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 Post subject: Stage 3 Chassis
PostPosted: May 4, 2009, 6:26 pm 
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04 May, 2009 Update
The main chassis is pretty much finished except for a couple of chassis plates, which I prefer to model as assemblies.. I'll be adding the suspension brackets, A-arms, etc., next.


Attachments:
Third-Stage-2.jpg
Third-Stage-2.jpg [ 231.73 KiB | Viewed 7962 times ]
Third-Stage-3.jpg
Third-Stage-3.jpg [ 248.48 KiB | Viewed 7962 times ]
Third-Stage-1.jpg
Third-Stage-1.jpg [ 226.1 KiB | Viewed 7968 times ]

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886
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PostPosted: May 4, 2009, 7:01 pm 
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After all of your work I was expecting a left hand drive chassis.

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PostPosted: May 5, 2009, 10:40 am 
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The left hand drive version will be Phase II. I wanted to do the first 3D model based on the book chassis since it has the most information available for it in both visually and technical terms (including other information in the forums in the UK and here). That gives me the best chance to validate my work and accuracy in SolidWorks.

I'll use the left hand drive version as the basis for my own, real life chassis, which will be modified to suit the mechanicals of my donor vehicle, a 1994, V6 Mustang.

Cheers,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: May 11, 2009, 7:21 pm 
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11 May Update:

Details, details, details; it never seems to stop. It's fun, but a whole world of hard work. I've started on the suspension parts and have almost all the frontend done. I still have to do the upright, which is pretty complicated as a casting with a 2-part mold, etc. The later is required as part of my final project in the advanced SolidWorks class I'm taking. Modeling the Locost is my self-selected, final project, which is totally cool I must say.

Cheers,

Lonnie


Attachments:
File comment: This is just the lower, front wishbone with shock bracket, Austin Maxi ball joint, stainless compression tubes, poly bushings and some nuts and bolts.
Lwr-Front-Wish-Assembly.jpg
Lwr-Front-Wish-Assembly.jpg [ 119.99 KiB | Viewed 7961 times ]

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886
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PostPosted: May 16, 2009, 1:18 pm 
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16 May 2009

The book chassis should be all complete by next week. It is indeed true that the "Devil lives in the details" and while they are typically 20% of the task, they often require 80% of the effort. Below are some of this weeks details and how they look in the chassis assembly, which is only partially complete, but rapidly coming together.


Attachments:
File comment: Completed rear upright. I'm very happy with this piece.
Rear-Upright.jpg
Rear-Upright.jpg [ 71.45 KiB | Viewed 7960 times ]
File comment: I'm pretty happy with this model, but will add some small details if time permits. The gray body will render as polished aluminum in the final presentation.
Coilover.jpg
Coilover.jpg [ 96.18 KiB | Viewed 7959 times ]
File comment: Partially completed chassis assembly. The actual chassis structure is all complete. It's a matter of adding the details and sub-assemblies.
05-16-09-Chassis.jpg
05-16-09-Chassis.jpg [ 204.01 KiB | Viewed 7971 times ]

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886
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PostPosted: May 21, 2009, 7:50 pm 
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12 May, 2009 Update

The book chassis in SolidWorks is finished. The front upright is a little bit of a cook-up since hard engineering data on the Sierra/Merkur upright wasn't available to me. It does have some validity since I was sent a drawing that had some dimensions for it, but not all the necessary ones.

As I continue to research regarding adaptations of my donor (primarily front suspension), I'll do the left hand drive version of the book chassis. After that, it will be on to creating a new variation for my specific donor vehicle.

Cheers,

Lonnie


Attachments:
File comment: Good except for the upright, which is only partially correct in terms of dimensions and shape.
Small-Front-Suspension-Assembly-White.jpg
Small-Front-Suspension-Assembly-White.jpg [ 95.71 KiB | Viewed 8932 times ]
File comment: Very accurate. The rear upright was built in SolidWorks in such a way that it looks smoother than the book version. However, it is dimensionally very accurate and would fit if realized in steel.
Small-LHS-Rear-Suspen-White.jpg
Small-LHS-Rear-Suspen-White.jpg [ 109.36 KiB | Viewed 8942 times ]
File comment: Essentially completed.
Small-Chassis-ISO-View.jpg
Small-Chassis-ISO-View.jpg [ 123.11 KiB | Viewed 8935 times ]

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886
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PostPosted: May 21, 2009, 11:03 pm 
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I love seeing Locost frame's drawn up in Solidworks. I use Solidworks at work. Every day I think about how much better my car would have been if I modeled everything before I made it. (Locost came before Solidworks was a part of my life).

