Gosainthan, Competition RC Rock Crawler (Super Class) OpenRC

THIS PROJECT IS STILL ON PROGRESS, WILL BE UPDATED PERIODICALLY.

This is the design of a Competition RC Rock Crawler for the Super Class competition category.

This kind of RC cars are not designed for speed they are designed to climb over obstacles (usually rocks) remarkably well and manny times very surprising. You can see how they perform in this video:https://www.youtube.com/watch?v=q-tF0uGzCNE&t=11s

You can find more information about this kind of RC cars and competitions in this forum: http://www.rccrawler.com

You can download the competition rules where the different categories (Classes) are defined and how the competitions go from here: https://docs.google.com/document/d/1LWjbpH_yxB0n_0F3WMOmRx4DMo_LsBE-DuquBto_nok/edit

Some notes about this vehicle:

• The superclass category is provably the most technically advanced of the RC crawlers.

• Manny of characteristics of a Rock-Crawler are very different than from a speed-racing car.

• Vehicle weight should be as low as possible.

• CG should be as low and forward as possible. In order to achieve that CG position weights are installed on the front wheels.

• As low overall weight the better.

• As much suspended mass the better.

• As much turning radius the better.

• Brushless motors are not well suited for the task unless they are sensored (difficult to find).

• Suspensions work more like a energy reservoirs systems for climbing than a normal car suspension.

• On a Superclass both axles are able to steer.

So in order to meet those parameters I come up with this design/idea of how to install all equipment (most of the weight) inside of the wheel rim.

You can access to the CAD files of this project here: https://cad.onshape.com/documents/27bacf61b020beec43556ddc/w/e8cdb36f8c358f6e6ad41942/e/4e156028111cbb92cec77030

You can see the design just clicking on the link.

You need and Onshape account (it is free) in order to be able to copy, modify, etc. the design.

The CAD file will change and improve as time passes, it is more tested and ideas from others are added to the design.

You can find more information on the design, characteristics, and group discussion in this forum thread: http://www.rccrawler.com/forum/superclass-crawlers/594046-crazy-axles-idea-design.html

• Some parts can be printed or CNC cut on Glass Fiber, Carbon Fiber or Alum. plate.

• Some parts have to be made on Aluminium or Steel with a lathe.

• The steering and suspension links can be made from different materials, CF tube, GF tube, Alum. bar, Steel tube, Ti Tube, etc.

• There is 4 different wheels rims to choose from depending what tire you want to use and how you want to make them (CNC or 3Dprint)

• There is two versions of the chassis on the CAD: V1 Gosainthan and V2 Gasherbrum. V2 version is not finished or tested.

Equipment planning to use. The links are just suggestions, there can be other compatible options:

4 x 380/385 brushed motors

380SA-3065-55 https://www.aliexpress.com/item/1PCS-Car-ship-Model-motor-380SA-3065-55-6-11V-small-electric-drill-motor-2-3MM/32847454353.html?spm=a2g0s.9042311.0.0.168b4c4d7gABNr

4 x 20-25A Motor Speed Controllers with reverse function

JMT 20A Brushed ESC https://www.aliexpress.com/item/JMT-20A-Brushed-ESC-Car-Motor-Speed-Controller-Bothway-No-brake-function-For-1-16-1/32766637613.html?spm=2114.13010708.0.0.73b94c4dwuB975

2 x 7.4V (2S) 750-850mAh Lipo batteries (one on each front wheel)

800mAh 2S https://hobbyking.com/en_us/turnigy-800mah-2s-40c-lipo-pack.html

4 x 15-25Kg/cm 180º or 270º Standard size servos

DS3218 or DS3120 https://www.aliexpress.com/item/5pcs-lot-20kg-RC-Servo-Waterproof-Aluminum-Shell-Servo-Metal-Gear-Digital-Servo-Baja-Servo-For/32832143326.html?spm=2114.13010708.0.0.73b94c4dwuB975

1 x 6+ Chanels Receiver + 1 x 6+ Programmable Transmitter

Flysky FS-i6X https://www.aliexpress.com/item/Flysky-FS-i6X-2-4GHz-6CH-AFHDS-2A-RC-Transmitter-with-FS-iA6B-Receiver-FS-I6X/32840184468.html?spm=2114.13010708.0.0.3a994c4d25zFcZ

4 x Worm gear sets 30:1

1M-30T reduction ratio:1:30 copper worm gear model A https://www.aliexpress.com/item/Free-shipping-1M-30T-reduction-ratio-1-30-copper-worm-gear-reducer-transmission-parts-gear-hole/32517750717.html?spm=2114.13010708.0.0.3a994c4deod5cN

20 x Ball rod end bearings

A2 Straight plastic https://www.aliexpress.com/item/Free-Shipping-10Pcs-length-19-27mm-Bending-18-Straight-M3-ball-head-hole-Rod-End-Buckle/32680854552.html?spm=2114.13010708.0.0.3a994c4d5CXREa

Carbon tube

8x6mm tube https://www.aliexpress.com/item/TianYuQi-3k-100-full-Carbon-fiber-circular-tube-500mm-Length-OD-10mm-12mm-14mm-15mm-16mm/32815243370.html?spm=2114.13010708.0.0.3a994c4d5CXREa

4 x 90 to 110mm Shock absorbers

100mm Shock absorbers https://www.aliexpress.com/item/AXSPEED-4-PCS-lot-100mm-Axial-SCX10-D90-SUSPENSION-SHOCKS-SHOCKS-ABSORBER-100MM-RED-Blue-Green/32804872230.html?spm=2114.13010708.0.0.3a994c4d5CXREa

2 x 90mm stands off

90mm stands off https://www.aliexpress.com/item/2pcs-lot-Lightweight-aluminum-hexagonal-column-M3x50mm-M3x60mm-M3x70mm-M3x80mm-M3x90mm-M3x100mm-flight-models/32837303726.html?spm=2114.13010708.0.0.3a994c4d5CXREa

12 x Motors capacitors

1 x Capacitors array

Tires

Bearings

Screws, nuts, washers.

Pending Updates:

TO FINISH BOM AND LINKS TO POSSIBLE SUPLIERS

ASSEMBLY INSTRUCTIONS WILL BE ADDED SHORTLY

TRANSMITTER PROGRAMMING AND MIXES WILL BE ADDED SHORTLY

MORE PICTURES AND ACTION VIDEOS WILL BE ADDED SHORTLY

• Recommended materials: PLA+, ABS, PC, Nylon, High temperature PLA.

• I used Cura slicer.

• Print with walls and top/bottom thickness of around 1.6mm to 2mm

• Recommended nozzle size 0.4 to 0.6mm

• Recommended layer high 0.2 to 0.3mm

• Infill: 15-20%

• Recommended to add "Alternate extra wall" in order to improve strength.

• Tolerances for the screws, gears and other parts are included on the design. But you have to make sure that print comes out accurate so all parts will mount together properly. So in some printers or with some materials it is necessary to adjust the horizontal expansion usually around -0.1 to -0.2mm

• Retraction minimum travel 5mm to 6mm

• Recommended to increase printing temperature in order to get good layer adhesion.

• Recommended to decrease printing speed in order to get good layer adhesion and accuracy.

• Wheel rims, Details, Gearbox cover, and Gearbox servo holder do not need support. all the other parts need support.

• Maker sure to realign the flat faces of the parts to the bed on the slicer.

• Make sure the parts are touching the bed on the slicer.

• Axle spurs recommended to be printed horizontal instead of vertically.

Post-Printing

• Remove supports and brims on the parts printed with them.

• Some screw holes may need to be trimmed.