Took so long to make.
This might be the easiest to build electric bike there is, versus power and reliability.
Front 18" wheel direct drive, using DeWalt's DCD961 brushless drill.
The fork is standard, so it can be put on any small bicycle frame. Functionally not much different than a hub motor, but there are probably significant differences in performance (what exactly, I do not know).
The speed switch is intact, so I can play around with that. It is meant to be on the lowest speed setting, should be fast enough.
This design has been tested, but the prior version was not nearly as efficient. Then, it drove a chain that drove the rear wheel. All that is unnecessary given a drift trike front wheel with a pedal hub (without the pedals) and a low-geared cordless drill at no more than about 450 RPM (no load).
The drill kit cost about $280. Depending on your application, extra batteries might be required. The drift trike front wheel (an adult "Big Wheel") costs about $150-$200. Seems overpriced, but oh well. Difficult to find many replacement parts for drift trikes. Seems they enjoy it in Australia. Mad Max on a Big Wheel.