sway bar diameter

[gat]

hey everyone, i just joined my school's fsae and i've started working on the front sway bar and mounts. i am having trouble establishing some equations to come up with an appropriate sway bar diameter. i have looked over the RCVD, however, it seems to me that there are too many inputs and necessary assumptions in addition to those used to derive the equations, which makes me uncomfortable about how meaningful any results i might get would be. Is this likely a problem due to my infamiliarity with my teams car, or are there some simplifications which can be made to this problem, to narrow in on a reasonable range of possible diameters. thanks in advance.

[dr47watson]

You basically have to go through all the "inputs and assumptions". Your car will have a certain roll stiffness. This is a function of your springs and sway bars. You get to pick how many degrees per lateral G you want the car to roll. RCVD implies that 1.5 deg/g is in the ballpark. Based then on many factors including (but not limited to) cg height, track width, roll center heights, and spring rates you can figure out what part of the roll stiffness will be provided by the sway bars. Then you can calculate the diameter (and length and actuating arm length) of your bar. Read chapter 16 two or three more times; at first that book seems like crap, but the more you read the better it gets. There are few easy answers. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Rich