b14wrc
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| posted on 3/10/13 at 05:07 PM |
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Caster angle
Hi all,
Done a search but can't find the exact answer I'm looking for.
Tomorrow I am going to finish off my upper front arms on the locost. Basically my design will not allow for any caster adjustment so need to consider
the angle required, don't want to remake them later but will always be an option.
I am running mk 5 cortina uprights and the car is mid engined. I have been considering 4-5degrees of positive caster as this is what my suspension
book says as a maximum. Does this sound like what others have?
I'm going to use the suck it and see method with this but if any one has some experience with a similar setup please let me know, might save me
time and money.
Regards, Rob
[Edited on 3/10/13 by b14wrc]
20vt powered rear engined locost
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big_wasa
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| posted on 3/10/13 at 05:48 PM |
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" The book " says 7 and a little bit deg but its really half that due to an error. If your basing your front geo on the book I would aim
for at least 7.
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Not Anumber
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| posted on 3/10/13 at 06:45 PM |
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I'd very much suggest you go for adjustable top wishbones using rose joints. I had no caster angle on my Indy until i replaced the top
wishbones with adjustable after market ones. Using washers as spacers either side of the rose joints means you can increase and decrease caster angle
to suit until it's right. Dont put up with poor self centreing on the steering if you dont have to.
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bi22le
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| posted on 3/10/13 at 09:43 PM |
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not built so take with a pinch of salt if you wish.
design with adjustment. if you don't and it don't handle as you expect it to then you will regret it
build it once, build it right.
check out current factory designs, ask for photos and advice. adjustment is mandatory, especially if your building something that is a less proven
path like your weapon.
good luck with th build.
biz
Track days ARE the best thing since sliced bread, until I get a supercharger that is!
Please read my ring story:
http://www.locostbuilders.co.uk/forum/13/viewthread.php?tid=139152&page=1
Me doing a sub 56sec lap around Brands Indy. I need a geo set up! http://www.youtube.com/watch?v=EHksfvIGB3I
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johnH20
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| posted on 4/10/13 at 10:01 AM |
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I have measured the castor on my Cyclone ( mid engine ) at 9 deg. Its a difficult thing to do DIY so I might be out by a degree or so. According to
press reports the Cyclone was a great handling car and had no SVA issues with steering. If mine was on the road I could give you a personal report!
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froggy
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| posted on 4/10/13 at 02:38 PM |
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I started with 7 but ended up running 12 with a quick rack and an epas column to take the effort off when parking . I'm no stig but I find that
with 12 deg it self centres nicely and you can let the wheel slip through your hands when winding the lock off if you get a bit too sideways .
[IMG]http://i144.photobucket.com/albums/r187/froggy_0[IMG]
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907
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| posted on 4/10/13 at 04:38 PM |
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Hi Rob.
I made a book set , and then made a second set with more caster.
Don't know if this is of any help. Dimensions are in mm's as I find it easier than angles.
Anyway these are pics of mine.
Pic 1 shows the jig with a c/l (centre line) and the old and new top B/J c/l
dims are l<13>l<9>l (=22mm)
 
Front top wish bone jig
Pic 2 shows ....
 
Wish bone dims extra castor
And pic 3 shows an old w/b laying on top of it's replacement.
 
Book w/b on top of modded w/b
Pic 4 shows final assembly.
 
Stainless WB set up
HTH
Paul G
[Edited on 4/10/13 by 907]
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Mark Allanson
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| posted on 4/10/13 at 07:46 PM |
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looks strangely familiar!
If you can keep you head, whilst all others around you are losing theirs, you are not fully aware of the situation
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b14wrc
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| posted on 4/10/13 at 10:57 PM |
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Hi guys,
Thanks for the advice, some really useful tips there.
Had a frustrating day as I came home from work to try and get sorted with the front end, planned to use rose joints as advised but it didn't
work out......
So I have added plenty of caster and come up with this:
Paul G, thanks for your photos, they have helped me.
Regards Rob
20vt powered rear engined locost
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907
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| posted on 5/10/13 at 07:47 AM |
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quote:
Originally posted by Mark Allanson
looks strangely familiar!
Originally it was thanks to Mark for the dims.
Cheers,
Paul G
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b14wrc
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| posted on 5/10/13 at 08:08 AM |
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Thanks everyone.
I may end up making new arms later once the car is drivable, at this stage, I can live with that idea,at the moment the key for me is to keep the
momentum up and get it finished, stills hell of a lot of work to do.
Rob
20vt powered rear engined locost
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iank
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| posted on 5/10/13 at 08:45 AM |
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Not sure what the centre tube is for on the top wishbone.
On the rose joints, while I appreciate most of the kitcar manufacturers use rose joints in that orientation (so they can use the same brackets/jigs)
they are ideally mounted with the bolts vertical from a strength and minimising friction point of view.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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big_wasa
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| posted on 5/10/13 at 08:46 AM |
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quote:
Originally posted by 907
quote:
Originally posted by Mark Allanson
looks strangely familiar!
Originally it was thanks to Mark for the dims.
Cheers,
Paul G
Ha ha I based mine on yours and used Marks Dims for the tunnel to clear the diff
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b14wrc
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| posted on 5/10/13 at 09:54 AM |
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The centre tube is just to get the alignment, it gets chopped off once I have set up the angles. 
I know what your say with regards to the rose joints, I've reverted back to my original plan as I was not happy with the look and engineering of
the rose jointed arm, over complicated!
The simple option may mean I need to redo it once the car is on the road, but until I've driven it, it's hard to tell, I have put about 8
- 10 deg of positive Caster in, will see what it's like.
20vt powered rear engined locost
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iank
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| posted on 5/10/13 at 11:17 AM |
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quote:
Originally posted by b14wrc
The centre tube is just to get the alignment, it gets chopped off once I have set up the angles.
I know what your say with regards to the rose joints, I've reverted back to my original plan as I was not happy with the look and engineering of
the rose jointed arm, over complicated!
The simple option may mean I need to redo it once the car is on the road, but until I've driven it, it's hard to tell, I have put about 8
- 10 deg of positive Caster in, will see what it's like.
Ah, I see now.
With so much work to do around the rest of the car I think you're wise keeping momentum and not getting bogged down.
Suspension is one of those things where there is only so much design you can do before trying it out and fiddling to get it how you want (even the f1
teams/drivers work like that).
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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