What is a common designation for right-hand rotating propellers in model numbers?

The designation for right-hand rotating propellers typically includes an "R" at the last position of the hub model designation. This system provides a clear and standardized way to indicate the direction of rotation, which is crucial for installation and operational compatibility.

Having the "R" at the end ensures that after a mechanic reviews the model number, they can easily identify that the propeller is designed for right-hand rotation. This clarity helps prevent potential mistakes during maintenance or when installing propellers on aircraft, where rotation direction is essential for proper performance and safety.

Other options do not follow the standard designations established in aviation. For example, placing the designation in the penultimate or first position does not conform to the recognized practices in model numbering and could lead to confusion about the propeller's intended rotation. Additionally, providing no specific designation would leave mechanics and operators without necessary information regarding the propeller's rotation, exacerbating the chances for installation errors.