Advanced Fixed Wing Tool

The Advanced Fixed Wing Tool allows you to define a highly precise set of physical properties for the aircraft that you are modeling. These physical properties are mapped to the advanced class of performance models. The properties defined in this tool are saved at the catalog level, and each aircraft model is limited to one set of definitions for them.

Geometry

The Geometry properties group describes the dimensions of individual control surfaces of the aircraft. You can define the total Wing Area, Flaps Area, and Speedbrakes Area.

Aerodynamics

The Aerodynamics properties group describes the aircraft's aerodynamic performance using one of three broad strategies:

Click to open the properties window for the currently selected strategy. Click Create Aero File... to create an .aero file using the current property settings of the Advanced Fixed Wing Tool. Select Cache Aero Data to store intermediate results for aerodynamics calculations; this option can improve calculation speed at a small cost in accuracy.

The Advanced Fixed Wing Tool requires the following additional information in the external .aero file:
  • cl0
  • clAlpha
  • cd0
  • k
  • clmax
If the file does not contain these columns, an error displays indicating that DetailedAeroData must be specified.

Powerplant

The Powerplant properties group describes the aircraft's propulsion performance using one of several empirical models of aircraft engine systems:

Click to open the properties window for the currently selected strategy. Click Create Prop File... to create a .prop file using the current property settings of the Advanced Fixed Wing Tool. Select Cache Fuel Flow to store intermediate results for fuel flow calculations; this option can improve calculation speed at a small cost in accuracy.

The No Thrust When No Fuel checkbox, if enabled, stops the aircraft when the fuel runs out. If the checkbox is not enabled, the aircraft travels the length you set despite being out of fuel.

Dynamics/Moments

The Dynamics/Moments tab offers a SimpleAero strategy, which is intended to capture aerodynamic control surfaces. It enables you to specify the maximum torques that can be generated at a specified flight condition, and the minimum level of attitude control.

Click to open the properties window for the currently selected strategy.

Structural and Human Factors Limits

The Structural and Human Factors Limits properties group describes the performance limitations of the aircraft with respect to the structural integrity of the aircraft or the survival of humans flying in it. You can define the following properties that the aircraft or the occupants can bear:

The Max Mach Number cannot be greater than the Mach limits of the currently selected Aerodynamics and Powerplant strategies; if you modify a Mach limit in one of those strategies so that it is less than the Max Mach Number, STK's Aviator capability displays a warning message that it must reduce the Max Mach Number to a compliant value. You can click OK to accept the new value or Cancel to undo the change that you made to the strategy's Mach limit.

Temperature Limit

The Temperature Limit section can be used to limit the maximum speed of the aircraft so the specified temperature is not exceeded. Select the Enforce Limit check box and define the Max Total Temp to enforce this temperature limit.

Flight Aero

The Plot Aero... option enables you to evaluate how parameter changes affect the vehicle's aerodynamics performance.

Flight Prop

The Plot Prop... option enables you to evaluate how parameter changes affect the vehicle's propulsion performance.

Flight Envelope

The Flight Envelope tool allows you to compare the performance characteristics of various aircraft designs. The Contours and Levels drop-down menus allows you to control the data being displayed in the profile. Click Compare to Reference Envelope to load an Advanced Performance Fixed Wing Configuration (.fwcf) file and display its data in the profile for comparison with the current property settings. Click anywhere in the profile to view information about the aircraft's performance in the properties group. The Font Size and Show Colored Lines and Legend options allow you to adjust the appearance of the profile.

You can define the Weight, Drag Index, Load Factor, Delta Temp, Power, and Airspeed Type that you want to evaluate. Properties that you set in this tool are defined only within this tool, for analysis purposes; the aircraft's actual property settings remain unchanged.

The Flight Envelope tool can be used alongside the Flight Test tool and the main window of the Advanced Fixed Wing Tool so that you can make a change in any of the windows and evaluate the impact of that change across all three tools.

Flight Test

The Flight Test tool allows you to compare the performance characteristics of the current aircraft design with the actual performance of another aircraft, loaded from a .ftinput file. You can use this tool to make direct comparisons to a known aircraft and then redefine properties in the main window of the Advanced Fixed Wing tool to iterate your design closer to that of the compared aircraft.

Click to browse to the .ftinput file that you want evaluate. Click Reload to update the current .ftinput file if it has been changed. Click Save FTOUTPUT ... to save the calculated and actual data in the tool to an .ftoutput reference file.

The Flight Test tool can be used alongside the Flight Envelope tool and the main window of the Advanced Fixed Wing Tool so that you can make a change in any of the windows and evaluate the impact of that change across all three tools.

Create Performance Models

The "advanced" class of performance models is comprised of Acceleration, Climb, Cruise, Descent, Landing, and Takeoff models that provide a set of parameters that define the operational performance of the aircraft while incorporating the physical properties of the aircraft that are currently defined in the Advanced Fixed Wing Tool.

To create advanced Acceleration, Climb, Cruise, Descent, Landing, and Takeoff performance models from the Advanced Fixed Wing Tool, click Create Performance Models.... In the Create Advanced Performance Models window, you can use the Perf Model Name field to give each performance model in the created set the same name. Select the Overwrite existing performance models check box to replace any performance models with the same name that is in the Perf Model Name field. Select the Copy to clipboard check box to place a copy of the performance models on the clipboard, in addition to saving them to the performance models list for the aircraft. Select the Set as default check box to set the performance models that are created as the default performance models for the aircraft.

Advanced performance models do not embed the properties defined in the Advanced Fixed Wing Tool; they are always mapped to the current definitions in the Advanced Fixed Wing Tool.

Exporting and Importing Configurations

The settings specified in the Advanced Fixed Wing Tool can be saved to an Advanced Performance Fixed Wing Configuration file, which has a .fwcf extension.

Click Export... to save your current settings to a file. If the current configuration includes an external aerodynamics or propulsion file, the file will be embedded in the .fwcf file when it is created.

Click Import... to populate the Advanced Fixed Wing Tool with the settings from a previously saved file. If the imported .fwcf file contains embedded aerodynamics or propulsion files, these files will be extracted and implemented automatically.