RCCrawler Forums
Page 5 of 8 1234 5 678
Show 40 post(s) from this thread on one page

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

12earth 05-13-2018 11:47 AM
Re: Crazy axles idea design
 
Quote:
Originally Posted by gonper (Post 5830856)



Most of the looses of that torque are on the worm gears that have lots of friction.

Fascinated by this project. I am not an engineer nor do I know if you can scale it down but, have you seen the Cyclo transmissions.

https://m.youtube.com/watch?v=dYVPU47c9WA



Sent from my iPhone using Tapatalk

CM9000 05-14-2018 08:44 PM
Re: Crazy axles idea design
 
Quote:
Originally Posted by TheLetterJ (Post 5831130)
Maybe 380 sized outrunners could be packaged better and avoid the need for sensors?




I might have been wrong, 280 size. found here...

Losi: 1/18 Xcelorin Sensored ESC/Motor Combo: MRC: Losi (LOSB9567)

and maybe with a re design to accommodate the bolt patern and flipping the shaft you could go with something like this.

https://www.amazon.com/LHI-920KV-Bru...ss+motor&psc=1

might be to big though.

Gandalf The White 05-15-2018 10:54 AM
Re: Crazy axles idea design
 
Quote:
Originally Posted by CM9000 (Post 5831828)
I might have been wrong, 280 size. found here...

Losi: 1/18 Xcelorin Sensored ESC/Motor Combo: MRC: Losi (LOSB9567)
The problem with that is the rpm, it claims free speed upward of 20,000 rpm, at only 7.2v. http://www.losi.com/ProdInfo/Files/LOSB9464_Manual.pdf
At only 30:1 reduction thats pushing 700 rpm on the wheels... say a 7in diameter wheel * pi * 700rpm = 15,000 ipm or about 20fps/13mph. Thats pretty fast for a crawler, and was only at 20k rpm... it could be closer to 30k rpm on lipo voltage.

Gandalf The White 05-15-2018 11:03 AM
Re: Crazy axles idea design
 
Quote:
Originally Posted by CM9000 (Post 5831828)
Maybe with a re design to accommodate the bolt patern and flipping the shaft you could go with something like this.

https://www.amazon.com/LHI-920KV-Bru...ss+motor&psc=1

might be to big though.
Those say they are 2212, 22mm diam. 12mm tall (on the stator, I think). If gonper has 380 size motors fitting now, which are about 28mm diam. those motors are actually too small (probably). But you are correct, something like that would be my recommendation. 920kv on 3s is only 11,500 rpm, so a much more reasonable range. A slightly larger motor with lower kv (like 750 or something) would be what I would look for.

gonper 05-16-2018 05:50 AM
Re: Crazy axles idea design
 
My first idea was to use brushless motors but as you say it is difficult to find sensored ones with the right size and speed (KV) and sometimes they are overpriced as well... That is why I decided to go brushed way.

About brushed motors that I have to test:

- JRS-385RA/SA: 8500rpm at 7.4V (This one was too slow and low power, so not suitable)
- Mabuchi RS380PH-3270: 10000rpm at 7.4V (Speed of this one is OK but limited power, with lower friction may be a good candidate)
- SRC-380SA-3065-55: 13000rpm at 7.4V (Waiting to receive it and test...)

And there is easy to find higher KV ones but that will require changing the gear ratio, that will mean as well to redesign the gearbox, not a big drama, just some hours on the CAD drawing and printer.

I already have found different worm gears suitable for that modification that can allow use higher revs. motors:
1:60 worm gears
1:50 worm gears

gonper 05-16-2018 06:00 AM
Re: Crazy axles idea design
 
Thank you for all the inputs.

Quote:
Fascinated by this project. I am not an engineer nor do I know if you can scale it down but, have you seen the Cyclo transmissions.

https://m.youtube.com/watch?v=dYVPU47c9WA
That is great but that kind of gearboxes are used for CNC positioning and other precision staff that actually its not need in this case.

Quote:
I might have been wrong, 280 size. found here...

Losi: 1/18 Xcelorin Sensored ESC/Motor Combo: MRC: Losi (LOSB9567)

and maybe with a re design to accommodate the bolt patern and flipping the shaft you could go with something like this.

https://www.amazon.com/LHI-920KV-Bru...ss+motor&psc=1

might be to big though.
Both are a bit too small and sensored is a must, else the motor starts with almost no torque.

gonper 05-16-2018 06:06 AM
Re: Crazy axles idea design
 
One question:

What is the top speed of a crawler this kind?
Have anyone checked that?
I was guessing around 10 to 12Km/h (6-7.5mph), am I right?

Gandalf The White 05-16-2018 09:18 AM
Re: Crazy axles idea design
 
Quote:
Originally Posted by gonper (Post 5832273)
One question:

What is the top speed of a crawler this kind?
Have anyone checked that?
I was guessing around 10 to 12Km/h (6-7.5mph), am I right?
That's about the max I would want, yes... generally speaking.


Quote:
Originally Posted by gonper (Post 5832273)
My first idea was to use brushless motors but as you say it is difficult to find sensored ones with the right size and speed (KV) and sometimes they are overpriced as well... That is why I decided to go brushed way.

About brushed motors that I have to test:

- JRS-385RA/SA: 8500rpm at 7.4V (This one was too slow and low power, so not suitable)
- Mabuchi RS380PH-3270: 10000rpm at 7.4V (Speed of this one is OK but limited power, with lower friction may be a good candidate)
- SRC-380SA-3065-55: 13000rpm at 7.4V (Waiting to receive it and test...)

