the Green Machine project dragging out with potential aerodynamic
issues, and receiving word that other guys were already
successfully testing electric tether cars, we decided to step things
up. George and I were reasonably sure that a closed wheel car with
suspension, that was designed from the ground up as an electric powered
car, was the ultimate answer. We also realized that we had very little
solid information behind us to dive into such a program of extensive
engineering, and costly manufacturing. Our thoughts were to take a
3.5cc gas car called the Ramrunner, put an electric motor in it, and
use it to learn with.
For the Voltswagen, as we called it, we looked for a powerful motor
that was not too big, and would fit the cast aluminum Ramrunner pan
without any modifications. Such a motor was found at Offshore
Electrics, a leading supplier to the RC boat enthusiasts. The motor we
used is made by Leopard Motors, and costs about $100. Similarly, a
small, not too expensive, 120amp ESC was used, and it fit perfectly.
The batteries play an extremely important role so a 65C
Thunder Power pack was chosen.
George designed a custom, programmable, on-board throttle control to
“ramp up” the power to the motor, just as you would
with the throttle lever on your RC transmitter. The rate at which it
does this can be changed by throwing switches on the printed circuit
board. In tether racing, the use of external radio control is not
permitted here in the United States.
After the Voltswagen showed really exciting results with the Leopard
motor, it was changed over to test the motor/controller combination
that we planned on using in the new car. At the end of the 2012 season,
it posted 170mph lap speeds, and became the Worlds fastest electric
powered tether car.