Abstract: A three wheeled amphibian vehicle operated by pedal power and including an air blower coupled to a disk turbine. The turbine is a flat circular rotatable structure having blade cavities on both upper and lower faces. Twin nozzles, connected to the blower, direct air streams toward the blades and form a coupling means which can be controlled to provide a variable speed ratio between the pedals and the driving wheel, thereby acting as a gear box including Drive, Neutral and Reverse. A spring coupled by a clutch mechanism to the driving shaft may be used to store energy while coasting down hill and then deliver the stored energy to the shaft when climbing up hill. Retractable pontoons are provided for traveling on water.