Author Topic: Scratch built giant rc car  (Read 8347 times)

Offline Perry

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Re: Scratch built giant rc car
« Reply #15 on: February 27, 2018, 04:40:20 PM »
Wow what a project! I'm following  :whoohoo:

Offline KB

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Re: Scratch built giant rc car
« Reply #16 on: February 27, 2018, 07:43:34 PM »
Thanks for the encouragement.

Mike yes it is a window motor and if that is not enough I have a wiper motor. And yes the servo is there for positional feedback. It has been gutted and is essentially just a pot with a servo case for mounting.
I am electronically illiterate so I was thrilled to find this H-Bridge which is pretty much plug and play. "Servo Thor-15" at the bottom of this page; https://www.model-truck.ch/cti-elektronik-inkl-neuheiten/cti-fahrregler-mit-neuheiten/

Quote
If you're going to run it off-road won't you need a lock for that diff?

Allen, I hope not... If it starts unloading too much I can try packing it with sticky grease?

Cheers Perry,

KB


Online Vixen

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Re: Scratch built giant rc car
« Reply #17 on: February 27, 2018, 07:57:10 PM »
Hello KevinB

Thanks for getting back.

I also made a giant servo for one of my tracked vehicles (a 1/6 scale tank) using a window winder motor slaved to a feedback pot in a servo housing. I also used the 'Servo Thor-15' amplifier. The first one smoked itself within minutes and I have a tad too much dead band on the second one I bought. The idea of maybe having to buy a third one if anything goes wrong is holding me back from experimenting with the electronics to fine tune the dead band. I was hoping you might have discovered an alternative manufacturer.

Mike
It is the journey that matters, not the destination

Offline KB

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Re: Scratch built giant rc car
« Reply #18 on: February 27, 2018, 08:25:32 PM »
Mike,

Hmm, now I am worried. I bought three. The first one I set up, was fine after some tinkering. I took it apart and some time later somebody asked how I wired it up so I put it back together and smoked it right away. I assumed I shorted the power or something. I'll fuse the power lead in the future.

There is a discussion here where someone mentions 7 points of rotation instead of 64. May be the dead spot you refer to? Love those giant RC tanks. Let's see it.

https://translate.google.ca/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.rc-baustelle.de%2Fthread.php%3Fthreadid%3D5848&edit-text=

Offline Art K

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Re: Scratch built giant rc car
« Reply #19 on: February 27, 2018, 09:12:01 PM »
Kevin,
As everyone else has said already that's way to cool. I have to admit recognizing that as a Honda 50 motor.
Art
« Last Edit: March 20, 2018, 03:14:21 PM by Art K »

Online Vixen

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Re: Scratch built giant rc car
« Reply #20 on: February 27, 2018, 09:50:43 PM »
Hi Kevin,
I think the Servo-Thor-15 is a fragile design. There seems to be no reverse polarity protection or short circuit protection. I would advise well-made non-reversible connectors to avoid the unprotected conditions. You can understand why I was looking for an alternative. I am not sure a fuse will help, I expect the module to die before the fuse goes. Iwill check out the link you sent tomorrow.

If you wish to see my 1/6 scale StuG 111 self propelled gun go to
If you poke around the 'more' button, there are some other of my videos.

Mike
« Last Edit: February 27, 2018, 10:01:57 PM by Vixen »
It is the journey that matters, not the destination

Offline KB

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Re: Scratch built giant rc car
« Reply #21 on: February 28, 2018, 01:19:11 AM »
Thanks Art!

Mike, outstanding. The V-8 alone is an amazing project. Recoil, smoke and everything.

I'll try a Deans connector or something of the like. It sure seams light for 18 amps. I was planning on mounting it to a fan cooled heat-sink.
There are arduino options but I prefer building to research...

http://www.instructables.com/id/Wiper-Motor-and-Arduino-Mega-Servo/

https://www.pololu.com/product/1392

Edit : They also say it is supposed to be short circuit and temp. protected;

https://translate.google.ca/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=https%3A%2F%2Fwww.model-truck.ch%2Fapp%2Fdownload%2F5587893211%2FAnleitung-SERVO%2BTHOR15%2BCH%2BServoelektronik.pdf%3Ft%3D1465139799&edit-text=
« Last Edit: February 28, 2018, 01:40:51 AM by KB »

Offline KB

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Re: Scratch built giant rc car
« Reply #22 on: March 20, 2018, 03:49:55 AM »
Spring is here and the jobs are piling up but we got a little time in.







Offline bent

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Re: Scratch built giant rc car
« Reply #23 on: March 20, 2018, 05:20:57 PM »
Dang!  Very cool, Kevin!

Offline KB

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Re: Scratch built giant rc car
« Reply #24 on: March 30, 2018, 01:17:52 AM »
Thanks Bent!

I had a little time to make this chain tensioner;


Offline Admiral_dk

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Re: Scratch built giant rc car
« Reply #25 on: March 30, 2018, 06:57:17 PM »
A good chain tensioner is a great thing to prevent problems and bad temper after the fact  :ThumbsUp:

Offline steamer

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Re: Scratch built giant rc car
« Reply #26 on: March 30, 2018, 10:40:32 PM »
Great work!     Consider allowing for adjustment of roll center   antisquat and kick up as well as provision to move the shock mounting points.     Will make set up at the track very easy.    What are you using for diff oils?
« Last Edit: March 30, 2018, 11:15:36 PM by steamer »
"Mister M'Andrew, don't you think steam spoils romance at sea?"
Damned ijjit!

Offline KB

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Re: Scratch built giant rc car
« Reply #27 on: May 02, 2018, 03:53:33 AM »
A_dk, indeed!

Thanks Dave,

The way I made the top caps of the shocks didn't allow me to have room for additional mounting points.
I should have used rod-ends on both ends
The front lowers have a few options.

I just have high pressure grease in the diff for now.

The shocks are 11/2" bore by 3" stroke, what do you think I should try as a starting point for piston holes? Do you have any recommendations for cheap shock oil?

I don't have a lot of time these days but I am starting to look at the drive train;





Offline KB

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Re: Scratch built giant rc car
« Reply #28 on: May 05, 2018, 01:47:47 AM »
Quote
I was hoping you might have discovered an alternative manufacturer.

Mike

Mike, I have figured out a higher amperage set-up;



Offline KB

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Re: Scratch built giant rc car
« Reply #29 on: May 05, 2018, 02:04:22 AM »