Figure 2-1 Chord

CHAPTER 2

HELICOPTER AERODYNAMICS WORKBOOK

ROTOR BLADE AERODYNAMICS

DEFINITIONS

To begin our discussion of rotary wing aerodynamics, we will start with a few basic

definitions using figure 2-1 as a reference. A chord line is the line connecting the leading edge

of the blade to the tip of the trailing edge. The chord is defined as the distance between these

two points. The camber line is the line halfway between the upper and lower surface, camber

being the distance between camber line and chord line (figure 2-2). The tip-path-plane (TPP) is

defined as the plane of rotation of the rotor blade tips as the blades rotate (figure 2-3). The area

of the circle bounded in the TPP is the rotor disk, which is very apparent from an overhead view.

Figure 2-1 Chord

Figure 2-2 Camber

2-2 ROTOR BLADE AERODYNAMICS