Ripsaw

[Zerobricks]

I wanted to try out the new(er) treads with RC motors. The only problem using RC motors is, the PF system isnt powerfull enough, so I used the RC unit, which has no independent control for 2 motors. In order to make the model steer, both motors power the tracks via a diff. Using two brakes, one for each side, the model can steer, and by blocking one side the other side spins with 2x the speed, therebye keeping the original model's speed constant.

The differential was reinforced, because the 8 tooth gear tended to slip:

Body details with tracks removed:

Front tracks ends are lifted for better climbing abilityes:

Tracks are supported by a total of 24 wheels per side. They are all suspended. The suspension has two functions, the usual bump absorbing and keeping the tracks tentioned.

Watch the video for more details:

Edited August 15, 2010 by Zblj

[efferman]

i like the steering brake

[Jurgen Krooshoop]

Is this cool or what ? The fastest tracked vehicule on the planet moddeled in Lego !! Great MOC.

[eMHa]

Yeah! Great! Fast!

The technique reminds me about a MOC I build in about 1985. I wanted to build a strong tracked vehicle, but I only had one motor (8700). So I used a diff like you did and I had to block the left or right track manually with a lever. I was proud to made a tracked vehicle with one motor which can steer. And I let it drive over my LEGO bricks. Well, you just revived my memories....

Yours is very fast and it has very good suspension. Now you just have to build a nice (tank?) body around

[DLuders]

Americans may have seen the Discovery Channel TV show called "Howe & Howe Tech", the Maine USA inventors of the real "Ripsaw MS2" manned and unmanned tank. Their website is fertile ground for more "wicked" Lego Technic MOC ideas....

[CP5670]

This thing is quite fast. I also like how the suspension is designed.

[grohl]

I do not want to dissapoint you, but I have seen much faster one two weeks ago. There were just two buggy motors...well a picture should be better.

Edited August 15, 2010 by grohl

[mahjqa]

The brake and differential is a brilliant idea. Great work!

[Burf2000]

How does the brake work? I wish I had details of this months ago

[Zerobricks]

The steering works quite simple. Both motors power a diff. The diff power the tracks and two brakes. When you brake the left side, the diff transmitts power to right. So basically I used the open diff disadvantage to my advantage.

[Burf2000]

Thanks mate for replying but now is the steering (from the rc unit) locking the diff as it does not have much movement

The reason I ask Is I actually made something like this but instead of a break, I used 9v pole reverses

[Sam42]

that thing is rapid....