12.72 Propellers

12.72.2 With respect to propeller terminology, define the meaning of the following:

(a) blade section;

In propeller terminology, the blade section refers to the cross-sectional profile of a propeller blade. The blade section can vary depending on the design and intended use of the propeller. Some common types of blade sections include: 1. Flat plate: A flat plate blade section is a simple, flat profile that is often used in low-speed applications. 2. Symmetrical: A symmetrical blade section has the same profile on both sides of the blade, which allows it to produce equal lift in both directions. This type of blade section is often used in aerobatic or acrobatic aircraft. 3. Asymmetrical: An asymmetrical blade section has a different profile on each side of the blade, which allows it to produce more lift in one direction than the other. This type of blade section is often used in high-performance or racing aircraft. 4. Cambered: A cambered blade section has a curved profile that produces more lift than a flat plate blade section. This type of blade section is often used in general aviation and commercial aircraft. Overall, the blade section is an important factor in determining the performance and efficiency of a propeller. Different blade sections can produce different amounts of lift, drag, and thrust, depending on the design and intended use of the propeller.