# (Mean) Chord line, Mean chamber line – 2 reference lines for an airfoil

2 Reference lines for an airfoil:
[Ref. Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25B Page 4-6]
reference line often used in discussing the airfoil-
1. Chord line
2. Mean chamber line
[Ref Fig. 4-5] Typical airfoil section.
[Ref. Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25B Page 4-6]
chord line, a straight line drawn through the profile
connecting the extremities of the leading and trailing edges.
(i.e imaginary straight line joining the leading and trailing edges)
`Tag: #chord line #reference line #airfoil`
[Ref. Pilot’s Handbook of Aeronautical Knowledge, FAA-H-8083-25B Page 4-6]
mean camber line. This mean line is equidistant at all points from the upper and lower surfaces.
`Tag: #mean camber line #reference line #airfoil`

Remember :
1. Chord line                     ≠       Chord
2. Mean Chord Line          ≠       Mean aerodynamic chord
3. Mean camber line         ≠       Camber
[Ref PPL Instruction Kit Vol1 (306) – 9th Edition, V9.2 P.2]
Chord line  ≠   Chord    !!!
Chord is the distance along this chord line between the leading and trailing edges (i.e., the length of the chord line)
[Ref. ACE The Technical Pilot Interview 362/6496]
Mean Chord Line = Standard mean chord (SMC),
wing area over wing span
[Ref. wikipedia]
Mean Chord Line is the chord of a rectangular wing with the same area and span as those of the given wing.
This is a purely geometric figure and is rarely used in aerodynamics.
BUT….
Mean Chord Line ≠ Mean aerodynamic chord

[Ref PPL Instruction Kit Vol1 (306) – 9th Edition, V9.2 P.3]
camber of an aerofoil (= curvature) is measured as the maximum distance between the mean camber line and the (straight) chord line. An aerofoil with zero camber is said to be ‘symmetrical’.
`Tag: #curvatures #Curvature #Curvatures #curvatures`
My Hand Notes:

# Significance of “Camber” – Why we tend to use cambered aerofoil? – Symmetrical (Non-cambered) v.s Non-symmetrical (Cambered)

`Tag: #mean chord line #mean #What's #camber`