Cheaper and easier, but still awesome speed tank by conquestdz

Last crawled date: 3 years ago

Here are a few clips showing how it performs. https://youtu.be/dae_LeZtj3M
I was thinking about printing the really awesome RC tank by Staind: https://www.thingiverse.com/thing:2414983,
but when I went online shopping and looked at the complexity of the project I hit the brakes and decided to come up with something a bit easier and less expensive to print. I also wanted to use TPU for the tracks, and that required scaling things down to get a track circle that would fit on my print bed. A 200mm square print bed will have room to spare.
I redesigned the axles to be separate parts with steps to locate the bearings. With this setup you can thoroughly tighten the axle bolts without side loading the bearings. The axles should slip fit into the holes on the side plates.
I had 2 of the super cheap 2212 1400 kv motors and esc's laying around from another project and decided to build around those. This motor and ESC combo is about $16 on Amazon. That goes a long way towards keeping the project cost down. So does using TPU tracks. you don't need about 100 m3 bolts to make a linked track that breaks every time you put the hammer down. These tracks have been super durable under heavy thrashing and get awesome traction.
Print instructions:
The orientations are not necessarily correct. You will have to lay the flat side down in your slicer.
I printed everything with white Overture PETG with the following settings:
Cura "low quality" setting of .28 layer height
cooling off
30% gyroid infill with a .6 infill line width
Printing with cooling off makes the PETG very tough and flexible which is a good thing to avoid breakage.
Supports everywhere at 50 degrees for the chassis only. All other parts print without support.
Print the drive wheels with the gear side up.
The tracks should be printed hollow for good shock absorption.
Overture high speed TPU
1 wall, no tops or bottoms, no infill
I ended up needing a narrow brim
Shopping list:
2 motors and esc:https://www.amazon.com/BGNing-Brushless-Outrunner-Controller-Quadcopter/dp/B00PXVG7VM/ref=sr_1_2?crid=L155TMKMFUAY&dchild=1&keywords=2212+brushless+motor+1400kv&qid=1617899985&sprefix=2212+brushless+motor+1400%2Caps%2C220&sr=8-2
Note: These ESC do not have reverse. If you really want reverse and are willing to add to the project cost consider a bidirectional esc like this:https://www.amazon.com/Baoer-Bidirectional-Brushless-Pneumatic-Underwater/dp/B08D3G45J7/ref=sr_1_12?dchild=1&keywords=bidirectional%2Besc%2B30A&qid=1617900314&s=toys-and-games&sr=1-12&th=1
Alternative bigger motor (it's awesome):https://www.amazon.com/DYS-1300KV-Brushless-Multicopters-Helicopter/dp/B077HLPP4N/ref=sr_1_3?crid=1ZYBDVRP92ORU&dchild=1&keywords=2830+brushless+motor&qid=1617900442&s=toys-and-games&sprefix=2830%2Ctoys-and-games%2C221&sr=1-3
11T MOD1 Pinion gear:https://www.hobbytown.com/traxxas-hardened-steel-mod-1.0-pinion-gear-w-5mm-bore-11t-tra6484x/p661892?v=636143
Shaft adapter for pinion gear:https://www.amazon.com/ShareGoo-Adapter-Change-Over-Hobbywing-EZRUN-3656/dp/B081CFT28V/ref=sr_1_1?dchild=1&keywords=pinion+shaft+adapter&qid=1617900514&s=toys-and-games&sr=1-1
608zz bearings 12 required:https://www.amazon.com/Sackorange-Skateboard-Bearings-Miniature-Bearings（Pack/dp/B07216D1SZ/ref=sr_1_3?dchild=1&keywords=608zz&qid=1617900948&sr=8-3
604zz bearing 4 requiredhttps://www.amazon.com/XiKe-604ZZ-Pre-Lubricated-Performance-Cost-Effective/dp/B07JGT587B/ref=sr_1_5?dchild=1&keywords=604zz&qid=1617901069&sr=8-5
M4x60mm socket head cap screw 12 required
M4x40mm Hex head bolt 2 required
M4x30mm socket head cap screw 2 required
M4 lock nuts 16 required
M3x6mm socket head screw 8 required
M3x10mm socket head screw 4 required
Battery
A 3s 3000mah battery fits nicely and gives good run time. There is room in the chassis for 2 of these if you really want long run time, but I found it unnecessary.
Radio
You will need a radio capable of channel mixing. This is a cheap and simple example:https://www.amazon.com/DUMBORC-Transmitter-Receiver-Controller-400m-500m/dp/B07RR81GSB/ref=sr_1_2?dchild=1&keywords=dumborc&qid=1617901713&sr=8-2
Assembly:
Start by putting the M4 hex head bolt through the back of the gear case. It is intentionally a tight fit. It will need a few love taps to seat all the way in.
Mount the motors to the motor mounts with M3 screws and add the pinion gears with adapters.
Put the inner bearings into the gears. They should fit easily.
Slide gear onto the shaft add the bearing spacer and then the outer bearing, secure with a lock nut. Don't over tighten. It should spin freely.
Test assemble the motor and mount to the gear case and adjust the pinion gear for full contact.
Bolt the motor gearbox combo to the side plate and snug everything down.
Press 6 lock nuts into the recesses in the chassis.
Use 2 m3 bolts to attach the front cover to each side plate by the bottom holes only for now. Leave these bolts loose enough that the cover can pivot.
Put the inner bearing in all of the wheels
Drop the axles into the wheels with the long side towards the body.
Add outer bearings.
Add the outer side plate and use a M4x60 bolt through each axle to secure the assembly to the nuts in the chassis.
Add your ESC and radio in the front.
Secure the front cover with 2 more M3 screws.
Roll the tracks onto the wheels and you are all set.
Note:
Some radios may not like having 2 BEC plugged in. You can remove the power wire from the BEC on one ESC is this happens to you. I had no problem with the receiver linked above but your experience may be different.