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-   -   Crazy axles idea design (http://www.rccrawler.com/forum/superclass-crawlers/594046-crazy-axles-idea-design.html)

gonper 01-13-2018 05:35 AM

Crazy axles idea design
 
Hi, I am new to the forum but not to the hobby. I have been designing, constructing and piloting RC cars, planes and helicopters. I designed my first RC car when I was 13 years old and that was 35 years ago...

I lately come interested on Rock-Crawlers, mainly on the superclass, because I think it is the more technically advanced.
After some research I come to some conclusions about Crawlers that I hope they are correct, you let me know:
- Manny of characteristics of a Rock-Crawler are very different than from a speed-racing car.
- Vehicle weight should be as low as possible.
- CG should be as low and forward as posible. In order to achieve that weights are installed on the front wheels.
- As much suspended mass the better.
- As much turning radius the better.
- Brushless motors are not well suited for the task unless they are sensored (difficult to find)

So in order to meet those parameters I come up with this design/idea of how to install all equipment (weight) inside of the wheel rim. It is just a quick render and before going further with it i will like that you have a look to it and give your opinion/suggestions and if I you think it can work.
If I go forward with this I will need some assistance on setups and other details and hope you can help me.
Let me know if you can see the pictures, if not I will link them differently.

https://scontent-mad1-1.xx.fbcdn.net...4d&oe=5AE779B3

https://scontent-mad1-1.xx.fbcdn.net...98&oe=5AF7CDE5

Equipment planing to use:
4 x 380/385 brushed motors
4 x 20-25A ESCs
2 x 7.4V (2S) 800-850mAh batteries (one on each front wheel)
4 x 15-20Kg Standard size servo

Teng 01-13-2018 05:41 AM

Re: Crazy axles idea design
 
Sound like motor on wheel system ?

winnerone23 01-13-2018 05:58 AM

Re: Crazy axles idea design
 
Here ya go.. a little inspiration!

Bc-brian of Lattice Innovation (a vendor here, that makes the Sickest hubs on the market, Shift hubs) designed this little beauty..

http://www.rccrawler.com/forum/unlim...ing-crazy.html

gonper 01-15-2018 06:16 PM

Re: Crazy axles idea design
 
Quote:

Sound like motor on wheel system ?
Yes, that is right Teng MOW system.

Quote:

Here ya go.. a little inspiration!
Bc-brian of Lattice Innovation (a vendor here, that makes the Sickest hubs on the market, Shift hubs) designed this little beauty..
Thank you Bc-brian, I seen your rig, it is great, it was quite inspirational for this idea. Actually after seeing/reading you post I decided to go brushed way instead of brushless.

gonper 01-15-2018 06:36 PM

Re: Crazy axles idea design
 
Calculating the steering geometry, actually not an easy task. Thanks that Ackerman Geometry is not needed :ror:

https://scontent-mad1-1.xx.fbcdn.net...bb&oe=5AE5BF0B

About 70º, not bad I think.

https://scontent-mad1-1.xx.fbcdn.net...1d&oe=5AE38243

gonper 01-17-2018 07:14 PM

Re: Crazy axles idea design
 
Gear box taking shape. I will 3Dprint it.
Now needs servo, and battery support, Kingpin hears and some more details.


https://scontent-mad1-1.xx.fbcdn.net...b0&oe=5AF1E9F3

makya 01-17-2018 07:26 PM

Re: Crazy axles idea design
 
What size wheel are you using to be able to fit a 380 motor and gear box inside like that?

gonper 01-18-2018 06:46 AM

Re: Crazy axles idea design
 
Quote:

What size wheel are you using to be able to fit a 380 motor and gear box inside like that?
Wheel rim diameter is 152.8mm (around 6") and tire diameter 205mm (around 8")
Moreless the same wheels sizes as other Superclass that are around.

gonper 01-22-2018 07:23 AM

Re: Crazy axles idea design
 
First iteration of the gearbox finished, lets see if I can print it latter today, in order to see if everything fits and check tolerances...

