Steering design

[nquattro4]

So, I've read, I've talked and I got what I thought was pretty good steering design. Only when I ended up modeling and setting it up in the car in Pro-E it sets a really high angle on the inner wheel when at full lock (39 degrees). It's causing all kinds of issues with rubbing the control arms on the wheel at full lock. My Pro-E models are what I want, so it isn't simply that. I have to be missing something someplace, does anyone have any suggestions where to start looking?

Thanks in advance,
Nick

[nquattro4]

So, I've read, I've talked and I got what I thought was pretty good steering design. Only when I ended up modeling and setting it up in the car in Pro-E it sets a really high angle on the inner wheel when at full lock (39 degrees). It's causing all kinds of issues with rubbing the control arms on the wheel at full lock. My Pro-E models are what I want, so it isn't simply that. I have to be missing something someplace, does anyone have any suggestions where to start looking?

Thanks in advance,
Nick

[Pete Marsh]

Why steer so much? simply put your steering stops where you think is right.

39 deg is a lot of steering angle, more than you will need with any reasonable wheelbase IMO.

Pete

[JDS]

Yeah, there is no need for FSAE cars to angle their wheels 39 deg. Most of our cars would run into interference issues. For us it would probably be the uprights running into the control arms.

A good way to determine your max wheel angle is to find the Ackerman steer angle using the your wheelbase and the minimum turn radius allowed by competition rules (although they ignored that rule last year at Michigan in auto-x, so be careful). Remember also that when your car is running with slip angle (which it always is to some extent) that the Ackerman angle no longer applies, so estimate the new required angle based on different slip scenarios, give yourself a comfortable factor of safety, and you should come up with number significantly less than 39 deg.