what are advantages & disadvantages of putting steering rack higher than driver legs?

[mohab]

sorry it's first time for me to design suspension & steering systems.

what are advantages & disadvantages of putting steering rack higher than driver legs?

what are the correct steps to select suitable steering rack and what are the companies you suggest for us ?

sorry if these are stupid questions http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[PatClarke]

Mohab,

It used to be almost standard design to put the rack above the drivers legs. This was seen as a very dangerous design solution because of the risk of drivers being injured or trapped in even a fairly minor crash.

So, the cockpit template rules were introduced.

If you can design an effective high rack car and still pass the template rules, then that is a design option for you.

Now you have some research to do. Google is your friend http://fsae.com/groupee_common/emoticons/icon_wink.gif

Pat

[mohab]

thank you for quick replay http://fsae.com/groupee_common/emoticons/icon_smile.gif

after choosing inner and outer joint position of tie rods in the front view according to A-arms position

i don't know what I must do now

and what the data that the manufacturer needs from me and I didn't find any characteristics of products for any manufacturer so how I can compare between products

sorry I know this is stupid but rely I don't know

[Marvel]

There are many things to be thought of with the rack position..
Ackerman or Anti-ackerman or a parallel steer?
Bump steer?
Inner v/s Outer steered tire angle
Driver safety
and many..many others!
Search related topics on this forum.
Hope this helps...

[Warpspeed]

The simplest bump steer solution is usually to place the tie rod at the same height as either the upper or lower wishbone.
If the tie rod length and wishbone length are made the same, the outer ends will describe similar arcs.
That is a bit simplistic, but it is always a very good initial starting position with a fresh design.

Once you have designed your SLA suspension pickup points, the rack location can be placed ahead or behind the axle centreline, positioned at either upper or lower wishbone height.

If you take into account what else gets into the way, especially the driver's feet, that usually narrows down the options very quickly.