Bruder MAN TGS construction dump truck conversion

[beppo]

Hi all,

I am pretty new to the great world of RC construction vehicles of all sorts, I do have some RC experience from helicopters and airplanes but that was some time ago and now I will go back into the RC hobby but staying on the ground. Actually, my little boy loves RC vehicles and already has some Bruder Toys so what would be more obvious than converting one of them to RC.
Luckily I have some tools available and I have a little experience with CAD that was all I needed to start.
Here and in some other places I found some great examples how to attack such a task and I started by drawing the front axle in CAD. The pieces appearing kinda rough and bulky but for my first project I am going to focus on "get it done" and later I will probably go more into detail.
So here you can see the front axis how it shows up in CAD and I already printed some parts to see how they would fit the tire and finally the car. As I mentioned a little bulky but for now I will go with that if it fits into the car and the wheelhouse.
The Bruder model which I chose is the MAN TGS Construction Dump Truck with two drive wheels on either site in the rear.



Since making my own gearbox is currently a little bit too complicated I will use four motors, one for each wheel like shown in many conversion threads before.
I am going to use geared bs motors for that but here I would need some information. The most common ones I can find on Amazon (which might not be the best place) are pretty bulky with a diameter of almost 1.4".
In addition, I am not so sure what motor controller to use, it is a brushed motor and I would like to run 4 motors, is that possible with the same controller or do I need four controllers?

more to come

Thanks
Chris

[markturbo]

Look forward to seeing more. I have a Bruder dozer im planing to convert.

As far as running 4 motors, Im not sure. But this esc is for powering dual motors:

http://www.rcmart.com/quicrun-wp860-...Path=1560_1021

[skeeter]

For dual motors...................If you DON'T need the motors to steer, (Ie, to drive a bulldozer, tank or similar setup) You can run them on almost any speed controller. The LEFT HAND side motors wire ESC red to the motor red, ESC blackto motor black. On the RIGHT HAND side, you'll wire opposite polarity, ESC black to motor red, & ESC red to motor black. In the event you DON'T wire them this way they'll try to drive opposite directions of each other. The LHS would drive forward, while the RHS drives reverse.

[frizzen]

Adding on to what they already said, I'd just grab a cheap Reversable *BRUSHED* ESC of some type made for 1/10 scale made for 540 or 550 motors rated to maybe 15 turns or lower. It'll be more than enough amps for 4 gearmotors run together.

There are some options you don't need, that can be kinda nice to have like Brakes or Dragbrake, Punch control... You might want something with a Lipo cutoff.

[beppo]

Hi there,

thanks for all the input very helpful for somebody who is just starting with that.

Somehow I had some issues with pictures in my first post, they don't show up so here is another try.



a screenshot from solidworks

[beppo]

OK ...
not sure why but the picture appears to be pretty skewed

Anyhow here are some more.
Meanwhile, I was able to print some of the stuff and it looks doable I think.

[beppo]

OK and some more..










I need to remove a decent amount of material in the wheelhouse so that the tire had actually room to turn.

As you can see I was able to get the front axle out in one piece ... but that is not really an advantage since I can't get the tire off the axle. I really can't figure out what is holding it on the axle, I can turn the whole tire while holding the axle with pliers, but the tire didn't come off.

[skeeter]

The axle has ribs on it. The rims are molded around those ribs. I cut my axle in half. I placed it into a drill, & pulled it off while the drill was running. It still took a bit of doing to make it happen. Hope this helps

[beppo]

thanks for the info!
I tried it with a cordless drill, maybe not enough RPM and I wasn't patient enough. So I will try it again.

[skeeter]

It takes a LONG time. You're basically melting the plastic with the friction caused from the drill, so that it lets the ribs of the axle slide out of it's grasp.

[beppo]

OK, I get it, I think I need to get my air drill out ... lots of RPM

Made some progress on the drawing board, so far the axel is rigid no suspension or the like...
This is the reason for the gap between the axle and the mounting plate maybe I can put some sort of suspension in there.

[Giuseppe]

Originally Posted by beppo

OK, I get it, I think I need to get my air drill out ... lots of RPM

Made some progress on the drawing board, so far the axel is rigid no suspension or the like...
This is the reason for the gap between the axle and the mounting plate maybe I can put some sort of suspension in there.

You,could insert,small springs,under the fixing,screws,of the hub holder.Regards.

[PetervR]

You need to put the trackrod at the rear of te front axle
To have the right stering angle ;-)
For the rest it looks good!

[skeeter]

I'm interested to see what if any kin of suspension you can squeeze in there. I have a conversion much like yours I'm working on. All my 3D print parts for it are completed. It just hasn't found it's way to the front of the projects to be completed line......yet.

[beppo]

thanks for the input folks!

OK, I corrected the position of the track rod, the servo is in front so the track rod is now facing rearward.

I thought about the suspension for about an hour and than skipped it, the way you could do it with this setup is just enough for about 1/4" movement, there has to be a better way to do that but that will look pretty different, so, for now, I just try to get the thing rolling.

Here is what I would suggest the almost final version and I will start printing some parts.
BTW the servo is a mini servo normally used in a 450 Helicopter, it should have plenty of power to do the steering, at least I hope...

[beppo]

I was able to print some parts during the weekend and I think overall it came out OK.
3D printed parts are not as true to size as you would think. Especially screw holes and such can be a sometimes a problem and you have to make them bigger from the beginning to fit.
Anyhow, here are some pictures of the now almost complete front axle.









somehow some of the pictures don't show up, so that's all for now

[markturbo]

Nice progress, the parts look good.

[beppo]

Hi all,

I have actually started the work on the rear axles, my goal was as little as possible changes, I wanted to use original axles and keep the way they are attached to the chassis. Currently I am not planning to carry huge loads around, it should just drive. Hence I have used pretty small engines, 12 V with a gear and going 300 RPM. The base plate is 3d printed but not ideal yet, still somewhat to high.

Video MAN Dump truck drivetrain

The biggest pain was actually how to get the wheels off the axles without cutting the axles, here my lathe was very helpful, just a few seconds by full speed and done.

I had to make my own bushings to fit the sprocket to the original axle.