This lesson covers the pressure distribution on an airfoil, airfoil nomenclature, and airfoil characteristics. It delves into the concept of symmetric and cambered airfoils, explaining how the pressure distribution on these airfoils would look like at different angles of attack. The lesson also introduces the concept of NACA series of airfoils, explaining the nomenclature and characteristics of four, five, and six-digit series. It further discusses the development of high-speed airfoils and their advantages in high-speed flows. For instance, using the NACA 23012 airfoil as an example, the lesson explains how its design lift coefficient, maximum camber location, and maximum thickness can be determined from its nomenclature.
01:10 - Introduction to the concept of symmetric airfoil.
04:55 - Explanation of how the pressure distributions look like on the upper and lower surfaces of the airfoil.
06:35 - Explanation of how the pressure distribution changes with the angle of attack.
18:41 - Discussion about airfoil nomenclature, specifically NACA series of airfoils.
29:25 - Discussion about the development of NASA low-speed airfoils and high-speed airfoils.
- Symmetric airfoils have identical pressure distribution on their upper and lower surfaces, resulting in a net zero lift.
- Cambered airfoils have unequal pressure distribution on their upper and lower surfaces, resulting in a non-zero lift even at an angle of attack of zero degrees.
- NACA series of airfoils, including four, five, and six-digit series, have specific nomenclature that provides information about their maximum camber, location of maximum camber, and maximum thickness.
- High-speed airfoils, such as supercritical airfoils, are designed to increase the drag divergence Mach number, delaying the increase in drag due to shock wave formation at higher free stream Mach numbers.