Build a crawler type CC01 using 3D print parts

[ShouryLiu]

Hello CC01 fans, I'm new here at RCC, and I've been enthusiastic about TAMIYA CC01 for years since it become my first 1:10 RC, now I want to introduce my work on CC01.
No doubt CC01 is a great chassis for trail run, but for me, I need a more performance CC01, to climb the mountain with my friends' SCX10 or other more modern chassis. I do own a MST CFX-W chassis with much better performance on rock, but I love the compact size of CC01, which can be easily packed by an ordinary backpack and let me travel light.
So eventually I decide to modify my stock CC01, before started, I listed some rules for my work:
1.Keep the original wheelbase and tread---bigger size does come with better performance, but I think CC01 is better with 2xx wheelbase, no need to try to become a SCX10.
2.NO cuttings to the bathtub---OK except the terrible front lower block.
3.Good performance, limited scale detail---I even removed the rear mirror of the Bronco body, in case it get stuck by the rock...hmm...

[ShouryLiu]

Here's the current setup:
-35 turn 540 motor from Cross RC: Cheap and light weight, though not as powerful as a tekin T35.
-HW 1080 ESC: Performs well on rock, with adjustable drag break, I believe this is the entry level crawler ESC, not 1060.
-pHD 20kg servo.
-a sealed receiver box.
-belt driven reduction unit, made by 3D print Nylon.
-horizontal rear shock unit, also made by 3D print.


One problem about using CC01 as a scale crawler is the standard gear ratio is too low, gear reduction unit is definitely a solution for this, but GRUs on the market have two disadvantages: the motor will occupy the space of battery, and running with a high gear ratio with no clutch to protect the transmission would be dangerous to CC01.
For this, I came up with the idea of building a Level 1 belt drive reduction unit for CC01, Lv1 belt drive is nothing new, but it solves the problem of transmission protection(when the tires got stuck, the belt will skid to prevent the transmission from overload), which I think is very meaningful to CC01.

I use 2GT(also been called GT2, I don't know which is right...) type belt drive parts, they are standard products, very cheap and easy to access. Currently I found a combination of 16T and 40T pulleys with 20T pinion gear inside will provide feasible gear ratio for crawling(the final ratio is 11.73×2.5≈29.3).The structure of the reduction unit is produced by 3D print, these nylon parts have good mechanical property.

I never got in touch with a stroke extension kit, don't know how they work on trail, but I decide to develop a horizontal shock unit to give the chassis more flex. It also require no cuttings to the rear fender, but I got to say it significantly increased the torsion effect(sorry, I don't know the right word...the torque made the right front wheel leave the ground) on steep surface, I tried the hardest barrel spring from TAMIYA, but it did not completely solve the problem. Should I add a sway bar on the rear axle? sounds wired too...
Also I designed a L-shape support, which is installed from the upper side of the fender to avoid any contact with the rear tires. I don't want to drill holes on the white roof of the body, this L-shape support will help.


Anyway it does give my CC01 more flex, the stack of the plastic rims should be 3 inch high.

[OSRC]

Very interesting .... I've seen lots of GRU's stuffed into CC's, but never a belt drive. Nice work!

[ShouryLiu]

Originally Posted by OSRC

Very interesting .... I've seen lots of GRU's stuffed into CC's, but never a belt drive. Nice work!

Thanks! belt drive is easiler to DIY, and easy to change reduction ratio, I think they work just fine on CC!

[ShouryLiu]

We all know how the big front block could stop CC01 on rocks, to get rid of the front block, I also use 3D print parts. It consist of two pieces, which is the skid plate and the bumper. I designed the bumper as thin as possible, and it fits right in the front. Considering the removed piece weakened the front, I think this structure could strengthen it back a little.


I glued a piece of aluminium plate on the 3D print nylon part, but...apperently the shoegoo does not work well on these surfaces...


I decide to keep the third screw hole on the bottom and use all three screw holes to install the 3D print "skid plate", not the most effective way, but I hope it could be more secure.
Some building pics were lost and I can only use the pic from CAD software...I don't think this nylon part is strong enough to take the repeated impact from rocks, so a metal "armor" should be needed. Maybe try a steel plate in the future.


Here's the over all look of the bottom, many many scratches made by rocks...

[ShouryLiu]

Trying to keep the drive shaft close to the bathtub, and make more space under the chassis:

The former shaft is super short, I can't find one suitable on the market, so I cutted a much longer one and weld the two little cups togther...The latter one is the original shaft from the kit, they work just fine. Oh, I have to say the shaft from TAMIYA is much tougher than the cheapie I bought online...I can only cut it by grinding wheel.

Copied the design of CR01's OP lower link, and made 3D printed one. it's crazy to make lower link by nylon, but I can't believe they even survived:

These two lower links is shorter than original design about 25mm, this should also make more space under the chassis, and reduce the chance of getting stuck, I hope...

I got to tell TAMIYA, that CC02 really need to have a flat "belly"(if there's any possibility of TAMIYA will develop CC02), look at the horrible gear cover in the front, and the protruding ball joint in the rear, they make me so sad...

[Tossedman]

Cool build, looks well thought out. I like the belt drive. Well done!

