What is the definition of propeller slip?

Propeller slip is defined as the difference between the geometric pitch and the effective pitch of a propeller. Geometric pitch refers to the theoretical distance a propeller would move forward in one complete revolution if there were no slippage, while effective pitch takes into account real-world factors such as air resistance and performance characteristics that often result in a lower-than-expected advancement through the air. By measuring this disparity, one can understand how efficiently the propeller converts rotational energy into forward thrust. This concept is crucial in assessing the performance of an aircraft's propulsion system, as it informs operators about the efficiency and slip characteristics of the propeller in various flight conditions.

In contrast, the theoretical distance a propeller should advance in one revolution specifically refers to the geometric pitch, not accounting for real-world effects. The actual amount a propeller moves forward in one revolution reflects the effective pitch and does not capture the difference that defines slip. Lastly, the angle between the blade chord and the plane of rotation pertains to the aerodynamic design of the blades rather than the concept of slip itself. Understanding propeller slip is essential for analyzing flight performance and ensuring optimal engine and propeller operation.