Sanity check please - front spindle
Sanity check please - front spindle
(OP)
Could I get a sanity check from the members here?
I've been working out the geometry for a revised front spindle on a hillclimb/sprint car and have decided to keep the camber recovery lowish using medium length swing arms around the same length as the track and use caster to recover the camber.There was some compromise packing it all inside the wheel and I ended up with 3 degrees kpi, 9 degrees caster and to keep the trail down to 15mm placed the wheel spindle 27mm in front of the steering axis. The scrub, due to the available wheels ended up at 52mm. The geometric roll center - for what it is worth ended up at 35mm above ground and does not move relative to the c of g.
Does this sound sensible for a mid engined 60/40 car that is used on tight circuits/hillclimbs?
Cheers
David
I've been working out the geometry for a revised front spindle on a hillclimb/sprint car and have decided to keep the camber recovery lowish using medium length swing arms around the same length as the track and use caster to recover the camber.There was some compromise packing it all inside the wheel and I ended up with 3 degrees kpi, 9 degrees caster and to keep the trail down to 15mm placed the wheel spindle 27mm in front of the steering axis. The scrub, due to the available wheels ended up at 52mm. The geometric roll center - for what it is worth ended up at 35mm above ground and does not move relative to the c of g.
Does this sound sensible for a mid engined 60/40 car that is used on tight circuits/hillclimbs?
Cheers
David
David Child





RE: Sanity check please - front spindle
52 scrub is fine, might fidget a bit in straight line braking but at least that tells you which wheel is locking.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Sanity check please - front spindle
Is it worth reducing the scrub by increasing the kpi do you think?
David Child
RE: Sanity check please - front spindle
Also on trail braking you dont want the torque due to the scrub overpowering the feedback from the pneumatic trail/self aligning torque of the tyre.
RE: Sanity check please - front spindle
Regards
Pat
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RE: Sanity check please - front spindle
What apex speed are you designing for?
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: Sanity check please - front spindle
also the steering weight is more a factor of the castor trail not the castor angle. 15mm castor trail is very little.
RE: Sanity check please - front spindle
I forgot about the spindle being forward of the steering axis.
Regards
Pat
See FAQ731-376: Eng-Tips.com Forum Policies for tips on use of eng-tips by professional engineers &
http://eng-tips.com/market.cfm
for site rules
RE: Sanity check please - front spindle
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?