And there is easy to find higher KV ones but that will require changing the gear ratio, that will mean as well to redesign the gearbox, not a big drama, just some hours on the CAD drawing and printer.

I already have found different worm gears suitable for that modification that can allow use higher revs. motors:
1:60 worm gears
1:50 worm gears
So that middle motor (Mabuchi), is it a 3270 can size (32mm diam 70mm long)? If so, can you squeeze an extra 3-4mm on the diam? Because normal (read: readily available) 10th scale motors are 3650-3665, and have plenty of sensored options, as well as brushed options with a lot of power.
45t 540 Brushed
Sensored Brushless

gonper 05-16-2018 04:04 PM
Re: Crazy axles idea design
 
Quote:
Originally Posted by Gandalf The White (Post 5832361)

So that middle motor (Mabuchi), is it a 3270 can size (32mm diam 70mm long)? If so, can you squeeze an extra 3-4mm on the diam? Because normal (read: readily available) 10th scale motors are 3650-3665, and have plenty of sensored options, as well as brushed options with a lot of power.
All are same 380 size (38mm length 28mm diameter) the other numbers/letters relate to the windings and other characteristics, each manufacturer has different reference numbers...
I doubt that it will be possible to fit a 540 size motor this way...

gonper 05-16-2018 04:22 PM
Re: Crazy axles idea design
 
BTW, I managed to cut and shut the tires.
This is my first time I cut and shut tires so I decided to use the cheap tires I found on Alibaba that will allow me to learn how to do so and test the rig.
I am very happy with the results.
Then latter will make comp ones with other kind of tires.

https://scontent-mad1-1.xx.fbcdn.net...e2&oe=5B7D60C3

Gandalf The White 05-16-2018 06:04 PM
Re: Crazy axles idea design
 
Quote:
Originally Posted by gonper (Post 5832499)
All are same 380 size (38mm length 28mm diameter) the other numbers/letters relate to the windings and other characteristics, each manufacturer has different reference numbers...
I doubt that it will be possible to fit a 540 size motor this way...
Hmmm, OK.

That wheel looks great, too.

gonper 05-17-2018 01:50 PM
Re: Crazy axles idea design
 
All parts printed. :ror:
Now need to make the suspension and steering links.
And wait for the motors to arrive :roll:

https://scontent-mad1-1.xx.fbcdn.net...3a&oe=5B9228CE

CM9000 05-18-2018 01:19 PM
Re: Crazy axles idea design
 
does that say "version" 5? in the one case?

also, lets get a sneak peak at that chassis!

sorry if I was no help with finding motors. I thought for sure leopard rc had a 380 sensored motor. but when I was on their site, I could not locate one.

gonper 05-18-2018 05:17 PM
Re: Crazy axles idea design
 
Quote:
Originally Posted by CM9000 (Post 5833202)
does that say "version" 5? in the one case?

also, lets get a sneak peak at that chassis!

sorry if I was no help with finding motors. I thought for sure leopard rc had a 380 sensored motor. but when I was on their site, I could not locate one.
Yes, it is printed iteration number 5, it is very difficult to get the tolerances correct with 3D printing when a precision of around 0.2mm is need...

Thank you for your search, I am going to keep with the brushed option for now, I have a couple of ideas in order to make it work well.

gonper 05-18-2018 05:42 PM
Re: Crazy axles idea design
 
Et voila :ror:

Steering and suspension links.

https://scontent-mad1-1.xx.fbcdn.net...5e&oe=5B7C26CF

Gandalf The White 05-18-2018 09:06 PM
Re: Crazy axles idea design
 
Wow, those look really, really sweet. So close to a full assembly.

gonper 05-19-2018 02:07 AM
Re: Crazy axles idea design
 
And here we go, first assembly.
Please let me know your thoughts.
It looks like everything goes together quite well.
May need to order some more screws sizes as some are short some others are long, and add some washers/seams here and there, not a big deal

And wait for the motors to arrive that I hope they come next week.

https://scontent-mad1-1.xx.fbcdn.net...ff&oe=5B8E8325

https://scontent-mad1-1.xx.fbcdn.net...2c&oe=5B8A53B6

https://scontent-mad1-1.xx.fbcdn.net...46&oe=5B7DB00B

Gandalf The White 05-19-2018 09:19 AM
Re: Crazy axles idea design
 
Amazing!!! What is you plan for battery placement/size? Are they in the wheel assemblies?

CM9000 05-19-2018 01:25 PM
Re: Crazy axles idea design
 
wow... that's probably going to be one of the lightest supers on the planet.

I bet.. as it sits in the last picture it doesn't weigh more than 1.5 lb.

gonper 05-19-2018 02:13 PM
Re: Crazy axles idea design
 
Quote:
Originally Posted by Gandalf The White (Post 5833399)
Amazing!!! What is you plan for battery placement/size? Are they in the wheel assemblies?
2 batteries 7.4V (2S) 800-900mAh
One on each front wheel.
Everything is inside of the wheels: motor, gears, battery, servo, ESC. Only receiver is outside. "thumbsup"


All times are GMT -6. The time now is 08:21 AM.
Page 5 of 8 1234 5 678
Show 40 post(s) from this thread on one page

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO ©2011, Crawlability, Inc.
Copyright 2004-2014 RCCrawler.com