I live in a world full of magical thinking...

But I don't believe in magical thinking, except insofar as sometimes good thinking produces something that works like magic. It's just a matter of keeping the ordering of things correctly. New must replace old. Good must displace bad. You don't just discard the old and bad and wait for the new and good to appear as if by magic. Maybe the old and bad is neither. I think marketing can be an environmental toxin. How to know when we've been reduced to nothing more than a host for a revenue stream? So too with trends and ideas.

Which brings me to my favorite old hobby horse. God I am so tired of this subject. And I can tell you are too. I can tell.

But see the picture below of Muller and Huff in their 2011 BTCC Chevy Cruzes. Note the location of Huff's inside rear. Yawn. Yes. Indeed. You know they were 1-2 in the final points. Ah, so, the Honda's we've discussed previously don't lift. Don't have to. They "very cleverly" steer the rear wheels out of the turn. Tricky that I guess. Getting it right. Too much being bad.

Some day, every wheel will turn and brake and do whatever else it does under the mediating influence of benevolent algorithms, and leave us to reveal ourselves almost soley as possessed of either sufficient or insufficient judgement. In that day they will call that fun. And knowing what they will likely know, it will be.

But for now, in this last twinkling of violently solid and mostly analog direct control, the old ways can still be seen in the now. Einstein was wrong. ONLY Man changes. God help him.

Scott, who will try to never never never post another such picture again...unless there are extenuating artistic considerations or somesuch thing...

 

Some day, every wheel will turn and brake and do whatever else it does under the mediating influence of benevolent algorithms, and leave us to reveal ourselves almost soley as possessed of either sufficient or insufficient judgement. In that day they will call that fun. And knowing what they will likely know, it will be.

^^^^ferrari is close with the 458 sending more power to the outside wheels and firming the outside dampers, measuring and adjusting it all in milliseconds to rotate the car through corners...... Maybe there is a future for the enthusiast in blindfolded school bus racing on a figure of 8.

 

hahaha, everytime RR98ITR posts, I automatically enforce the Wadsworth Constant on his post... skip 30% of the post and I get to the point of the thread.

you forgot about the RWD guys.

 

Is this in reference to the Racecar Engineering article?

 

the main reason i still log into the forum parts of this forum, and not the for sale section, is to search and see if RR98ITR has made another post.

 

wtcc, you mean. doesn't matter regardless, this is what the chebies saw in btcc 2011.

 

I got about 10% of that.... but don't stop posting pictures.

Thank you.

P.S. Brad are they even turning? Need a slower turn example!

-Ryan, who may have opened a can of worms... fast vs. slow speed cornering.

 

I solved this delema that torments Scott a long time ago.
Idk if its selective reading or its a obsession... probably the later.

Velcro on the tires and tracks. Sure it will be noisy, and all the cars will have to be boosted to even move, but no matter where the car is on the track it wont lift off the ground.


I think maybe scott should look into other avenues of physics.

Like "how high is up"
Terminal velocity... what is it and how do you get there?
If a wood chuck chucks wood, then what do rock chucks chuck?
Mayonaise vs Mustard an analogy of condiments.

The chicken or the egg... Darwin's theory on what crossed the road first.

 

I think they need to increase the nitrogen pressure in their shocks.

 

lol. i am just posting that picture saying that honda went 1-2 this year in btcc. not posting to show tire lift or the lack there of.

 

Scott,

are you actually enjoying watching th BTCC and WTCC races on Speed this winter, or are you just searching for the same old pictures on the net? They are also running the FIA GT1 and DTM races if you don't mind cars with the driven axle at the proper end of the car. Have you seen the new full carbon fibre bodies they will be running next year in DTM. BMW was showing theirs in naked CF in the last DT exhibition round. Nice.