[ShouryLiu]

Originally Posted by Tossedman

Cool build, looks well thought out. I like the belt drive. Well done!

I'm happy you like that! thanks for the comment!

[ShouryLiu]

Here's some small stuff---the battery door adapt to soft pack 2S Lipo:

It is narrowed compare to the original door, so the wire of soft pack Lipo can pass by. Just trim the ribs under the cover of battery case and enlarge the entrance a bit, and no more Ni-MH battery!

I almost forgot the steering system! The original steering parts are rubbish, especially on rocks. Instead of GPM or HR or YR, I chose a steering kit from a personal developer.
I'm sorry for the dirt...this is a home made kit which can replace the original steering parts directly, without any modification to the chassis. It works really good with the aluminium servo arm, the front wheel steer firmly on rocks.


Lost more building pics...I post the photo took by the developer here:

[Nicadraus]

I like what you did with the reduction gear by belt. Very unique for a crawler.

[ShouryLiu]

Originally Posted by Nicadraus

I like what you did with the reduction gear by belt. Very unique for a crawler.

Thanks for your appreciation! The unit is quite simple, I didn't photo the building process, here's the assembling model in my CAD:

[ShouryLiu]

I took the CC01 bronco to the mountain I usually go with my MST, it performs well on most part of the trail, but there's no way it can catch up with an SCX10 on those really rough terrains, CC01 is a small chassis any way, if don't change the dimensions, the limit is there.
In earlier time I use 96mm tires with plastic rims, the electroplate coat looks good.








After several trail run I changed the 96mm wheel to 100mm, with new beadlock rims from GRC, the GRC rim is extremly heavy(180grams per rim), I believe it's main part is forged by zinc, no CNC process means it is quite cheap, yet it is well-made.
Worring that the heavy rim could cause too much load on the rear shaft and broke the spline of the diff gear, I replaced the rear diff gear with King-Kong RC's steel kit---the spline bites firmly to the rear shaft.

[Sneetches]

Cool, never thought about a belt drive GRU for something like this before. The other parts are looking good too, maybe a CC02 platform would have to be a joint community project fueled by 3d printing.

[Gula]

Would you mind sharing the stl file you used for printing the belt drive reduction mount?

[ShouryLiu]

Originally Posted by Gula

Would you mind sharing the stl file you used for printing the belt drive reduction mount?

Yeah, sure! Will OneDrive sharing link work in here? I think I'll post a short thread for this little stuff.

[ShouryLiu]

Originally Posted by Sneetches

Cool, never thought about a belt drive GRU for something like this before. The other parts are looking good too, maybe a CC02 platform would have to be a joint community project fueled by 3d printing.

Thanks! I feel that 3D print tech created new field for RC!

[ShouryLiu]

After some days I decide to pull my CC01 out from corner, and make some thing new for it. I found my CC01 has an obvious torque twist (finally I learned this word!) on steep surface, with my weird rear shock setup. It might be too soft, yet I can't find any harder springs in hand. Meanwhile I learned the great work of OSRC---CC01 with under drive rear axle! I'm so curious how it works on a short wheelbased CC01, how much can it improve the torque twist problem.
However it turns out that I can not find any rear axle that has a slightly bigger gear ratio than the stock one, while has a same tread. I decide to put a 1:1.1 reduction box in front of the stock rear axle.


Got some M08 steel pinion, I'm going to try a combo of 19T and 21T pinion. I got to say that these pinions is a little too big, I believe some smaller M06 ones will also be enough.


Some 5mm steel shaft, 1150 ball bearings and M5 washer.

[OSRC]

Awesome! I really need to learn how to 3D print..opens up so many possibilities! Assuming you are going then to flip over the rear axle?

Interesting that you have a lot of torque twist, that's one problem I don't think I've ever had with my CC01's no matter what kind of suspension I used.

Very curious to see how it all comes out! Great work!

[ShouryLiu]

Originally Posted by OSRC

Awesome! I really need to learn how to 3D print..opens up so many possibilities! Assuming you are going then to flip over the rear axle?

Interesting that you have a lot of torque twist, that's one problem I don't think I've ever had with my CC01's no matter what kind of suspension I used.

Very curious to see how it all comes out! Great work!

Thanks! You know I kinda become your fan after seeing so many possibilities of CC01 from your work! Love every one of your build!
Actually I don't know how to use a 3D printer, I only learned some modeling skill using CAD software, and then I sent my design to a 3D print workshop from Internet (like Shapeways.com), they'll take care of the rest! I just sit in my home and wait for the parts I ordered...very easy.

Yes I already fliped over my rear axle, cause there's not much room for a gearbox with three pinions in it. I don't know why my chassis have that much torque twist, but it becomes even more after I installed my weird rear shock. Maybe this complicated design contained too much play in it. Now I would rather use some simpler solution...

[ShouryLiu]

Have the bottom cutted to make way for the oversized reduction box, since there's no motor behind this area, there's no worry about any interference.


29 July
Assembled both gear shafts, had to knock the bearings on since these 5mm shafts are tight fit.

Received the 3D printed gearbox yesterday, the pinions seem to be in right place.