z,

Thank you very much for your assistance and for re-kindling my interest in reviewing my classical mechanics. Being a grey beard I did learn all of the above many, many years ago around 1977 to 1982 but my skills had atrophied from lack of use.

In my view the best references I have in my library are Mechanics by Den Hartog and Statics by J.L. Meriam. I have many, many other texts concerning general physics, kinematics, machine design, descriptive and analytic geometry etc. etc. but these two works are by far the clearest. Hartog is a little unclear in describing your figure 3 above concerning the relocation of a force by the use of a force and couple but Meriam cites it almost verbatim as you have presented it. It is included in Hartog of course but presented with some subtlety that doesn't reach out and grab you.

Another good resource for a general review is MIT's Open Courseware 8.01 classical mechanics video lectures by physicist Walter Lewin. This is a video archive of his freshman fall lectures on the subject. While the students on here might view this as very trivial it is a great review of the very essence of classical mechanics and if you don't find Prof. Lewy, as he is known, as one of the most entertaining and informative lecturers you've ever seen I would be surprised. To have a single professor like him in your college careers is a very rare thing, at least in my experience.

Link: http://ocw.mit.edu/courses/physics/8...1999/index.htm

To the students who may read this thread and wonder 'why in the heck would you design a beam axle like that??' all I can say is 'I' didn't.

The cars as described have evolved over the course of some sixty years. They started as modified U.S. passenger cars of the 1930's and are mostly the product of 'trial and error' garage engineering. Don't laugh, it might be a slow process, but cut and try has produced many beneficial pieces of machinery.

The biggest advances in these cars over those sixty years have been in the area of construction materials available, fabrication techniques, tire size & compounding and as in all things racing aerodynamics. However, to my knowledge at least, only one car has made it to a wind tunnel test which yielded some hard data and which was published in an SAE paper by Eric Koster. The rest, cut and try.

Why did I get involved?

Well, I was actually perplexed that after all these years of evolution that all of the cars produced by basically four builders wound up in the same tiny corner of the box of design possibilities. The beam axles are a product of the rulebook so that is not a design choice. But how to suspend a beam axle car has many possibilities and many have been used over the years on these car.

So, why is a twin trailing link, torque arm, short offset cockpit adjustable panhard bar system the winner for the last ten or so years?

The ever thickening rulebooks are one possibility. Never think that what happens at the upper echelons of automobile racing doesn't eventually trickle down in some form to the grassroots level. It does, if for no other reason, than the illogical reason, of 'I want to be like the 'Big Boys' mentality of the rules makers.

The era of 'credit card' racers may also be a factor as very few participants actually build and develop their own cars anymore. Break it, buy a new shrink wrapped piece from the parts truck.

However, there are some who have asked, who think I might know at least a little bit of engineering, to have a look and explain what and more importantly why the cars are designed as they are. And what might be done to improve them. The driver behind this of course is that like in many current forms of motorsports they have achieved parity and that makes winning frequently very difficult.

Why would anyone pick driver adjustability of the panhard bar angle as a design criteria? I don't know but I am working to find out.

Thanks for allowing me to participate in this forum even though my questions and thoughts may not pertain directly to formula SAE.

Thank you again Z for the great illustrations and explanations. (Expect more PM's )

Ralph