 

All I gotta say to that is:




FWD finished 1-2 in both BTCC and WTCC... Just sayin'

 

Claude - no watching, no channels, no time, just reading in Autosport. And none too closely apparently (WTCC). I don't mind any car with a driven axle or two. Even ones with solid chain driven rear axles! Spending $20 for a night at indoor karts is the most rational thing I've ever done with 4 wheels.

Scott, who shouldn't sound so snotty about the Honda's excessive rear droop travel...whatever works good enough to win with is certainly ok...

 

Paul - Pretty sure Not a delema. And it don't torment me neither. And, appearances to the contrary I'm not even obsessed with it...any more...if I even was...though I admit that's debatable. Darwin throws the checkered! What do I win?

Scott, who just picked up a full tank of argon...so as soon as I pick up my new bifocals I'm good to go!

 

Maybe FWD has a favorable rules set. Just because FWD wins or if RWD wins doesn't say much. You have to really look closely at what avantages/disadvantage the rules allow for both types of cars. Maybe the RWD have to carry more weight, or maybe they can't make the power, or whatever. After all, you could make a rules set that would allow any particular type of vehicle superior depending on the track layouts, the allowed weights (including but not limited to F-R weight bias), tire sizes, engine restrictor sizes, allowable aero, ect.

I hate to say it, because it seems that there shouldn't be two opposing but correct approaches to solve the ultimate handling setup, but I believe that both Scott Rinde and Nathan (Descartesfool) can be correct about whether tricycling or four-on-the-floor can both generate the necessary cornering power to be ultimately competitive, even at the highest levels of tin-top motorsports. With all the possible factors involved including the tire parameters (i.e. grip vs. slip angle, the tire's nonlinear grip vs. vertical load graph, the allowed tire sizes, the dynamic alignment factors such as toe curve and camber curve, the caster and its affect on weight jacking vs. steering angle, the particular tire's temperture sweet spot, ect.) it would be very possible to have a set up that allows inner rear tire lift and one that doesn't allow any lift to give the same overall performance both in terms of ultimate grip for a given corner, but also maybe for the most important corners, and the even the tire longevity for the full length of the race.

 

There's a chance that Claude and I, especially I, make it into more of an opposing camp kind of thing than it really is. If we're talking about a wheel that barely lifts as opposed to a wheel that just barely doesn't then we're not arguing about much (unless you believe that those few fractions of an inch and those few single digits of pounds are the only thing between you and dynamic armageddon).

It would be interesting to know how much turning of the outside rear was just right and how much was too much.

Scott, who will have to go back - way back - and check his numbers...but I think you can get a setup out of a DC2 that does a tiny bit of that too and I think that's what I've set mine up to do...cobwebs - the worst ones are in my brain which is saying something considering how much my race kaa resembles a barn find...

 

One of the most import aspects, especially when considering feedback to the driver, is that the inner tire doesn't leave the ground while loaded leading to a possible snap oversteer.

 

Ohhh gawd.. never thought of darwin throwing the checkered.
Best I can offer at this minute is an ice cream wrapper, and a freshly opened jumbo box of nerds.
So much fun reading these threads

 

Future BTCC cars: not quite your off the lot tin-top. Read this from RCE:

http://www.penskeshocks.com/files/Racecar2.pdf

Same chassis for both RWD and FWD, double A-arms all around.

Of course the 2 litre turbocharged Honda Racing Team cars that won the BTCC championship this year were based on the regular Honda shell. Not all cars running the new spec chassis. It had this: Rear suspension: Twist beam designed and manufactured by Team Dynamics Motorsport
http://www.honda.co.uk/cars/btcc/aboutthecars/

and from watching this year's races on TV, they don't lift much if at all.

Next year they will be running a new chassis, not sure if it is the new spec chassis.

Of course they did launch nicely over bumps!

 

Johnny Mac, please describe how this happens exactly. I've long considered this one of Smith's canards. Tires usually unload before lifting, so that at the instant just before they lift they have no load. But lets say you clung to this concern - would you eschew preloaded springs? Sway bars? Stiff springs and low cars in general? How many FWD racers have struggled with inside rear lift induced snap oversteer? I've never heard of a one.

