INTRODUCTION FP is a CFD (computational fluid dynamics) method coded in Fortran for calculating the flow field and aerodynamic forces of an isolated wing (denoted usually as a wing alone) or a wing-body combination (denoted usually as a wing-body) in a subsonic freestream@ including the effects of shock waves. FP uses a relaxation process to solve finite-difference forms of the full nonlinear velocity-potential equation for the flow around the three-dimensional geometry. The FP program was developed over a period of years at ARA@ Bedford and RAE (now QinetiQ)@ Farnborough and is made available by ESDU International plc under the terms of an agreement with QinetiQ. Used originally on mainframe computers@ FP has provided valuable data in the design of a number of aircraft. With advances in computers@ it has become possible to perform runs of FP on a PC within a few minutes. The FP code dealt with in this Item is for use on a PC. The version presented takes no account of the boundary layer or viscous wake@ but it is intended that an enhanced version (denoted VFP)@ that does take account of viscous effects@ albeit in a simplified manner@ will be issued subsequently. An account of the principles of FP@ and a number of results and comparisons with other methods and with experiment@ are given in Part 1 (Reference 1). This Item@ Part 2 in the Series dealing with FP@ is concerned primarily with the practical aspects of running FP and its associated programs in order to obtain reliable results. Section 2 presents the Notation and Conventions adopted@ and also@ for convenience@ gives an index to the computer programs@ parameters and filenames used. A run of FP is described in Section 3. For any run of FP@ in order to deal with a specific geometry at a particular Mach number and incidence@ the following three input files are required: GEO.DAT@ which specifies the geometry of the wing alone or wing-body@ MAP.DAT@ which specifies the parameters that affect the computational grid@ FLOW.DAT@ which specifies the flow conditions (namely the freestream Mach number and the angle of incidence)@ parameters that control the iterative calculations (including the form of finite-difference scheme used) and parameters that govern the extent of the output produced at each level of grid refinement. The specification of these files is given in Section 4. The generation of the three input files is facilitated by a program (named FPCON) which performs this task for the particular cases of swept and tapered wings and wings which have a single planform crank. In each case@ an 'infinite' cylindrical body may be present. As described in Part 1 (Reference 1)@ as an alternative to direct calculation by FP@ the effects of a finite body on the wing flow can be approximated by calculating the infinite body case@ and utilising a facility within FP for adding spanwise varying increments to the freestream Mach number. (These increments may be found from calculations of the flow about the isolated body. It is intended to issue a suitable method for performing such calculations in a forthcoming Data Item.) Use of the input file program FPCON is described in Section 5. In Section 6@ output files are presented for a typical run of FP. In some cases@ the input files generated by the program FPCON fail to produce reliable results from FP. Often the cause is due to the grid layout@ generally because the distribution of streamwise grid lines across the span is not suited to the particular planform being considered. Procedures for examining the grid line distribution and for introducing modifications to the file MAP.DAT in order to effect improvements are presented in Section 7. Section 8 deals with a number of points relevant to cases where a body is present@ whilst Section 9 gives some guidance for dealing with wings having planforms not covered by FPCON. In Section 10 some of the reasons for the occasional failure of FP to give reliable results are reviewed@ and actions that may be tried to remedy any such failure are given.