steering geometry and the template for FSAE-A

[Chris B]

hey all,

So this is mostly a quesiton for australian teams but anyone else subject to a similar sized template is welcome to answer.

so in the process of designing the 2012 front suspension and steering geometry our guys, myself included, wanted to evaluate the merits of running a top mounted steering rack. the conclusion we later came to, after a fairly extensive effort to make it work, was that for our car at least, we wouldn't be able to run a top mount rack while maintaining compliance with the template. Or you could comply with the template but then couldnt package it to provide any sane geometry (or indeed to even fit in any sane way). so as a result we've scrapped that idea.

i read in an older post on here that the idea of the template was to encourage teams away from top mount racks and their shin breaking characteristics. I'm just curious as to whether anyone has been able to get one to work successfully in the time since then?

i'm not after any actual design details nor am i asking how it should be done, this post is purely meant for casual discussion of what teams have found in their experience.

for us it was a valuable exercise as we learnt alot from it.

best regards,

chris

PS sorry for my bulk essay

[Demon Of Speed]

As far as I know of all the steering racks are bottom mounted these days.

[coastertrav]

Colombia did a top mounted rack that actuated through levers two years ago.

[Dash]

Our baja team from about 10 years ago did a cable and pulley system that seems like it could function.

[Joji]

well from our research, we found out that if we want to keep the rack high enough to clear the template rule then there are two possibilities:
1. We dont project the tie rod line to pass through IC, resulting in horrible bump steer.
2. Or to remove bump steer we keep our inboard pivots high enough, but this will cause IC to be outside the track and a roll center below ground http://fsae.com/groupee_common/emoticons/icon_smile.gif

therefore we concluded "Template rule is quite successful in discouraging high mounted racks." http://fsae.com/groupee_common/emoticons/icon_razz.gif
Hats off to rules commitee

[coastertrav]

Originally posted by Joji:

therefore we concluded "Template rule is quite successful in discouraging high mounted racks." http://fsae.com/groupee_common/emoticons/icon_razz.gif
Hats off to rules commitee

I'm not sure why, but this made me chuckle.

[Chris B]

cheers guys. as i said it was mostly a curiosity question to see if anyone has been able to get it to work since we couldn't. Joji we pretty much came to the same conclusion lol. i saw on here earlier this year someone state that the point of the template was to discourage high rack designs and we've now proven it ourselves so it was at least an educational experience.

[sbrenaman]

Originally posted by Chris B:
I'm just curious as to whether anyone has been able to get one to work successfully in the time since then?

What about a zero-keel suspension? Seems like that would be your best shot at implementing a top mounted rack.