Rule Zero
| Rule Zero | |
|---|---|
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| Built By | Mark Mellors |
| Theme | Fire Engine |
| First Race | Scrumpy Cup 2018 |
| Current Status | Active |
| Motor | Vevor/Mophorn 1800W |
| ESC | Vevor/Mophorn 1800W |
| Battery | 12S (48V) of EIG CO20B Lithium Ion 20Ah cells |
| Transmission | 13:80 6mm Chain |
| Contact | @MarkMellors |
| View all Racer Profiles | |
Background
The name comes from the 0th rule of Hitchin Hackspace - Rule Zero - Do Not Be On Fire! The theme of the body is based around a fire engine from local Hertfordshire Fire & Rescue, constructed from a PVC pipe frame, ABS sheets, and printed vinyl
Construction
The chassis is based on a mobility scooter, with the main changes being:
- removing the seat and replacing it with one from a drift trike
- rear transaxle replaced with a solid (19mm 304 SS) rear axle, with a hydraulic disk brake and drive sprocket
- handle bars converted into a steering wheel
- steering goemetry slightly modified to give some trail, and reduced sensitivty
The wheels and tyres are from karts. the front wheels had their bearings replaced to match the scooters spindles. I machined adapters for the rears to bolt to the keyed rear axle.
The throttle and brakes are actuated by pedals. the pedals pull cables which turn a spring-loaded pot for the throttle, or the (hand) brake lever from the bike hydraulic brake.
The bodywork is PVC tube covered in heat-formed recycled ABS sheet, and vinyl wrapped. The bumpers are ~70mm HDPE water pipe, also heat bent to form the rounded corners.
Build videos:
https://www.youtube.com/watch?v=_2zzuY2yD6Q
https://www.youtube.com/watch?v=Uy0oinC1whU
https://www.youtube.com/watch?v=M5zO_7-MICA
https://www.youtube.com/watch?v=xP7fHLw0Fgw
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Powertrain
10-12Ah, 12S Multistar lipos from Hobbyking, or custom 20ah Eig cell packs with BMS. (details?) 2kw scooter motor & 1.5kw ebike controller. (details?) Source: https://vevor.co.uk/brushless-dc-motor-c_11227/48v-1800w-brushless-motor-controller-throttle-grip-powerful-quad-p_010700081791
The reduction is 13:80 with 6mm chain. The chain's certainly strong enough, but quite sensitive to misalignment, and keeps coming off, especially in reverse...
Other Features
Sound? Lights? Remote steering? Great on two wheels!
Race Results
BOM
BOM for original build: https://docs.google.com/spreadsheets/d/13LH8uYXNQv7zIFvCdWGZtBPLQ-ZO0K0W6goraVPJs_k/edit?usp=sharing
Limitations
Slicks have limited grip in mud, but does corner well in almost all other conditions.
Resources
Twitter Account @MarkMellors
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