i am new member of fsae. i wud like to know what be the optimum values of
1.toe angle (rear and front for a rear wheel drive car)
2.caster angle
3.camber angle and shud all the wheels have same camber??
4.kpi
5.caster trail
6.scrub radius
plz reply soon
its urgent
There was also a thread on F1 Technical asking about benefits of a pull-rod suspension in comparison to a push-rod setup as well... not nearly as bad but generally oversimplified. Point of both of these is that there generally aren't all-encompassing answers to problems, even if problems in undergrad engineering tend to lead you to one precise solution, arrived at by some fixed process. I think most people grasp that things will be more difficult in industry, but perhaps the true scope of which isn't put in the right magnitude.
Allow me to illustrate!
Classroom Engineering Problem
"Find the minimum of this function."Not too difficult! Illustrates a concept (minimization / optimization) in a pretty straight-forward manner. The problem is well-defined, and even if you're not 100% sure of the best way to solve it, you can fake it. Alternatively, you can just copy the solution off someone, or consult The All-Knowing Oracle.
FSAE-Level Engineering Problem
"Find the minimum of the function with respect to x- and y-. No worries, you have a few months to work on it."Shit's starting to get real. Not quite as simple and straightforward if you're used to looking things in a purely one dimension manner of y = f(x). You'll get a different answer looking at it along one slice of x as another. Furthermore, if you ask different people how to go about analyzing it, you might start getting different answers. Lay a few line plots on top of each other at discrete input values? Plot a surface?
Harder to "brute force" these problems too. Takes some time to run through thousands, or tens of thousands of combinations of toe, camber, spring rate, ride height, etc. Overall it's manageable, and ultimately you're competing to be less of an idiot and have your shit held together by fewer zip ties than the competitor in the paddock stall next to you - who is asking for 1" chro-moly tube and a welder, after the first round of tech inspection.
Real World / Pro Motorsport Engineering
"Here's a rough idea of what you're looking at. Try and figure out what the problem is, because it's not really even defined. The number of variables you have to worry about is somewhere between 1 and infinity - depending on who you talk to - and the people who claim they have all the answers are usually full of shit. You have 5 minutes to find the global minimum, and at some point between 2 and 4 minutes in, the problem is going to change. Also, you will lose partial credit for every minute you take to solve the problem, even if you get it entirely correct at the end of your allotted time. Try to score the most points."Ouch. The problems really are that challenging, open-ended, and undefined. There are generally dozens of theories and opinions on how to solve the damn thing, and the people who are probably the best source of an answer are the ones you're in competition with.
It's really challenging to prepare for this sort of work. Can attack the problem a number of ways and get different answers every time, depending on where you start and what you feel is important. Then there's always the feeling that's similar to what inevitably goes through your head during at least one exam you've taken...
Oh hell... I don't know any of this shit! Any confidence I had just flew out the window. Fuck. I wonder if anyone else is as clueless, let me take a look around... OK good we have some other blank stares... who are these people who are already furiously writing answers?! Oh well, guess I'll write something down and hope for the best. So long as everyone else fails out I will look brilliant by comparison!
The point of all this is what I feel is important to teach in engineering. Equations for principle stresses? Guess they're good to know, but you can look those up in a book at some point in the future. More so, how to approach problem solving when you don't know the answers, the process, or even the problem. That's what engineers and scientists get paid to do - pull answers out of chaos, and/or data that's typically shitty, insufficient, and can be interpreted in many ways. Some institutions, and seemingly even areas of the world, emphasize this more than others.
It's another reason why FSAE teaches you really good life skills - beyond just cooking with a blowtorch or heat treating oven (done them both!).
1 comment:
Hey Tom,
Long time reader, first time commenter...
I can't agree more with this post. As an FSAE alumnus that has done both pull-rod and push-rod front suspensions, I found the F1technical thread pretty amusing, given the background of some of the posters. Similar to the engineer you quoted, the decision to switch to pull rod was an easy one, as it made packaging easier with the newer chassis templates in FSAE. Kinematically, the MRs were nearly identical, and the CG change probably amounted to peanuts. But when it came to making our lives easier, it was a no brainer.
Anyway, I really enjoy this blog, and always learn something new. Keep it up man!
Ross
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