Hello ;) Sorry my question,

Archive OpenRC
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1

Hello :wink:
Sorry my question, but have you an full tutorial for this Car was you have designed ?
OpenRC 1:10 4WD Truggy Concept RC Car
in PDF ?

Lg

2

There are pdf’s with exploded views to help you assemble. You will find them together with the STL’s.

3

Is there a detailed list of sourced parts and their sources? For example, there are many versions of ball joints for sale but I don’t know which are suitable. What diameter?

4

There’s a bom list available where the other files are. There’s also STEP file of the full assembly.

5

The .csv file I presume to be the BOM just says “Ball Joint 5”. I guess I can discover the attributes of the ball by measuring radii and distances using the STEP file and then compare with the various ball joint vendors, but it seems a long way around.

6

OK, from the STEP file they seem to be 5mm diameter with 3mm diam probably 3mm screw thread mounting pin, 5.5mm hex base. That probably rules out all the 2-56 versions I found.
Harder is the shock/spring mechanism. Dimensions aren’t enough to specify its characteristics. Surely somewhere there is a list of things people have found to work well? Shocks, motor, battery, etc.?
Who are favorite vendors? That might set a context.

7

I bought Tamiya 5mm ball connectors off eBay and they fit perfectly.

8

Thank you, Stephen! That was a big help. What did you use for shocks/springs?

9

Hi David. Again eBay - 4 x Dark Blue 108004 RC1:10 Model Trucks Aluminium Alloy Shock Absorber for HSP and all the way from China so allow about 3 weeks delivery.

The eBay UK link is: http://www.ebay.co.uk/itm/272334571919?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I have received then but haven’t fitted them yet, but I see no reason why they wouldn’t fit. They are inexpensive though, so long term I’m not sure how they will perform, but they are perfect for me as I am doing this for fun and not serious completion.

10

Hello :wink:
Have you an part list of the srews ? My Rc car would be ready so far today :slight_smile: I hope differenttial will persevere.I have all the parts printed 0.2mm and 20mm / s and 100% fill in :wink:

lg

11

I’d like to scale up the steering and suspension system to use in a much larger project with my grandson.
I can’t just scale uniformly, because things like the ball joints are only available in a few sizes for example; so I wonder how you designed the steering and suspension geometry? Did you use a book or paper I could read? Or was it a matter of replicating dimensions/geometry from a known working car?
It would be handy to have the design formulas (my wheelbase probably doesn’t scale proportionally to the track width, another reason scaling is hard to do).

12

Daniel has provided a STEP file of his design and my approach would be:

  1. Open the STEP file in Autodesk Fusion 360.
  2. Save As to a new file so as not to over right the original data.
  3. Scale to desired scale.
  4. Remove non-printed parts from scaled model.
  5. Place the new larger scale components in the model and modify the printed parts to suit.

You could use any CAD system that imports STEP files, but my preferred choice is Fusion 360 because it is free to use for hobbyists and when used in direct modelling mode is very good for modifying STEP files.

13

Stephen—Your approach would work fine if I don’t change the proportional distance between the front and rear axles. I’ll investigate to see whether I can change my grandson’s design enough to make that possible. If that distance isn’t proportional, then the steering geometry has to change differently from just scaling it. (The turning radius centers of the two front wheels have to lie on the line through the rear wheels.)
I too love Fusion 360, it’s really nice to use.

14

Hi David. The front and rear suspension/axles are separate sub-assemblies so you could apply different scale factors to them and a different factor to the body/chassis. Also, have you tried the non-uniform scaling feature? It can be quite useful in some cases. You will also be able to move holes etc. using direct modelling - I have found this works better if you select ‘Do not capture design history’ from the settings icon bottom right of the screen.

Whatever you do though, I don’t think there will be a ‘quick fix’ - you have quite a lot of work ahead!

15

The tricky part is the mathematics. The proportions of the steering arms and angles depend on the distance between front wheels and also on the distance from front wheels to rear wheels. You can’t get there by scaling except if you scale everything uniformly. That’s why I’d like to know the formula that was used in this design. But if I have to, there are plenty of online designs for Ackerman and other steering geometries. It’s just a lot of work to relate them to this design.