nacaProfileType

The airfoil families of the National Advisory Committee for Aeronautics (NACA) define an airfoil by a few digits. The airfoil is normalized: it lies in the x-z plane with the leading edge at (0, 0) and the trailing edge at (1, 0), i.e. the chord line runs along the x axis and has the length 1. Size, position and orientation are defined by the referencing element, e.g. the scaling of a wing element gives the chord length.

4-digit series

A code MPXX, e.g. 2412, gives the maximum camber m = M/100, its chordwise position p = P/10 and the maximum thickness t = XX/100, each relative to the chord. M and P are either both 0, which gives a symmetric airfoil such as 0012, or both greater than 0. The thickness distribution z_t is applied perpendicular to the camber line z_c, which gives the upper (U) and lower (L) side:

NACA 2412 with chord, camber line, maximum camber m at position p and thickness t; trailing edge of NACA 0012 without, with zero and with given trailing edge thickness

5-digit series

A code LPSXX, e.g. 23012, gives the design lift coefficient 0.15·L, the chordwise position of the maximum camber 0.05·P, the type of camber line (S = 0: normal, S = 1: reflexed) and the maximum thickness t = XX/100. The thickness distribution is the same as for the 4-digit series, including the trailing edge thickness described below. The camber lines and their coefficients are those of NACA Report 537 and Abbott and von Doenhoff (see references).

Trailing edge thickness

Without trailingEdgeThickness, the airfoil follows the original definition with the coefficient a₄ = −0.1015, which leaves a small total thickness of 0.021·t at the trailing edge, e.g. 0.00252 for NACA 0012. With trailingEdgeThickness, a₄ is chosen such that the total thickness at x = 1 equals the given value Δz_TE; a value of 0 gives a closed trailing edge. A trailing edge thickness requires a maximum thickness t greater than 0.

Example

The first two of the following airfoils are the ones shown in the figure above.

<wingAirfoils>
    <wingAirfoil uID="NACA2412">
        <name>NACA 2412</name>
        <nacaProfile>
            <naca4DigitCode>2412</naca4DigitCode>
        </nacaProfile>
    </wingAirfoil>
    <wingAirfoil uID="NACA0012_closedTE">
        <name>NACA 0012 with closed trailing edge</name>
        <nacaProfile>
            <naca4DigitCode>0012</naca4DigitCode>
            <trailingEdgeThickness>0</trailingEdgeThickness>
        </nacaProfile>
    </wingAirfoil>
    <wingAirfoil uID="NACA23012">
        <name>NACA 23012</name>
        <nacaProfile>
            <naca5DigitCode>23012</naca5DigitCode>
        </nacaProfile>
    </wingAirfoil>
</wingAirfoils>

Wing airfoils defined by NACA codes

References

E. N. Jacobs, K. E. Ward, R. M. Pinkerton: "The Characteristics of 78 Related Airfoil Sections from Tests in the Variable-Density Wind Tunnel", NACA Report 460, 1933, NTRS 19930091108.
E. N. Jacobs, R. M. Pinkerton: "Tests in the Variable-Density Wind Tunnel of Related Airfoils Having the Maximum Camber Unusually Far Forward", NACA Report 537, 1935, NTRS 19930091610.
I. H. Abbott, A. E. von Doenhoff: "Theory of Wing Sections", Dover Publications, 1959.

Attributes

Name	Type	Use	Description
`@externalDataDirectory`	`xsd:string`	optional	Directory of the external data file
`@externalDataNodePath`	`xsd:string`	optional	Path of the node inside the external data file
`@externalFileName`	`xsd:string`	optional	Name of the external data file

Child elements

Name	Type	Constraints	OccurrenceHow often the element may appear at this place. The schema writes it as minOccurs and maxOccurs on the declaration.	Description
sequenceThe children below must appear in exactly this order. Each may repeat as often as its own occurrence allows.
choiceExactly one of the alternatives below may appear, unless the occurrence next to this line says otherwise.
`naca4DigitCode`	`xsd:string`	pattern	[1..1] required	Code MPXX: maximum camber in percent of the chord, its position in tenths of the chord, maximum thickness in percent of the chord
`naca5DigitCode`	`xsd:string`	pattern	[1..1] required	Code LPSXX: design lift coefficient in steps of 0.15, position of maximum camber in steps of 5 % of the chord, camber line (0: normal, 1: reflexed), maximum thickness in percent of the chord
`trailingEdgeThickness`	`xsd:double`	minInclusive	[0..1] optional	Total trailing edge thickness relative to the chord (if omitted: original NACA definition)

nacaProfileType

Attributes

Child elements

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In a dataset · 3 paths

In the schema · 1 declaration