NACA initially developed the numbered airfoil system which was further refined by the United States Air Force at Langley Research Center. According to the NASA website:
During the late 1920s and

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The NACA four-digit wing sections define the profile by:
1. First digit describing maximum camber as percentage of the chord.
2. Second digit describing the distance of

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The NACA five-digit series describes more complex airfoil shapes. Its format is LPSTT, where:
• L: a single digit representing the theoretical optimal lift coefficient at ideal angle of attack CLI = 0.15 L (this is not the same as the lift coefficient

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Four- and five-digit series airfoils can be modified with a two-digit code preceded by a hyphen in the following sequence:
1. One

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An improvement over 1-series airfoils with emphasis on maximizing laminar flow. The airfoil is described using six digits in the following sequence:
1. The number "6" indicating the series.
2. One digit describing the distance of the minimum pressure area in

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Further advancement in maximizing laminar flow achieved by separately identifying the low-pressure zones on upper and lower surfaces of the airfoil. The airfoil is described by

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A new approach to airfoil design pioneered in the 1930s, in which the airfoil shape was mathematically derived from the desired lift characteristics. Prior to this, airfoil shapes were first created

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