From BillyShope, "When empirical evidence appears to contradict the information in books, he knows that either his observations are incorrect or that he has incorrectly applied the scientific information found in the books. He would be choosing to reject the principles upon which his profession is based if he were to deliberately se aside the "book world" and base his analysis on that which he perceives to be the 'real world.'"
I whole-heartedly agree with your statements. There are at least 2 other possibilities to consider, however.
1. The 'book' is wrong. All of us, Billy, Greg, Warps, myself, etc. disagree with what Herb Adams wrote in his book. This is what prompted Milano's questions in the first place, and what prompted me to do what I did 10 years ago.
2. The simplifications that we have chosen to allow us to use the engineering principles and equations we have taken from our books makes our model invalid. Keep in mind, we aren't talking about a simple problem. We are talking about a mechanical system with many degrees of freedom, a couple interconnected mass/spring/dampers, various linkages with assorted compliances, and a couple inter-related force inputs. Greg says CarSim isn't up to the task of figuring it all out. I didn't correctly predict what was going to happen, and I'm willing to bet that Billy can work his slide rule 'till the cows come home and he won't have a definitive answer either.
When the problem is complicated enough, sometimes the quickest, simplest, and most cost effective approach is to simply try it. That's what I did. I'm not alone.
Every auto manufacturer in the world spends considerable time, effort, and money on vehicle testing. They have access to the most sophisticated simulation systems available and have entire departments who spend their days running these simulations. Even with all of that ability to get the 'book' answer, they still find it mandatory to physically test their vehicles. If anything, that should be a pretty good clue as to the complexity of the issues we are dealing with.
Does that mean that an engineer that draws conclusions based on empirical findings has abandoned "the priciples upon which his profession is based"? Or, does it mean that the engineer is smart enough to realize that there are things going on that he doesn't fully understand. He is willing to accept the fact that he cannot fully quantify everything that is going on even though he understands that this indeed is a mechanism that must be governed by the laws of physics.
I reckon it's the latter.
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Pat writes that "many books were written by people who actual did things in the real world, then wrote it down so others could benifit from their findings "
Smith set an anti-squat limit of "about 20% seems to be the maximum before we get into tire compliance problems".
Van Valkenburgh doesn't give a number, but allows, "An excess, however, can cause wheel chatter under hard acceleration."
Milliken doesn't seem to have an opinion on the matter; he just shows how to calculate the percentages.
I'd be interested at to what Gillespie and Dixon say on the matter, I don't have those books handy. Staniforth and Puhn could probably chime in as well.
My point is this, there are people besides me that have had the same basic experience. No one has an equation that shows how much is enough or how much is too much. I designed this into a racecar, but I did it to a lesser extent to my street car around the same time as well. It exhibited the same bad characteristics. I can report what I felt by having my butt in the seat(s). By saying that 100% anti-squat is not going to effect the car over bumps, BillyShope is absolutely sending Milanoguy down the wrong road. I have no question in my mind about this. So we end up with 'a good practical engineer' that apparently has never played with this particular tuning feature, but is, in as many words, championing it's use. Sorry, that's poor form where I come from.
