Critique my chassis design

Whether it's a "book" chassis or another variant, FEA talk or roll cage advice that you're looking for, this is the place to talk frame construction.

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carguy123
Toyotaphobe
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Building: Choppercrosser
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Re: Critique my chassis design

Post by carguy123 »

horizenjob wrote:carguy, you quoted 2001 above...

It looks like a nice package for this job.


I forgot my meds?????
mobilito ergo sum
I drive therefore I am

I can explain it to you,
but I can't understand it for you.
stinger
Posts: 327
Joined: January 1, 2015, 1:55 pm
Building: mid engine

Re: Critique my chassis design

Post by stinger »

I like your build. I've used C5 suspension in a few builds. The rear lower control arms are angled. I can't tell if you've duplicated that angle. Just wondering.

Happy building!
Lemans1956
Posts: 41
Joined: May 13, 2016, 9:28 pm
Building: Ferrari replica

Re: Critique my chassis design

Post by Lemans1956 »

Stinger, yes I incorporated the anti dive into the frt & rear suspensions on the chassis, They’re set up With stock geometry. The rear lower arms are angled , and likewise the front uppers are angled .
MangPong
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Joined: March 15, 2018, 6:03 am
Building: reverse-trike

Re: Critique my chassis design

Post by MangPong »

Just a brief compliment on the SketchUp drawings here - god, I wish I could understand CAD programmes - I've tried about two dozen over the years (and SketchUp just a couple of months ago), but just can't get started.
I was brought up with T-squares and set-squares and can manage almost everything I need (and much more) in the old Macromedia FreeHand - my all-time favourite com. programme.
I can't wait to actually get a hacksaw into some steel tubing... lol.
Best wishes, MangPong.
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ngpmike
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Re: Critique my chassis design

Post by ngpmike »

MangPong wrote:I was brought up with T-squares and set-squares and can manage almost everything I need (and much more) in the old...


I know what you mean! I learned with T-squares, triangles, and compasses. But when you get 2/3 of the way through a drawing and discover a goof you made at the beginning that will require starting over, or a helluva lot of erasing, you learn to appreciate the electronic advantage. Don't ask me how I know!!! ShetchUp is actually pretty easy to learn, and while it's not the ultimate weapon available to a cad draftsman, for an old duffer like myself, it's good enough!
Mike - Read my story at http://twinlakesseven.blogspot.com/
MangPong
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Building: reverse-trike

Re: Critique my chassis design

Post by MangPong »

Hi ngpmike - many thanks for your comment - one old duffer to another... lol.
I have now moved on to electronics and do all my drawings in FreeHand, so I don't ever have to start again and, when I have a new idea, I make a copy of the file and adapt that - if I don't like it I can revert to the previous version. But I cannot make an adjustment in, say, the plan and have this automatically change in the elevations.
About sixteen years ago I had a demo version of DenebaCAD which was quite good but seems to have disappeared, and probably isn't compatible with present-day Systems. But it could import the FreeHand files so I could do plan views in FreeHand, import them into DenebaCAD and then stipulate heights for each 'point' - it was magic. But, being a 'demo' I couldn't save any work I did, and I couldn't afford to buy it.
I just tried SketchUp, after several recommendations like yours, but I couldn't even work out how to create a six-sided box shape. Maybe if I had someone nearby who could just get me started... but don't get me started... lol.
At the moment I prefer to spend my time actually drawing my ideas than failing to draw my ideas better... (I don't thinks that's good grammar, but maybe you'll get the point.)

Thanks for commenting - Mangpong.
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horizenjob
The voice of reason
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Re: Critique my chassis design

Post by horizenjob »

Hi Mangpong! Hmm, do we call you Mang or Pong for short?

I think you should give SketchUp another try. I understand it's frustrating, but I think you need to get over a hurdle or two and then you will have knowledge to build on and it will start seeming easier. I suggest watching and performing the beginner's tutorials, it will take a couple of hours - but that is just a drop in the bucket.

The next reason I will give you for learning SketchUp is that members on our forum have already done a great deal of work that you can use right away. For example I created a library area in the SketchUp warehouse that contains drawings for my car design and there are several others included too. In addition I made something like a garage drawing called something like the "musty shop" where I drew shelves and put various parts like spindles, wheels rod end joints and steering racks on the shelves. What can I say I have a weird sense of humor. In theory you can open your drawing and then open the musty shop drawing and click and paste the parts into your drawing.

