Abstract:

ESDU 99031 introduces the LiCrA (Lift Curve Aerodynamics) application. This program applies to aerofoils, wings and wing-fuselage combinations with or without leading-edge and trailing-edge devices deployed.

When calculations are made for the aerofoil and wing without high-lift devices, the prediction of the shape of the non-linear part of the lift curve should be treated with caution because it employs a simple technique developed for use when high-lift devices are deployed.

Calculations may be made at a number of pairs of Mach number and Reynolds number values. At each pair there may be one or more settings of the leading-edge device. At each leading-edge device setting there may be one or more trailing-edge flap settings. Sketches from the Data Items from which prediction methods have been taken are reproduced to aid the user in determining geometric parameters of the high-lift devices but the underlying methods are not repeated. The method is intended for free-stream Mach numbers up to about 0.25. No allowance is made for ground effect.

The user may select from a number of different types of run. A run may be restricted to the calculation of the lift coefficient at zero angle of attack or to the calculation of the increment in the lift coefficient at zero angle of attack, with or without the calculation of the increment in maximum lift coefficient. There is also a provision for user-defined lift coefficients to be used for the basic aerofoil, wing or wing-fuselage combination.

There may be different types of high-lift devices over different spanwise segments of a wing. In the case of leading-edge devices, if the calculation is to include the prediction of maximum lift coefficient, there can be only a single device panel which must extend to the wing tip. An auxiliary program allows the prior calculation of the spanwise position of the section of the basic wing that has the peak loading due to angle of attack. It is necessary to know that section because full runs of the main program for wings and wing-fuselage combinations require its geometry.

The original ESDUpacs associated with ESDU 99031 are retained (for the purposes of running legacy input files).