Scott, who has the opposite problem...none of my wheels touches the ground...

 

In actuality you are correct that only as the tire's vertical load diminishes to zero does it leave the ground. The suspension is after all a Tire Force = (Effective Spring Stiffness)*(spring deflection) entity and there isn't any zero suspension displacement vertical tire load - otherwise known as - tire preload. So, from a strictly correct physical point-of-view, a loaded tire doesn't leave the ground instantaneously.

However, the problem is really one of how fast does the vertical tire load on the inside rear diminish while cornering? On a stiffly-sprung and highly damped suspension especially like that found on FWD race cars, the inner rear unloading occurs very rapidly especially in slower corners. So while the vertical tire unloading doesn't occur spontaneously, it can occur very quickly so that it "seems" as though it unloaded abuptly. After all, just about everything that occurs in the handling department of a racecar is transient in nature, even when we may think it is in a steady state.

 

this was not informative at all. i want my 2min back, scott :p

 

Johnny Mac...you slingin' some flim-flam there in your non-response to the second half of my paragraph...but that's ok...we ain't disagreeing on much. What I think Carroll Smith was alluding to was rear wheel drive with a spool or a locker and if you lift the inside on one of those under power you could get busy quick. Buuuut on most of those with same size tires f/r they try as hard to keep the inside rear loaded as we try to keep the inside front loaded. So I still think he was telling boogeyman stories. Maybe even for pedagogical effect.

Scott, who has run way too stiff...it was harder to drive...at first...but I never got no snap oversteer...I always seem to wind up with crap understeer...

 

Oh, sorry, I thought I would get through the first part of your post about the tire preload concept before continuing on to the next topic of snap oversteer or snap understeer. Remember, when a driver says to you that the car is doing this or doing that you first have to make sure he knows what he is talking about. If he says "it's snap oversteering" you have to question whether he means it is snap oversteering or just plain oversteering. Once this issue is resolved, and only when it is resolved, can you start looking for the culprit.

I can't think of too many cases where a car has a snap oversteering problem resulting from the inner rear coming off the track surface. Sure, the faster the wheel comes off the track, the faster this oversteering can occur due to the effects of outside rear dynamic camber and tire load sensitivity. But, this isn't snap oversteer just plain oversteer. Even a wet track will exacerbate the tendency to oversteer quicker, but this is still considered fast onset oversteer and not snap oversteer.

Almost always the snap oversteer is caused on the outside rear tire due to too little bump travel or suspension binding where either of them could be causing tire shock. What is tire shock? It may sound obvious that it is caused by the sudden application of vertical load to the tire, which is true. The real problem isn't that the vertical load just went sky high in a thousandth of a second, but the problem is rooted in the tire's inability to build slip angle fast enough to generate sufficient lateral force to maintain yaw stability (i.e. oversteer/understeer balance). Depending on the carcass and tread stiffnesses, most tires require a constant load and half to three quarters of a wheel revolution to build up to the final slip angle and the consequent lateral force to keep OS/US balance. In tire shock, the vertical load is very large for a short period of time and then it diminishes before ultimate slip angle is reached. By this time, the car is already pirouetting uncontrollably.

An easy way to experience this "tire shock" to know what it feels like at the front of the car is to go out on track and turn in way too quickly (just don't crash) in a low to medium speed corner (it does the same in high speed corners but it is just as instructive and safer to do in lower speed corners). When you do this, the fronts do not bite since the tire didn't have the chance to build slip angle and the consequent lateral grip and the car will understeer. Now, do the same corner with the correct turn in approach and you can feel the difference in front end bite.

 

So it (lifting) is not really as big a problem as some discussion might lead one to fear. More a theoretical problem that nobody actually has, perhaps a litmus test of sorts for the bibliography.

Scott, who knows the tires like it nice and slow...and I wanna give em that...as fast and hard as they'll take it...