Help needed! I wan´t your thoughts on requests on upcoming changes! Let me know

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Help needed!

I wan´t your thoughts on requests on upcoming changes!

Let me know what you think of the following:

  1. Wishbones. These are sensitive parts and exposed to substantial force if they suffer a direct hit after let´s say a jump or a crash. I can´t spend to much time on this but i was thinking i just “beef them up” and do some droptests or something.
    First thing that comes to mind is making them 9mm (maybe even 10mm?) thick instead of 7mm. It´s the parts around the axles that suffers the most stress on impact. Some connecting parts will need minor changes.

  2. Car body holders! I will do these on the top of my head unless anyone have specififc requests. Keep in mind they have to be somewhat “generic”. This will also mean minor changes to the shocktowers.

  3. Front bumper

  4. I need to do some sort of arrangement to fix the ESC and reciever on the top deck… maybe even a box to protect them from water and such? Again, could this be done as some sort of generic part? There are many different parts being used… Or should i do a few to fit the most common parts?

  5. Minor changes that will “stabilize” the steering. I would rather see a complete redesign of these parts but that will be for someone else to do. [done]

That´s it for now, my first priority is the “complete” the design and once that is done we can start working on improvements.

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I can do some basic FE simulation (Solidworks) on the parts if you wish.

  1. They can never be beefy enough :wink: At a certain point, though, it will be the chassi that breaks. This was a common issue on Tamiya’s DF-02, both on the front and the rear.

  2. Body holders are a must. Don’t worry too about positioning, though, since the bodies’ mounting holes are custom drilled anyways.

  3. Look at regular truggies’ bumpers, you don’t need much there. It just needs to flex a little, ince a truggie’s speed is rarely neck-breaking.

  4. A box is not needed, neither a fixed arrrangement, since the components are mounted with double-sided tape anyways. A flat surface to mount them onto is sufficient.

  5. Precise steering is one of the most important aspects in the maneuvrability of an RC car.

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@Thomas_Sanladerer Thanks for the comment! Ok, i´ll make the wishbones 10mm while i´m at it! I´ll send it to you for analasys!

About the steering, do you have an example of a really good design i can look at? I feel like i´m shooting in the dark…

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@Thomas_Sanladerer Here´s a 10mm thick wishbone for analasys: https://docs.google.com/file/d/0B7TCLh-I8q6YTnFhUGlmZlVfQm8/edit?usp=sharing

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I’m pretty happy with the way my B4 does it. That car is winning pretty much all races, so it must be at least half-decent :wink: Other cars, like the Tamiya DF-03 or the Ansmann Buggies / Truggies are copying this mechanism, but don’t acheive the same results due to loose tolerances.
http://www.teamassociated.com/manuals/RC10B4.2/ has detailed assemblies in the manual.

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I’ll have a look at it tonight.

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@Thomas_Sanladerer awesome, thanks!!

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@Thomas_Sanladerer I replaced the file but just go to the specified folder and you will find the right one!

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Will the damper be mounted towards the front or the rear?

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Towards the front.

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I’ll upload the results as an edrawing, which is Solidworks’ equivalent of a pdf file. Is that ok?
http://www.edrawingsviewer.com/

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Ah, one more thing: Can you reshare a proper link, the one you posted only takes me to the file that’s you’ve deleted, with no way to look through the other files you have :slight_smile:

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Edrawings is ok!

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@Thomas_Sanladerer Can you browse the folder now: https://docs.google.com/folder/d/0B7TCLh-I8q6YczZXNUJuWXhCQjA/edit?usp=sharing

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Yup, that works.

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Here’s three that i did, each trying to simulate a load as if the tyre get caught while driving forward - this is the typical case where whishbones would give in. I guesstimated the loads and used an average ABS plastic as input. Material strain increases linearly with load, so if you think that it’s going to 100N instead of 50, simply multiply the stresses by 2.

  1. 50N axial load https://dl.dropbox.com/u/16628890/sim%2050N%20front%20-%20min%20safety%207.5.eprt
  2. 25N axial load and 25N as “torque” https://dl.dropbox.com/u/16628890/sim%2025N%20front%2C%2025N%20as%20torque%20-%20min%20safety%2012.analysis.eprt
  3. 100N as “torque” https://dl.dropbox.com/u/16628890/sim%20100N%20torque%20only.%20-%20min%20safety%207.eprt

Each give satisfactory safeties (for injection-molded ABS), but it’s easy to see that adding some radii here and there would ease the stresses some more. This being printed ABS, i’d still think that the parts would hold up to regular use, even when printed at, say, 50% infill and a 2mm shell.

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@Thomas_Sanladerer Thanks, looks promising!