4x4, 4 Wheel Steer Trial Chassis

[lukeandahalf]

Hello All, I present a trial truck chassis I built a few nights ago. Performance is my goal, not aesthetics so there will be no body for this truck. My top concerns are LOW center of gravity, large suspension travel, and above all, simplicity.

Total weight:1.021KG

Frame: 232G

Tires and Rims: 236G

Axles: 336

PF: 217G (excluding drive and steering motors)

Yellow Chassis by lukeandahalf, on Flickr

The suspension was designed to be very soft for maximum traction, as well the frame and axles were built to slide past each other when maximum compression or extension is reached - almost like a pendular system.

Yellow Chassis by lukeandahalf, on Flickr

Turntables provide rotation as well as location for the axles.

Yellow Chassis by lukeandahalf, on Flickr

Yellow Chassis by lukeandahalf, on Flickr

The build started with the frame in the center for the battery box, I took a very modular approach to this moc! A nice plus I've found when tromping thorugh the forest on lunch break from work to find a place to off-road

Yellow Chassis by lukeandahalf, on Flickr

One L motor per axle is used for drive, and one SV for steering each axle. The SV motors are geared 1:1 on the front axle, and 1:3 on the rear axle.

Yellow Chassis by lukeandahalf, on Flickr

Easily broken down

Yellow Chassis by lukeandahalf, on Flickr

Yellow Chassis by lukeandahalf, on Flickr

12/36 then 8/24 for (I think) a total reduction of 1:9

Yellow Chassis by lukeandahalf, on Flickr

[z3_2drive]

Perfect! Simple and modular! Do you plan a video?

[jorgeopesi]

When I saw these motors I thought the same, nice use of them.

[lukeandahalf]

Thanks! I may try a video on the weekend when I am off work.

[Gee]

Nice! I like the way you've attached the L motors direct to a turntable. Makes things a whole lot more simple. Be good to see the performance.

[Zerobricks]

While its a good idea, I would change few things... I would use a small turntable instead of the large ones. That would allow the to raise the low center by about 2-3 studs so you dont get the chassis stuck.

[Technyk32231]

Man that's cool! Do you mind if I try to reconstruct it?

[lukeandahalf]

Thanks No problem, build away, build a body on it and post!

Unfortunately I poses no skill for video editing and production, and no camera capable other than my phone Maybe in the future, but not likely.

While its a good idea, I would change few things... I would use a small turntable instead of the large ones. That would allow the to raise the low center by about 2-3 studs so you don't get the chassis stuck.

The large turntables in this instance serve two purposes: to locate the axle laterally, and provide a pivot point to suspension. I agree that the added ground clearance would be beneficial (with the small TT), but the axle would be very poorly secured with the only one stud wide bracing that the small turntable provides, therefore two floppy axles I don't mind the trade off, at least not in this iteration. I know people like efferman have successfully used the small TT, but I don't think in their MOCs the TT was the only point of connection between frame and axle apart from shocks. What do you think?

[Technyk32231]

Thanks No problem, build away, build a body on it and post!

Unfortunately I poses no skill for video editing and production, and no camera capable other than my phone Maybe in the future, but not likely.

The large turntables in this instance serve two purposes: to locate the axle laterally, and provide a pivot point to suspension. I agree that the added ground clearance would be beneficial (with the small TT), but the axle would be very poorly secured with the only one stud wide bracing that the small turntable provides, therefore two floppy axles I don't mind the trade off, at least not in this iteration. I know people like efferman have successfully used the small TT, but I don't think in their MOCs the TT was the only point of connection between frame and axle apart from shocks. What do you think?

I probably won't build a body, as I find that unless the body is really light weight, the performance decreases. I think you would be fine with small turntables if you then located the axle in front, like this solution by efferman:

http://m.flickr.com/lightbox?id=7984676530&context=set-72157631531884400

Edited January 22, 2014 by Technyk32231

[Gee]

I recently built a small vehicle with the only link between axle and chassis being the small TT. Even in that small lightweight model there was considerable flexing. I concluded that anything bigger (and especially a 4x4 with performance at its heart) would need the large TT.

[Junpei]

Amazing work, lukeandahalf! I was actually just fooling around with the same concept with the turntables, I might have to use it too.

May I ask, what is the point in linking the shocks together with 9L links?

TLH

[lukeandahalf]

Technyk32231: I find the same with bodies! Always takes the fun out of truck trial... Until my skills increase anyways

Gee: Nice having someone back me up

TwentyLeggedHen: Thanks! The 9L links are a hold over from an earlier design stage, before the frame got any reinforcement. I liked them so they stayed Not sure they serve much purpose here other than maybe aesthetics. (and the more I Think about it they may just be limiting travel...Will have to do some more research this evening)