? Most "feed back loops" are denied until Yaw is exceeded beyond mechanical saturation limits.... Human perception is an interesting equation>

In order to truly understand chassis dynamics we must understand both sides of the Car vs Driver partnership. We must essentially listen to the chassis’s side of the story and then the driver’s side of the story. When we get this right we produce a capable chassis that is easily exploitable by the intended driver.

The human element of chassis dynamics is without doubt the most important and the hardest aspect for engineer’s to understand, the consequence is that this area of the science is often totally ignored and leads to drivers being blamed for poor skills or lack of commitment, either that or an acceptable outcome is eventually totally fluked via hours of trail and error.

The driving process:

• Step one: A driver looks at the oncoming road and estimates the required inputs to complete the task at hand, we make this estimate based on a model of the car held in our memory, the more accurate this model the more accurate our initial guess.

• Step two: An “Open Loop” input is made according to our guess

• Step 3: Then “Closed Loop” trimming modifies these inputs to take account of emerging conditions or errors in the initial guess

There are 3 main channels of feed back used for “Closed Loop” driving

1. Visual feedback

2. Inner ear (yaw rate, lateral acceleration etc) feedback

3. Muscle tension or Steering wheel torque feedback

It is through these communication channels that a car can speak to a driver.

Ok firstly, the drivers eyes….

Processing visual stimuli is actually quite a complex procedure and incurs a delay of around 600msec in most people between seeing and understanding, so that’s a maximum update rate of around 1.8Hz

Driving by your eyes alone is only possible if no quick action is required.

• If the roads and bend radius's are known and learned

• And of course as long as no chassis control task’s are required

The inner ear….

Processing the yaw and latt acc information from the inner ear is a far simpler process and is therefore faster but even so this feed-back process still suffers a delay of around 300msec so this loop can actually update at around 3.2Hz which is pretty fast.

Muscle tension in the drivers body….

The task of moving the steering wheel is a function carried out by the brain stem, the brain stem works automatically to maintain the correct steering angle by varying your arms muscle tension. Changes in the steering resistance cause the brain stem to get confused and flag up the problem to a higher part of the brain that is responsible for processing the overall task of driving the car. This form of feedback is extremely fast at around 100msec so this can provide you feedback at 10Hz (ten times per second).

Some interesting points to note:

• A driver’s in-head car model is almost exclusively linear

• Excessive anxiety in a driver can easily cause the steer torque mechanism to be completely “swamped” by muscle tension and therefore useless.

• Inexperienced drivers are frequently unable to interpret inner ear signals or are too confused to act on them so they are discarded by the brains automatic information filters in the brain stem

• A surprising level of confusion exists in the inner ear between yaw and chassis roll, this lead some drivers to “dislike” body roll

• Many drivers are found to revert back to an entirely visual driving strategy in emergency circumstances

• Many drivers are overwhelmed and lose control even though the car was capable of completing the manoeuvre

• A maximum practicable hand steering wheel rate is around 1100 degrees / second –but not for long

• Typical hand wheel rates are much slower - < 100 degrees / second in “Sensible” driving

All this and we haven't even offered a reason why the rear rotated Geometrically..... Interesting stuff though don't you think.

This is by far the most interesting post in this thread. Excellent stuff Tony. You should do some more stuff like this in its own thread.

[rig-pig]

:D :P :D

[WylieCoyote]

I did say no more bickering but I'm actually enjoying the thread now! Thanks Tony for your comments - it's really good to hear some of the technical stuff - I agree with Tigerfish and think you should do more stuff like that - I sound really clued-up at dinner parties now - although I admit I have absolutely no idea what I'm talking about when I do!!! Still it sounds good and that's enough for me.

Oldcro, your point and criticism are valid. I for one fully agree with what you said about irresponsible driving but Vyker isn't trying to 'big up' his little faux pas for heavens sake - cut him (and others) some slack - the forums are merely a vent for us to post these little things to get them off our chest. Most things on here are said tongue-in-cheek and it's very difficult to assess how something is meant when it's on text. Not everything written should be taken as a literal translation.

Safe driving everyone :)

[loggyboy]

Better to read (my sort of posts) than that someone has had a serious accident.

Woooa there Mr Ego.. i doubt you telling someone off on a forum is going to help them in avoiding a serious accident!

WIM's posts regarding the techics of cars may help, and without wishing to compete with your ego, my single point about blipping the throttle on down change is more helpful than your 'sort of post'.

[WylieCoyote]

Better to read (my sort of posts) than that someone has had a serious accident.

Woooa there Mr Ego.. i doubt you telling someone off on a forum is going to help them in avoiding a serious accident!

WIM's posts regarding the techics of cars may help, and without wishing to compete with your ego, my single point about blipping the throttle on down change is more helpful than your 'sort of post'.

Seconded - blipping the throttle to match engine speed to road/gear speed is a well-proven method and to not blip the throttle on an advanced test is frowned upon.

[DJ Wozza]

blipping the throttle to match engine speed to road/gear speed is a well-proven method and to not blip the throttle on an advanced test is frowned upon.

unless you drive an Auto

[WylieCoyote]

blipping the throttle to match engine speed to road/gear speed is a well-proven method and to not blip the throttle on an advanced test is frowned upon.

unless you drive an Auto

Hehe, that could get interesting!

[Unregistered_User]

No, I am really p***ed of with Jamie's snide remark. So tell you what Jamie, print off Vykers original post, show it to a Police Traffic Officer and ask his/her opinion of the driver involved. I look forward to hearing what the reply is, and will accept his answer without reservation.

Wahay, someone's temperature soared there

Got a crisped-up tan from this distance ;)

Wasn't snide, t'was clearly visible and rather apparent me thinks.

Kind regards,

Jamie

[dazz32]

just been reading all the comments on this topic....why are you all bickering with each other???? Vyker wasnt ( in my minds eye ) trying to BIG UP that he done a 360 or was trying to drive like knight rider but just pointing out ( ME vyker was driving to fast for the road and its conditions and also beyond his and the cars abilitys....we ALL make mistakes every now and then it could end up fatal or in this instance no damage was done...yes i agree with all peoples advise / comments ......but please can we ALL just stop picking fault with each other?

I believe in all what Tony WIM does and says on LOC to do with cars geometry...he chooses to express his comments ( doesnt have to ) to do with the set up with cars etc for all of us to see and learn from and to how many factors go into doing or changing a cars personality....

No one was killed injured etc but... vyker learned a lesson.... :)

[Rory]

AMEN