RC Propeller Size LabellingĪll rc propellers are designated two measurements, traditionally given in inches. nearer to the hub of the propeller), the AoA has to be greater to generate a similar amount of thrust being generated at the faster moving tips. This difference in thrust occurs because the tips of the prop blades move faster than the inner portions of the blades, so the AoA has to change accordingly along the length of the blades more thrust is generated at faster speeds, just like more lift is generated over a faster moving wing. The picture to the right approximately illustrates how the Angle of Attack varies along the blade length. The twist is greater towards the hub of the prop because of varying airspeeds along the length of the blades, and hence varying thrust generation. The 'twist' in the propeller is there to create the essential Angle of Attack of each blade, just like a wing has an AoA. Thrust is generated in exactly the same way as lift is generated by the wing, and that's why props have a profile airfoil section. The prop's job is to convert the motor power in to thrust, to pull/push the plane through the air. Simply put, props are nothing more than vertically mounted rotating wings. You'd be forgiven for just thinking of your rc plane's prop as the thing that pulls the plane along, but understanding a bit about exactly how propellers actually work is no bad thing. Most engines / motors will come with propeller size information, likely this will be a range of suitable sizes. The first and foremost plan of attack is to follow the manufacturer recommendations for the engine or motor that you have. In the worst case scenario, the wrong prop can cause serious damage to components and this is especially true for electric powered rc airplanes. Selecting the correct propeller for your rc airplane is crucial if you want to get the optimum performance from your plane, regardless of its power type. Radio control propeller size selection can be a minefield, especially for the beginner to the hobby, so outlined below are some generally accepted guidelines and recommendations for choosing the right prop for your rc plane. Home Site search Site Map About Me Contact Me Site FAQ Privacy/Cookie Info Testimonials