When installing the engine in an aircraft the thrust of the engine as a system reduces due to several drag effects. These drag effects are calculated post-convergence and added to the net thrust (FN) to obtain the installed net thrust (FNinst). Use the global output options to select the installed thrust output parameter.

Current modeled effects include:

•Spill Drag

The spill drag calculation is based on the following equation: Dspill = CdSpill * Highlight Area * Dynamic Pressure,

wherein CdSpill is the spill drag coefficient which is a function of flight Mach number and area ratio (area ratio is defined as free stream area/intake highlight area, which usually is A0/A1) and the dynamic pressure is defined as ½ * Rho * V². The spill drag coefficient will be read from a separate map for values of Mach and area ratio.

The checkbox enables/disables the calculation of spill drag.

The highlight area can be specified as:

•Area

user defined value

•Total inlet area

total calculated inlet area (could be from more than 1 inlet component)

•Outp. param.

select an output parameter (e.g. a calculated column or an Additional Output Parameter)

The free stream capture area can be specified as:

•A0 (total free stream area)

calculated value based on number of inlets, and the equation of continuity

•Outp. param.

select an output parameter (e.g. a calculated column or an Additional Output Parameter)

Use the map functionality to select a spill drag coefficients map.

•Afterbody Drag

The exhaust nozzle drag (afterbody drag) calculation is based on the following equation: Daftbody = CdAftbody * Reference Area * Dynamic Pressure,

wherein CdAftbody is the afterbody drag coefficient which is a function of flight mach number and Nozzle Pressure Ratio (NPR) and the dynamic pressure is defined as ½ * Rho * V². The afterbody drag coefficient will be calculated by reading the CdAftbody from a separate map for values of Mach and Nozzle Pressure Ratio.

The checkbox enables/disables the calculation of afterbody drag.

The reference area can be specified as:

•Area

user defined value

•Aexit (total exhaust area)

total calculated exhaust area (could be from more than 1 exhaust component)

•Outp. param.

select an output parameter (e.g. a calculated column)

The NPR can be specified as:

•Exhaust comp.

NPR is taken from the specified component

•Outp. param.

select an output parameter (e.g. a calculated column)

Use the map functionality to select an afterbody drag coefficients map.

Several output options have been added to monitor the installation effects, which can be found on the Output tab sheet. Output options include drag values, drag coefficients, etc.