A new series of propellers specially designed for electric power systems. These high-strength glass-reinforced plastic propellers feature exceptionally good torsional rigidity in spite of their ultra-thin, low-drag profile and high aspect ratio blades. For every propeller size there is an exactly matched counterpart for opposite rotation, which means that twin-motor model aircraft can easily be equipped with contra-rotating propellers. This makes take-off and launch of these models much safer, as the tendency for motor torque to stall the model or tip it onto one wingtip is suppressed.