The only trick you need to convince Pat is: Large toe-base (say 100mm), large mechanical trail (mmm, self aligning goodness! (100mm) and give it a horribly large rear scrub (100mm?) for an acceptable solution. Then extrapolate this down to, hey we run zero rear scrub (we did) a smaller mechanical trail (why not reversed?) and you can easily allow yourself a nice easy to package 10 mm toe base!Originally posted by Fyhr:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by PatClarke:
Of course it matters!!! Think about it.
Pat
But in all seriousness, refer to the videos above, calculate how your forces are affected by changing scrub and what you need to do to cope with those changes and you will be close to both a solution and answers to keep design judges happy. Remeber to read this too: http://www.formulastudent.de/d...ness-and-compliance/ </div></BLOCKQUOTE>
1) Large toe base, to maintain the desired toe while coping with compliance.
2) Why? Self aligning is desirable? It means both rear wheels will turn out in cornering, generating less lateral force. I can't see any beneficial effect, since in turn-in you won't have lateral force, then no turn-out (which could be useful in this phase). In mid-corner and exit under lateral load the behaviour will tend towards oversteer, beneficial? It depends, generally I would say not. Am I missing something?
3) Again, why? Positive scrub radius? It causes toe-out under braking and toe-in under acceleration. These are beneficial in some cases (e.g. may help in turn-in provided you don't spin and reduce power oversteer in corner exit), but how much? Is it important to implement a large rear scrub? And what about instability under braking?
Thank you for your contribution!
Vittorio