ESDU 84026: Aerofoil maximum lift coefficient for Mach numbers

Abstract:

ESDU 84026 provides a simple empirically derived method for estimating maximum lift coefficient. The method predicts the increment in lift coefficient by which the maximum exceeds the value at zero incidence, and a prediction method for lift coefficient at zero incidence is included. Graphs of the increment show its variation with aerofoil geometry and Reynolds number for aerofoils with smooth or rough leading-edges; rough here would cover ice formation while smooth includes the level of roughness required just to fix transition. A further empirical factor is provided to extend the method to apply to modern aerofoils with rear loading. The accuracy is assessed in terms of the standard deviation of prediction from experiment for nearly 500 points, sub-divided by aerofoil type, leading-edge condition and Reynolds number. The overall standard deviation was about 0.08. The method is programmed as part of ESDUpac A9315, see ESDU 93015.

A computer program of the method is included as part of ESDU LiCrA Toolbox apps and ESDUpacs A9931 and B9931 from (ESDU 99031). See the 'Software' tab, above.

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Details:

Data Item ESDU 84026
Format:	PDF with software with interactive graphs
Status:	Amendment (C), 01 Jan 1999 Published in Release 2000-03 (init)
Previous Releases:	ESDU 84026 Amendment B
ISBN:	978 0 85679 490 2

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This Data Item is complemented by the following software:

Toolbox Apps

Name

Details

Toolbox LiCrA-2D Run

Title

ESDU LiCrA: 2D Lift Curve Aerodynamics for Aerofoils

Version

1.0

Details

LiCrA 2D calculates the maximum lift coefficient, the lift coefficient at zero angle of attack and the lift curve of aerofoil sections with or without high-lift devices deployed at low speeds.

Calculations can be made for the aerofoil when there are no high-lift devices deployed but the prediction of the shape of the non-linear part of the lift curve should be treated with caution because it employs a technique developed for use when high-lift devices are deployed. The method is intended for use only for free-stream Mach numbers up to about 0.25.

Toolbox LiCrA-3D Run

Title

ESDU LiCrA: 3D Lift Curve Aerodynamics for Wings and Wing/Body Combinations

Version

1.0

Details

LiCrA 3D calculates the maximum lift coefficient, the lift coefficient at zero angle of attack and the lift curve of straight-tapered wings with or without high-lift devices deployed at low speeds. The basic wing (no devices deployed) may have camber and twist. The program includes methods that allow for the presence of a fuselage.

For completeness, calculations can be made for the wing when there are no high-lift devices deployed but the prediction of the shape of the non-linear part of the lift curve should be treated with caution because it employs a technique developed for use when high-lift devices are deployed. The method is intended for use only for free-stream Mach numbers up to about 0.25. No allowance is made for ground effect.

If required, it will also calculate the spanwise position of the section of the basic wing that has the peak loading due to angle of attack.

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This Data Item contains 7 interactive graph(s) as listed below.

Graph	Title
Figure 1	Lift coefficient increment for aerofoils with smooth leading edges z_u1.25 / c < 0.017
Figure 2	Lift coefficient increment for aerofoils with smooth leading edges z_u1.25 / c ≥ 0.017
Figure 3	Lift coefficient increment for aerofoils with rough leading edges z_u1.25 / c < 0.017
Figure 4	Lift coefficient increment for aerofoils with rough leading edges z_u1.25 /c ≥ 0.017
Figure 5	Factor on C_Lm for modern aerofoils
Figure 6	Parameter in equation (7.1)
Figure 7	Parameter in equation (7.1)

ESDU 84026

Aerofoil maximum lift coefficient for Mach numbers up to 0.4.