Inner side (Servo, motor, battery)

https://scontent-mad1-1.xx.fbcdn.net...94&oe=5AF25DEA


Outer side (Space for the ESC and weight box)

https://scontent-mad1-1.xx.fbcdn.net...63&oe=5AECD127

Ditchrat 01-22-2018 09:23 AM

Re: Crazy axles idea design
 
Its already been done. You might want to do some reaearch.

WHITE-TRASH 01-22-2018 12:11 PM

Re: Crazy axles idea design
 
Quote:

Originally Posted by Ditchrat (Post 5791357)
Its already been done. You might want to do some reaearch.

Everything has been done but there is always room for someone else to try something similar.

Jslick 01-22-2018 08:38 PM

Re: Crazy axles idea design
 
Keep up the good work, always to see cool stuff that continues to innovative.

rockhugger 01-22-2018 09:57 PM

Re: Crazy axles idea design
 
Quote:

Originally Posted by Ditchrat (Post 5791357)
Its already been done. You might want to do some reaearch.

Say that again when this dude hands you you're hiney on a platter at worlds and says.... Would you like some tapas and sangria to compliment your ass. :mrgreen:


Good work.

filotr14lsdude 01-22-2018 10:21 PM

Re: Crazy axles idea design
 
I can’t wait to see how this pans out.

Looks like it will be a great build.

Gandalf The White 01-22-2018 10:57 PM

Re: Crazy axles idea design
 
This looks so sweet!!
What kind of gear reduction you getting out of that worm drive, somewhere around 30:1?
Cant wait to see how this turns out.

Ditchrat 01-23-2018 04:14 AM

Re: Crazy axles idea design
 
Hey f@#$heads did i tell the guy not to do it or offer an opinion?

No i told him its been done and to do research. There is literally no reason to reinvent the wheel when you can go do research on how it is done.

filotr14lsdude 01-23-2018 04:49 AM

Re: Crazy axles idea design
 
Quote:

Originally Posted by Ditchrat (Post 5791781)
Hey f@#$heads did i tell the guy not to do it or offer an opinion?

No i told him its been done and to do research. There is literally no reason to reinvent the wheel when you can go do research on how it is done.

Or you can see what’s been done, find the flaws and improve on it.

Ditchrat 01-23-2018 05:10 AM

Re: Crazy axles idea design
 
Quote:

Originally Posted by filotr14lsdude (Post 5791789)
Or you can see what’s been done, find the flaws and improve on it.

Yeah exactly why you should do your research.

Try not to inject your bias when you read. A statement is a statement and nowwhere in mine does it offer an opinion. You people want it to be negative so you can have something to post about.

WHITE-TRASH 01-23-2018 10:16 AM

Re: Crazy axles idea design
 
Just looking at the models posted it is pretty obvious the research has been done. :lol:

gonper 01-24-2018 05:00 AM

Re: Crazy axles idea design
 
Thank you all for your kind words.

Yeah, I have done quite of research in order to end up with this.
Actually a very helpful one was this thread from BC-Brian here: http://www.rccrawler.com/forum/unlim...ing-crazy.html

I was first thinking on using brushless motors as there is a huge offer and their higher power density, but that thread made me change mind and go brushed way, because I realized that a brushless motor without sensors will not give enough torque at 0-low rpms.
Even with a sensor motor it will be a bit complicated due to the great amount of cables (7 from each motor)

Quote:

What kind of gear reduction you getting out of that worm drive, somewhere around 30:1?
Yes that is right 30:1 (https://shop.framo-morat.com/en/Worm...r-distance-25/)
Planning to use this motors reference RS-380PH-4045 from Mabuchi, if I can find them: https://www.mpja.com/download/17946md.pdf
If not there is similar KV 385 motors from other brands that may be even better suited than the 380.
It will be a test error thing…

I did not had time to print the gear box test, it will have to wait till the weekend probably.
Anyway I had time to work on the axles design. Still do not know where to place the shock absorbers, do you think that the lower links rods is a good place?. Note that the rods will be straight, they do not need to be bended as they are on a very high position.

Axles taking shape:

https://scontent-mad1-1.xx.fbcdn.net...44&oe=5AE79115


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