With an electric outrunner type motor that the OP has you are able to spin a larger prop at a slower rpm which we are finding to be more efficient for an airplane like the Kadet Sr. Pretty much the same reason why guys started flying 4 strokes on them only better. Another advantage of electric is that you don't need to prop to run in the power band. Electrics have torque at any rpm and as long as you don't exceed amperage for any of the components you can keep adding more prop. Depending on the type of airplane you can adjust cell count and prop size to suit the airplane type. Fewer cells allow for bigger props at less rpm for a Kadet type or more cells with a smaller prop at higher rpm for more sporty airplanes. Running a glow prop on an electric only reduces efficiency.