What is the area swept by the rotor blades, a circle centered at the hub with a radius of one blade length?

What is the area swept by the rotor blades, a circle centered at the hub with a radius of one blade length?

• A. Rotor Disk Area
• B. Rotor Sweep Area
• C. Disk Radius
• D. Blade Circle

Answer: (A)

The key idea is that the area swept by the rotor blades is a circular area formed by the motion of the blade tips. As the rotor spins, the tip traces a circle centered at the hub with a radius equal to the blade length. The region enclosed by that circle is the rotor disk area. This is why the area is calculated as A = πr^2, using r = blade length. The term rotor disk area specifically describes this swept region, whereas disk radius is just the distance from hub to tip (a length), and blade circle or rotor sweep area aren’t the standard way to name the swept area.

The key idea is that the area swept by the rotor blades is a circular area formed by the motion of the blade tips. As the rotor spins, the tip traces a circle centered at the hub with a radius equal to the blade length. The region enclosed by that circle is the rotor disk area. This is why the area is calculated as A = πr^2, using r = blade length. The term rotor disk area specifically describes this swept region, whereas disk radius is just the distance from hub to tip (a length), and blade circle or rotor sweep area aren’t the standard way to name the swept area.