If you make the effort to use this stuff I will revisit the subject and do some more updating.

The basis for recommending SKetchUp is that it is free and well supported. That makes it suitable for sharing your work and that makes your work more valuable.

As for your frame design, you are at a point where you need to consider how to connect your suspension to it. Don't go too far before you do that or you will land up with more compromises than are good. The main strength needs to be connection of where the coilovers attach. Then you need rigid support for the loads of the suspension arms. To help make this easier for my car, Car9, I decided to use suspension arms with 1 leg perpendicular to the chassis. That means only one bulkhead for the front and the rear needs to take sideways loads and only one bulkhead front and rear has to take the braking and acceleration loads. On the rear I used the traditional trailing arms for the acceleration and braking loads with a single upper rod and a reverse wishbone for the lower arm. That means no suspension box has to be designed around the differential and these are often poorly and weakly designed in my opinion.

On the front suspension my perpendicular arm goes to the frontmost bulkhead which also holds the steering rack.
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.
MangPong
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Building: reverse-trike

Re: Critique my chassis design

Post by MangPong »

Hello horizenjob - "Hi Mangpong! Hmm, do we call you Mang or Pong for short?"
Hahaha... actually neither syllable on its own is very polite... but your question made me realise I've not been called anything 'short' since I was back in school - isn't that odd. Then I was called Mac, the first part of my surname. I had a friend in the 90s who always called me Mate...

Anyway, thanks for the extra push on SketchUp - I wasn't aware they had tutorials - I've been trying YouTube vlogs - Hmmm...

Do I assume (for the moment, at least) that my chassis design is basically 'sound'...?
I have an additional point to mention on the chassis, which I'll try to post a drawing tomorrow.
Then I'll try to work out where is best to post my suspension queries...

Thanks for your help, Mangpong / Mac
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horizenjob
The voice of reason
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Re: Critique my chassis design

Post by horizenjob »

I see your explanation of MangPong = scorpion in another post. The funny thing is my spelling autocorrect keeps trying to change MangPong to Mangling, so appologies if that ever sneaks by me.

Your frame design is going fine, the problem is in the further details when you begin to attach more things to it. Keep posting and working on it, you will do fine.
Marcus Barrow - Car9 an open design community supported sports car for home builders!
SketchUp collection for LocostUSA: "Dream it, Build it, Drive it!"
Car9 Roadster information - models, drawings, resources etc.
MangPong
Posts: 162
Joined: March 15, 2018, 6:03 am
Building: reverse-trike

Re: Critique my chassis design

Post by MangPong »

Hello Marcus - I have posted another section on my 'diagonal bracing' thread for your perusal... and then we can consider the esoteric mysteries of 'arms & brackets'... I am not worrying too much about this because I started with the suspension and have attempted to wrap the space-frame around it... but I fear I might have made one or two basic errors in my attempts at simplicity - and sleekness... I dislike seeing visible suspensions that look as if they've been stuck on as an afterthought.

I promise I won't have any issues with 'mangling' - in fact it somehow seems to have a charm all its own... lol.

Many thanks, Mangpong
Precocious Jeremiah
Posts: 1
Joined: July 20, 2016, 6:02 pm
Building: lotus 7

Re: Critique my chassis design

Post by Precocious Jeremiah »

Hello from "down under". Some decades ago during my apprenticeship, we used both imperial and metric. Unfortunately metric has become the norm.
As the old saying goes, use it or lose it. Well most of us old bastards have lost it!!!
Is there any chance of humouring us old buggars with posting dimensions in both mm and inches ?
Cheers Christopha.
Lemans1956
Posts: 41
Joined: May 13, 2016, 9:28 pm
Building: Ferrari replica

Re: Critique my chassis design

Post by Lemans1956 »

Updated Chassis in progress pics
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Lemans1956
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Joined: May 13, 2016, 9:28 pm
Building: Ferrari replica

Re: Critique my chassis design

Post by Lemans1956 »

Hope everyone here is doing well. I've been making some progress on the car.
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