Keep up the good work!

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PostPosted: May 22, 2009, 8:32 am 
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I don't see any caster adjustment for the front or toe adjustment for the rear unless your using soft bushings and eccentrics.

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PostPosted: May 22, 2009, 12:26 pm 
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Thanks for the encouragement, maxlessca. I think the fact that I can model my modifications in 3D prior to cutting metal will save me lots of time and frustration in the end. It should result in a much better end-product too.

Cheers,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: May 22, 2009, 12:47 pm 
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You have an eye for detail, Miatav8. Actually the adjustments are there in both cases. Due to the peculiar way in which SolidWorks renders threads I had to suppress them in the two assembly renderings. When you elect to show them it does a nice job on the threads that are visible, but unfortunately also shows the internal threads too. It's a distraction since they look like blemishes in the rendering. You see what I mean if you look closely at the two items below, which are: 1) the exploded camber adjuster from the top, rear wishbones; and the lower tie rod end. It can get very busy visually in a complex assembly where lots of internal threads show.

In the design as published, the caster at front is set my the natural inclination of the wishbones while camber adjustment come through the upper ball joint assembly threaded into the upper wishbones. There is no caster (anti-squat) at rear; only camber adjustment.

All bushings are specified as polyurethane. I consider that material pretty rigid. The bolts in the bushing assemblies all ride in a stainless steel crush tube as shown, which is 0.5 mm larger than the bolts.

Cheers,

Lonnie


Attachments:
File comment: Camber adjuster exploded. Both upper, rear wishbones have one.
Exploded-Rear-Caster-Adjuster.jpg
Exploded-Rear-Caster-Adjuster.jpg [ 64.43 KiB | Viewed 8798 times ]
File comment: End threaded to steering provide toe-in/toe-out.
Lower-Tie-Rod-Assembly.jpg
Lower-Tie-Rod-Assembly.jpg [ 52.75 KiB | Viewed 8798 times ]

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886
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PostPosted: May 22, 2009, 12:51 pm 
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MV8 was asking about toe adjustment on the rear, not the front :)
I can't see one either..

Moti

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PostPosted: May 22, 2009, 1:40 pm 
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With enough attention to detail, I'm sure you can build the car to have exactly the right amount of front caster and rear toe without adding adjustability.

However, if you change your mind on what the settings should be, run over something, etc then you will wish for adjustability.

Making the front adjustable for caster is as easy as adding threaded sphericals to the uca or lca pivots. The rear is a little more effort because adjusting one arm puts the other in a bind.

Just another consideration.

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PostPosted: May 22, 2009, 1:47 pm 
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You are correct, Moti. There is no adjustment for toe-in/toe-out at the rear provided in the (Gibbs) book design. A person wanting such would have to create their own setup. So far, I haven't seen any Internet chatter about the need for it in the design. I can see where it would be desireable for those who are really into suspension tuning, however.

Honestly, I haven't gotten far enough into the details of my reference books (Staniforth, Aird, Adams, Smith, etc.) to have a strong opinion - yet. I'll have to start thinking about those things in a month or so.

Cheers,

Lonnie

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Damn! That front slip angle is way too large and the Ackerman is just a muddle.

Build Log: viewtopic.php?f=35&t=5886


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PostPosted: May 22, 2009, 2:05 pm 
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Lonnie-S wrote:
So far, I haven't seen any Internet chatter about the need for it in the design.


You wouldn't, because most cars are made adjustable from the factory. For those car makers that do not include adjustment on some of their models (GM pickups come to mind) the aftermarket companies (usually Moog and TRW) sell adjustment kits.

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PostPosted: May 22, 2009, 2:07 pm 
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I'd consider rear toe adjustment to be a must, even if only to be able to tune out welding deformation.
Say your weld deformed just enough to create very slight toe out, fat chance that your car will scare the crap out of you.

Moti

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