Chris_R
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| posted on 18/5/04 at 08:54 PM |
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Compound angles of tubes LA and LB
I’m having some problems measuring the compound angles of tubes LA and LB. I’ve looked at previous threads, but haven’t yet found an answer. I was
hoping some of you guys could let me know how you did it.
Cheers,
Chris.
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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alfasudsprint
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| posted on 18/5/04 at 09:51 PM |
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Have you tried Mcsorely plans? I did mine before that, it was bloody difficult, but you get there eventually. a bit of trial and error in the abscence
of calcs, ie a piece of scrap worst case!
tim
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Chris_R
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| posted on 18/5/04 at 10:20 PM |
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Mcsorely plans? Please excuse my ignorance.
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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Chris_R
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| posted on 18/5/04 at 10:24 PM |
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Ah, http://mcsorley.net/
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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James
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| posted on 19/5/04 at 09:56 AM |
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Using Trig' I just worked out the angle that each cut needed to be along each face of the tube. I then cut each face individually.
Took me three attempts but worked in the end! 
Cheers,
James
EDIT:
You could of course cheat and make the nosecone angled in only one plane- then just lean it back! I think Conrod did that on his first Locost.
Additionally it's worth noting that the top/bottom offset should really be 4" not 3" so you can fit the wishbones on better. Mark
Allanson knows more about that than me though.
[Edited on 19/5/04 by James]
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ned
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| posted on 19/5/04 at 10:32 AM |
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well mine is probably bu**ered because I just cut them by eye and then set them by the location of the suspension brackets using the jig i made.
Ned.
beware, I've got yellow skin
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Steve Hnz
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| posted on 19/5/04 at 11:52 AM |
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James, could you please expand on your comments re top to bottom offset, or maybe Mark should? Thanks, Steve.
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flak monkey
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| posted on 19/5/04 at 12:24 PM |
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Basically if you want to use book wishbones AND get the correct castor angle (5.3 or 5.5 deg) you need to shift the top wishbone back by about 20mm.
If you do this with the standard front assembly one of your wishbone brackets ends up with nothing to fix to! You can either change the L assembly, or
change the design of the wishbone to overcome this. But you need to change one or the other to get the castor right.
Cheers,
David 
Sera
http://www.motosera.com
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James
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| posted on 19/5/04 at 01:51 PM |
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'Nuff said!
James
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Peteff
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| posted on 19/5/04 at 05:05 PM |
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The one I'm doing now has the front top 25mm further back and the fu's the same to give more castor and still leave something to fasten
the bracket to. The chassis is 25mm taller as well
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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Chris_R
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| posted on 19/5/04 at 05:22 PM |
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I'd intended to use GTS's wide track wishbones. will that effect the position of the L & F tubes?
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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flak monkey
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| posted on 19/5/04 at 05:29 PM |
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In a word....yes...(AFAIK) you still need to lean the L assembly back further and leave the FU tubes out until you have the wishbones....
Anyone else agree with me?
Cheers,
David
Sera
http://www.motosera.com
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Chris_R
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| posted on 19/5/04 at 06:21 PM |
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I'm using sierra uprights so will have to use mushroom inserts. It's possible to get the inserts with an offset hole, so will this help
the castor without having to move the wishbones?
[Edited on 19/5/04 by Chris_R]
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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leto
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| posted on 19/5/04 at 06:48 PM |
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This might help if you are to lazy to use a hacksaw, like I am.
Drawings for more reclined versions in following posts.
Oh! I forgot! Please check the dimension, I don't have The Book around.
Happy building
[Edited on 04-5-19 by leto]
[Edited on 04-5-19 by leto]
“I'm gonna ride around in style
I'm gonna drive everybody wild
'Cause I'll have the only one there is a round”. (J. Cash)
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leto
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| posted on 19/5/04 at 06:49 PM |
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Reclined 20mm
[Edited on 04-5-19 by leto]
[Edited on 04-5-19 by leto]
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leto
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| posted on 19/5/04 at 06:50 PM |
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Reclined 40mm
[Edited on 04-5-19 by leto]
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leto
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| posted on 19/5/04 at 07:31 PM |
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quote:
Originally posted by Chris_R
I'm using sierra uprights so will have to use mushroom inserts. It's possible to get the inserts with an offset hole, so will this help
the castor without having to move the wishbones?
I believe Castor is defined by a line through the joints and they will not be moved by a offset mushroom. This have most probably been discussed
before. But I can bee wrong in both cases.
“I'm gonna ride around in style
I'm gonna drive everybody wild
'Cause I'll have the only one there is a round”. (J. Cash)
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flak monkey
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| posted on 19/5/04 at 08:00 PM |
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quote:
I believe Castor is defined by a line through the joints and they will not be moved by a offset mushroom. This have most probably been discussed
before. But I can bee wrong in both cases.
Correct....'nuff said.... (It has been posted before too....)
David
Sera
http://www.motosera.com
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Chris_R
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| posted on 19/5/04 at 08:27 PM |
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would turning the offset to the front of the vehicle not angle the upright toward the rear?
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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flak monkey
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| posted on 19/5/04 at 08:32 PM |
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I always assumed that too, but i remember reading something to the contrary...if you can find the topic thread you can read all about it...i dont
remember what it was called....all i remember is that the adjustable inserts dont do much for you....
Anyone remember?
And i stand to be corrected as usual.... 
[Edited on 19/5/04 by flak monkey]
Sera
http://www.motosera.com
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Chris_R
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| posted on 19/5/04 at 08:52 PM |
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so, the basic advice is make the 76mm lean of the L section around 101mm and don't add the F tubes until wishbones arrive? Knowing my luck
something will go wrong somewhere along the line.
A bit of slapstick never hurt anyone.
http://www.chris.renney.dsl.pipex.com/
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flak monkey
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| posted on 19/5/04 at 08:54 PM |
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Yup, sounds about right to me Then your brakets will definately end up with something to fix to...and not be hanging in mid air!
Cheers
David
Sera
http://www.motosera.com
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leto
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| posted on 20/5/04 at 07:08 AM |
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Reclined 25mm
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davef
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 posted on 20/5/04 at 01:32 PM |
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LA & LB
Hi Chris
this subject is a real old one, go into search, look for castor angle, and check accurate front suspension date 13/2/03,all will be explained in
detail. i discovered the cockup in the book a long time ago, and did my own alterations to the chassis to accomodate the suspension brackets better.
while i am typing just to make clear for people looking at the castor angle for the first time 5.3 degrees means 5 degrees 30 minutes. or 5.5 which
means five and one half degrees, cos theres 60 minutes in a degree. cheers davef.
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James
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| posted on 20/5/04 at 01:54 PM |
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quote:
Originally posted by Chris_R
so, the basic advice is make the 76mm lean of the L section around 101mm and don't add the F tubes until wishbones arrive? Knowing my luck
something will go wrong somewhere along the line.
Yup- sounds right.
And make sure you make a decent bracket jig- makes life many times easier!
There's a couple of pictures in my archive:
http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=bracketjig_fr_small.jpg
and
http://www.locostbuilders.co.uk/photos.php?action=showphoto&photo=bracketjig_rr_small1.jpg
If you don't have spare metal then I guess you could do what Ned did and replace the 19mm with MDF.
HTH,
James
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