Hybrid Bike
A friend and I decided to first create an electric bike using a winch motor that belonged to the robotics teacher at our high school. We then attached an engine from a used weedwacker that we bought to increase the power and speed.
The weedwacker engine was attached only to the seat so it could be removed and used on another bike with the same diameter bike seat. The electric motor was used to start the weedwacker engine.
Construction
The winch motor was placed where the pedals usually are and was attached to an aluminum plate which was bolted to the frame. The shaft was press fit into the existing gearing after some modification and was used as is. A wooden battery holder was created and attached to the other side of the frame. For the weedwacker engine, a frame was stick welded together with material from an old bed frame. The engine was bolted onto the frame through the existing mounting holes and the frame was bolted to the seat pole on the bike. A bike peg was attached to the output of the weedwacker engine to increase the diameter and make the grip better. The weedwacker and peg friction drove the rear wheel of the bike once running.
Below are a rear shot of the hybrid bike and the engine/seat moved to another bike.
Testing
Below are tests ranging from electric motor testing to full assembly operation. The weedwacker engine added significant resistance when trying to use the bike manually, but was easier while running. The winch motor needed 4 12v lead acid batteries to provide enough torque to start while loaded.
